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  • 1.
    Ainegren, Mats
    et al.
    Mid Sweden University.
    Jensen, Kurt
    University of Southern Denmark.
    Rosdahl, Hans
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Breathing resistance in automated metabolic systems is high in comparison with the Douglas Bag method and previous recommendations2018In: Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology, ISSN 1754-3371, Vol. 232, no 2, p. 122-130Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to investigate the resistance to breathing in metabolic systems used for the distribution and measurement of pulmonary gas exchange. A mechanical lung simulator was used to standardize selected air flow rates (V·, L/s). The delta pressure (?p, Pa) between the ambient air and the air inside the equipment was measured in the breathing valve?s mouthpiece adapter for four metabolic systems and four types of breathing valves. Resistance for the inspiratory and expiratory sides was calculated as RES?=?(?p/V·)?Pa/L/s. The results for resistance showed significant (p?<?0.05) between-group variance among the tested metabolic systems, breathing valves, and between most of the completed V·. The lowest resistance among the metabolic systems was found for a Douglas Bag system which had approximately half of the resistance compared to the automated metabolic systems. The automated systems were found to have higher resistance even at low V· in comparison with previous findings and recommendations. For the hardware components, the highest resistance was found for the breathing valves, while the lowest resistance was found for the hoses. The results showed that resistance in metabolic systems can be minimized through conscious choices of system design and hardware components.

  • 2.
    Alfvén, G
    et al.
    Karolinska institutet.
    Grillner, S
    Karolinska institutet.
    Andersson, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control. Karolinska institutet.
    Children with chronic stress-induced recurrent muscle pain have enhanced startle reaction.2017In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 21, no 9, p. 1561-1570Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Children with recurrent pain of negative chronic stress origin from different locations have a characteristic pattern of tender points in the temporal, trapezoid, great pectoral and abdominal muscles. We tested the hypothesis that the startle reaction is activated in these children and that some of the startle-activated muscles are related to the tender point pattern and the recurrent pain.

    METHODS: In children/adolescents, aged 10-17 years, 19 with recurrent psychosomatic pain (PAIN) and 23 controls (CON) we measured and analysed resting activity and acoustic startle response with electromyography (EMG) for the muscles involved in the pattern of tender points and also the lumbar erector spinae.

    RESULTS: The PAIN group showed higher resting activity and higher acoustic startle response values than the CON group for all six muscles together regarding the mean amplitude in the initial 200 ms, and during the burst of activity, and longer burst duration and shorter burst latency. For PAIN versus CON, all separate muscles showed generally higher values of EMG amplitudes and burst durations, and shorter latencies for the burst onset in all measures; with significance or strong trends for several parameters and muscles.

    CONCLUSION: For the first time in children with recurrent psychosomatic pain, increased resting activity and potentiated startle response were demonstrated in the muscles involved in the stress tender point pattern.

    SIGNIFICANCE: This study demonstrates in adolescents how recurrent pain of negative stress origin from the head, stomach, back and chest is related to increased startle reaction and increased muscular tension in these regions. This study contributes to the understanding of the mechanisms underlying the global burden of recurrent pain.

  • 3.
    Andersson, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Physical fitness: I. Muscle strength II. Aerobic fitness: Muscle oxygen uptake and heart rate2014In: Women and sport, Stockholm: SISU idrottsböcker , 2014Chapter in book (Other academic)
    Abstract [en]

    Improved muscle strength and aerobic fitness are of great importance in many sports and are also associated with increased life expectancy and a reduced incidence of a number of diseases. In this chapter, we will discuss some of the factors that influence muscle strength and aerobic fitness, including sex-related factors. The way physical fitness is measured is also important when making comparisons. An increased understanding of the assessment of strength and aerobic fitness may inspire fruitful improvements in practical test and training programs in various sport and health contexts.

  • 4.
    Andersson, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Rygg-, buk- och höftmuskulatur - styrka, träningsövningar och stabilitet.2001In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, no 3, p. 43-49Article in journal (Other academic)
  • 5.
    Andersson, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Rygg- och bukmuskelträning samt bålstabilitet1998In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, no 4, p. 4-7Article in journal (Other academic)
  • 6.
    Andersson, Eva A
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Analys av träningsövningar för buk- och höftböjarmuskulatur1994In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, no 3, p. 16-18Article in journal (Other academic)
  • 7.
    Andersson, Eva A
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    EMG and strength in trunk and hip muscles1997Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The overall aim of this thesis was to study the myouelectric activity of all major muscles involved in the movements and stabilization of the trunk, pelvis and hips during training exercises, postures, motor tasks, maximal strength performance and locomotion. By use of ultra-sound, EMG electrodes could be guided safely and accurately into muscles situated even close to the spinal column, such as psoas, quadratus lumborum and deep parts of erector spinae.

         A task specific variation in activation levels were seen between muscle synergies, as well as between individual muscles within a synergy. Selective engagement of the abdominal muscles could be achieved in trunk flexion sit-ups, that is lifting only the upper trunk from the floor. An even higher activation of abdominal muscles was needed for static stabilization of the trunk and pelvis during hip flexion sit-ups, whereas single leg lifts were performed without involvement of the abdominal muscles. A selective activation of either the iliacus or psoas muscle was observed, for example in certain types of training exercises and in walking and running. Applying bending moments to the spine, resulted in a grading of the muscle activation response according to mechanical advantage, that is highest in the quadratus lumborum in lateral loading and in the superficial erector spinae in ventral loading. An exception was the most forward flexed position in standing where the superficial erector spinae "relaxed" but quadratus lumborum remained active. In general, the level of EMG in maximal efforts was maintained at the same high level irrespective of position in the range of motion, despite a marked variation in strength output. This position-dependency, as well as the strength values as such, varied in a specific way in groups of athletes, related to previous background.

         These data contribute to the understanding of muscle function and motor control of the trunk , pelvis and hips. They are also of relevance when evaluating and designing tests and training programs in rehabilitation and sport contexts as well as for improving biomechanical models of spinal loading.  

  • 8.
    Andersson, Eva A
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    EMG and strength in trunk and hip muscles1997In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, no 1, p. 48-Article in journal (Other academic)
  • 9.
    Andersson, Eva A
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Grundström, Helen
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Diverging intramuscular activity patterns in back and abdominal muscles during trunk rotation.2002In: Spine, ISSN 1528-1159, Vol. 27, no 6, p. E152-60Article in journal (Refereed)
    Abstract [en]

    STUDY DESIGN: An intramuscular electromyographic study was performed on trunk rotations during sitting and standing. OBJECTIVE: The aim was to provide new information on activation levels for deep trunk muscles in various unresisted and resisted trunk rotations. SUMMARY AND BACKGROUND DATA: Frequent daily trunk twisting and decreased maximal strength during trunk rotation have been associated with low back pain or sciatic pain. However, the involvement of deep trunk muscles during different trunk rotations is relatively unknown. METHODS: Ten healthy subjects participated. Fine-wire electrodes were inserted, under ultrasound guidance, into psoas, quadratus lumborum, the superficial medial lumbar erector spinae (ES-s, multifidus) and its deep lateral portion (ES-d, iliocostalis), iliacus, rectus abdominis, obliquus externus, and obliquus internus. RESULTS: The highest involvement for all muscles was observed on the ipsilateral side, in maximal trunk twists with shoulder resistance, except obliquus externus, which showed a dominant contralateral side, and rectus abdominis, which was little activated in all rotations. In contrast, maximal trunk twist without shoulder resistance, i.e., freely performed, resulted generally in lower levels for all muscles involved and in a shift of side dominance for the lumbar muscles quadratus lumborum, psoas, and ES-s. CONCLUSIONS: During trunk rotations the activity patterns for various trunk muscles could drastically change, and even be the opposite, between the two body sides, within the same type of task, depending on several factors such as initial position, effort level, sitting or standing, and external shoulder resistance.

  • 10.
    Andersson, Eva A
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Ma, Z
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Relative EMG levels in training exercises for abdominal and hip flexor muscles.1998In: Scandinavian Journal of Rehabilitation Medicine, ISSN 0036-5505, E-ISSN 1940-2228, Vol. 30, no 3, p. 175-83Article in journal (Refereed)
    Abstract [en]

    The main purpose of our study was to compare systematically EMG levels in sub-maximal training exercises for the trunk and hip flexor muscles with those voluntarily attainable in corresponding situations. Six healthy subjects performed three types of standardized training exercises, whose static positions, movement velocity and range of motion were reproduced during maximal voluntary isokinetic strength tests. EMG was recorded with wire electrodes from the iliacus muscle and with surface electrodes from the rectus femoris, sartorius, rectus abdominis, obliquus externus and internus muscles. The relative EMG values demonstrated a task dependency which could differ between individual muscles. The maximal voluntary activation levels were relatively constant across conditions. Exceptions were present, particularly for the rectus femoris and iliacus muscles. These findings highlight the consequences of using different methods of normalizing EMG. The relative EMG values presented may serve as guidelines when selecting training exercises for specific trunk and hip flexor muscles in sports and rehabilitation.

  • 11.
    Andersson, Eva A
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Nilsson, Johnny
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Ma, Z
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Abdominal and hip flexor muscle activation during various training exercises.1997In: European Journal of Applied Physiology and Occupational Physiology, ISSN 0301-5548, E-ISSN 1432-1025, Vol. 75, no 2, p. 115-23Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to provide objective information on the involvement of different abdominal and hip flexor muscles during various types of common training exercises used in rehabilitation and sport. Six healthy male subjects performed altogether 38 different static and dynamic training exercises trunk and hip flexion sit-ups, with various combinations of leg position and support, and bi- and unilateral leg lifts. Myoelectric activity was recorded with surface electrodes from the rectus abdominis, obliquus externus, obliquus internus, rectus femoris, and sartorius muscles and with indwelling fine-wire electrodes from the iliacus muscle. The mean electromyogram amplitude, normalised to the highest observed value, was compared between static and dynamic exercises separately. The hip flexors were highly activated only in exercises involving hip flexion, either lifting the whole upper body or the legs. In contrast, the abdominal muscles showed marked activation both during trunk and hip flexion sit-ups. In hip flexion sit-ups, flexed and supported legs increased hip flexor activation, whereas such modifications did not generally alter the activation level of the abdominals. Bilateral, but not unilateral, leg lifts required activation of abdominal muscles. In trunk flexion sit-ups an increased activation of the abdominal muscles was observed with increased flexion angle, whereas the opposite was true for hip flexion sit-ups. Bilateral leg lifts resulted in higher activity levels than hip flexion sit-ups for the iliacus and sartorius muscles, while the opposite was true for rectus femoris muscles. These data could serve as a basis for improving the design and specificity of test and training exercises.

  • 12.
    Andersson, Eva A
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Nilsson, Johnny
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Intramuscular EMG from the hip flexor muscles during human locomotion.1997In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 161, no 3, p. 361-70Article in journal (Refereed)
    Abstract [en]

    The purpose was to investigate the activation pattern of five major hip flexor muscles and its adaptation to changing speed and mode of progression. A total of 11 healthy subjects performed walking and running on a motor-driven treadmill at speeds ranging from 1.0 to 6.0 m s-1. Intramuscular fine-wire electrodes were used to record myoelectric signals from the iliacus, psoas, sartorius, rectus femoris and tensor fascia latae muscles. The basic pattern, with respect to number of activation periods, remained the same irrespective of speed and mode of progression. However, differences in the relative duration and timing of onset of activation occurred between individual muscles. Over the speed range in walking, a progressively earlier onset was generally seen for the activation period related to hip flexion. Changes in EMG amplitude were measured in the iliacus and psoas muscles and showed a marked increase and difference between walking and running at speeds above 2.0 m s-1. Thus, the alternating flexion-extension movements at the hip during locomotion appear to be governed by a rather fixed 'neural program' which normally only needs minor modulations to accomplish the adjustments accompanying an increase in speed of progression as well as a change from walking to running.

  • 13.
    Andersson, Eva A.
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Rönquist, Gustaf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Oddsson, Kristjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Nilsson, Johnny
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Laboratory of Applied Sports Science (LTIV).
    Äldre blir starkare av Hälsoprojektet2013In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, Vol. 22, no 1, p. 25-27Article in journal (Other academic)
    Abstract [sv]

    En god kondition och styrka har samband med förbättrad hälsa, minskad förekomst av flera folksjukdomar samt ökad livslängd. Fysiologiska tester kan vara stimulerande för äldre att följa utvecklingen av sin fysiska kapacitet och för olika aktörer som vill göra hälsoutvärderingar.

  • 14.
    Andersson, Eva A
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Utvärdering av träningsövningar för buk- och höftmuskulaturen.1993In: Arbetsmiljöfondens Sammanfattningar, no 1563, p. 1-8Article, review/survey (Other academic)
  • 15.
    Andersson, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Hovland, Anders
    Kjellman, Bengt
    Taube, Jill
    Martinsen, Egil W.
    Fysisk aktivitet är lika bra som läkemedel eller samtalsterapi vid depression2016In: Idrottsmedicin, ISSN 2001-3302, Vol. 35, no 1, p. 4-7Article in journal (Other academic)
  • 16.
    Andersson, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Kallings, Lena
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Hultgren, Staffan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Kraepelien Strid, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Hälsopedagogprogrammet2014In: Från Kungl. Gymnastiska Centralinstitutet till Gymnastik- och idrottshögskolan: en betraktelse av de senaste 25 åren som del av en 200-årig historia / [ed] Suzanne Lundvall, Stockholm: Gymnastik- och idrottshögskolan, GIH , 2014, p. 108-116Chapter in book (Other (popular science, discussion, etc.))
  • 17.
    Andersson, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Oddsson, L
    Grundström, H
    Nilsson, Johnny
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    EMG activities of the quadratus lumborum and erector spinae muscles during flexion-relaxation and other motor tasks.1996In: Clinical biomechanics (Bristol, Avon), Vol. 11, no 7, p. 392-400Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: The aim of this study was to provide new information on the myoelectrical activation of the quadratus lumborum, the deep lateral and the superficial medial lumbar erector spinae, the psoas, and the iliacus muscles in various motor tasks. DESIGN: An intramuscular electromyographic study was performed. BACKGROUND: The contribution of individual deep trunk muscles to the stability of the lumbar spine is relatively unknown in different tasks, including the flexion-relaxation phenomenon. METHODS: Seven healthy subjects participated. Fine-wire electrodes were inserted with a needle guided by ultrasound. RESULTS: The highest activity observed for quadratus lumborum and deep lateral erector spinae occurred in ipsilateral trunk flexion in a side-lying position and for superficial medial erector spinae during bilateral leg lift in a prone position. Quadratus lumborum and deep lateral erector spinae were activated when the flexion-relaxation phenomenon was present for superficial medial erector spinae, i.e. when its activity ceased in the latter part of full forward flexion of the trunk, held relaxed and kyphotic. CONCLUSIONS: In general, the activation of the investigated muscles showed a high degree of task specificity, where activation of a certain muscle was not always predictable from its anatomical arrangement and mechanical advantage.

  • 18.
    Andersson, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Oddsson, L
    Grundström, H
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    The role of the psoas and iliacus muscles for stability and movement of the lumbar spine, pelvis and hip.1995In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 5, no 1, p. 10-6Article in journal (Refereed)
    Abstract [en]

    The activation patterns of the psoas and iliacus muscles were investigated in 7 healthy adult subjects (4 men and 3 women) during a variety of motor tasks in standing, sitting and lying. Myoelectric activity was recorded simultaneously from the 2 muscles using thin wire electrodes inserted under guidance of high-resolution ultrasound. In general, both muscles were coactivated, albeit to different relative levels, particularly when hip flexor torque was required. Selective activation of the iliacus could, however, be seen to stabilize the pelvis in contralateral hip extension during standing. Psoas was found to be selectively involved in sitting with a straight back and in contralateral loading situations requiring stabilization of the spine in the frontal plane. During training exercises from a supine position, such as sit-ups, the contribution of the psoas and iliacus muscles could be varied by changing the range of motion as well as the position and support for the legs. Thus, the 2 anatomically different muscles of the iliopsoas complex were shown to have individual and task-specific activation patterns depending on the particular demands for stability and movement at the lumbar spine, pelvis and hip.

  • 19.
    Andersson, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Swärd, L
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Trunk muscle strength in athletes.1988In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 20, no 6, p. 587-93Article in journal (Refereed)
    Abstract [en]

    Maximal voluntary strength of the trunk muscles was measured in 57 male elite athletes (soccer players, wrestlers, tennis players, and gymnasts), 14 female elite gymnasts, and in a normal group of 87 conscripts. Mean ages in the different groups ranged from 18-22 yr. An isokinetic (constant velocity) technique was used to record maximal torque produced by trunk and hip muscles during flexion, extension, and lateral flexion over the range of motion. The constant angular velocities used were 15 deg.s-1 and 30 deg.s-1, respectively. Isometric strength was measured in a straight body position (0 deg. of flexion). The measurements were made with the subjects in a horizontal position with the pivot point at the hip and at the lumbar (L2-L3) level. All male athlete groups showed higher peak torque values than the normals. The differences were largest in hip extension and trunk flexion. The male gymnasts also showed significantly higher peak values in hip flexion as compared to all other categories. There was no difference in strength per kg body weight between female gymnasts and untrained males, except in trunk extension. The position for peak torque occurred earlier in the movements for the athletes, especially for the gymnasts in extension movements and for the tennis players in flexion movements. In isometric contractions essentially the same strength differences were present as in the slow isokinetic contractions. In lateral flexion wrestlers and tennis players showed significantly higher strength in movements toward the nondominant side. Thus, differences were present between the athletes and the normals, some of which appeared to be sport specific and related to long-term systematic training.(ABSTRACT TRUNCATED AT 250 WORDS)

  • 20. Andersson, Helena
    et al.
    Raastad, Truls
    Nilsson, Johnny
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Paulsen, Gøran
    Garthe, Ina
    Kadi, Fawzi
    Neuromuscular fatigue and recovery in elite female soccer: effects of active recovery.2008In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 40, no 2, p. 372-80Article in journal (Refereed)
    Abstract [en]

    PURPOSE: To investigate the time course of recovery from neuromuscular fatigue and some biochemical changes between two female soccer matches separated by an active or passive recovery regime. METHODS: Countermovement jump (CMJ), sprint performance, maximal isokinetic knee flexion and extension, creatine kinase (CK), urea, uric acid, and perceived muscle soreness were measured in 17 elite female soccer players before, immediately after, 5, 21, 45, 51, and 69 h after a first match, and immediately after a second match. Eight players performed active recovery (submaximal cycling at 60% of HRpeak and low-intensity resistance training at < 50% 1RM) 22 and 46 h after the first match. RESULTS: In response to the first match, a significant decrease in sprint performance (-3.0 +/- 0.5%), CMJ (-4.4 +/- 0.8%), peak torque in knee extension (-7.1 +/- 1.9%) and flexion (-9.4 +/- 1.8%), and an increase in CK (+ 152 +/- 28%), urea (15 +/- 2), uric acid (+ 11 +/- 2%), and muscle soreness occurred. Sprint ability was first to return to baseline (5 h) followed by urea and uric acid (21 h), isokinetic knee extension (27 h) and flexion (51 h), CK, and muscle soreness (69 h), whereas CMJ was still reduced at the beginning of the second match. There were no significant differences in the recovery pattern between the active and passive recovery groups. The magnitude of the neuromuscular and biochemical changes after the second match was similar to that observed after the first match. CONCLUSION: The present study reveals differences in the recovery pattern of the various neuromuscular and biochemical parameters in response to a female soccer match. The active recovery had no effects on the recovery pattern of the four neuromuscular and three biochemical parameters.

  • 21.
    Arndt, Anton
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Achilles tendon biomechanics and functional anatomy2012Conference paper (Other academic)
  • 22.
    Arndt, Anton
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Biomechanical concepts of Achilles Tendon pathogenesis2012Conference paper (Other academic)
  • 23.
    Arndt, Anton
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    In vivo, intrinsic kinematics of the foot and ankle2012Conference paper (Other academic)
  • 24.
    Arndt, Anton
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    The evolution of running shoes2012Conference paper (Other academic)
  • 25.
    Arndt, Anton
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Bengtsson, Ann-Sophie
    Peolsson, Michael
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Movin, Tomas
    Non-uniform displacement within the Achilles tendon durig passive ankle joint motion.2012In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 20, no 9, p. 1868-74Article in journal (Refereed)
    Abstract [en]

    PURPOSE:

    An initial step in the understanding of Achilles tendon dynamics is to investigate the effects of passive motion, thereby minimising muscle activation and reducing internal joint forces. Internal tendon dynamics during passive ankle joint motion have direct implications for clinical rehabilitation protocols after Achilles tendon surgery. The aim of this study was to test the hypothesis that tendon tissue displacement is different in different layers of the Achilles tendon during controlled passive ankle joint movements.

    METHODS:

    Ultrasound imaging was conducted on the right Achilles tendon of nine healthy recreationally active males. Standardised isokinetic passive dorsi-plantar-flexion movements were performed with a total range of motion of 35°. The tendon was divided into superficial, central and deep layers in the resulting B-mode ultrasound images viewed in the sagittal plane. A block-matching speckle tracking algorithm was applied post-process, with kernels for the measurement of displacement placed in each of the layers.

    RESULTS:

    The mean (SD) displacement of the Achilles tendon during passive dorsiflexion was 8.4 (1.9) mm in the superficial layer, 9.4 (1.9) mm in the central portion and 10.4 (2.1) mm in the deep layer, respectively. In all cases, the movement of the deep layer of the tendon was greater than that of the superficial one (P < 0.01).

    CONCLUSIONS:

    These results, achieved in vivo with ultrasonographic speckle tracking, indicated complex dynamic differences in different layers of the Achilles tendon, which could have implications for the understanding of healing processes of tendon pathologies and also of normal tendon function.

  • 26.
    Arndt, Anton
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Lundgren, Paul
    Liu, Anmin
    Nester, Christopher
    Maiwald, Christian
    Jones, Richard
    Lundberg, Arne
    The effect of a midfoot cut in the outer sole of a shoe on intrinsic foot kinematics during walking.2013In: Footwear Science, ISSN 1942-4280, Vol. 5, no 1, p. 63-69Article in journal (Refereed)
    Abstract [en]

    Modifications in shoe outer soles are frequently made with the intention of altering biomechanics of the foot inside the shoe. These modifications are however, generally based upon intuition with little or no scientific data for support. The purpose of this study was to quantify changes in intrinsic foot segmental kinematics between walking in a neutral shoe and a shoe modified with a clear cut forming a break underneath the midfoot, approximating the Lisfrancs joint.

    Five healthy male subjects participated in the study. Intracortical pins were inserted under sterile conditions and local anaesthetic in nine different bones of the foot and shank. The subjects performed 10 walking trials in both a neutral, standard, flatsoled, flexible walking shoe and in the same shoe with an approximately 1 cm deep cut aligned with the subjects’ Lisfrancs joint. Material tests showed that the cut reduced midfoot shoe bending stiffness by 23% to 38% and torsional stiffness by 23% to 28%. A helical axis approach was applied for calculating the 3D rotations about relevant joints.

    Kinematic trajectories in the sagittal, frontal, and transverse planes were normalised to the stance phase for seven selected joints to compare rotation patterns when wearing the two shoe conditions. Although one out of 21 ranges of motion (ROM) showed a significant difference, there is strong reason to regard this as the result of a type 1 error. Apart from this no differences in ROM occurred between the shoe conditions.

    The low subject number reduced the statistical power of the results. However, the study indicated that outer sole modifications that may be assumed to have clear effects upon foot kinematics, do not necessarily do so.

  • 27.
    Arndt, Toni
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Barfota eller rejäl stötdämpning – vilka löparskor är bäst?2016In: Idrottsforskning, ISSN 2002-3944, article id 18 majArticle in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Kraftig dämpning i våra löparskor skulle minska skadorna. Men att stötarna i nedslaget är ett problem har svagt stöd i forskningen. Är det då bättre att springa i minimalistiska skor eller helt barfota? Vad ska motionären välja?

  • 28.
    Arndt, Toni
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Forskning inom rörelselära2014In: Från Kungl. Gymnastiska Centralinstitutet till Gymnastik- och idrottshögskolan: en betraktelse av de senaste 25 åren som del av en 200-årig historia / [ed] Suzanne Lundvall, Stockholm: Gymnastik- och idrottshögskolan, GIH , 2014, p. 245-252Chapter in book (Other (popular science, discussion, etc.))
  • 29.
    Askling, Carl
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Acute hamstring injurise in sports - types, rehabilitation, prevention2015Conference paper (Other academic)
  • 30.
    Askling, Carl
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Akut hamstringsskada vanlig inom svensk elitfotboll2013In: Idrottsmedicin, ISSN 2001-3302, no 2, p. 26-27Article in journal (Other academic)
  • 31.
    Askling, Carl
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Akuta hamstringskador2018In: Idrottsskada: från prevention till säker återgång till idrott / [ed] Eva Rasmussen Barr & Anette Heijne, Studentlitteratur AB, 2018, 1, p. 243-246Chapter in book (Other academic)
    Abstract [sv]

    I detta kapitel avhandlas de två huvudtyperna av hamstringskada, hur hamstringmuskulaturen ska tränas, preventivt samt efter skada, och slutligen tester som underlättar beslutet om när återgång i idrott är lämplig.

  • 32.
    Askling, Carl
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Hamstring muscle strain2008Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Background: Acute hamstring strains are common injuries in different sports. They are often serious, causing long rehabilitation times and a proneness for re-injury. Preliminary observations indicate that the injuries can be of at least two types, one occurring during high-speed running and the other during motions where the hamstring muscles reach extreme lengths.

    Aims: To investigate the possible existence of different types of acute hamstring strains in two specific athletic groups, namely sprinters and dancers, as well as the generality of these findings in other sports.

    Methods: In the first project, 18 sprinters and 15 dancers with acute first time hamstring strains were prospectively included. All subjects were examined, clinically and with magnetic resonance imaging (MRI), on 4 occasions after injury: at day 2-4, 10, 21 and 42. The follow-up period was 2 years. In the second project, 30 subjects from 21 different sports were prospectively included. All subjects were examined clinically and with MRI. The follow-up period lasted until the subjects returned to sport or finished their sport activity due to the injury.

    Results: All sprinters sustained their injuries during competitive high-speed running. In contrast, all dancers encountered their injuries during slow-speed stretching type of exercises. The initial loss of strength and flexibility was significantly greater in sprinters than in dancers. At 42 days after injury, both groups could perform more than 90% of the test values of the uninjured leg. All the sprinters’ injuries were primarily located in biceps femoris long head, whereas the dancers’ injuries were mainly (87%) involving the proximal free tendon of semimembranosus. For the sprinters, involvement of the proximal free tendon, as estimated by MRI, and proximity to the ischial tuberosity, as estimated both by palpation and MRI, were associated with significantly longer time to return to pre-injury level. In the dancers, there were no significant correlations between clinical or MRI parameters and time to return to per-injury level. The time to pre-injury level was significantly longer (median 50 weeks, range 30-76) for the dancers compared to the sprinters (16, 6-50). In the second project, all injuries occurred during movements reaching a position with combined extensive hip flexion and knee extension. They were all located close to the ischial tuberosity and 83% involved the proximal free tendon of semimembranosus. Fourteen subjects (47%) decided to end their sport activity and for the remaining 16 subjects the median time back to sport was 31 (range 9-104) weeks. There were no significant correlations between clinical and MRI parameters and time to return to sport.

    Conclusions: There seems to be a link between the injury situation and the two types of acute hamstring strain in sprinters and dancers with respect to clinical findings, injury location, muscles and tissues involved, and time to return to pre-injury level. Proximity of the injury to the ischial tuberosity, as estimated both by palpation and MRI, is associated with longer recovery time. Also in other sports, an injury situation where the hamstrings reach extensive lengths caused a specific injury to the proximal posterior thigh similar to that described in dancers. Due to the prolonged recovery time associated with this type of injury, correct diagnosis based on history, clinical and MRI investigation, and adequate information to the athletes are essential.

  • 33.
    Askling, Carl
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Hamstrings – så hanterar du fotbollens vanligaste skada2016In: Idrottsforskning.se, ISSN 2002-3944, article id 13 juniArticle in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Hamstrings är fotbollsspelarens mest skadedrabbade muskelgrupp. Återfallsskador är också ett stort problem. Rehabiliteringstiden kan halveras med rätt övningar. Och Asklings H-test ger vägledning om när det är dags för spel igen.

  • 34.
    Askling, Carl
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Lengthening hamstring exercises - the key to rehabilitation success?2015Conference paper (Refereed)
  • 35.
    Askling, Carl
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Prevention of hamstring injuries2015Conference paper (Refereed)
  • 36.
    Askling, Carl
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Why do so many hamstring injuries occur/recur?2015Conference paper (Refereed)
  • 37.
    Askling, Carl
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Karlsson, J
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Hamstring injury occurrence in elite soccer players after preseason strength training with eccentric overload.2003In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 13, no 4, p. 244-50Article in journal (Refereed)
    Abstract [en]

    The primary purpose of this study was to evaluate whether a preseason strength training programme for the hamstring muscle group - emphasising eccentric overloading - could affect the occurrence and severity of hamstring injuries during the subsequent competition season in elite male soccer players. Thirty players from two of the best premier-league division teams in Sweden were divided into two groups; one group received additional specific hamstring training, whereas the other did not. The extra training was performed 1-2 times a week for 10 weeks by using a special device aiming at specific eccentric overloading of the hamstrings. Isokinetic hamstring strength and maximal running speed were measured in both groups before and after the training period and all hamstring injuries were registered during the total observational period of 10 months. The results showed that the occurrence of hamstring strain injuries was clearly lower in the training group (3/15) than in the control group (10/15). In addition, there were significant increases in strength and speed in the training group. However, there were no obvious coupling between performance parameters and injury occurrence. These results indicate that addition of specific preseason strength training for the hamstrings - including eccentric overloading - would be beneficial for elite soccer players, both from an injury prevention and from performance enhancement point of view.

  • 38.
    Askling, Carl
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Lund, H
    Saartok, T
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Self-reported hamstring injuries in student-dancers.2002In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 12, no 4, p. 230-5Article in journal (Refereed)
    Abstract [en]

    Dancing involves powerful movements as well as flexibility exercises, both of which may be related to specific injuries to the musculo-tendinosus tissue, e.g., the hamstring muscle complex. In this study, the occurrence of acute and overuse injuries to the rear thigh in dancers was investigated retrospectively by means of a questionnaire. All but one (n = 98) of the student-dancers (age 17-25 years) at the Ballet Academy in Stockholm participated. The results demonstrated that, during the past 10 years, every third dancer (34%) reported that they had acute injuries and every sixth dancer (17%) had overuse injuries to the rear thigh. Most (91%) of the acute injuries were subjectively located to an area close to tuber ischiadicum. The majority (88%) stated that the acute injury occurred during slow activities in flexibility training, e.g., splits, and only a few (12%) in powerful movements. Continuing problems were reported by 70% of the acutely injured dancers. Many of the dancers neglected their acute injury (14 did not even stop the ongoing dance activity) and they also greatly underestimated the recovery time. Only 4 dancers (12%) received acute medical assistance. Thus the results, based on the recollection of the subjects, indicated that stretching could induce severe strain injuries to the proximal hamstrings in dancers. Extrapolating these results to the practice, it can be recommended that stretching exercises be executed with caution in connection with dancing sessions and training, and that, information about the seriousness and acute treatment of such injuries be added to the student-dancers' curriculum.

  • 39.
    Askling, Carl M.
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Heiderscheit, Bryan C.
    Acute Hamstring Muscle Injury: Types, Rehabilitation, and Return to Sports2015In: Sports injuries: Prevention, Diagnosis, Treatment and Rehabilitation / [ed] Mahmut Nedim Doral, Jon Karlsson, Berlin: Springer, 2015, p. 2137-2147Chapter in book (Refereed)
    Abstract [en]

    Acute hamstring muscle injury is the most frequent cause of acute posterior thigh pain, but referred pain to this area is also common. This chapter will focus only on acute hamstring injuries that are detectable on MRI (structural hamstring injuries). Hamstring injuries remain a challenge for clinicians, athletes, and coaches given the high incidence rate and often with persistent symptoms. The primary objective of all rehabilitation protocols is to return the athlete as soon as possible to the prior level of performance with a minimal risk of injury recurrence. The aim of this chapter is to describe the management of acute hamstring injuries including clinical examination, rehabilitation exercises, and return-to-sport criteria.

  • 40.
    Askling, Carl M
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Koulouris, George
    Saartok, Tönu
    Werner, Suzanne
    Best, Thomas M
    Total proximal hamstring ruptures: clinical and MRI aspects including guidelines for postoperative rehabilitation.2013In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 21, no 3, p. 515-33Article in journal (Refereed)
    Abstract [en]

    The aim of this article is to provide a state-of-the-art review for treatment of acute, total proximal hamstring tendon ruptures. For total proximal hamstring tendon ruptures, early (<2-3 w) surgical refixation minimizes muscle atrophy and facilitates a somewhat predictable time course for healing and rehabilitation. A postoperative rehabilitation program is detailed that has been used by one physical therapist for the past 7 years on over 200 patients with surgical repair for total proximal hamstring tendon rupture. One re-rupture has occurred, 7 months after surgery, following the rehabilitation program described herein. The rehabilitation program, including avoidance of postoperative bracing, appears effective for total proximal hamstring ruptures. Early surgery together with a specific rehabilitation program appears to be the treatment of choice for timely and safe return to sport and an active lifestyle. Level of evidence V.

  • 41.
    Askling, Carl M
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Tengvar, Magnus
    Saartok, Tönu
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Acute first-time hamstring strains during high-speed running: a longitudinal study including clinical and magnetic resonance imaging findings.2007In: American Journal of Sports Medicine, ISSN 0363-5465, E-ISSN 1552-3365, Vol. 35, no 2, p. 197-206Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Hamstring muscle strain is one of the most common injuries in sports. Still, knowledge is limited about the progression of clinical and magnetic resonance imaging characteristics and their association with recovery time in athletes. HYPOTHESIS: Knowing the anatomical location and extent of an acute first-time hamstring strain in athletes is critical for the prognosis of recovery time. STUDY DESIGN: Case series (prognosis); Level of evidence, 2. METHODS: Eighteen elite sprinters with acute first-time hamstring strains were prospectively included in the study. All subjects were examined, clinically and with magnetic resonance imaging, on 4 occasions after injury: at day 2 to 4, 10, 21, and 42. The clinical follow-up period was 2 years. RESULTS: All sprinters were injured during competitive sprinting, and the primary injuries were all located in the long head of the biceps femoris muscle. There was an association between the time to return to pre-injury level (median, 16; range, 6-50 weeks) and the extent of the injury, as indicated by the magnetic resonance imaging parameters. Involvement of the proximal free tendon, as estimated by MRI, and proximity to the ischial tuberosity, as estimated both by palpation and magnetic resonance imaging, were associated with longer time to return to pre-injury level. CONCLUSION: Careful palpation during the first 3 weeks after injury and magnetic resonance imaging investigation performed during the first 6 weeks after injury provide valuable information that can be used to predict the time to return to pre-injury level of performance in elite sprinting.

  • 42.
    Askling, Carl M
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Tengvar, Magnus
    Saartok, Tönu
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Acute first-time hamstring strains during slow-speed stretching: clinical, magnetic resonance imaging, and recovery characteristics.2007In: The American journal of sports medicine, ISSN 1552-3365, Vol. 35, no 10, p. 1716-24Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Hamstring strains can be of 2 types with different injury mechanisms, 1 occurring during high-speed running and the other during stretching exercises. HYPOTHESIS: A stretching type of injury to the proximal rear thigh may involve specific muscle-tendon structures that could affect recovery time. STUDY DESIGN: Case series (prognosis); Level of evidence, 2. METHODS: Fifteen professional dancers with acute first-time hamstring strains were prospectively included in the study. All subjects were examined, clinically and with magnetic resonance imaging, on 4 occasions after injury: at day 2 to 4, 10, 21, and 42. The clinical follow-up period was 2 years. RESULTS: All dancers were injured during slow hip-flexion movements with extended knee and experienced relatively mild acute symptoms. All injuries were located proximally in the posterior thigh close to the ischial tuberosity. The injury involved the semimembranosus (87%), quadratus femoris (87%), and adductor magnus (33%). All injuries to the semimembranosus involved its proximal free tendon. There were no significant correlations between clinical or magnetic resonance imaging parameters and the time to return to preinjury level (median, 50 weeks; range, 30-76 weeks). CONCLUSION: Stretching exercises can give rise to a specific type of strain injury to the posterior thigh. A precise history and careful palpation provide the clinician enough information to predict a prolonged time until return to preinjury level. One factor underlying prolonged recovery time could be the involvement of the free tendon of the semimembranosus muscle.

  • 43.
    Askling, Carl M
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Tengvar, Magnus
    Saartok, Tönu
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Proximal hamstring strains of stretching type in different sports: injury situations, clinical and magnetic resonance imaging characteristics, and return to sport.2008In: The American journal of sports medicine, ISSN 1552-3365, Vol. 36, no 9, p. 1799-804Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Hamstring strains can be of at least 2 types, 1 occurring during high-speed running and the other during motions in which the hamstring muscles reach extreme lengths, as documented for sprinters and dancers. HYPOTHESIS: Hamstring strains in different sports, with similar injury situations to dancers, also show similarities in symptoms, injury location, and recovery time. STUDY DESIGN: Case series (prognosis); Level of evidence, 4. METHODS: Thirty subjects from 21 different sports were prospectively included. All subjects were examined clinically and with magnetic resonance imaging (MRI). The follow-up period lasted until the subjects returned to or finished their sport activity. RESULTS: All injuries occurred during movements reaching a position with combined extensive hip flexion and knee extension. They were located proximally in the posterior thigh, close to the ischial tuberosity. The injuries were often complex, but 83% involved the semimembranosus and its proximal free tendon. Fourteen subjects (47%) decided to end their sports activity. For the remaining 16 subjects, the median time for return to sport was 31 weeks (range, 9-104). There were no significant correlations between specific clinical or MRI parameters and time to return to sport. CONCLUSIONS: In different sports, an injury situation in which the hamstring muscles reach extensive length causes a specific injury to the proximal posterior thigh, earlier described in dancers. Because of the prolonged recovery time associated with this type of injury, correct diagnosis, based on history and palpation, and adequate information to the subject are essential.

  • 44.
    Askling, Carl M
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Tengvar, Magnus
    Tarassova, Olga
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Acute hamstring injuries in Swedish elite sprinters and jumpers: a prospective randomised controlled clinical trial comparing two rehabilitation protocols.2014In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 48, no 7, p. 532-9Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Hamstring strain is a common injury in sprinters and jumpers, and therefore time to return to sport and secondary prevention become of particular concern.

    OBJECTIVE: To compare the effectiveness of two rehabilitation protocols after acute hamstring injury in Swedish elite sprinters and jumpers by evaluating time needed to return to full participation in the training process.

    STUDY DESIGN: Prospective randomised comparison of two rehabilitation protocols.

    METHODS: Fifty-six Swedish elite sprinters and jumpers with acute hamstring injury, verified by MRI, were randomly assigned to one of two rehabilitation protocols. Twenty-eight athletes were assigned to a protocol emphasising lengthening exercises, L-protocol, and 28 athletes to a protocol consisting of conventional exercises, C-protocol. The outcome measure was the number of days to return to full training. Re-injuries were registered during a period of 12 months after return.

    RESULTS: Time to return was significantly shorter for the athletes in the L-protocol, mean 49 days (1SD±26, range 18-107 days), compared with the C-protocol, mean 86 days (1SD±34, range 26-140 days). Irrespective of protocol, hamstring injuries where the proximal free tendon was involved took a significantly longer time to return than injuries that did not involve the free tendon, L-protocol: mean 73 vs 31 days and C-protocol: mean 116 vs 63 days, respectively. Two reinjuries were registered, both in the C-protocol.

    CONCLUSIONS: A rehabilitation protocol emphasising lengthening type of exercises is more effective than a protocol containing conventional exercises in promoting time to return in Swedish elite sprinters and jumpers.

  • 45.
    Askling, Carl M
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Tengvar, Magnus
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Acute hamstring injuries in Swedish elite football: a prospective randomised controlled clinical trial comparing two rehabilitation protocols.2013In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 47, no 15, p. 953-9Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Hamstring injury is the single most common injury in European professional football and, therefore, time to return and secondary prevention are of particular concern.

    OBJECTIVE: To compare the effectiveness of two rehabilitation protocols after acute hamstring injury in Swedish elite football players by evaluating time needed to return to full participation in football team-training and availability for match selection.

    STUDY DESIGN: Prospective randomised comparison of two rehabilitation protocols.

    METHODS: Seventy-five football players with an acute hamstring injury, verified by MRI, were randomly assigned to one of two rehabilitation protocols. Thirty-seven players were assigned to a protocol emphasising lengthening exercises, L-protocol and 38 players to a protocol consisting of conventional exercises, C-protocol. The outcome measure was the number of days to return to full-team training and availability for match selection. Reinjuries were registered during a period of 12 months after return.

    RESULTS: Time to return was significantly shorter for the players in the L-protocol, mean 28 days (1SD±15, range 8-58 days), compared with the C-protocol, mean 51 days (1SD±21, range 12-94 days). Irrespective of protocol, stretching-type of hamstring injury took significantly longer time to return than sprinting-type, L-protocol: mean 43 vs 23 days and C-protocol: mean 74 vs 41 days, respectively. The L-protocol was significantly more effective than the C-protocol in both injury types. One reinjury was registered, in the C-protocol.

    CONCLUSIONS: A rehabilitation protocol emphasising lengthening type of exercises is more effective than a protocol containing conventional exercises in promoting time to return in Swedish elite football.

  • 46.
    Askling, Carl Magnus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    ACUTE HAMSTRING INJURIES IN ELITE FOOTBALL: REHABILITATION - RETURN - PREVENTION2016Conference paper (Refereed)
  • 47.
    Askling, Carl Magnus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    LENGTHENING EXERCISES - THE KEY TO REHABILITATION SUCCESS?2016Conference paper (Other academic)
  • 48.
    Askling, Carl Magnus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    MANAGING RETURN TO PLAY IN PLAYERS WITH RECURRENT HAMSTRING INJURIES2016Conference paper (Refereed)
  • 49.
    Askling, Carl Magnus
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Karlsson, Jon
    Sahlgrenska University Hospital, Gothenburg, Sweden.
    Malliaropoulos, N
    High-speed running type or stretching-type of hamstring injuries makes a difference to treatment and prognosis2012In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 46, no 2, p. 86-87Article in journal (Refereed)
    Abstract [en]

    The article focuses on the two distinct types of hamstring muscle strains, highlighting the applicable rehabilitation approaches. It notes that acute hamstring strains are distinguished by the injury situations, namely the high-speed running type, and the stretching type, with the former requiring shorter rehabilitation period than the latter. It cites a comparative study of two rehabilitation protocols, pointing out that rehabilitation is shorter with lengthening exercises.

  • 50.
    Askling, Carl
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Nilsson, Johnny
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    A new hamstring test to complement the common clinical examination before return to sport after injury2010In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 18, no 12, p. 1788-1803Article in journal (Refereed)
    Abstract [en]

    PURPOSE: The aim was to introduce and evaluate the reliability and validity of an active hamstring flexibility test as a complement to common clinical examination when determining safe return to sport after hamstring injury.

    METHODS: Eleven healthy subjects (28 years) were tested on repeated occasions, and 11 athletes (21 years) with MRI-verified acute hamstring strain were tested when common clinical examination revealed no signs of remaining injury, i.e. there was no differences between the legs in palpation pain, manual strength tests, and passive straight leg raise. Flexibility, i.e. highest range of motion of three consecutive trials, was calculated from electrogoniometer data during active ballistic hip flexions and conventional passive slow hip-flexions in a supine position. A VAS-scale (0-100) was used to estimate experience of insecurity during active tests.

    RESULTS: No significant test-retest differences were observed. Intra-class correlation coefficients ranged 0.94-0.99 and coefficients of variation 1.52-4.53%. Active flexibility was greater (23%) than passive flexibility. In the athletes, the injured leg showed smaller (8%) active, but not passive, flexibility than the uninjured leg. Average insecurity estimation was 52 (range 28-98) for the injured and 0 for the uninjured leg, respectively.

    CONCLUSION: The new test showed high reliability and construct validity; furthermore, it seems to be sensitive enough to detect differences both in active flexibility and in insecurity after acute hamstring strains at a point in time when the commonly used clinical examination fails to reveal injury signs. Thus, the test could be a complement to the common clinical examination before the final decision to return to sport is made.

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