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  • 251.
    Nordlund Ekblom, Maria M
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Cresswell, Andrew G
    Variations in the soleus H-reflex as a function of activation during controlled lengthening and shortening actions.2002Inngår i: Brain Research, ISSN 0006-8993, E-ISSN 1872-6240, Vol. 952, nr 2, s. 301-7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of soleus activation on the soleus H-reflex was investigated during controlled lengthening and shortening of the plantar flexor muscles. Maximal H-reflexes and M-waves were evoked at the same muscle length (ankle angle 90 degrees ) during lengthening and shortening (ankle angular velocity 5 degrees s(-1)) with soleus either passive or with its electromyographic activity at 10, 20 and 30% of that during a maximal voluntary isometric plantar flexion. In passive trials, the H(MAX):M(MAX) ratio during lengthening was lower than during shortening. In active trials at 10 and 20%, the H(MAX):M(MAX) ratio tended to be lower during lengthening than shortening. Within the active trials, H(MAX):M(MAX) ratios were not different between the three levels of soleus activation, neither for lengthening nor shortening actions. When all active trials were pooled, the lengthening H(MAX):M(MAX) ratio was significantly lower than the shortening one. In lengthening, the H(MAX):M(MAX) ratio increased in the active with respect to the passive condition, whereas no change occurred in active with respect to the passive shortening. These results indicate action type specificity in the way the Ia-excitatory effect is modulated as the soleus muscle is voluntarily activated.

  • 252.
    Nordlund Ekblom, Maria
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Strength training effects of whole-body vibration?2007Inngår i: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 17, nr 1, s. 12-7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Whole-body vibration (WBV) has been suggested to have a beneficial effect on muscle strength. Manufacturers of vibration platforms promote WBV as an effective alternative or complement to resistance training. This study aimed to review systematically the current (August 2005) scientific support for effects of WBV on muscle strength and jump performance. MEDLINE and SPORT DISCUS were searched for the word vibration in combination with strength or training. Twelve articles were included in the final analysis. In four of the five studies that used an adequate design with a control group performing the same exercises as the WBV group, no difference in performance improvement was found between groups, suggesting no or only minor additional effects of WBV as such. Proposed neural mechanisms are discussed.

  • 253.
    Nordlund, Maria M.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    On spinal mechanisms for reflex control in man: modulation of Ia-afferent excitation with changes in muscle length, activation level and fatigue2004Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    To control muscle force, neural activation has to take alterations in muscle mechanics into account. This thesis assesses modulations in excitatory efficacy of Ia-afferents during muscle length changes at different levels of voluntary activation and during fatigue. Excitatory efficacy of Iaafferents was inferred from modulations in the Hoffmann reflex (Hreflex) elicited in the triceps surae. The H-reflex is affected by the excitability of the motoneurones, as well as presynaptic inhibition of Iaafferents. The latter can be induced by primary afferent depolarization (PAD) and homosynaptic post activation depression (HPAD) within the terminal. The H-reflex was depressed with increasing velocities of passive plantar flexor lengthening and was smaller during passive muscle lengthening than when the muscles were isometric or undergoing passive shortening. The depression was probably induced by a peripheral mechanism since it was present at a latency too short for supra-spinal involvement. The rapid modulation and the velocity dependency suggest that during muscle lengthening, muscle spindle firing may have induced HPAD in the Ia-terminal. The H-reflex increased from passive to active lengthening, whereas it remained unchanged from passive to active shortening. Despite similar neural activation during the active tasks, the H-reflex was lower during muscle lengthening than shortening, indicating more presynaptic inhibition during lengthening. When Iaafferents were conditioned by electrical stimulation to emulate muscle spindle activation, the H-reflex was depressed only during passive shortening. No depression of the H-reflex during active shortening implies that HPAD was already present in the active condition. The lack of increase in the H-reflex from passive to active shortening may thus be caused by muscle spindle activation reducing the efficacy of Ia-excitation in the active muscle via HPAD. During fatigue from maximal voluntary intermittent isometric plantar flexor actions, both central and peripheral fatigue developed. The stronger the subjects and the higher their ability to fully activate the plantar flexors, the greater was the amount of peripheral fatigue. After the first bout, presynaptic inhibition had increased, most likely due to HPAD. During the fatigue protocol, the amount of presynaptic inhibition decreased slightly, either due to decreased PAD-mediated inhibition or due to less HPAD as a result of reduced muscle spindle firing. Having two separate mechanisms, independently capable of modulating the efficacy of Iaafferents, provides the central nervous system with a high flexibility for regulating motoneurone excitability.

  • 254.
    Norrbrink, Cecilia
    et al.
    Department of Clinical Sciences, Karolinska Institutet Danderyd Hospital, Stockholm.
    Lindberg, Thomas
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Wahman, Kerstin
    Department of Neurobiology, Care Sciences and Society (NVS), Division of Neurorehabilitation, Karolinska Institutet.
    Bjerkefors, Anna
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Effects of an exercise programme on musculoskeletal and neuropathic pain after spinal cord injury - results from a seated double-poling ergometer study2012Inngår i: Spinal Cord, ISSN 1362-4393, E-ISSN 1476-5624, Vol. 50, nr 6, s. 457-461Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVES: To assess pain relieving effects of an intensive exercise programme on a seated double-poling ergometer in individuals with spinal cord injury (SCI).

    SETTING: Stockholm, Sweden.

    METHODS: A total of 13 wheelchair-dependent individuals with a thoracic or lumbar SCI were recruited to a 10-week training period (three times weekly) assessing the effects of regular training on upper-body strength, aerobic and mechanical power, and crossover effects on functional performance, as well as cardiovascular risk factors. Eight of the participants reported pain and were included in this exploratory pain protocol and assessed using the International SCI Basic Pain Data set, the Wheelchair Users' Shoulder Pain Index and International SCI Quality of Life Basic Data set.

    RESULTS: For those with neuropathic pain, median pain intensity ratings decreased from 5 on a 0-10 numerical rating scale at base-line to 3 at the end of study, and four of seven participants reported an improvement on the Patient Global Impression of Change scale. For those with musculoskeletal pain (n = 5), median pain intensity ratings improved from 4 at baseline to 0 at the end of study. All but one rated no musculoskeletal pain at all at the end of study and number of days with pain per week decreased from 5.5 to 0.7. None of the participants developed pain, because of overuse during the training period and few reported unwanted side effects.

    CONCLUSION: Considering its promising effects and safety, an intensive exercise programme can be tried for treating musculoskeletal pain and also neuropathic pain following SCI.

  • 255.
    Oddsson, Kristjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Integrated Sports Massage Therapy2011Inngår i: Integrated Sports Massage Therapy, Elsevier Ltd. , 2011, s. 181-205Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 256.
    Oddsson, Kristjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Vad är balans?: Balansförmåga hos barn i skolåldern2012Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Aim

    The specific questions in the theoretic part were:

    • What is contained in the terms "balance and balance skill" and how can this skill be measured?

    The specific questions in the empirical part were:

    • How does balance skill in different age categories of children correlate with biological and physiological parameters such as age, gender, body height, weight and level of physical activity?

    Methods

    Literature search based on books and scientific papers related to the questions posed above. Selection was made at libraries and on–line through "Pubmed". Specific search words were used. Data collected during the SIH-project, including balance tests of approximately 1700 children 10-, 13- and 16 years old, were used for the empirical part of the project.

    Results

    The literature search concluded that there is little consensus about terms such as "balance" and "balance skill". Several scientific disciplines have "their own" definition of these terms depending on whether the interpretation is purely mechanical/biomechanical, neurophysiological or from a more behaviouristic point of view. There are a number of clinical/functional as well as more "lab based" test procedures of balance function that are considered to be reliable. The empirical study showed that balance skill varies in school children 10-, 13- and 16 years of age such that the older children display better balance skills that the younger ones. There was no effect of gender on balance skill. Overweight and obese children display lower balance skill than those of normal body weight. Body height appears to have little influence on balance skill. Children with high level of physical activity seem to display better balance skills than more inactive ones.

    Conclusion

    Definitions of terms used in balance related research have not been standardized and are therefore both difficult to interpret and to implement. Balance skill in children correlates with age, body weight and level of physical activity.

  • 257. Oddsson, L I
    et al.
    Persson, T
    Cresswell, Andrew G
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Interaction between voluntary and postural motor commands during perturbed lifting.1999Inngår i: Spine, ISSN 0362-2436, E-ISSN 1528-1159, Vol. 24, nr 6, s. 545-52Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    STUDY DESIGN: An experimental study was conducted to evaluate the effect of an unexpected postural perturbation during a lifting task. OBJECTIVES: To investigate electromyographic responses in the erector spinae to a postural perturbation, simulating slipping, during an ongoing voluntary lifting movement. It was hypothesized that specific combinations of voluntary movement and postural perturbation present a situation in which injury caused by a rapid switch between conflicting motor commands can occur. SUMMARY OF BACKGROUND DATA: Studies of postural perturbations have mainly focused on behavior during static tasks such as quiet, upright standing. To date, there are no published studies of the effect of a perturbation during an ongoing voluntary lifting movement. METHODS: Subjects standing on a movable platform were exposed to random perturbations while lifting a 20-kg load. Muscle activity was recorded from flexor and extensor muscles of the trunk and hip. Trunk flexion angle in the sagittal plane was recorded with a video system. RESULTS: Perturbations forward were followed by an increased activity in erector spinae superimposed on the background activation present during the lift, indicating that both the voluntary and postural motor programs caused an activation of erector spinae. During backward perturbation, however, there was a sudden cessation of erector spinae activity followed by an extended period of rapid electromyographic amplitude fluctuations while the trunk was flexing, indicating an eccentric contraction of the erector spinae. CONCLUSIONS: This erratic behavior with large electromyographic amplitude fluctuations in the erector spinae after a backward slip during lifting may indicate a rapid switch between voluntary and postural motor programs that require conflicting functions of the back muscles. This may cause rapid force changes in load-carrying tissue, particularly in those surrounding the spine, thus increasing the risk of slip-and-fall-related back injuries.

  • 258. Oddsson, L
    et al.
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Fast voluntary trunk flexion movements in standing: motor patterns.1987Inngår i: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 129, nr 1, s. 93-106Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The electromyographical (EMG) activity was studied during voluntary flexion movements of the trunk in erect standing man. The movements were performed at maximal velocity with successively increasing amplitude to cover the whole range of motion. The EMG activity was recorded from agonist-antagonist pairs of muscles at the ankle, knee, hip and trunk. The angular displacements at the corresponding joints were recorded using a Selspot optoelectronic system. The duration of initiating activity in prime movers (rectus abdominis and rectus femoris) as well as time to onset of activity in muscles braking the primary movement (erector spinae, gluteus maximus and hamstrings) were highly correlated with amplitude, duration, peak velocity and time to peak velocity of the movement (r = 0.59-0.91). The corresponding correlations for peak acceleration and deceleration of the movement were low (r = 0.03-0.38), indicating that acceleration and deceleration of a movement was not coded in the temporal aspects of the EMG. Onset of activity in rectus abdominis and rectus femoris as well as an early appearing burst of activity in vastus lateralis were invariant in relation to start of movement over the whole movement range. In the initial phase of a fast trunk flexion, activity in tibialis anterior appeared successively earlier with increasing movement amplitude. This resulted in a changed order of activation for the muscles from proximal to distal (rectus abdominis first) to distal to proximal (tibialis anterior first). Two different forms of associated postural adjustments are present during a fast trunk flexion, one early fast knee flexion and a later slower angle extension. Prior to knee flexion, no activity was recorded from muscles flexing at the knee implying that some other force must create a flexing torque around the knee. It is suggested that activity in rectus abdominis initiating the primary movement also initiates knee flexion through the upward pulling of pelvis. This would be possible since rectus femoris stabilizes the pelvis in relation to the leg, allowing the force in rectus abdominis to be transmitted below the hip joint and act extending around the ankle joint. However, when tibialis anterior is activated it stabilizes the shank which in turn will cause a knee flexion controlled by a lengthening contraction in vastus lateralis. During the subsequent ankle extension activity appears in lateral gastrocnemius and soleus causing the associated postural adjustment at the ankle. It can be concluded that activation of postural muscles prior to prime mover muscles is not always necessary.(ABSTRACT TRUNCATED AT 400 WORDS)

  • 259. Oddsson, L
    et al.
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Fast voluntary trunk flexion movements in standing: primary movements and associated postural adjustments.1986Inngår i: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 128, nr 3, s. 341-9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Movement patterns were studied during fast voluntary forward flexions of the trunk from an erect standing position. Three healthy subjects performed three series of six consecutive trunk flexions at maximum velocity and with successively increasing amplitude, covering a major part of the range of motion (range for all subjects: 13-97 degrees). Angular displacements of the trunk, hip, knee and ankle were measured together with the tilt of the pelvis and the flexion of the spine using a Selspot optoelectronic system. Trunk flexion was the result of a simultaneous forward pelvic tilt and flexion of the spine. For trunk movements up to 55 degrees, spine flexion dominated the movement, whereas for larger movements a major part of the amplitude was caused by pelvic tilt. During flexion of the trunk a simultaneous hip flexion and ankle extension was seen. At the knee there was an initial flexion and a subsequent extension. The net amplitude of the knee flexion showed a negative correlation with net trunk flexion amplitude for movements up to 50 degrees, whereas for larger amplitudes the correlation was positive. Time from onset of the trunk movement to peak knee flexion showed a weak correlation to net trunk flexion amplitude (r = 0.34) whereas the corresponding correlation was higher for pelvic tilt, spine flexion, hip flexion, ankle extension, and knee extension (r = 0.60-0.91). Each successive trial during a series of trunk movements was started from an increasing degree of knee flexion. This gradual adaptation was also present when successive trunk flexions were performed with constant movement amplitude.(ABSTRACT TRUNCATED AT 250 WORDS)

  • 260. Oddsson, L
    et al.
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Task specificity in the control of intrinsic trunk muscles in man.1990Inngår i: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 139, nr 1, s. 123-31Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The human trunk is a complex mechanical system comprised of large and small segments interconnected with several layers of muscles. An accurate control of this system is important during a variety of everyday tasks such as voluntary movements of the trunk, walking and running. This study was designed to investigate the interaction between muscles controlling the pelvis and the trunk during a variety of movements requiring a finely tuned coordination. Four subjects carried out seven different forms of fast oscillatory movements of the pelvis and trunk in the sagittal and transverse planes. Electromyographical activity (EMG) was recorded with surface electrodes from the abdominal muscles rectus abdominis (RA), obliquus externus (OE), obliquus internus (OI), and erector spinae (ES), from the hip flexor muscle rectus femoris (RF), the hip extensor muscle gluteus maximus (GM) and from the hip extensor/knee flexor muscles of the hamstrings group (HAM). Movements were recorded with an optoelectronic system (Selspot). The results indicate that during spontaneous flexion-extension movements of the trunk there was a basic alternating activation between a pure flexor (RF-RA-OE-OI) and an extensor synergy (ES-GM-HAM). Different mixed synergies appeared when more specific patterns of coordination of the pelvis and spine were performed. For example, during pelvic tilts in the sagittal plane, RA-OE-OI-GM formed a synergy which was activated reciprocally with ES. The neural circuitry controlling muscles of the pelvis and trunk is apparently adaptable to a variety of different tasks. Individual muscles were shown to either cause, brake or prevent a movement and to be integrated in several different task-specific motor synergies.(ABSTRACT TRUNCATED AT 250 WORDS)

  • 261.
    Oddsson, Lars
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Moritani, Toshio
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Andersson, Eva A
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Differences between males and females in EMG and fatiguability of lumbar back muscles.1991Inngår i: Electromyographical Kinesiology / [ed] Anderson PA, Hobart DJ, Danoff JV, Amsterdam: Elsevier Science Publisher (Biomedical Division) , 1991, s. 295-298Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 262.
    Paanalahti, Markku
    et al.
    University of Gothenburg.
    Berzina, Guna
    Riga Stradiņš University, Latvia.
    Lundgren-Nilsson, Åsa
    University of Gothenburg .
    Arndt, Anton
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Sunnerhagen, Katharina S
    University of Gothenburg .
    Examination of the relevance of the ICF cores set for stroke by comparing with the Stroke Impact Scale.2018Inngår i: Disability and Rehabilitation, ISSN 0963-8288, E-ISSN 1464-5165, s. 1-6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    PURPOSE: To examine if the International Classification of Functioning (ICF) core set for stoke contains problems that are relevant for the persons living with stroke as expressed in the Stroke Impact Scale (SIS).

    METHODS: Cross-sectional study of 242 persons with previous stroke. The agreement between the perceived problems in the SIS items and problems in the categories of Comprehensive ICF Core Set for stroke were analyzed using percent of agreement and Kappa statistic.

    RESULTS: The analyses between 57 items of the SIS and 31 second-level categories of the ICF were conducted. The problems in domains of "Mobility", "Activities of daily living", "Hand function", "Strength" in the SIS had moderate agreement when compared to ICF categories. The SIS domains of "Emotion" and "Communication", as well as some aspects of the "Memory" had slight or fair agreement with corresponding ICF categories. The results of the study suggest that there is acceptable agreement between persons after stroke and health professionals in the physical aspects, but rather poor agreement in the cognitive and emotional aspects of functioning.

    CONCLUSIONS: Health professionals do not fully capture the magnitude of emotional or social problems experienced by persons after stroke when using the ICF Core Set as a framework for evaluation. Implications for Rehabilitation The ICF Core Set for Stroke provides comprehensive list of possible health and health related outcomes for persons after stroke. Problems reported in condition-specific patient-reported outcome scales can be important in decision making in rehabilitation. Patients and health professionals tend to agree more on physical than cognitive problems. Examination of the relevance of the ICF cores set for stroke by comparing with the Stroke Impact Scale.

  • 263. Paanalahti, Markku
    et al.
    Lundgren-Nilsson, Asa
    Arndt, Anton
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Sunnerhagen, Katharina S
    Applying the Comprehensive International Classification of Functioning, Disability and Health Core Sets for stroke framework to stroke survivors living in the community.2013Inngår i: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 45, nr 4, s. 331-40Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE: The aims of this study were to explore the perspective of functioning in community-dwelling people with prior stroke and to confirm, if possible, the comprehensive international classification of functioning, disability and health (ICF) Comprehensive Core Set for stroke.

    METHODS: Qualitative interviews were analysed (using the content analysis method and established ICF linking rules) from 22 persons following stroke (age range 59-87 years), as well as their spouses/partners, where relevant.

    RESULTS: Ninety-nine (76%) of 130 second-level ICF categories in the existing Comprehensive ICF Core Set for stroke were confirmed: 31 categories (of 41) in the component of body functions, 38 categories (of 51) in the component of activities and participation, 26 (of 33) in the component of environmental factors and 4 (of 5) in the component of body structures. Eleven additional ICF categories and one personal factor, a coping style of "I take it as it comes" were also identified in the transcribed text.

    CONCLUSION: The Comprehensive ICF Core Set for stroke was largely confirmed.

  • 264.
    Pantzar, Alexandra
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap.
    Jonasson, Lars S.
    Umeå University.
    Ekblom, Örjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Boraxbekk, Carl-Johan
    Umeå University.
    Ekblom, Maria
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC). Karolinska Institutet.
    Relationships Between Aerobic Fitness Levels and Cognitive Performance in Swedish Office Workers2018Inngår i: Frontiers in Psychology, ISSN 1664-1078, E-ISSN 1664-1078, Vol. 9, artikkel-id 2612Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objectives: Aerobic exercise influence cognition in elderly, children, and neuropsychiatric populations. Less is known about the influence of aerobic exercise in healthy samples (particularly working age), and of different fitness levels on cognition. Two hypotheses were posed: 1) low fitness levels, compared to moderate and high, will be related to poorer cognitive performance, and 2) breakpoints for the beneficial relationship between VO2 and cognition will be observed within the moderate-to-high fitness span. Design and Methods: The sample consisted of n=362 office workers. A submaximal cycle ergometer test estimated maximal oxygen consumption (VO2max, mL•kg-1•min-1). Based on estimated VO2max participants were split into tertiles; low (n=121), moderate (n=119), and high (n=122). A cognitive test battery (9 tests), assessed processing speed, working memory, executive functions and episodic memory. Results: Both hypotheses were confirmed. Groups of moderate (≈40) and high (≈49) fitness outperformed the group of low (≈31) fitness for inhibition and episodic recognition, whereas no significant differences between moderate and high fitness were observed (ANCOVAs). Breakpoints between benefits fromVO2max for inhibition and recognition were estimated to ≈44/43 mL•kg-1•min-1 (multivariate broken line regressions). Conclusions: Results suggest that it is conceivable to expect a beneficial relationship between VO2max and some cognitive domains up to a certain fitness level. In a sample of healthy office workers, this level was estimated to 44 mL•kg-1•min-1. This has implications on organizational and societal levels; where incentives to improve fitness levels from low to moderate could yield desirable cognitive and health benefits in adults.

  • 265. Peolsson, Michael
    et al.
    Löfstedt, Tommy
    Vogt, Susanna
    Stenlund, Hans
    Arndt, Anton
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Trygg, Johan
    Modelling human musculoskeletal functional movements using ultrasound imaging.2010Inngår i: BMC Medical Imaging, ISSN 1471-2342, E-ISSN 1471-2342, Vol. 10, s. 9-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This new objective method is a powerful tool to use when visualising tissue activity and dynamics of musculoskeletal ultrasound registrations.

  • 266.
    Peter, Annamaria
    et al.
    Neuromuscular Research Center, University of Jyväskylä, Finland.
    Andersson, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Arndt, Anton
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Finni, T
    Neuromuscular Research Center, University of Jyväskylä, Finland.
    Cronin, NJ
    Neuromuscular Research Center, University of Jyväskylä, Finland.
    Impact of footwear type and walking speed on ankle plantar flexor fine-wire electromyographic activity2018Inngår i: Sport science at the cutting edge, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    INTRODUCTION:

    Ankle plantar flexors substantially contribute to propulsion in human walking, and their relative contributions may be affected by the type of footwear used. In this study, we aimed to examine plantar flexor fine-wire electromyography (wEMG) activity in different footwear types and barefoot walking. We further examined the effect of walking speed on the relative activity of ankle plantar flexors.

    METHODS:

    Nine healthy people volunteered to this study (five males) with two sessions. In session 1, participants were familiarized to the study protocol. In session 2, electrical activity of flexor hallucis longus (FHL), soleus (SOL), medial and lateral gastrocnemius (MG and LG) muscles were measured with wEMG during eight overground walking tasks: preferred speed walking with shoes, barefoot and with flip-flops; with shoes: 30% slower and faster than preferred speed walking with shoes, and maximum walking speed; walking barefoot and with flip-flops at the same speed as preferred speed walking with shoes (matched speed). Then they performed maximal isometric plantar flexion contractions and maximal big toe flexions superimposed on ankle plantar flexion (MVICs) in an isokinetic dynamometer for wEMG normalization. Root mean square activity was calculated in the push-off phase of individual step cycles based on ground reaction force data. The relative contribution of each muscle to propulsion was calculated as: (mean RMS value %MVIC of the given muscle / mean RMS value %MVIC of all muscles) * 100. Cohen’s d±90% confidence intervals were calculated to define the magnitude of differences.

    RESULTS:

    In all muscles, wEMG activity increased with speed. With increasing speed the relative contribution to propulsion increased in FHL (from 19 to 22%), did not change in SOL (32%), decreased in MG (from 32 to 25%) and increased in LG (from 18 to 21%). There were no differences between preferred and matched barefoot walking speed or wEMG activity level (d range = 0.06-0.17). wEMG activity for all muscles was lower during matched barefoot walking than preferred speed walking with shoes (7-10% MVIC, d range=0.31-0.47). Flip-flop data are under analysis.

    CONCLUSION:

    We found that relative wEMG activity of the examined muscles was affected by speed and absence or presence of shoes. During barefoot walking, wEMG activity of plantar flexor muscles was lower than during shod walking at the same speed, which presumably means that shod walking limits the contribution of intrinsic foot muscles to propulsion, which should be further examined.

    REFERENCES:

    1 Murley GS, Menz HB, Landorf KB. (2014). Gait & Posture, 39(4), 1080-5.

    2 Goldmann JP, Potthast W, Brüggemann GP. (2013). Footwear Sci, 5 (1): 19-25.

    3 Franklin et al., Gait & Posture. 60: 1-5, 2018.

    CONTACT:

    annamaria.a.peter@jyu.fi

  • 267. Pinniger, G J
    et al.
    Nordlund Ekblom, Maria
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Steele, J R
    Cresswell, Andrew G
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap.
    H-reflex modulation during passive lengthening and shortening of the human triceps surae.2001Inngår i: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 534, nr Pt 3, s. 913-23Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    1. The present study investigated the effects of lengthening and shortening actions on H-reflex amplitude. H-reflexes were evoked in the soleus (SOL) and medial gastrocnemius (MG) of human subjects during passive isometric, lengthening and shortening actions performed at angular velocities of 0, +/-2, +/-5 and +/-15 deg s(-1). 2. H-reflex amplitudes in both SOL and MG were significantly depressed during passive lengthening actions and facilitated during passive shortening actions, when compared with the isometric H-reflex amplitude. 3. Four experiments were performed in which the latencies from the onset of movement to delivery of the stimulus were altered. Passive H-reflex modulation during lengthening actions was found to begin at latencies of less than 60 ms suggesting that this inhibition was due to peripheral and/or spinal mechanisms. 4. It is postulated that the H-reflex modulation seen in the present study is related to the tonic discharge of muscle spindle afferents and the consequent effects of transmission within the Ia pathway. Inhibition of the H-reflex at less than 60 ms after the onset of muscle lengthening may be attributed to several mechanisms, which cannot be distinguished using the current protocol. These may include the inability to evoke volleys in Ia fibres that are refractory following muscle spindle discharge during rapid muscle lengthening, a reduced probability of transmitter release from the presynaptic terminal (homosynaptic post-activation depression) and presynaptic inhibition of Ia afferents from plantar flexor agonists. Short latency facilitation of the H-reflex may be attributed to temporal summation of excitatory postsynaptic potentials arising from muscle spindle afferents during rapid muscle lengthening. At longer latencies, presynaptic inhibition of Ia afferents cannot be excluded as a potential inhibitory mechanism.

  • 268. Pinniger, G J
    et al.
    Steele, J R
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Cresswell, A G
    Tension regulation during lengthening and shortening actions of the human soleus muscle.2000Inngår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 81, nr 5, s. 375-83Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present study we investigated tension regulation in the human soleus (SOL) muscle during controlled lengthening and shortening actions. Eleven subjects performed plantar flexor efforts on an ankle torque motor through 30 degrees of ankle displacement (75 degrees -105 degrees internal ankle angle) at lengthening and shortening velocities of 5, 15 and 30 degrees. S(-1). To isolate the SOL from the remainder of the triceps surae, the subject's knee was flexed to 60 degrees during all trials. Voluntary plantar flexor efforts were performed under two test conditions: (1) maximal voluntary activation (MVA) of the SOL, and (2) constant submaximal voluntary activation (SVA) of the SOL. SVA trials were performed with direct visual feedback of the SOL electromyogram (EMG) at a level resulting in a torque output of 30% of isometric maximum. Angle-specific (90 degrees ankle angle) torque and EMG of the SOL, medial gastrocnemius (MG) and tibialis anterior (TA) were recorded. In seven subjects from the initial group, the test protocol was repeated under submaximal percutaneous electrical activation (SEA) of SOL (to 30% isometric maximal effort). Lengthening torques were significantly greater than shortening torques in all test conditions. Lengthening torques in MVA and SVA were independent of velocity and remained at the isometric level, whereas SEA torques were greater than isometric torques and increased at higher lengthening velocities. Shortening torques were lower than the isometric level for all conditions. However, whereas SVA and SEA torques decreased at higher velocities of shortening, MVA torques were independent of velocity. These results indicate velocity- and activation-type-specific tension regulation in the human SOL muscle.

  • 269.
    Potthast, W
    et al.
    German Sport University Cologne, Institute of Biomechanics and Orthopaedics.
    Brüggemann, GP
    Lundberg, A
    Arndt, Toni
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Relative movements between the tibia and femur induced by external plantar shocks are controlled by muscle forces in vivo.2011Inngår i: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 44, nr 6, s. 1144-1148Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose of this study was to investigate the role of muscle activation on the relative motion between tibia and femur. Impacts were initiated under the heels of four volunteers in three different activation levels of muscles crossing the extended knee joint: 0%, 30% and 60% of previously performed maximal voluntary isometric contractions. Impact forces were measured and tibial and femoral accelerations and displacements were determined by means of accelerometry. The accelerometers were mounted on the protruding ends of intracortical pins, inserted into the distal aspect of the femur and proximal aspect of the tibia. Under the 0%-condition the impact force (475±64N) led to 2.3±1.2mm knee compression and to 2.4±1.9mm medio-lateral and 4.4±1.1mm antero-posterior shear. The impact forces increased significantly with higher activation levels (619±33N (30%), 643±147N (60%)), while the knee compression (1.5±1.2, 1.4±1.3mm) and both medio-lateral shear (1.8±1.4, 1.5±1.1mm) and antero-posterior shear (2.6±1.3, 1.5±1.1mm) were significantly reduced. This study indicated that muscles are effective in controlling the relative motion between tibia and femur when the knee is subjected to external forces.

  • 270.
    Priego Quesada, Jose Ignacio
    et al.
    University of Valencia, Spain.
    Jacques, Tiago Canal
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Bini, Rodrigo R.
    School of Physical Education of the Army, Rio de Janeiro, Brazil. .
    Carpes, Felipe P.
    Federal University of Pampa, Uruguaiana, Brazil.
    Importance of static adjustment of knee angle to determine saddle height in cycling2016Inngår i: Journal of Science and Cycling, ISSN 2254-7053, Vol. 5, nr 1, s. 26-31Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Knee flexion angle is used to determine saddle height during pedaling. However, it is unclear how knee flexion angle at upright standing posture affects measures and interpretation of knee flexion angle during cycling. The objective of this study was to highlight the importance of adjusting knee angle during pedaling according to the knee angle at upright posture. Seventeen cyclists performed three 10 min cycling trials at different saddle heights to induce knee flexion angles (40º, 30º or 20º when crank was at the 6 o’clock position). Knee flexion angle was determined at the sagittal plane during cycling using a 2D motion analysis system. Alteration of saddle height was performed by subtracting the knee flexion determined during an upright standing posture from the observed knee flexion during cycling. Repeatability of knee angles at upright posture in the three trials was very good (ICC=0.73). A reduction in knee flexion angle of 10.6° (95%CI [8.6, 12.6º]) during cycling was found using the adjustment for upright standing posture (p<0.01; effect size>3.0). As a result, saddle height is affected by adjustments based on knee angle measured in upright standing posture. Determining saddle height without adjusting knee angle for upright standing posture could lead to errors with possible effects on performance and/or injury risk.

  • 271.
    Rosdahl, Hans
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för tillämpad idrottsvetenskap (LTIV). Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, FoU-gruppen för rörelse, hälsa och miljö. Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Gullstrand, Lennart
    Salier Eriksson, Jane
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, FoU-gruppen för rörelse, hälsa och miljö.
    Johansson, Patrik
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Schantz, Peter
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, FoU-gruppen för rörelse, hälsa och miljö.
    Evaluation of the Oxycon Mobile metabolic system against the Douglas bag method.2010Inngår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 109, nr 2, s. 159-171Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this study was to evaluate two versions of the Oxycon Mobile portable metabolic system (OMPS1 and OMPS2) in a wide range of oxygen uptake, using the Douglas bag method (DBM) as criterion method. The metabolic variables VO2, VCO2, respiratory exchange ratio and VE were measured during submaximal and maximal cycle ergometer exercise with sedentary, moderately trained individuals and athletes as participants. Test-retest reliability was investigated using the OMPS1. The coefficients of variation varied between 2 and 7% for the metabolic parameters measured at different work rates and resembled those obtained with the DBM. With the OMPS1, systematic errors were found in the determination of VO2 and VCO2. At submaximal work rates VO2 was 6-14% and VCO2 5-9% higher than with the DBM. At VO2max both VO2 and VCO2 were slightly lower as compared to DBM (-4.1 and -2.8% respectively). With OMPS2, VO2 was determined accurately within a wide measurement range (about 1-5.5 L min(-1)), while VCO2 was overestimated (3-7%). VE was accurate at submaximal work rates with both OMPS1 and OMPS2, whereas underestimations (4-8%) were noted at VO2max. The present study is the first to demonstrate that a wide range of VO2 can be measured accurately with the Oxycon Mobile portable metabolic system (second generation). Future investigations are suggested to clarify reasons for the small errors noted for VE and VCO2 versus the Douglas bag measurements, and also to gain knowledge of the performance of the device under applied and non-laboratory conditions.

  • 272.
    Rosdahl, Hans
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Lindberg, Thomas
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för tillämpad idrottsvetenskap (LTIV).
    Edin, Fredrik
    Nilsson, Johnny
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    The Moxus Modular metabolic sustem evaluated with two sensors for ventilation against the Douglas bag method2013Inngår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 113, nr 5, s. 1353-1367Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study evaluated the Moxus metabolic system with the Douglas bag method (DBM) as criterion. Reliability and validity were investigated in a wide range of ventilation and oxygen uptake and two sensors for determining ventilation were included. Thirteen well-trained athletes participated in one pre-test and four tests for data collection, exercising on a cycle ergometer at five submaximal powers (50-263 W) and at [Formula: see text]. Gas exchange variables were measured simultaneously using a serial setup with data collected on different days in an order randomized between Moxus with pneumotachometer (MP) and turbine flowmeter (MT) sensors for ventilation. Reliability with both sensors was comparable to the DBM. Average CV (%) of all exercise intensities were with MP: 3.0 ± 1.3 for VO(2), 3.8 ± 1.5 for VCO(2), 3.1 ± 1.2 for the respiratory exchange ratio (RER) and 4.2 ± 0.8 for V (E). The corresponding values with MT were: 2.7 ± 0.3 for VO(2), 4.7 ± 0.4 for VCO(2), 3.3 ± 0.9 for RER and 4.8 ± 1.4 for V (E). Validity was acceptable except for small differences related to the determination of ventilation. The relative differences in relation to DBM at the powers including [Formula: see text] were similar for both sensors with the ranges being: +4 to -2 % for V (E), +5 to -3 % for VO(2) and +5 to -4 % for VCO(2) while RER did not differ at any power. The Moxus metabolic system shows high and adequate reliability and reasonable validity over a wide measurement range. At a few exercise levels, V (E) differed slightly from DBM, resulting in concomitant changes in VO(2) and VCO(2).

  • 273. Rusaw, David
    et al.
    Hagberg, Kerstin
    Nolan, Lee
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Ramstrand, Nerrolyn
    Bilateral electromyogram response latency following platform perturbation in unilateral transtibial prosthesis users: influence of weight distribution and limb position.2013Inngår i: Journal of rehabilitation research and development, ISSN 0748-7711, E-ISSN 1938-1352, Vol. 50, nr 4, s. 531-44Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Appropriate muscular response following an external perturbation is essential in preventing falls. Transtibial prosthesis users lack a foot-ankle complex and associated sensorimotor structures on the side with the prosthesis. The effect of this lack on rapid responses of the lower limb to external surface perturbations is unknown. The aim of the present study was to compare electromyogram (EMG) response latencies of otherwise healthy, unilateral, transtibial prosthesis users (n = 23, mean +/- standard deviation [SD] age = 48 +/- 14 yr) and a matched control group (n = 23, mean +/- SD age = 48 +/- 13 yr) following sudden support-surface rotations in the pitch plane (toes-up and toes-down). Perturbations were elicited in various weight-bearing and limb-perturbed conditions. The results indicated that transtibial prosthesis users have delayed responses of multiple muscles of the lower limb following perturbation, both in the intact and residual limbs. Weight-bearing had no influence on the response latency in the residual limb, but did on the intact limb. Which limb received the perturbation was found to influence the muscular response, with the intact limb showing a significantly delayed response when the perturbation was received only on the side with a prosthesis. These delayed responses may represent an increased risk of falling for individuals who use transtibial prostheses.

  • 274. Saldanha, A
    et al.
    Nordlund Ekblom, Maria M
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Central fatigue affects plantar flexor strength after prolonged running.2008Inngår i: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 18, nr 3, s. 383-8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The primary aim of this study was to examine central fatigue of the plantar flexor muscle group after prolonged running using the twitch interpolation technique. Eight healthy, habitually active male subjects ran on a motorized treadmill for 2 h at a speed corresponding to 75% of peak oxygen uptake (VO(2peak)). Maximal voluntary isometric contraction (MVC) strength as well as the electrically induced twitch produced during MVC [interpolated twitch (IT)] and at rest [resting twitch (RT)] were measured before and after running. The level of activation (LOA) during each MVC was calculated as LOA (%)=100(1-IT/RT). Both MVC and LOA decreased (17+/-16% and 19+/-15%, respectively, P<0.05) after running, whereas RT did not change. The decrease in MVC was correlated with the decrease in LOA (r=0.87, P<0.05). The results demonstrate that after 2 h of treadmill running at an intensity of 75% of VO(2peak), there was a reduction in maximal voluntary plantar flexor muscle strength that was mainly related to central fatigue.

  • 275.
    Sandamas, Paul
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Gutierrez-Farewik, Elena M
    KTH, Karolinska institutet.
    Arndt, Anton
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC). Karolinska institutet.
    The effect of a reduced first step width on starting block and first stance power and impulses during an athletic sprint start.2018Inngår i: Journal of Sports Sciences, ISSN 0264-0414, E-ISSN 1466-447X, s. 1-9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study investigated how manipulating first step width affects 3D external force production, centre of mass (CoM) motion and performance in athletic sprinting. Eight male and 2 female competitive sprinters (100m PB: 11.03 ± 0.36 s male and 11.6 ± 0.45 s female) performed 10 maximal effort block starts. External force and three-dimensional kinematics were recorded in both the block and first stance phases. Five trials were performed with the athletes performing their preferred technique (Skating) and five trials with the athletes running inside a 0.3 m lane (Narrow). By reducing step width from a mean of 0.31 ± 0.06 m (Skating) to 0.19 ± 0.03 m (Narrow), reductions were found between the two styles in medial block and medial 1st stance impulses, 1st stance anterior toe-off velocity and mediolateral motion of the CoM. No differences were found in block time, step length, stance time, average net resultant force vector, net anteroposterior impulse nor normalised external power. Step width correlated positively with medial impulse but not with braking nor net anteroposterior impulse. Despite less medially directed forces and less mediolateral motion of the CoM in the Narrow trials, no immediate improvement to performance was found by restricting step width.

  • 276.
    Seger, Jan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Neuromuscular aspects of eccentric knee extensor actions: effects of electrical stimulation, age, gender and training1998Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The overall aim of this thesis was to study the effects of electrical stimulation, age, gender and training on the torque- and EMG-velocity relationships during eccentric knee extensor muscle actions in man. An isokinetic custom-built dynamometer was evaluated and used throughout the thesis.

    During maximal voluntary efforts eccentric torque output was similar to isometric and did not change with velocity. Superimposing electrical stimulation onto a maximal effort caused a specific increase in eccentric torque output. Submaximal electrical stimulation alone also produced a relatively higher eccentric than concentric torque. These results indicate the presence of a neural tension-regulating mechanism during maximal voluntary eccentric muscle actions in man.

    The hypothesis that such a mechanism would be more pronounced in children than adultswas not corroborated by the results from children, pre- and postpuberty. The adult pattern of interdependence between torque, EMG and muscle action type seemed to be established before puberty in both males and females. Comparisons between genders indicated a higher eccentric to concentric ratio of electromechanical eficiency at high velocity in postpuberty and adult females.

    Training with either pure eccentric or concentric maximal isokinetic muscle actions resulted in mode and velocity specific adaptations, particularly for eccentric training, in peak torque, muscle cross-sectional area, electromechanical efficiency and cross education, that is increase in strength of the contralateral leg. On the other hand, no or only minor training effects were seen on mean torque, muscle fibre morphology, eccentric to concentric EMG ratios and antagonist muscle activity.

    The expression of net eccentric torque output during maximal voluntary eccentric knee extensor actions have shown several distinct features separating it from concentric and isometric actions. Clarification of the underlying neuromuscular mechanisms remains a challenge for future research.

  • 277.
    Seger, Jan
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap.
    Arvidsson, Britt
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Specific effects of eccentric and concentric training on muscle strength and morphology in humans.1998Inngår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 79, s. 49-57Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose of this study was to compare pure eccentric and concentric isokinetic training with respect to their possible specificity in the adaptation of strength and morphology of the knee extensor muscles. Ten moderately trained male physical education students were divided into groups undertaking eccentric (ETG) and concentric (CTG) training. They performed 10 weeks of maximal isokinetic (90 degrees x s(-1)) training of the left leg, 4x10 repetitions - three times a week, followed by a second 10-week period of similar training of the right-leg. Mean eccentric and concentric peak torques increased by 18% and 2% for ETG and by 10% and 14% for CTG, respectively. The highest increase in peak torque occurred in the eccentric 90 degrees x s(-1) test for ETG (35%) whereas in CTG strength gains ranged 8%-15% at velocities equal or lower than the training velocity. Significant increases in strength were observed in the untrained contra-lateral leg only at the velocity and mode used in ipsilateral training. Cross-sectional area of the quadriceps muscle increased 3%-4% with training in both groups, reaching statistical significance only in ETG. No major changes in muscle fibre composition or areas were detected in biopsies from the vastus lateralis muscle for either leg or training group. In conclusion, effects of eccentric training on muscle strength appeared to be more mode and speed specific than corresponding concentric training. Only minor adaptations in gross muscle morphology indicated that other factors, such as changes in neural activation patterns, were causing the specific training-induced gains in muscle strength.

  • 278.
    Seger, Jan
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap.
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Effects of eccentric versus concentric training on thigh muscle strength and EMG.2005Inngår i: International Journal of Sports Medicine, ISSN 0172-4622, E-ISSN 1439-3964, Vol. 26, s. 45-52Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose of this study was to compare pure eccentric and concentric strength training regarding possible specific effects of muscle action type on neuromuscular parameters, such as a decreased inhibition during maximal voluntary eccentric actions. Two groups of young healthy adult men performed 10 weeks of either eccentric or concentric unilateral isokinetic knee extensor training at 90 degrees.s(-1), 4 sets of 10 maximal efforts, 3 days a week. Knee extensor torque and surface EMG from the quadriceps and hamstring muscle groups were collected and quantified in a window between 30 and 70 degrees knee angle (range of motion 90-5 degrees ) during maximal voluntary eccentric and concentric knee extensor actions at 30, 90, and 270 degrees.s(-1). Changes in strength of the trained legs revealed more signs of specificity related to velocity and contraction type after eccentric than concentric training. No major training effects were present in eccentric to concentric ratios of agonist EMG or in relative antagonist (hamstring) activation. Thus, for the trained leg, the muscle action type and speed specific changes in maximal voluntary eccentric strength could not be related to any effects on neural mechanisms, such as a selective increase in muscle activation during eccentric actions. Interestingly, with both types of training there were specific cross-education effects, that is, action type and velocity specific increases in strength occurred in the contralateral, untrained, leg, accompanied by a specific increase in eccentric to concentric EMG ratio after eccentric training.

  • 279.
    Seger, Jan
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap.
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Electrically evoked eccentric and concentric torque-velocity relationships in human knee extensor muscles.2000Inngår i: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 169, s. 63-69Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The torque-velocity relationship, obtained during in situ conditions in humans, demonstrates a levelling-off of eccentric torque output at the isometric torque level, at least for knee extensor actions. In contrast, the in vitro force-velocity relationship for animal muscle preparations is characterized by a sharp rise in eccentric force from isometric maximum. A force-regulating 'protective' mechanism has been suggested during maximal voluntary high-tension eccentric muscle actions. To investigate this phenomenon, maximal voluntary and three different levels of submaximal, electrically induced torques were compared during isometric and low velocity (10, 20 and 30 degrees s-1) isokinetic eccentric and concentric knee extensor actions in 10 healthy, moderately trained subjects. Eccentric torque was higher than isometric during electrically evoked, but not during maximal voluntary muscle actions. In contrast, concentric torque was significantly lower than isometric for both maximal voluntary and submaximal, electrically evoked conditions. Comparisons of normalized torques (isometric value under each condition set to 100%) demonstrated that the maximal voluntary eccentric torque had to be increased by 20%, and the isometric by 10% in order for the maximal voluntary torque-velocity curve to coincide with the electrically stimulated submaximal ones. These results support the notion that a tension-regulating mechanism is present primarily during eccentric maximal voluntary knee extensor actions.

  • 280.
    Seger, Jan
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap.
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Muscle strength and electromyogram in boys and girls followed through puberty.2000Inngår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 81, s. 54-61Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The main purpose of this study was to investigate the changes in anthropometric measures and muscle strength that occur during puberty in children from the age of 11 to 16 years. Special attention was paid to possible gender- and muscle action-type-specific alterations in torque/velocity and EMG/velocity characteristics. Sixteen children participated in the study (9 boys and 7 girls). Eccentric and concentric muscle strength was measured on an isokinetic dynamometer at angular velocities of 45, 90 and 180 degrees x s(-1). Simultaneously, a surface electromyogram (EMG) was recorded from the quadriceps muscle. At the age of 11, the boys and girls exhibited equal anthropometric measures and strength performance. In both genders, body measures and muscle strength increased significantly during the 5-year period, with larger increases being recorded for the boys. In addition, the boys increased selectively their eccentric torque per body mass, indicating an action-type-specific change in muscle quality. The general shape of the torque/velocity relationship exhibited an adult-like pattern both before and after puberty, and did not differ between genders. Both pre- and postpuberty, myoelectric activity was generally lower during eccentric than concentric actions, the highest values occurring for both genders in the concentric 180 degrees x s(-1) test. Ratios of eccentric to concentric torque per EMG, which reflect electromechanical efficiency, showed no significant changes with age. A significant velocity- and gender-specific change in electromechanical efficiency was observed at the highest speed at postpuberty, where the ratio for the girls was higher than for the boys.

  • 281.
    Seger, Jan
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap.
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Muscle strength and myoelectric activity in prepubertal and adult males and females.1994Inngår i: European Journal of Applied Physiology and Occupational Physiology, ISSN 0301-5548, E-ISSN 1432-1025, Vol. 69, s. 81-87Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The compare children and adults of both genders with respect to torque-velocity, electromyogram (EMG)-velocity and torque-EMG relationships during maximal voluntary knee extensor muscle actions. Four groups of purpose of this investigation was to ten subjects each were studied comprising 11-year-old girls and boys and female and male physical education students (22-35 years). Maximal voluntary eccentric (lengthening) and concentric (shortening) actions of the knee extensors were performed at the constant velocities of 45, 90 and 180 degrees.s-1. Average values for torque and EMG activity, recorded by surface electrodes from the quadriceps muscle, were taken for the mid 40 degrees of the 80 degrees range of motion. The overall shapes of the torque- and EMG-velocity relationships were similar for all four groups, showing effects of velocity under concentric (torque decrease and EMG increase) but not under eccentric conditions. Eccentric torques were always greater than velocity-matched concentric ones, whereas the eccentric EMG values were lower than the concentric ones at corresponding velocities. Torque output per unit EMG activity was clearly higher for eccentric than for concentric conditions and the difference was of similar magnitude for all groups. Thus, the torque-EMG-velocity relationships would appear to have been largely independent of gender and to be fully developed at a prepubertal age.

  • 282. Seynnes, Olivier R
    et al.
    Bojsen-Møller, Jens
    Albracht, Kirsten
    Arndt, Anton
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Cronin, Neil J
    Finni, Taija
    Magnusson, S Peter
    Ultrasound-Based Testing Of Tendon Mechanical Properties: A Critical Evaluation.2015Inngår i: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 118, nr 2, s. 133-141Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the past twenty years, the use of ultrasound-based methods has become a standard approach to measure tendon mechanical properties in vivo. Yet, the multitude of methodological approaches adopted by various research groups probably contributes to the large variability of reported values. The technique of obtaining and relating tendon deformation to tensile force in vivo has been applied differently, depending on practical constraints or scientific points of view. Divergence can be seen in i) methodological considerations such as the choice of anatomical features to scan and to track, force measurements or signal synchronisation and ii), in physiological considerations related to the viscoelastic behaviour or length measurements of tendons. Hence, the purpose of the present review is to assess and discuss the physiological and technical aspects connected to in vivo testing of tendon mechanical properties. In doing so, our aim is to provide the reader with a systematic, qualitative analysis of ultrasound-based techniques. Finally, a list of recommendations is proposed for a number of selected issues.

  • 283.
    Sirevåg, K
    et al.
    University of Bergen, Faculty of Psychology, Solli DPS, Nestun, Norway.
    Stavestrand, S
    Endal, T
    Sjøbø, T
    Nordhus, IH
    Pallesen, S
    Nordahl, H
    Specht, K
    Martinsen, EW
    Hammar, Å
    Mohlman, J
    Halmøy, A
    Andersson, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Thayer, JF
    Hjelmervik, H
    Hovland, A
    Physical EXercise Augmented COGnitive Behaviour Therapy for Older Adults with Generalised Anxiety Disorder (PEXACOG)2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Generalised anxiety disorder (GAD) is the most prevalent severe anxiety disorder among older adults. The disorder has a pervasive influence on the lives of those affected, and is a risk factor for other severe disorders such as depression, dementia and coronary heart disease. Cognitive behaviour therapy (CBT) is the treatment of choice for this disorder, but older adults have shown reduced effect of treatment compared to working age adults. Physical exercise has been suggested as intervention to improve the effects of treatment for GAD, via its demonstrated positive effect on cognitive functioning, increased plasticity in the brain, and increased availability of neurotrophins important for extinction of fear associations. The aim of the current research project is to investigate whether augmenting CBT with physical exercise will lead to improved effects of CBT on GAD in older adults in a randomized controlled trial (RCT). Participants between 60-75 years of age with a primary diagnosis of GAD will be randomised to one of two treatment conditions. The effects of treatment will be assessed on outcome measures, biological, physiological and cognitive measures at pre- interim-, and post-treatment, and follow-up assessments at 6- and 12-months post intervention. Participants in both groups will receive five weeks of pre-treatment intervention consisting of either physical exercise or weekly telephone contact. Participants thereafter receive either ten weeks of manualised CBT for GAD combined with manualised physical exercise or ten weeks of manualised CBT for GAD combined with weekly telephone contact. We expect that the treatment effect of the physical exercise augmented CBT will be greater than that of CBT combined with weekly telephone contact, as measured by a reduction in GAD symptoms on the Penn State Worry Questionnaire and in the proportion of remitted patients. The study also aims to determining the possible beneficial and augmenting properties of physical exercise in combination with CBT, and our understanding of clinical characteristics of GAD and mechanisms involved in treatment effect. Treatment rationale, procedures and protocols will be presented in detail together with preliminary results from the initial feasibility study comprises eight participants

  • 284.
    Sirivåg, K
    et al.
    University of Bergen, Faculty of Psychology, Bergen,Solli DPS, Nesttun, Norway.
    Haukenes Stavestrand, S
    Hilde Nordhus, I
    Pallesen, S
    Sjøbø, T
    Bruun Endal, T
    Nordahl, HM
    Specht, K
    Hammar, Å
    Halmøy, A
    Martinsen, EW
    Andersson, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Hjelmervik, H
    Mohlman, J
    Thayer, JF
    Hovland, A
    Physical exercise augmented cognitive behaviour therapy for older adults with generalised anxiety disorder (PEXACOG): Study protocol and feasibility results from a randomised controlled trial2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Background. Generalised anxiety disorder (GAD) is prevalent among older adults. These patients exhibit impaired response to cognitive behaviour therapy (CBT), and physical exercise has been recommended as a potential add-on intervention to improve efficacy. The current study is a randomised clinical trial that will compare CBT augmented with physical exercise, or CBT combined with attention placebo, and the current study assessing the feasibility of testing procedures and the experimental combined treatment measures.

    Methods. 4 participants were included in the feasibility study, and feasibility was assessed trough completion and attendance rates of testing and treatment sessions. Primary outcome measures were remission as assessed by an independent clinical rater using the Anxiety Disorders Interview Schedule for DSM-IV, and by symptom reduction on Penn State Worry Questionnaire. Manipulation check was assessed by physical tests of change in aerobic capacity and strength. Participants were measured on clinical, biological, physiological and neuropsychological tests at pre-, interim and post-treatment.

    Results. Completed treatment protocol for the RCT will be presented. 3 of 4 participants completed the full protocol including testing and the experimental augmented treatment. Participants completed 100% and 80% of CBT and physical exercise content, respectively. The three completers had large improvements on primary outcome and on manipulation checks.

    Conclusion. The testing procedures and experimental augmented treatment appear to be feasible. The preliminary findings indicate that this combined intervention can be efficacious.

  • 285.
    Sirivåg, K
    et al.
    Universitetet i Bergen; Solli Distriktspsykiatriske Senter (DPS), Nesttun, Norge.
    Stavestrand, SH
    Sjøbø, T
    Endal, T
    Nordhus, IH
    Pallesen, S
    Nordahl, H
    Pallesen, S
    Nordahl, H
    Mohlman, J
    Specht, K
    Andersson, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Hammar, Å
    Halmøy, A
    Harkestad, N
    Hjelmervik, H
    Martinsen, E
    Thayer, J
    Harvey, A
    Hovland, A
    Universitetet i Bergen; Solli Distriktspsykiatriske Senter (DPS), Nesttun, Norge.
    Physical EXercise Augmented COGnitive Behaviour Therapy for Older Adults with Generalised Anxiety Disorder (PEXACOG)2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Generalised anxiety disorder (GAD) is the most prevalent severe anxiety disorder among older adults. The disorder has a pervasive influence on the lives of those affected, and is a risk factor for other severe disorders such as depression, dementia and coronary heart disease. Cognitive behaviour therapy (CBT) is the treatment of choice for this disorder, but older adults have shown reduced effect of treatment compared to working age adults. Physical exercise has been suggested as intervention to improve the effects of treatment for GAD, via its demonstrated positive effect on cognitive functioning, increased plasticity in the brain, and increased availability of neurotrophins important for extinction of fear associations. The aim of the current research project is to investigate whether augmenting CBT with physical exercise will lead to improved effects of CBT on GAD in older adults in a randomized controlled trial (RCT). Participants between 60-75 years of age with a primary diagnosis of GAD will be randomised to one of two treatment conditions. The effects of treatment will be assessed on outcome measures, biological, physiological and cognitive measures at pre- interim-, and post-treatment, and follow-up assessments at 6- and 12-months post intervention. Participants in both groups will receive five weeks of pre-treatment intervention consisting of either physical exercise or weekly telephone contact. Participants thereafter receive either ten weeks of manualised CBT for GAD combined with manualised physical exercise or ten weeks of manualised CBT for GAD combined with weekly telephone contact. We expect that the treatment effect of the physical exercise augmented CBT will be greater than that of CBT combined with weekly telephone contact, as measured by a reduction in GAD symptoms on the Penn State Worry Questionnaire and in the proportion of remitted patients. The study also aims to determining the possible beneficial and augmenting properties of physical exercise in combination with CBT, and our understanding of clinical characteristics of GAD and mechanisms involved in treatment effect. Treatment rationale, procedures and protocols will be presented in detail together with preliminary results from the initial feasibility study comprises eight participants.

  • 286. Sjödin, B
    et al.
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Frith, K
    Karlsson, J
    Effect of physical training on LDH activity and LDH isozyme pattern in human skeletal muscle.1976Inngår i: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 97, nr 2, s. 150-7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Total lactate dehydrogenase (LDH) activity and LDH isozyme pattern were studied in muscle biopsies obtained from m. vastus lateralis after 1) "aerobic" training performed as interval and extreme distance running, respectively (3 subjects); and 2) "anaerobic" training for two months, carried out as repeated maximal bursts of approximately 1 min running (6 subjects). After the "anaerobic training" no changes in LDH properties could be detected, although running performance improved. The extreme distance running resulted in a decrease in total LDH activity and an increase in relative activity of the heart specific isozymes. A relationship was also shown between the relative activity of these isozymes and the training distance covered. The relatively more aerobic prevailing during distance running as compared to "anaerobic training" were proposed to decrease muscle specific subunits and/or increase synthesis of heart specific subunits in both muscle fiber types. This suggestion was supported by isozyme analysis of lyophilized and dissected single muscle fibres.

  • 287. Squair, Jordan W
    et al.
    Bjerkefors, Anna
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Inglis, J Timothy
    Lam, Tania
    Carpenter, Mark G
    Cortical and vestibular stimulation reveal preserved descending motor pathways in individuals with motor-complete spinal cord injury.2016Inngår i: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 48, nr 7, s. 589-596Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE: To use a combination of electrophysiological techniques to determine the extent of preserved muscle activity below the clinically-defined level of motor-complete spinal cord injury.

    METHODS: Transcranial magnetic stimulation and vestibular-evoked myogenic potentials were used to investigate whether there was any preserved muscle activity in trunk, hip and leg muscles of 16 individuals with motor-complete spinal cord injury (C4-T12) and 16 able-bodied matched controls.

    RESULTS: Most individuals (14/16) with motor-complete spinal cord injury were found to have transcranial magnetic stimulation evoked, and/or voluntary evoked muscle activity in muscles innervated below the clinically classified lesion level. In most cases voluntary muscle activation was accompanied by a present transcranial magnetic stimulation response. Furthermore, motor-evoked potentials to transcranial magnetic stimulation could be observed in muscles that could not be voluntarily activated. Vestibular-evoked myogenic potentials responses were also observed in a small number of subjects, indicating the potential preservation of other descending pathways.

    CONCLUSION: These results highlight the importance of using multiple electrophysiological techniques to assist in determining the potential preservation of muscle activity below the clinically-defined level of injury in individuals with a motor-complete spinal cord injury. These techniques may provide clinicians with more accurate information about the state of various motor pathways, and could offer a method to more accurately target rehabilitation.

  • 288.
    Stavestrand, Silje Haukenes
    et al.
    University of Bergen, Norway.
    Sirevåg, Kristine
    University of Bergen, Norway.
    Nordhus, Inger Hilde
    University of Bergen, Norway.
    Sjøbø, Trond
    Solli DPS, Nesttun, Norway.
    Endal, Trygve Bruun
    Solli DPS, Nesttun, Norway.
    Nordahl, Hans M
    Norwegian University of Science and Technology, Trondheim, Norway..
    Specht, Karsten
    University of Bergen, Norway.
    Hammar, Åsa
    University of Bergen, Norway.
    Halmøy, Anne
    University of Bergen, Norway.
    Martinsen, Egil W
    University of Oslo, Norway.
    Andersson, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Hjelmervik, Helene
    University of Bergen, Norway.
    Mohlman, Jan
    William Paterson University, NJ, USA.
    Thayer, Julian F
    Ohio State University, OH, USA.
    Hovland, Anders
    University of Bergen, Norway.
    Physical exercise augmented cognitive behaviour therapy for older adults with generalised anxiety disorder (PEXACOG): study protocol for a randomized controlled trial.2019Inngår i: Trials, ISSN 1745-6215, E-ISSN 1745-6215, Vol. 20, nr 1, artikkel-id 174Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: Generalised anxiety disorder (GAD) is a frequent and severe anxiety disorder among older adults. GAD increases the risk of developing other disorders such as depression and coronary heart disease. Older adults with GAD exhibit a poorer response to cognitive behaviour therapy (CBT) compared to younger patients with GAD. The normal age-related cognitive decline can be a contributor to reduced treatment efficacy. One strategy for improving treatment efficacy is to combine CBT with adjunctive interventions targeted at improving cognitive functions. Physical exercise is a viable intervention in this regard. Increased levels of brain-derived neurotrophic factor may mediate improvement in cognitive function. The present study aims to investigate the proposed effects and mechanisms related to concomitant physical exercise.

    METHODS: The sample comprises 70 participants aged 60-75 years, who have GAD. Exclusion criteria comprise substance abuse and unstable medication; inability to participate in physical exercise; and conditions which precludes GAD as primary diagnosis. The interventions are individual treatment in the outpatient clinic at the local psychiatric hospital, with two experimental arms: (1) CBT + physical exercise and (2) CBT + telephone calls. The primary outcome measure is symptom reduction on the Penn State Worry Questionnaire. Other measures include questionnaires, clinical interviews, physiological, biological and neuropsychological tests. A subset of 40 participants will undergo magnetic resonance imaging (MRI). After inclusion, participants undergo baseline testing, and are subsequently randomized to a treatment condition. Participants attend five sessions of the add-on treatment in the pre-treatment phase, and move on to interim testing. After interim testing, participants attend 10 sessions of CBT in parallel with continued add-on treatment. Participants are tested post-intervention within 2 weeks of completing treatment, with follow-up testing 6 and 12 months later.

    DISCUSSION: This study aims to develop better treatment for GAD in older adults. Enhancing treatment response will be valuable from both individual and societal perspectives, especially taking the aging of the general population into account.

    TRIAL REGISTRATION: ClinicalTrials.gov, NCT02690441 . Registered on 24 February 2016.

  • 289. Stokes, V P
    et al.
    Lanshammar, H
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Dominant pattern extraction from 3-D kinematic data.1999Inngår i: IEEE Transactions on Biomedical Engineering, ISSN 0018-9294, E-ISSN 1558-2531, Vol. 46, nr 1, s. 100-6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new method for the extraction of a repeating pattern in cyclic biomechanical data is proposed--singular value decomposition pattern analysis (SVDPA). This method is based on the recent work of Kanjilal and Palit [14], [15] and can be applied to both contiguous and repeated trials without being constrained to be strictly periodic. SVDPA is a data-driven approach that does not use a preselected set of basis functions; but instead utilizes a data matrix with a special structure to identify repeating patterns. Several important features of SVDPA are described including its close relationship to the Kahunen-Loève transform. The dominant pattern is defined as the average energy component (AEC). The AEC is obtained from the SVD of the data matrix and is equivalent to the optimal [maximal signal-to-noise ratio (SNR)] ensemble average pattern. The degree of periodicity and SNR for the AEC are defined explicitly from the singular values of the data matrix. We illustrate the usefulness of SVDPA for dominant pattern extraction by applying it to the quasiperiodic three-dimensional trajectory of a marker attached to the trunk during treadmill locomotion. The AEC obtained for the normalized trajectory and error estimates at each point suggests that SVDPA could be a useful tool for the extraction of the fine details from cyclic biomechanical data.

  • 290. Stokes, V P
    et al.
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Lanshammar, H
    From stride period to stride frequency.1998Inngår i: Gait & posture, Vol. 7, nr 1, s. 35-38Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The stride-cycle frequency of gait data is often estimated by taking the inverse of the average stride-cycle time (stride period) over several stride-cycles. We derive the density function of the stride-cycle frequency frequency (stride frequency) and describe some of its properties. We also show the conditions under which the inverse of the mean stride period is a 'good' estimate of the mean stride frequency. Copyright 1998 Elsevier Science B.V.

  • 291.
    Tais, Senna
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Eriksson, Martin
    KTH.
    Halvorsen, Kjartan
    KTH och Uppsala Universitet.
    Ekblom, Maria
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Effects of training with concurrent EMG feedback on Quadriceps stength and activation2012Konferansepaper (Fagfellevurdert)
  • 292.
    Tarassova, Olga
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Halvorsen, Kjartan
    Åberg, Anna Christina
    Uppsala Universitet.
    Ekblom, Maria
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Balance mechanisms in children with and without motor coordination difficulties2012Inngår i: Balance mechanisms in children with and without motor coordination difficulties, 2012Konferansepaper (Fagfellevurdert)
  • 293. Tesch, P
    et al.
    Sjödin, B
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Karlsson, J
    Muscle fatigue and its relation to lactate accumulation and LDH activity in man.1978Inngår i: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 103, nr 4, s. 413-20Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The lactate concentration in different muscle fibre types was determined in biopsy specimens from human vastus lateralis muscle after 30 and 60 s of maximal dynamic leg exercise. In addition, muscle fibre type distribution, total lactate dehydrogenase (LDH) activity, and isozymes of LDH were determined. In accordance with previous studies (Thorstensson and Karlsson 1976, Nilsson et al. 1977) it was found that an increasing proportion of slow twitch (ST) fibres corresponded to better sustained muscle force. Lactate was found preferentially in fast twitch (FT) fibres after 30 s, but after 60 s this difference was abolished. Differences between the two main muscle fibre types in muscle lactate, total LDH activity, and M-LDH activity were correlated to muscle fatigue. It was concluded that lactate or associated pH changes primarily in FT fibres could be one factor responsible for the impaired muscle function.

  • 294.
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Effects of moderate external loading on the aerobic demand of submaximal running in men and 10 year-old boys.1986Inngår i: European Journal of Applied Physiology and Occupational Physiology, ISSN 0301-5548, E-ISSN 1432-1025, Vol. 55, nr 6, s. 569-74Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of moderate external loading on the aerobic demand of submaximal running were studied in habitually active adult men (29-37 yrs) and 10 year-old boys. The load was symmetrically placed around the trunk and adjusted to correspond to 10% of body weight. Running was performed on a treadmill at 8, 10 and 11 km X h-1 (2.2, 2.8 and 3.1 m X s-1). A small, but consistent decrease in net oxygen uptake (gross oxygen uptake in ml X kg-1 X min-1 minus calculated basal metabolic rate) with load was observed in both groups at all speeds, except for the men at 8 km X h-1. The decrease was larger for the boys and tended to enhance with speed. The boys had a higher net oxygen uptake than the adults at all unladen running velocities, whereas the difference in the loaded condition was significant only at the highest speed. The decrease in net oxygen uptake with load could not be directly correlated with differences in body weight or step frequency. It is hypothesized that a difference in the utilization of muscle elastic energy could underlie part of the age and load dependent changes observed in running economy.

  • 295.
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    How is the normal locomotor program modified to produce backward walking?1986Inngår i: Experimental Brain Research, ISSN 0014-4819, E-ISSN 1432-1106, Vol. 61, nr 3, s. 664-8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The modifications occurring in the movement and muscle activity patterns of the leg when changing from forward to backward walking were studied in five healthy subjects during walking on a motor driven treadmill. Movements were recorded with a Selspot optoelectronic system and muscle activity with electromyography using surface electrodes. The movement trajectories of the leg in forward and backward walking essentially mirrored each other, even though the movements occurred in the reversed direction. The angular displacements at the hip, knee and ankle joints showed similar overall magnitude and pattern in the two situations. Most of the investigated muscles changed their pattern of activity in relation to the different movement phases. At the ankle, there was a switch between flexors and extensors with flexor activation during support in backward walking. The bursts of activity in knee extensors were prolonged and shifted to the main part of the support phase. In the hip extensors, the activity periods retained their positions relative to the leg movements, but changed function due to the reversed direction of movement. Thus, drastic changes occur in the normal locomotor program to produce a reversal of leg movements and propulsion backwards.

  • 296.
    Thorstensson, Alf
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Observations on strength training and detraining.1977Inngår i: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 100, nr 4, s. 491-3Artikkel i tidsskrift (Fagfellevurdert)
  • 297.
    Thorstensson, Alf
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Arvidson, A
    Trunk muscle strength and low back pain.1982Inngår i: Scandinavian Journal of Rehabilitation Medicine, ISSN 0036-5505, E-ISSN 1940-2228, Vol. 14, nr 2, s. 69-75Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The strength of the trunk muscles was measured in a group of young males with low back insufficiency (n=7) and in an age matched (19-21 yrs) healthy control group (n=8). A recently designed new application of the isokinetic technique was used to record maximal torque produced by the trunk muscles during flexion, extension and lateral flexion. Trunk muscle strength was measured during isometric contractions in different trunk positions and during slow isokinetic contractions in the whole range of motion. No significant differences between the groups were observed for trunk extension, lateral flexion or flexion with the centre of rotation at L2-L3 level. However, in the initial part of isokinetic trunk flexion with the pivot point at the hip joint the strength values for the back patients were significantly lower than for the controls. The present results demonstrate the importance of a comprehensive approach to the assessment of trunk muscle strength, including different movement velocities, body positions and pivot points. Further studies are needed to evaluate the significance of the specific weakness observed in dynamic trunk flexion strength in the back patients.

  • 298.
    Thorstensson, Alf
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Carlson, H
    Fibre types in human lumbar back muscles.1987Inngår i: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 131, nr 2, s. 195-202Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The distribution of histochemically identified muscle fibre types was studied in biopsy samples from the two main muscles in the lumbar region of the human erector spinae, the multifidus and the longissimus, in 16 healthy subjects (nine males and seven females, age 20-30 years). Muscle fibres were classified as types I, IIA, IIB or IIC on the basis of the pH lability of their myofibrillar ATPases. There were no differences between the multifidus and the longissimus muscles in the relative occurrence of type I (62 vs. 57%), type IIA (20 vs. 22%) or type IIB fibres (18 vs. 22%), or in the absolute size of fibres (range of mean least diameters 58-66 micron). The oxidative potential (NADH-diaphorase staining intensity) was high in type I and low in type II fibres, irrespective of subgroups, in both muscles. In the females, the type I fibres occupied a relatively larger area (70-75 vs. 54-58% for the males) although the relative number of type I fibres was the same in both sexes. This was due to smaller type II fibres in the females resulting in higher type I/type II area ratios (1.70-1.90 vs. 0.88-0.92 for males). This suggests a difference in functional capacity of lumbar back muscles between males and females. On the other hand, the similarity in histochemical fibre-type distribution between the multifidus and the longissimus muscles does not give support for a functional differentiation between these two anatomically different parts of the lumbar erector spinae in man.

  • 299.
    Thorstensson, Alf
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Carlson, H
    Zomlefer, M R
    Nilsson, Johnny
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Lumbar back muscle activity in relation to trunk movements during locomotion in man.1982Inngår i: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 116, nr 1, s. 13-20Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The function of lumbar back muscles was studied by relating their activity patterns to trunk movements in 7 healthy adult males during normal walking (1.0-2.5 m/s) and running (2.0-7.0 m/s) on a treadmill. The movements of the trunk in the sagittal and frontal planes were recorded with a Selspot optoelectronic system using infrared light emitting diodes as markers. The electromyographic (EMG) activity from the two main portions of the lumbar erector spinae muscles (Multifidus and Longissimus) was recorded bilaterally with intramuscular wire electrodes. The angular displacements of the trunk showed regular oscillations, but their shape, magnitude and relation to the step cycle were different in the two planes (sagittal and frontal) and varied with speed and mode of progression. The EMG pattern in both muscles showed a bilateral cocontraction with two main bursts of activity per step cycle starting just before each foot was placed on the ground. Relating the EMG to the movements of the trunk indicated that the main function of the lumbar erector spinae muscles is to restrict excessive trunk movements. During walking this restricting action is most evident for movements in the frontal plane, whereas in running the lumbar back muscles mainly control the movements in the sagittal plane.

  • 300.
    Thorstensson, Alf
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Elwin, K
    Sjödin, B
    Karlsson, J
    Isozymes of creatine phosphokinase and myokinase in human heart and skeletal muscle.1976Inngår i: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 36, nr 8, s. 821-6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The isozyme patterns of creatine phosphokinase (CPK) and myokinase (MK) were investigated in biopsy material from human heart and skeletal muscle. The protein separation was performed on crude muscle homogenates by means of flat-bed isoelectric focusing. Two isozymes were demonstrated for each enzyme, irrespective of the sampling site. The pI values were, on the average, 9.8 (MK-1) and 8.9 (MK-2), 7.2 (CPK-1) and 6.9 (CPK-2), respectively. MK-1 and CPK-1 constituted an average of 81% and 70% of total staining density for each enzyme, respectively. The relative contribution of MK-1 differed, however. Heart muscle showed the highest values (mean 91%) and vastus lateralis the lowest (mean 74%). The mean value for soleus was 86% MK-1. Furthermore, the percentage of MK-1 present was negatively correlated with the percentage of fast twitch fibres in m. vastus lateralis (r = -0.67). No corresponding differences could be demonstrated for CPK isozyme distribution. In conclusion, it was demonstrated that MK and CPK each occurred as two isozymes in human heart and skeletal muscle, and that the relative distribution of MK isozymes, in contrast to CPK, was related to muscle fibre type composition, and thus to the metabolic profile of the muscle.

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