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  • 1.
    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.

  • 2.
    Arvidsson, Daniel
    et al.
    University of Gothenburg.
    Fridolfsson, Jonatan
    University of Gothenburg.
    Börjesson, Mats
    University of Gothenburg.
    Andersen, Lars Bo
    Western Norway University of Applied Sciences, Campus Sogndal, Norway..
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Dencker, Magnus
    Lund University.
    Brønd, Jan Christian
    University of Southern Denmark, Odense, Denmark.
    Re-examination of accelerometer data processing and calibration for the assessment of physical activity intensity.2019In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 29, no 10, p. 1442-1452Article in journal (Refereed)
    Abstract [en]

    This review reexamines use of accelerometer and oxygen uptake data for assessment of activity intensity. Accelerometers capture mechanical work, while oxygen uptake captures the energy cost of this work. Frequency filtering needs to be considered when processing acceleration data. A too restrictive filter attenuates the acceleration signal for walking and, to a higher degree, for running. This measurement error affects shorter (children) more than taller (adults) individuals due to their higher movement frequency. Less restrictive filtering includes more movement related signals and provide measures that better capture mechanical work, but may include more noise. An optimal filter cut-point is determined where most relevant acceleration signals are included. Further, accelerometer placement affects what part of mechanical work being captured. While the waist placement captures total mechanical work and therefore contributes to measures of activity intensity equivalent by age and stature, the thigh and wrist placements capture more internal work and do not provide equivalent measures. Value calibration of accelerometer measures is usually performed using measured oxygen uptake with the metabolic equivalent of task (MET) as reference measure of activity intensity. However, the use of MET is not stringent and is not a measure of activity intensity equivalent by age and stature. A candidate measure is the mass-specific net oxygen uptake, VO2 net (VO2 tot - VO2 stand). To improve measurement of physical activity intensity using accelerometers, research developments are suggested concerning processing of accelerometer data, use of energy expenditure as reference for activity intensity, and calibration procedure with absolute versus relative intensity. This article is protected by copyright. All rights reserved.

  • 3.
    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.

  • 4.
    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.

  • 5.
    Askling, Carl
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Tengvar, M
    Saartok, T
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Sports related hamstring strains--two cases with different etiologies and injury sites.2000In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 10, no 5, p. 304-7Article in journal (Refereed)
    Abstract [en]

    Hamstring strains are common injuries in sports. Knowledge about their etiology and localization is, however, limited. The two cases described here both had acute hamstring strains, but the etiologies were entirely different. The sprinter was injured when running at maximal speed, whereas the hamstring strain in the dancer occurred during slow stretching. Also the anatomical localizations of the injuries clearly differed. Magnetic resonance imaging (MRI) revealed pathological changes in the distal semitendinosus muscle in the sprinter and the proximal tendon of the semimembranosus muscle in the dancer. Subjectively, both athletes severely underestimated the recovery time. These case observations suggest a possible link between etiology and localization of hamstring strains.

  • 6.
    Berg, Ulrika
    et al.
    Institutionen för Kvinnors och Barns Hälsa (KBH), Karolinska Institutet.
    Enqvist, Jonas K
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Carlsson-Skwirut, Christine
    Institutionen för Kvinnors och Barns Hälsa (KBH), Karolinska Institutet.
    Sundberg, Carl-Johan
    Institutionen för Fysiologi och Farmakologi, Karolinska institutet.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Bang, Peter
    Institutionen för Kvinnors och Barns Hälsa (KBH), Karolinska Institutet.
    Lack of sex differences in the IGF-IGFBP response to ultra endurance exercise.2008In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 18, no 6, p. 706-714Article in journal (Refereed)
    Abstract [en]

    The insulin-like growth factor (IGF)-IGF binding proteins (BP) and the pituitary-gonadal axes were investigated during ultra endurance exercise in 16 endurance-trained athletes (seven women). Median duration of the race was 6.3 days. Although food and drink were ad libitum, energy balance was negative. Blood samples were drawn before (PRE), at the end of (END) and 24 h after (POST24h) the race. Serum concentrations of total IGF-I (t-IGF-I) and free IGF-I (f-IGF-I) decreased by 33 (SD 38)% and 54 (19)%, respectively. The decrease in t-IGF-I appeared to be associated to the total energy deficit during the race. At END, the IGFBP-3 fragmentation and IGFBP-1 were increased but these changes did not predict changes in f-IGF-I. An increase in POST24h IGFBP-2 levels in women was the only sex difference. Testosterone was decreased by 67 (12)% in the men and estradiol became undetectable in the women without any detectable increase in LH and/or FSH. In conclusion ultra endurance exercise results in similar IGF-IGFBP responses in men and women reflecting a catabolic state. IGFBP-2 was the only exception, with increased levels in women after exercise. A concomitant decrease in gonadal hormones was not related to endocrine changes in the IGF-IGFBP axis but may be related to local changes in IGF-I expression.

  • 7. Berglund, B
    et al.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Ekblom, Elin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Berglund, L
    Kallner, A
    Reinebo, P
    Lindeberg, S
    The Swedish Blood Pass project.2007In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 17, no 3, p. 292-7Article in journal (Refereed)
    Abstract [en]

    Manipulation of the blood's oxygen carrying capacity (CaO(2)) through reinfusion of red blood cells, injections of recombinant erythropoietin or by other means results in an increased maximal oxygen uptake and concomitantly enhanced endurance performance. Therefore, there is a need to establish a system--"A Blood Pass"--through which such illegal and unethical methods can be detected. Venous blood samples were taken under standardized conditions from 47 male and female Swedish national and international elite endurance athletes four times during the athletic year of the individual sport (beginning and end of the preparation period and at the beginning and during peak performance in the competition period). In these samples, different hematological values were determined. ON(hes) and OFF(hre) values were calculated according to the formula of Gore et al. A questionnaire regarding training at altitude, alcohol use and other important factors for hematological status was answered by the athletes. There were some individual variations comparing hematological values obtained at different times of the athletic year or at the same time in the athletic year but in different years. However, the median values of all individual hematological, ON(hes) and OFF(hre), values taken at the beginning and the end of the preparation or at the beginning and the end of the competition period, respectively, as well as median values for the preparation and competition periods in the respective sport, were all within the 95% confidence limit (CI) of each comparison. It must be mentioned that there was no gender difference in this respect. This study shows that even if there are some individual variations in different hematological values between different sampling times in the athletic year, median values of important hematological factors are stable over time. It must be emphasized that for each blood sample, the 95% CI in each athlete will be increasingly narrower. The conclusion is that there is a physiological basis for establishing an individual-based "Blood Pass" system, mainly for athletes competing at the international level. On indications of manipulations of hemoglobin concentration and red cell mass by deviations from established "Blood Pass" data, more specific methods can be applied.

  • 8.
    Bjerkefors, Anna
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Carpenter, M G
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Dynamic trunk stability is improved in paraplegics following kayak ergometer training.2007In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 17, no 6, p. 672-9Article in journal (Refereed)
    Abstract [en]

    The purpose of the study was to assess whether postural stability in persons with spinal cord injury (SCI) could be affected by training. Ten post-rehabilitated persons with thoracic SCI performed 30 sessions of kayak ergometer training during a 10-week period. The ergometer was modified with a balance module adjustable in the medio-lateral direction. Before and after the training period, horizontal support-surface translations were presented randomly, either in the forward or backward direction, or to the side, while subjects sat in their own wheelchairs. The platform perturbation consisted of an unpredictable initial acceleration, followed by a constant-velocity phase and a predictable deceleration. Markers were applied on the trunk and movement data were recorded in 3D. Four kinematic responses of trunk angular and linear displacement were investigated. In general, postural stability was improved after training with smaller rotational and linear displacements of the trunk observed during both predictable and unpredictable translations in all directions. Thus, the training was able to improve the ability of persons with long-standing SCI to maintain an upright sitting posture in response to externally generated balance perturbations, which should imply an increased capacity to master similar challenges to balance in everyday life.

  • 9. Boushel, Robert
    et al.
    Gnaiger, E
    Larsen, Filip J
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Helge, J W
    González-Alonso, J
    Ara, I
    Munch-Andersen, T
    van Hall, G
    Søndergaard, H
    Saltin, Bengt
    Calbet, J A L
    Maintained peak leg and pulmonary VO2 despite substantial reduction in muscle mitochondrial capacity.2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, no Suppl 4, p. 135-143Article in journal (Refereed)
    Abstract [en]

    We recently reported the circulatory and muscle oxidative capacities of the arm after prolonged low-intensity skiing in the arctic (Boushel et al., 2014). In the present study, leg VO2 was measured by the Fick method during leg cycling while muscle mitochondrial capacity was examined on a biopsy of the vastus lateralis in healthy volunteers (7 male, 2 female) before and after 42 days of skiing at 60% HR max. Peak pulmonary VO2 (3.52 ± 0.18 L.min(-1) pre vs 3.52 ± 0.19 post) and VO2 across the leg (2.8 ± 0.4L.min(-1) pre vs 3.0 ± 0.2 post) were unchanged after the ski journey. Peak leg O2 delivery (3.6 ± 0.2 L.min(-1) pre vs 3.8 ± 0.4 post), O2 extraction (82 ± 1% pre vs 83 ± 1 post), and muscle capillaries per mm(2) (576 ± 17 pre vs 612 ± 28 post) were also unchanged; however, leg muscle mitochondrial OXPHOS capacity was reduced (90 ± 3 pmol.sec(-1) .mg(-1) pre vs 70 ± 2 post, P < 0.05) as was citrate synthase activity (40 ± 3 μmol.min(-1) .g(-1) pre vs 34 ± 3 vs P < 0.05). These findings indicate that peak muscle VO2 can be sustained with a substantial reduction in mitochondrial OXPHOS capacity. This is achieved at a similar O2 delivery and a higher relative ADP-stimulated mitochondrial respiration at a higher mitochondrial p50. These findings support the concept that muscle mitochondrial respiration is submaximal at VO2max , and that mitochondrial volume can be downregulated by chronic energy demand.

  • 10. Calbet, J A L
    et al.
    Mortensen, S P
    Munch, G D W
    Curtelin, D
    Boushel, Robert
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Constant infusion transpulmonary thermodilution for the assessment of cardiac output in exercising humans.2016In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 26, no 5, p. 518-527Article in journal (Refereed)
    Abstract [en]

    To determine the accuracy and precision of constant infusion transpulmonary thermodilution cardiac output (CITT-Q) assessment during exercise in humans, using indocyanine green (ICG) dilution and bolus transpulmonary thermodilution (BTD) as reference methods, cardiac output (Q) was determined at rest and during incremental one- and two-legged pedaling on a cycle ergometer, and combined arm cranking with leg pedaling to exhaustion in 15 healthy men. Continuous infusions of iced saline in the femoral vein (n = 41) or simultaneously in the femoral and axillary (n = 66) veins with determination of temperature in the femoral artery were used for CITT-Q assessment. CITT-Q was linearly related to ICG-Q (r = 0.82, CITT-Q = 0.876 × ICG-Q + 3.638, P < 0.001; limits of agreement ranging from -1.43 to 3.07 L/min) and BTD-Q (r = 0.91, CITT-Q = 0.822 × BTD + 4.481 L/min, P < 0.001; limits of agreement ranging from -1.01 to 2.63 L/min). Compared with ICG-Q and BTD-Q, CITT-Q overestimated cardiac output by 1.6 L/min (≈ 10% of the mean ICG and BTD-Q values, P < 0.05). For Q between 20 and 28 L/min, we estimated an overestimation < 5%. The coefficient of variation of 23 repeated CITT-Q measurements was 6.0% (CI: 6.1-11.1%). In conclusion, cardiac output can be precisely and accurately determined with constant infusion transpulmonary thermodilution in exercising humans.

  • 11.
    Carlsson, Andreas
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Lundqvist, Carolina
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Sport Psychology research group.
    The Coaching Behavior Scale for Sport (CBS-S): A psychometric evaluation of the Swedish version.2016In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 26, no 1, p. 116-123Article in journal (Refereed)
    Abstract [en]

    The present study validated a Swedish version of the 47-item Coaching Behavior Scale for Sport (CBS-S). Sample 1 consisted of 506 team sport athletes [262 men and 244 women; mean age: 22.20, standard deviation (SD) = 3.90] distributed across 41 coaches at the two highest national levels of various sports. Athletes completed the CBS-S and established questionnaires of coaching behaviors (LSS), self-confidence (CSAI-2R), and coach-athlete relationship (CART-Q). An additional sample of 39 basketball players (21 men and 18 women; mean age = 17.40, SD = 2.39) completed the CBS-S twice, approximately 4 weeks apart. Confirmatory factor analysis showed an acceptable model fit for the seven-factor version of the CBS-S, although two items of the negative personal rapport subscale displayed insufficient factor loadings. Correlations between the subscales of the CBS-S and established instruments were in accordance with theoretical expectations, supporting the concurrent validity. Cronbach's alpha (> 0.82) for all dimensions provided support for the reliability of the CBS-S, and test-retest correlations indicated moderate stability over time. Cultural differences in the assessment of coaching behaviors and the usability of the CBS-S by coaches for self-reflection and development are discussed.

  • 12.
    Clement, Damien
    et al.
    College of Physical Activity and Sport Sciences, West Virginia University.
    Ivarsson, Andreas
    Center of Research on Welfare, Health and Sport (CVHI), Halmstad University..
    Tranaeus, Ulrika
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences. Musculoskeletal and Sports Injury Epidemiology Center, Institute of Environmental Medicine Karolinska Institutet.
    Johnson, Urban
    Center of Research on Welfare, Health and Sport (CVHI), Halmstad University..
    Stenling, Andreas
    Department of Psychology, Umeå University.
    Investigating the influence of intra-individual changes in perceived stress symptoms on injury risk in soccer.2018In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 28, no 4, p. 1461-1466Article in journal (Refereed)
    Abstract [en]

    Research has shown that high levels of stress and stress responsivity can increase the risk of injuries. However, most of the research that has supported this notion has focused on between-person relationships, ignoring the relationships at the within-person level. As a result, the objective of this study was to investigate if within-person changes in perceived stress symptoms over a one-month time period could predict injury rates during the subsequent three months. A prospective design with two measurement points (Time 1 - at the beginning of the season and Time 2 - one month into the season) was utilized. A total of 121 competitive soccer players (85 males and 36 females; Mage = 18.39, SD = 3.08) from Sweden and the United States completed the Kessler Psychological Distress Scale (KPDS) and a demographic sheet at Time 1. The KPDS was also completed at Time 2 and all acute injuries that occurred during the subsequent three-month period were recorded. A Bayesian latent change scores model was used to determine if within-person changes in stress symptoms could predict the risk of injury. Results revealed that there was a credible positive effect of changes in stress symptoms on injury rates, indicating that an increase in reported stress symptoms was related to an increased risk for injury. This finding highlights the importance of creating caring and supportive sporting environments and relationships and teaching stress management techniques, especially during the earlier portion of competitive seasons, to possibly reduce the occurrence of injuries. This article is protected by copyright. All rights reserved.

  • 13.
    Ekblom Bak, Elin
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Andersson, Gunnar
    HPI Health Profile Institute.
    Wallin, Peter
    HPI Health Profile Institute.
    Söderling, Jonas
    Karolinska Institutet.
    Hemmingsson, Erik
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences. Karolinska Institutet.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Decline in cardiorespiratory fitness in the Swedish working force between 1995 and 2017.2019In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 29, no 2, p. 232-239Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Long-term trend analyses of cardiorespiratory fitness (VO2 max) in the general population are limited.

    OBJECTIVES: To describe trends in VO2 max from 1995 to 2017 in the Swedish working force and to study developments across categories of sex, age, education, and geographic regions.

    METHODS: 354.277 participants (44% women, 18-74 years) who participated in a nationwide occupational health service screening between 1995 and 2017 were included. Changes in standardized mean values of absolute (L·min-1 ) and relative (ml·min-1 ·kg-1 ) VO2 max, and the proportion with low (<32) relative VO2 max are reported. VO2 max was estimated using a submaximal cycle test.

    RESULTS: Absolute VO2 max decreased by -6.7% (-0.19 L·min-1 ) in the total population. Relative VO2 max decreased by -10.8% (-4.2 ml·min-1 ·kg-1 ) with approximately one-third explained by a simultaneous increase in body mass. Decreases in absolute fitness were more pronounced in men vs. women (8.7% vs. 5.3%), in younger vs. older (6.5% vs 2.3%), in short (11.4%) vs. long (4.5%) education, and in rural vs. urban regions (6.5% vs 3.5%), all p<0.001. The proportions with low VO2 max increased from 27% to 46% (p<0.001).

    CONCLUSION: Between 1995 and 2017, there was a steady and pronounced decline in mean cardiorespiratory fitness in Swedish adults. Male gender, young age, short education and living in a rural area were predictive of greater reductions. The proportion with low cardiorespiratory fitness almost doubled. Given the strong associations between cardiorespiratory fitness and multiple morbidities and mortality, preventing further decreases is a clear public health priority, especially for vulnerable groups. This article is protected by copyright. All rights reserved.

  • 14.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    The muscle biopsy technique: Historical and methodological considerations.2017In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 27, no 5, p. 458-461Article, review/survey (Refereed)
    Abstract [en]

    The muscle biopsy method is an important tool for clinical and scientific work. In this study, the two most used instruments, the Bergström needle and the Well-Blakesley conchotome, are described. The technique of using those instruments, risks, and other considerations are discussed. Finally, a few consequences and the error of the method for determining muscle fiber type, fiber area, substrates, and metabolites are presented.

  • 15.
    Ekblom, Björn
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Stroke volume and the endurance athlete.2006In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 16, no 1, p. 70-1Article in journal (Refereed)
  • 16.
    Ekblom, Björn
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Malm, Christer
    Infectious episodes before and after a marathon race.2006In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 16, no 4, p. 287-93Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate the incidence of self-reported infectious episodes (IE) during 3 weeks before (pre-IE) and 3 weeks after (post-IE) a marathon race and relate these figures to training status, running time, socioeconomic and demographic factors. Two questionnaires, including questions about important factors for IE incidence, were given to a representative cohort of 1694 runners (17% of all finishers) in the Stockholm Marathon 2000. Pre-IE incidence in the cohort was 17% with no difference between women and men. Post-IE incidence in the whole cohort was 19% with no significant (P>0.05) difference between women and men. The post-IE incidence in runners without a pre-IE was 16% (P>0.05 to pre-IE incidence). In the group of runners with pre-IE, 33% experienced an IE after the race also (P<0.05 to Pre-IE incidence). A logistic regression analysis showed that younger age and pre race health status and, for men only, experienced nausea during and after the race were depended factors explaining post-IE incidence. Younger runners were more prone to experience IE both before and after the race. There was no relation between training volume 6 months before the race, finishing time and socioeconomic and demographic factors and pre-IE or post-IE. This study does not support the theory of increased infection rate after exhaustive long-distance running ("The Open Window Theory") in recreational runners, but suggests that the sometimes experienced increased rate of infections among athletes can be caused by strenuous exercise too soon after an infection.

  • 17.
    Ekblom, Björn
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Engström, Lars-Magnus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Forskningsgruppen för pedagogik, idrott och fritidskultur.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Secular trends of physical fitness in Swedish adults.2007In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 17, no 3, p. 267-73Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to study differences in fitness (maximal aerobic power (VO(2max)), balance control, abdominal strength and endurance) and anthropometric data in Swedish women and men (20-65 years of age) between two national cross-sectional samples, studied in 1990/1991 and 2000/2001, respectively. The absolute and relative VO(2max) (aerobic fitness), estimated from a submaximal test, declined with increasing age in both genders. The submaximal test was validated against running VO(2max). Furthermore, the relative aerobic fitness (mL/min/kg) was lower in the 2000/2001 sample in men but not in women. Overall physical activity level was unchanged in both genders. An unexpected finding was that in both samples there were no major differences in relative VO(2max) between men and women of the same age. Combined overweight and obesity (body mass index> or =25) is becoming more prevalent in men, but not in women with prevalence in 2000/2001 of 61% and 38% for men and women, respectively. Balance control and abdominal strength and endurance decrease with increasing age with no differences between the two samples. Thus, the near future health situation for men may be worse, while for women it may be less or no differences compared with today.

  • 18.
    Ekblom-Bak, Elin
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Björkman, Frida
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Hellenius, Maj-Lis
    Karolinska Institutet.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    A new submaximal cycle ergometer test for prediction of VO(2max).2014In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 24, no 2, p. 319-326Article in journal (Refereed)
    Abstract [en]

    Maximal oxygen uptake (VO(2max) ) is an important, independent predictor of cardiovascular health and mortality. Despite this, it is rarely measured in clinical practice. The aim of this study was to create and evaluate a submaximal cycle ergometry test based on change in heart rate (HR) between a lower standard work rate and an individually chosen higher work rate. In a mixed population (n = 143) with regard to sex (55% women), age (21-65 years), and activity status (inactive to highly active), a model included change in HR per unit change in power, sex, and age for the best estimate of VO(2max) . The association between estimated and observed VO(2max) for the mixed sample was r = 0.91, standard error of estimate = 0.302 L/min, and mean measured VO(2max)  = 3.23 L/min. The corresponding coefficient of variation was 9.3%, a significantly improved precision compared with one of the most commonly used submaximal exercise tests, the Åstrand test, which in the present study was estimated to be 18.1%. Test-retest reliability analysis over 1 week revealed no mean difference in the estimated VO(2max) (-0.02 L/min, 95% confidence interval: -0.07-0.03). The new test is low-risk, easily administered, and valid for a wide capacity range, and is therefore suitable in situations as health evaluations in the general population.

  • 19. Eriksson Crommert, Martin
    et al.
    Ekblom, Maria
    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.
    Motor control of the trunk during a modified clean and jerk lift.2014In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 24, no 5, p. 758-763Article in journal (Refereed)
    Abstract [en]

    The purpose of the present study was to investigate the pattern of trunk muscle activation and intra-abdominal pressure (IAP) in a somewhat modified version of the clean and jerk lift. Nine healthy physically active male amateurs performed the exercise with a 30-kg barbell. Muscle activity was registered with electromyography from transversus abdominis (TrA) and obliquus internus (OI) using intramuscular electrodes and from rectus abdominis (RA) and erector spinae (ES) with surface electrodes. IAP was recorded with a nasogastric catheter. Measurements were made in various static positions throughout the lift and in the transitional phases separating them, both during lifting and lowering. The results demonstrated that the innermost abdominal muscle, TrA, showed increased activation levels in the two highest positions, whereas ES was most active, together with the highest IAP, in the lowest position. OI and RA showed generally little activation and no obvious trend throughout the lift. The results strengthen the view of a contributing role of TrA to the upright control of the trunk and indicate that the clean and jerk lift might constitute a whole-body exercise, still targeting the TrA muscle, in late-stage rehabilitation, especially for athletes during return to sports.

  • 20.
    Frank, Per
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Andersson, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Pontén, Marjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Ekblom, Maria
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Strength training improves muscle aerobic capacity and glucose tolerance in elderly2016In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 26, no 7, p. 764-773Article in journal (Refereed)
    Abstract [en]

    The primary aim of this study was to investigate the effect of short-term resistance training (RET) on mitochondrial protein content and glucose tolerance in elderly. Elderly women and men (age 71 ± 1, mean ± SEM) were assigned to a group performing 8 weeks of resistance training (RET, n = 12) or no training (CON, n = 9). The RET group increased in (i) knee extensor strength (concentric +11 ± 3%, eccentric +8 ± 3% and static +12 ± 3%), (ii) initial (0-30 ms) rate of force development (+52 ± 26%) and (iii) contents of proteins related to signaling of muscle protein synthesis (Akt +69 ± 20 and mammalian target of rapamycin +69 ± 32%). Muscle fiber type composition changed to a more oxidative profile in RET with increased amount of type IIa fibers (+26.9 ± 6.8%) and a trend for decreased amount of type IIx fibers (-16.4 ± 18.2%, P = 0.068). Mitochondrial proteins (OXPHOS complex II, IV, and citrate synthase) increased in RET by +30 ± 11%, +99 ± 31% and +29 ± 8%, respectively. RET resulted in improved oral glucose tolerance measured as reduced area under curve for glucose (-21 ± 26%) and reduced plasma glucose 2 h post-glucose intake (-14 ± 5%). In CON parameters were unchanged or impaired. In conclusion, short-term resistance training in elderly not only improves muscular strength, but results in robust increases in several parameters related to muscle aerobic capacity.

  • 21. Grimby, G
    et al.
    Börjesson, Mats
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Jonsdottir, I H
    Schnohr, P
    Thelle, D S
    Saltin, Bengt
    The "Saltin-Grimby Physical Activity Level Scale" and its application to health research.2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, no Suppl 4, p. 119-125Article in journal (Refereed)
    Abstract [en]

    The use of a four-level questionnaire to assess leisure time physical activity (PA) and its validation is reviewed in this paper. This questionnaire was first published in 1968 and has then been used by more than 600 000 subjects, especially in different population studies in the Nordic countries. A number of modifications to the questionnaire have been published. These are mostly minor changes, such as adding practical examples of activities to illustrate the levels of PA. Some authors have also added duration requirements that were not included for all levels of PA in the original version. The concurrent validity, with respect to aerobic capacity and movement analysis using objective measurements has been shown to be good, as has the predictive validity with respect to various risk factors for health conditions and for morbidity and mortality.

  • 22.
    Holmberg, H-C
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Rosdahl, Hans
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control. Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Laboratory of Applied Sports Science (LTIV).
    Svedenhag, J
    Lung function, arterial saturation and oxygen uptake in elite cross country skiers: influence of exercise mode.2007In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 17, no 4, p. 437-44Article in journal (Refereed)
    Abstract [en]

    Arterial desaturation during exercise is common in endurance-trained athletes, a phenomenon often more pronounced when the muscle mass engaged in the exercise is large. With this background, the present study monitored seven international-level cross country skiers performing on a treadmill while running (RUN), double poling (DP; upper body exercise) and diagonal skiing (DIA; arm and leg exercise). Static and dynamic lung function tests were performed and oxygen uptake was measured during submaximal and maximal exercise. Lung function variables (including the diffusion capacity) were only 5-20% higher than reported in sedentary men. Vital capacity was considerably lower than expected from the skiers' maximal oxygen uptake (VO(2max)), but the maximal ventilation followed a linear relationship with VO(2max). None or only a mild desaturation was observed in DP, RUN and DIA. Blood lactate concentration was slightly higher in DIA than in DP but not different from RUN. In DIA, VO(2max) was 6.23 +/- 0.47 L/min (mean +/- SD), which was 3.8% and 13.9% higher than in RUN and DP, respectively, with similar peak heart rates for the three exercise modes. No relationships were present either between the degree of desaturation and pulmonary functions tests, or with peak oxygen uptakes. The low blood lactate accumulation during the exhaustive efforts contributed to the arterial oxygen saturation being mild in spite of the very high oxygen uptake observed in these skiers.

  • 23. Jönhagen, S
    et al.
    Halvorsen, Kjartan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Benoit, D L
    Muscle activation and length changes during two lunge exercises: implications for rehabilitation.2009In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 19, no 4, p. 561-8Article in journal (Refereed)
    Abstract [en]

    Eccentric exercises are commonly used as a treatment for various muscle and tendon injuries. During complex motions such as the forward lunge, however, it is not always clear which muscles may be contracting eccentrically and at what time. Because this exercise is used during rehabilitation, the purpose of this investigation was to determine what type of contractions take place during two different types of forward lunge and assess the implications for rehabilitation. Five experienced athletes performed five cycles for each of the walking and jumping forward lunges. Motion analysis was used to calculate the shortening or elongation of each muscle based on the change of position of their origin and insertion points during the lunge. Electromyography of the lateral hamstrings, rectus femoris and lateral gastrocnemius was combined with the muscle length change data to determine when isometric, concentric and eccentric activations occur during the lunge. Eccentric contractions in both the quadriceps and gastrocnemius were observed during the lunge. No hamstring eccentric contractions were found; however, the hamstrings showed isometric contractions during the first part of the stance phase.

  • 24.
    Kallings, Lena V
    et al.
    Karolinska institutet.
    Leijon, M
    Hellénius, M-L
    Ståhle, A
    Physical activity on prescription in primary health care: a follow-up of physical activity level and quality of life.2008In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 18, no 2, p. 154-161Article in journal (Refereed)
    Abstract [en]

    To examine whether physical activity on prescription in routine primary care patients would influence physical activity level and quality of life 6 months later. In 2001-2003, 13 Swedish primary health care units took part in an uncontrolled clinical study. If a patient in primary health care needed physical activity preventively or for treatment of a disease and patient-centered motivational counseling found physical activity to be suitable, individualized physical activity could be prescribed. Patients (n=481) of both sexes and all ages [75% women, mean age 50 (12-81)] participated in the study. Self-reported physical activity, readiness to change to a more physically active lifestyle and quality-of-life data were collected through questionnaires. The follow-up rate was 62% at 6 months. Intention-to-treat analysis showed a significant increase (P<0.01) in self-reported physical activity level, the stages of action and maintenance of physical activity as well as quality of life. Physical activity level, stages of change and quality of life increased analogically, indicating that physical activity on prescription may be suitable as a conventional treatment in an ordinary primary health care setting to promote a more physically active lifestyle.

  • 25.
    Lundkvist, Erik
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences. Stockholm University; University of St Andrews, UK.
    Gustafsson, H
    Karlstad university.
    Davis, P A
    Umeå university.
    Holmström, S
    Umeå university.
    Lemyre, N
    Norwegian School of Sport Sciences, Oslo, Norway.
    Ivarsson, A
    Halmstad university.
    The temporal relations across burnout dimensions in athletes.2018In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 28, no 3, p. 1215-1226Article in journal (Refereed)
    Abstract [en]

    Burnout is a construct that has garnered considerable attention in sport psychology within recent years. Several hypothesized models regarding how the three dimensions (exhaustion, devaluation, and reduced sense of accomplishment) temporally relate to each other have been advanced. One proposal outlined by Maslach and Leiter suggests that exhaustion predicts devaluation which predicts reduced sense of accomplishment. However, there is no consensus among researchers as it has been argued that exhaustion predicts devaluation and reduced accomplishment separately. The aim of this study was to test multiple alternative hypotheses regarding the relationships of the burnout dimensions in athletes. Two samples of Swedish youth elite athletes with differing time spans between measurements were used. Specifically, one sample involved time-intensive measures collected every week over an eight-week period, and the other sample included four measurement points across an 18-month period. Results showed that none of the previously proposed models outlining the temporal relations of burnout dimensions were supported. Statistical analysis of the models including the cross-lagged predictions of dimensions did not have any statistically significant impact except when exhaustion negatively predicted devaluation between time 1 (month 0) and time 2 (month 6) in the 18-month sample; this relation faded in the following time points. Further, issues regarding the stability of devaluation and reduced sense of accomplishment emerged as their autocorrelation were very weak in the time-intensive sample. These findings raise a number of points for further theoretical and practical discussions about the athlete burnout construct.

  • 26.
    Lundqvist, Carolina
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Sport Psychology research group.
    Kenttä, Göran
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Sport Psychology research group.
    Raglin, John. S
    Indiana University-Bloomington.
    Directional anxiety responses in elite and sub-elite young athletes:: Intensity of anxiety symptoms matter2011In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 21, no 6, p. 853-862Article in journal (Refereed)
    Abstract [en]

    The objective was to examine the differences in anxiety ratings of elite and sub-elite athletes when the relationship between intensity and direction scores of anxiety ratings is considered in analyses. Participants were 31 junior elite (Mean age: 17.7, SD = 1.1) and 53 sub-elite (Mean age: 17.5 years, SD = 1.1) cross-country skiers and swimmers who completed the direction modified CSAI-2R before important competitions. Results showed that elite athletes  rated a higher percent of items as facilitative to their performance whereas sub-elite athletes rated a higher percent of items as debilitative. No significant differences between the elite and sub-elite samples were displayed regarding rated direction scores of cognitive or somatic anxiety at moderate to high intensity levels. A significant difference in facilitative anxiety ratings was displayed at a low anxiety intensity level (Z = -2.20, p < .05). Outcome performance data showed no consistent congruence with athletes’ anxiety direction ratings. The findings suggest that facilitative direction scores are a consequence of low anxiety intensity, possibly combined with high self-confidence levels. Directional anxiety researchers analysing separate total scores of intensity and direction respectively, which is the traditional approach, may draw incorrect conclusions about the importance of facilitative ratings of anxiety symptoms.  

  • 27.
    Mattsson, C. Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Enqvist, Jonas K
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Brink-Elfegoun, Thibault
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Johansson, Patrik H
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Bakkman, Linda
    Swedish School of Sport and Health Sciences, GIH.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Reversed drift in heart rate but increased oxygen uptake at fixed work rate during 24 h ultra-endurance exercise.2010In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 20, no 2, p. 298-304Article in journal (Refereed)
    Abstract [en]

    In this paper we report a reversed drift in heart rate (HR) but increased oxygen uptake (VO(2)) during ultra-endurance exercise. Nine well-trained male athletes performed 24-h exercise in a controlled laboratory setting, with alternating blocks of kayaking, running and cycling. Each block included 110 min of exercise and 10 min of rest, with an average work intensity of approximately 55% of respective VO(2peak). Blood samples were taken and HR and VO(2) measured every 6th hour during steady-state cycling at fixed work rate. As assumed HR was increased at 6 h by 15 +/- 6 beats/min compared with initial level (0 h). Thereafter the drift did not progress continuously, but instead unexpectedly returned toward initial values, although the plasma levels of catecholamines increased continuously during exercise. VO(2) was increased by 0.22 +/- 0.15 L/min (10%) at 6 h and 0.37 +/- 0.18 L/min (17%) at 12 h compared with 0 h, and thereafter remained stable. This implies an increased oxygen pulse (VO(2)/HR) by approximately 10% at the last half of the 24-h exercise compared with 0 h. Consequently, sole use of HR would give inaccurate estimates of exercise intensity and energy expenditure during endurance exercise lasting more than 6 h, and different patterns of cardiovascular drift need to be taken into account.

  • 28.
    Nordlund Ekblom, Maria
    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.
    Strength training effects of whole-body vibration?2007In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 17, no 1, p. 12-7Article in journal (Refereed)
    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.

  • 29. Nordsborg, N B
    et al.
    Robach, P
    Boushel, Robert
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Calbet, J A L
    Lundby, C
    Erythropoietin does not reduce plasma lactate, H(+) , and K(+) during intense exercise.2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, no 6, p. e566-e575Article in journal (Refereed)
    Abstract [en]

    It is investigated if recombinant human erythropoietin (rHuEPO) treatment for 15 weeks (n = 8) reduces extracellular accumulation of metabolic stress markers such as lactate, H(+) , and K(+) during incremental exhaustive exercise. After rHuEPO treatment, normalization of blood volume and composition by hemodilution preceded an additional incremental test. Group averages were calculated for an exercise intensity ∼80% of pre-rHuEPO peak power output. After rHuEPO treatment, leg lactate release to the plasma compartment was similar to before (4.3 ± 1.6 vs 3.9 ± 2.5 mmol/min) and remained similar after hemodilution. Venous lactate concentration was higher (P < 0.05) after rHuEPO treatment (7.1 ± 1.6 vs 5.2 ± 2.1 mM). Leg H(+) release to the plasma compartment after rHuEPO was similar to before (19.6 ± 5.4 vs 17.6 ± 6.0 mmol/min) and remained similar after hemodilution. Nevertheless, venous pH was lower (P < 0.05) after rHuEPO treatment (7.18 ± 0.04 vs 7.22 ± 0.05). Leg K(+) release to the plasma compartment after rHuEPO treatment was similar to before (0.8 ± 0.5 vs 0.7 ± 0.7 mmol/min) and remained similar after hemodilution. Additionally, venous K(+) concentrations were similar after vs before rHuEPO (5.3 ± 0.3 vs 5.1 ± 0.4 mM). In conclusion, rHuEPO does not reduce plasma accumulation of lactate, H(+) , and K(+) at work rates corresponding to ∼80% of peak power output.

  • 30.
    Olsson, Sven Johan Gustav
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Ekblom-Bak, Elin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Kallings, Lena V
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Börjesson, Mats
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology. Göteborg University.
    Association of perceived physical health and physical fitness in two Swedish national samples from 1990 and 2015.2018In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 28, no 2, p. 717-724Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Perceived health and physical fitness have been shown to correlate, and low levels of either variable increase the risk for future illness and mortality. However, risk factors and their interrelationship may vary between societies and over time. In this study, the associations of physical fitness and perceived health were therefore assessed in two Swedish national samples 25 years apart.

    METHODS: Perceived physical health, dichotomized as "good" or "bad", maximal oxygen uptake (VO2 max), counter movement jump (CMJ), balance (one-legged 60 second stance), and self-reported demographics and lifestyle were recorded in two cross-sectional samples (sample size, number of eligible participants) of Swedish adults, aged 20 - 65 years, in 1990 - 1991 (2203, 1365), and 2013 - 2015 (3357, 422).

    RESULTS: The odds for good perceived physical health increased by 5% per mL · kg(-1) · min(-1) of VO2 max, 3% per cm CMJ height, and decreased by 4% per 1 time of overbalancing, in both samples. Mutually adjusted regression models showed that perceived physical health was best predicted by VO2 max and chronic illness in 1990 and by age, BMI, and educational level in 2015.

    CONCLUSION: Perceived physical health was related to physical fitness in two samples of Swedish adults from 1990 and 2015. However, multivariate, and mutually adjusted models, indicate that the most important covariates of perceived physical health may have changed from VO2 max and chronic illness in 1990, to age, BMI, and educational level in 2015. This article is protected by copyright. All rights reserved.

  • 31.
    Psilander, Niklas
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Frank, Per
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Flockhart, Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Adding strength to endurance training does not enhance aerobic capacity in cyclists2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, no 4, p. e353-e359Article in journal (Refereed)
    Abstract [en]

    The molecular signaling of mitochondrial biogenesis is enhanced when resistance exercise is added to a bout of endurance exercise. The purpose of the present study was to examine if this mode of concurrent training translates into increased mitochondrial content and improved endurance performance. Moderately trained cyclists performed 8 weeks (two sessions per week) of endurance training only (E, n = 10; 60-min cycling) or endurance training followed by strength training (ES, n = 9; 60-min cycling + leg press). Muscle biopsies were obtained before and after the training period and analyzed for enzyme activities and protein content. Only the ES group increased in leg strength (+19%, P < 0.01), sprint peak power (+5%, P < 0.05), and short-term endurance (+9%, P < 0.01). In contrast, only the E group increased in muscle citrate synthase activity (+11%, P = 0.06), lactate threshold intensity (+3%, P < 0.05), and long-term endurance performance (+4%, P < 0.05). Content of mitochondrial proteins and cycling economy was not affected by training. Contrary to our hypothesis, the results demonstrate that concurrent training does not enhance muscle aerobic capacity and endurance performance in cyclists.

  • 32. Rud, Bjarne
    et al.
    Secher, N H
    Nilsson, Johnny
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Laboratory of Applied Sports Science (LTIV).
    Smith, G
    Hallén, J
    Metabolic and mechanical involvement of arms and legs in simulated doule pole skiing2014In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 24, no 6, p. 913-919Article in journal (Refereed)
    Abstract [en]

    We evaluated arm and leg work rate and metabolism during double pole ergometer skiing. Thermodilution arm and leg blood flow was determined together with the arterial to venous difference for oxygen, while the work rate was assessed in eight male recreational skiers [24 (SD 7) years]. When work rate increased from 82 (SE 4) to 117 (7) W, leg power increased by 43% (enhanced vertical force and displacement of the body). The elbow angle tended to increase [from 71 (11.3)° to 75 (10.9)°; P = 0.07] and arm oxygen uptake increased by 20 (5)% [from 0.65 (0.07) to 0.78 (0.08) L/min; P < 0.05] because two-arm blood flow increased [from 5.4 (0.6) to 6.3 (0.7) L/min; P < 0.05] with no significant change in oxygen extraction [from 59 (2.3)% to 60 (1.9)%] accompanied with net arm lactate and potassium release. In contrast, two-leg blood flow [from 5.8 (0.5) to 8.0 (0.5) L/min] and oxygen extraction [from 67 (1.3)% to 75 (1.5)%] increased (P < 0.05), resulting in a 53 (8)% increase in leg oxygen uptake [from 0.82 (0.06) to 1.24 (0.07) L/min; P < 0.05]. In conclusion, during double poling on an ergometer, arm muscle metabolism and work rate increase only marginally and an increase in work intensity is covered mainly by the leg muscles.

  • 33. Saldanha, A
    et al.
    Nordlund Ekblom, Maria M
    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.
    Central fatigue affects plantar flexor strength after prolonged running.2008In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 18, no 3, p. 383-8Article in journal (Refereed)
    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.

  • 34.
    Schantz, Peter
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, The Research Unit for Movement, Health and Environment.
    Along paths converging to Bengt Saltin´s early contributions in exercise physiology2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, no Suppl. 4, p. 7-15Article in journal (Refereed)
    Abstract [en]

    A fascinating chain of events led in 1941 to the formation of the Department of Physiology at the Royal Gymnastic Central Institute (GCI) in Stockholm, Sweden. Erik Hohwü Christensen, from the scientifically advanced Lindhard School in Copenhagen, became its first professor. A central research question for him concerned determining the limiting factors for maximal physical performance in man. This was the academic setting where the sports interested medical student Bengt Saltin was introduced to exercise physiology. In the summer of 1959 he became involved in a study on intermittent versus continuous running. A doctoral project, with Per-Olof Åstrand as his tutor, resulted in 1964 as the thesis ‘Aerobic work capacity and circulation at exercise in man. With special reference to the effect of prolonged exercise and/or heat exposure’. In the decade that followed, Saltin continued along that path. However, he also added a vital research line involving pioneering studies on skeletal muscles in the exercising man, a series of novel studies on the physiological demands in various sports, and studies of the effects of physical training within the general population.

  • 35. Sundblad, Gunilla
    et al.
    Saartok, Tönu
    Engström, Lars-Magnus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Forskningsgruppen för pedagogik, idrott och fritidskultur.
    Renström, Per
    Injuries during physical activity in school children.2005In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 15, no 5, p. 313-23Article in journal (Refereed)
    Abstract [en]

    During the spring of 2001, 1975 children, from grades 3, 6 and 9 participated in a nationwide, multidisciplinary collaboration study. The students came from randomly selected classes throughout Sweden, representing different geographical and socio-economic areas. The aim of this study was to collect and evaluate self-reported injuries and associated factors during various physical activities as recalled retrospectively for 3 months by the students. Every sixth student (n=299 or 16%) reported 306 injuries. Twice as many girls than boys were injured during physical education class. Ninth-grade students reported relatively more injuries during organized sports than during physical education class and leisure activities. There were no age or gender differences in incidence rate during leisure activities. Most injuries were minor, as 70% were back in physical activity within a week. Half of the students (50%) reported that they previously had injured the same body part. Primary care of the injured student was, with the exception of a family member, most often carried out by the physical education teacher or coach, which accentuates the importance of continuous sports medicine first aid education for this group.

  • 36. Tokuno, C D
    et al.
    Cresswell, A G
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Carpenter, M G
    Recruitment order of the abdominal muscles varies with postural task.2013In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 23, no 3, p. 349-54Article in journal (Refereed)
    Abstract [en]

    Abdominal muscle recruitment strategies in response to a postural perturbation contradict the theory that the deeper abdominal muscles are always recruited in advance of the more superficial muscles. The purpose of this study was to determine whether such contrasting muscle recruitment patterns are due to the postural task or the predictability of a postural task. Participants performed an arm raise task as well as an unpredictable and a predictable balance perturbation task (i.e. support-surface translation) while intramuscular electromyographic (EMG) recordings were obtained from the deep [transversus abdominis (TrA)] and superficial [obliquus externus (OE)] abdominal muscles. The abdominal muscle recruitment order was dependent on the postural task but not on the predictability of a postural perturbation. Whereas arm raises elicited similar EMG onset latencies in TrA and OE, the OE onset latency was 48 ms earlier than the TrA following an unpredictable translation (P = 0.003). The early OE activation persisted when the translation was made predictable to the participant (P = 0.024). These results provide evidence that the abdominal muscle recruitment order varies with the trunk stability requirements specific to each task. Rehabilitation strategies focusing on an early TrA activation to improve postural stability may not be appropriate for all everyday tasks.

  • 37.
    Åman, Malin
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Forssblad, M
    Karolinska institutet.
    Henriksson-Larsén, Karin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Incidence and severity of reported acute sports injuries in 35 sports using insurance registry data2016In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 26, no 4, p. 451-462Article in journal (Refereed)
    Abstract [en]

    Acute injuries in sport are still a problem where limited knowledge of incidence and severity in different sports at national level exists. In Sweden, 80% of the sports federations have their mandatory injury insurance for all athletes in the same insurance company and injury data are systematically kept in a national database. The aim of the study was to identify high-risk sports with respect to incidence of acute and severe injuries in 35 sports reported to the database. The number and incidences of injuries as well as injuries leading to permanent medical impairment (PMI) were calculated during 2008–2011. Each year approximately 12 000 injuries and 1 162 660 licensed athletes were eligible for analysis. Eighty-five percent of the injuries were reported in football, ice hockey, floorball, and handball. The highest injury incidence as well as PMI was in motorcycle, handball, skating, and ice hockey. Females had higher risk of a PMI compared with males in automobile sport, handball, floorball, and football. High-risk sports with numerous injuries and high incidence of PMI injuries were motorcycle, handball, ice hockey, football, floorball, and automobile sports. Thus, these sports ought to be the target of preventive actions at national level.

  • 38.
    Åman, Malin
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Forssblad, M
    Karolinska institutet.
    Larsén, Karin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Incidence and body location of reported acute sport injuries in seven sports using a national insurance database.2018In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 28, no 3, p. 1147-1158Article in journal (Refereed)
    Abstract [en]

    Sports with high numbers of athletes and acute injuries are an important target for preventive actions at a national level. Both for the health of the athlete and to reduce costs associated with injury. The aim of this study was to identify injuries where injury prevention should focus, in order to have major impact on decreasing acute injury rates at a national level. All athletes in the seven investigated sport federations (automobile sports, basketball, floorball, football (soccer), handball, ice hockey, and motor sports) were insured by the same insurance company. Using this insurance database, the incidence and proportion of acute injuries, and injuries leading to permanent medical impairment (PMI), at each body location, was calculated. Comparisons were made between sports, sex, and age. In total, there were 84 754 registered injuries during the study period (year 2006-2013). Athletes in team sports, except in male ice hockey, had the highest risk to sustain an injury and PMI in the lower limb. Females had higher risk of injury and PMI in the lower limb compared to males, in all sports except in ice hockey. This study recommends that injury prevention at national level should particularly focus on lower limb injuries. In ice hockey and motor sports, head/neck and upper limb injuries also need attention.

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