A Thorstensson

The Swedish School of Sport and Health Sciences, Tukholma, Stockholm, Sweden

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Publications (158)354.74 Total impact

  • Carl M Askling · Magnus Tengvar · Olga Tarassova · Alf Thorstensson
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    ABSTRACT: Hamstring strain is a common injury in sprinters and jumpers, and therefore time to return to sport and secondary prevention become of particular concern. 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. Prospective randomised comparison of two rehabilitation protocols. 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. 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. 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.
    No preview · Article · Apr 2014 · British Journal of Sports Medicine
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    Carl M Askling · Magnus Tengvar · Alf Thorstensson
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    ABSTRACT: 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.
    Preview · Article · Mar 2013 · British Journal of Sports Medicine
  • M. Eriksson Crommert · M M Ekblom · A Thorstensson
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    ABSTRACT: 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.
    No preview · Article · Mar 2013 · Scandinavian Journal of Medicine and Science in Sports
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    ABSTRACT: 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. 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. 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). 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.
    No preview · Article · Nov 2011 · Knee Surgery Sports Traumatology Arthroscopy
  • C D Tokuno · A G Cresswell · A Thorstensson · M G Carpenter
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    ABSTRACT: 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.
    No preview · Article · Sep 2011 · Scandinavian Journal of Medicine and Science in Sports
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    A C Aberg · A Thorstensson · O Tarassova · K Halvorsen
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    ABSTRACT: For older people balance control in standing is critical for performance of activities of daily living without falling. The aims were to investigate reliability of quantification of the usage of the two balance mechanisms M(1) 'moving the centre of pressure' and M(2) 'segment acceleration' and also to compare calculation methods based on a combination of kinetic (K) and kinematic (Km) data, (K-Km), or Km data only concerning M(2). For this purpose nine physically fit persons aged 70-78 years were tested in narrow and single-leg standing. Data were collected by a 7-camera motion capture system and two force plates. Repeated measure ANOVA and Tukey's post hoc tests were used to detect differences between the standing tasks. Reliability was estimated by ICCs, standard error of measurement including its 95% CI, and minimal detectable change, whereas Pearson's correlation coefficient was used to investigate agreement between the two calculation methods. The results indicated that for the tasks investigated, M(1) and M(2) can be measured with acceptable inter- and intrasession reliability, and that both Km and K-Km based calculations may be useful for M(2), although Km data may give slightly lower values. The proportional M(1):M(2) usage was approximately 9:1, in both anterio-posterior (AP) and medio-lateral (ML) directions for narrow standing, and about 2:1 in the AP and of 1:2 in the ML direction in single-leg standing, respectively. In conclusion, the tested measurements and calculations appear to constitute a reliable way of quantifying one important aspect of balance capacity in fit older people.
    Full-text · Article · Jun 2011 · Gait & posture
  • Maria M Nordlund Ekblom · Alf Thorstensson
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    ABSTRACT: Neural activation is generally lower during maximal voluntary lengthening compared with shortening and isometric muscle actions, but the mechanisms underlying these differences are unclear. In maximal voluntary isometric actions, reduced Ia-afferent input induced by prolonged tendon vibration has been shown to impair neural activation and strength. This study aimed to investigate whether reducing Ia-afferent input influences neural activation in maximal voluntary dynamic muscle actions and, if so, whether it affects shortening and lengthening muscle actions differently. Eight women participated in three familiarization sessions and two randomly ordered experiments. In one experiment, 30-min vibration at 100 Hz was applied to the Achilles tendon to decrease Ia-afferent input as measured by the H-reflex. In the control experiment, rest substituted the vibration. Root mean square EMG from plantar and dorsiflexor muscles and plantar flexor strength were measured during maximal voluntary plantar flexor shortening and lengthening actions (20°·s(-1)) before and after vibration and rest, respectively. Soleus H-reflexes and M-waves were elicited before each set of strength tests. The vibration caused a decrease in H-reflex amplitude by, on the average, 33%, but root mean square EMG and plantar flexor strength remained largely unaffected in both action types. The findings suggest that Ia-afferent input may not substantially contribute to maximal voluntary dynamic muscle strength of the plantar flexor muscles, as tested here, and thus, the results do not support the notion that Ia-afferent excitation would contribute differently to neural activation in maximal voluntary lengthening and shortening muscle actions.
    No preview · Article · Mar 2011 · Medicine and science in sports and exercise
  • M Eriksson Crommert · M.M. Ekblom · A Thorstensson
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    ABSTRACT: Transversus abdominis (TrA) is a multifunctional muscle, being involved in pressure regulation within the abdominal cavity and thereby in direction independent stabilization of the spine and resistance to imposed trunk flexion moments. Indirect evidence suggests a role of TrA also in postural control of the erect human trunk. The main purpose here was to investigate if the magnitude of TrA activation is related to postural demand. Eleven healthy males performed seven different symmetrical static bilateral arm positions holding 3 kg in each hand. The arm positions were selected to systematically vary the height of the centre of mass (COM) keeping imposed moments constant and vice versa. EMG was recorded bilaterally with fine-wire intramuscular electrodes from TrA and obliquus internus (OI) and with surface electrodes from rectus abdominis (RA) and erector spinae (ES). Intra-abdominal pressure (IAP) was measured via a pressure transducer in the gastric ventricle. TrA was the only muscle that displayed activation co-varying with the vertical position of the COM. Further, TrA activation increased, together with IAP and ES activation, with imposed flexion moment, i.e. with arms extended horizontally forward. In contrast to OI, RA and ES, TrA activation was independent of the direction of the imposed moment (arms held inclined forward or backward). In conclusion, TrA activation level is uniquely associated with increased postural demand caused by elevated COM. Also, TrA appears to assist in counteracting trunk flexion via increased IAP, and contribute to general spine stabilization when the trunk is exposed to moderate flexion and extension moments.
    No preview · Article · Mar 2011 · Gait & posture
  • C. Tokuno · S J Garland · M G Carpenter · A Thorstensson · A. Cresswell
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    ABSTRACT: We have previously observed a change in the magnitude of the soleus (SOL) and medial gastrocnemius (MG) H-reflexes during different sway positions of quiet standing. The purpose of the present study was to extend the earlier finding by examining whether the SOL and MG H-reflexes are additionally influenced by the velocity of sway, i.e., whether the body is swaying in either the forward or backward direction. Five healthy subjects participated in the study. The mean position of the centre of pressure (COP) in the antero-posterior direction was determined while the subject stood quietly on a force plate for 60 s. In contrast to the earlier study, where the H-reflex was tested at the outermost positions of sway (±6 mm from the baseline mean), the current study elicited a SOL and MG H-reflex as the COP passed through the mean position of sway. This resulted in two sway conditions, where the position of the COP was the same but the sway velocity was different (10 mm s-1 forward and 10 mm s-1 backward). During the forward as compared to the backward velocity condition, there was a 20% and 25% increase in the amplitude of the H-reflex for the SOL and MG muscles, respectively, while the size of their respective background activities were the same. SOL and MG M-waves, as well as the level of background activity from the antagonist (tibialis anterior), were not different between the two sway conditions and thus cannot account for the observed changes to the amplitude of the H-reflexes. It can be concluded from these results that the direction (velocity) of sway has the ability to influence the size of the SOL and MG H-reflexes. The facilitation of the SOL and MG H-reflexes observed while swaying forward may be due to a reduction in presynaptic inhibition or an improvement in Ia synaptic efficacy brought about by changes in muscle length.
    No preview · Article · Jan 2011
  • P. Hodges · A Kaigle Holm · S Holm · L. Ekstrom · A. Cresswell · T Hansson · A Thorstensson

    No preview · Article · Jan 2011
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    C M Askling · J Nilsson · A Thorstensson
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    ABSTRACT: 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. 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. 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. 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.
    Preview · Article · Dec 2010 · Knee Surgery Sports Traumatology Arthroscopy
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    ABSTRACT: The aim of this study was to investigate whether kinematic proximal-to-distal sequencing (PDS) and speed-summation are common characteristics of both partial and full-swing shots in golf players of different skill levels and genders. A total of 45 golfers participated, 11 male tournament professionals, 21 male and 13 female elite amateurs. They performed partial shots with a wedge to targets at three submaximal distances, 40, 55 and 70 m, and full-swing shots with a 5 iron and a driver for maximal distance. Pelvis, upper torso and hand movements were recorded in 3D with an electromagnetic tracking system (Polhemus Liberty) at 240 Hz and the magnitude of the resultant angular velocity vector of each segment was computed. The results showed a significant proximal-to-distal temporal relationship and a concomitant successive increase in maximum (peak) segment angular speed in every shot condition for both genders and levels of expertise. A proximal-to-distal utilization of interaction torques is indicated. Using a common PDS movement strategy in partial and full-swing golf shots appears beneficial from mechanical and control points of view and could serve the purpose of providing both high speed and accuracy.
    Full-text · Article · Nov 2010 · Sports Biomechanics
  • Anna Bjerkefors · Maria M Ekblom · Karin Josefsson · Alf Thorstensson
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    ABSTRACT: The deepest muscle of the human ventro-lateral abdominal wall, the Transversus Abdominis (TrA), has been ascribed a specific role in spine stabilization, which has motivated special core stability exercises and hollowing instruction to specifically involve this muscle. The purpose here was to evaluate the levels of activation of the TrA and the superficial Rectus Abdominis (RA) muscles during five common stabilization exercises performed in supine, bridging and four-point kneeling positions, with and without instruction to hollow, i.e. to continuously pull the lower part of the abdomen towards the spine. Nine habitually active women participated and muscle activity was recorded bilaterally from TrA and RA with intramuscular fine-wire electrodes introduced under the guidance of ultrasound. Results showed that subjects were able to selectively increase the activation of the TrA, isolated from the RA, with the specific instruction to hollow and that side differences in the amplitude of TrA activity, related to the asymmetry of the exercises, remained even after the instruction to hollow. The exercises investigated caused levels of TrA activation from 4 to 43% of that during maximal effort and can thus be used clinically to grade the load on the TrA when designing programs aiming at training that muscle.
    No preview · Article · Oct 2010 · Manual therapy
  • A. Bjerkefors · F. Tinmark · L. Nolan · A. Arndt · S. Uchiyama · J. Nilsson · A. Thorstensson
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    ABSTRACT: Purpose: To introduce a new training device and its applicability for persons with spinal cord injury. Method: A person with a T4 spinal cord injury (SCI) and an able-bodied person (AB) performed double poling exercise at incremental intensities, submaximal to maximal, on a new ergometer. Forces in the right pole and movements were measured in 3D with a piezoelectric force sensor (Kistler) and an optoelectronic system (ProReflex), respectively. Results: Stroke rates showed similar ranges for the two subjects, 27-38 strokes/min in SCI and 24-35 strokes/min in AB. Mean power per stroke, calculated over 5 strokes, ranged 29-124 W for SCI and 30-255 W for AB. The highest single pole forces attained were 153 N (SCI) and 307 N (AB). Sagittal upper trunk movement increased with intensity in both subjects, 29-37 deg (SCI) and 8-20 deg (AB), the larger amplitude in SCI being due to additional backward lean. Conclusion: The results hitherto obtained in this study in progress have indicated that the new ergometer for seated double poling is a suitable tool for training of the upper body in persons with spinal cord injury. It provides a large range of controllable intensities making possible both endurance and strength/sprint type of training.
    No preview · Article · Jan 2010 · Assistive technology research series
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    ABSTRACT: The objectives were to examine (a) whether surface translations with a long, compared to a short, acceleration-deceleration interval could reveal more age-related differences in postural control and (b) whether age-related differences were associated with reactive or anticipatory postural mechanisms. Ten older (66-81years) and ten young adults (22-39years) stood on a moveable platform that was unexpectedly translated in the backward direction. Subjects' electromyographic (EMG) and kinematic responses were recorded in response to translations with either a SHORT (100ms) or LONG (2s) acceleration-deceleration interval presented in either a predictable or random order. Age-related differences in kinematic postural responses were greater during LONG compared to SHORT translations. However, both LONG and SHORT translations elicited a similar change in EMG latencies and amplitudes between the older and young adults. No age effects on the presentation order (predictable or random) of the translations were observed. LONG compared to SHORT surface translations magnify the age-related kinematic but not the EMG changes in reactive postural control. The anticipatory component of postural control was not affected by age. Translations with longer acceleration-deceleration intervals reveal more age-related differences in postural control, which are otherwise masked by the deceleration effects inherent to shorter translations.
    No preview · Article · Nov 2009 · Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology
  • A. E. Martin Eriksson Crommert · Alf Thorstensson
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    ABSTRACT: The aim was to increase the understanding of the multifunctional role of the trunk muscles in spine control, particularly transversus abdominis (TrA). In 11 healthy males, intramuscular fine-wire electromyography (EMG) was obtained bilaterally from TrA, obliquus externus (OE), rectus abdominis (RA) and erector spinae (ES). The subjects lay on their right side on a horizontal swivel-table with immobilized pelvis and lower limbs and the trunk strapped to a movable platform. Unexpected or expected release of loads attached to the table by steel cables produced a perturbation inducing either trunk flexion or extension. The timing and the amplitude of activation of TrA were independent of direction of induced trunk movement. Furthermore, timing of TrA activation was simultaneous to or later than that of the more superficial abdominal muscles. Expectation of the perturbation caused a general shortening of onset latencies. The results indicate a direction independent function of TrA in lumbar spine control. Balancing the trunk vertically appears to add specific demands, since the recruitment of TrA in relation to the other abdominal muscles differed from earlier experiments in standing.
    No preview · Article · Aug 2009 · Experimental Brain Research
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    ABSTRACT: The aim of this study was to assess if, and how, upper body muscles are activated in a person with high thoracic spinal cord injury, clinically classified as complete, during maximal voluntary contractions and in response to balance perturbations. Data from one person with spinal cord injury (T3 level) and one able-bodied person were recorded with electromyography from 4 abdominal muscles using indwelling fine-wire electrodes and from erector spinae and 3 upper trunk muscles with surface electrodes. Balance perturbations were carried out as forward or backward support surface translations. The person with spinal cord injury was able to activate all trunk muscles, even those below the injury level, both in voluntary efforts and in reaction to balance perturbations. Trunk movements were qualitatively similar in both participants, but the pattern and timing of muscle responses differed: upper trunk muscle involvement and occurrence of co-activation of ventral and dorsal muscles were more frequent in the person with spinal cord injury. These findings prompt further investigation into trunk muscle function in paraplegics, and highlight the importance of including motor tests for trunk muscles in persons with thoracic spinal cord injury, in relation to injury classification, prognosis and rehabilitation.
    No preview · Article · May 2009 · Journal of rehabilitation medicine: official journal of the UEMS European Board of Physical and Rehabilitation Medicine
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    ABSTRACT: The current study aimed to understand how deep and superficial abdominal muscles are coordinated with respect to activation onset times and amplitudes in response to unpredictable support-surface translations delivered in multiple directions. Electromyographic (EMG) data were recorded intra-muscularly using fine-wire electrodes inserted into the right rectus abdominis (RA), obliquus externus (OE), obliquus internus (OI) and transversus abdominis (TrA) muscles. Twelve young healthy male subjects were instructed to maintain their standing balance during 40 support surface translations (peak acceleration 1.3 m s(-2); total displacement 0.6 m) that were counter-balanced between four different directions (forward, backward, leftward, rightward). Differences between abdominal muscles in EMG onset times were found for specific translation directions. The more superficial RA (backward translations) and OE (forward and leftward translations) muscles had significantly earlier EMG onsets compared to TrA. EMG onset latencies were dependent on translation direction in RA, OE and OI, but independent of direction in TrA. EMG amplitudes in RA and OE were dependent on translation direction within the first 100 ms of activity, whereas responses from the two deeper muscles (TrA and OI) were independent of translation direction during this interval. The current results provide new insights into how abdominal muscles contribute to postural reactions during human stance. Response patterns of deep and superficial abdominal muscles during support surface translations are unlike those previously described during upper-body perturbations or voluntary arm movements, indicating that the neural mechanisms controlling individual abdominal muscles are task-specific to different postural demands.
    No preview · Article · Aug 2008 · Experimental Brain Research
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    ABSTRACT: Previous research has shown that changes in spinal excitability occur during the postural sway of quiet standing. In the present study, it was of interest to examine the independent effects of sway position and sway direction on the efficacy of the triceps surae Ia pathway, as reflected by the Hoffman (H)-reflex amplitude, during standing. Eighteen participants, tested under two different experimental protocols, stood quietly on a force platform. Percutaneous electrical stimulation was applied to the posterior tibial nerve when the position and direction of anteroposterior (A-P) center of pressure (COP) signal satisfied the criteria for the various experimental conditions. It was found that, regardless of sway position, a larger amplitude of the triceps surae H-reflex (difference of 9-14%; P = 0.005) occurred when subjects were swaying in the forward compared with the backward direction. The effects of sway position, independent of the sway direction, on spinal excitability exhibited a trend (P = 0.075), with an 8.9 +/- 3.7% increase in the H-reflex amplitude occurring when subjects were in a more forward position. The observed changes to the efficacy of the Ia pathway cannot be attributed to changes in stimulus intensity, as indicated by a constant M-wave amplitude, or to the small changes in the level of background electromyographic activity. One explanation for the changes in reflex excitability with respect to the postural sway of standing is that the neural modulation may be related to the small lengthening and shortening contractions occurring in the muscles of the triceps surae.
    Full-text · Article · Jun 2008 · Journal of Applied Physiology
  • A Saldanha · M. M. Nordlund Ekblom · A Thorstensson
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    ABSTRACT: 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.
    No preview · Article · Jun 2008 · Scandinavian Journal of Medicine and Science in Sports

Publication Stats

9k Citations
354.74 Total Impact Points


  • 1975-2014
    • The Swedish School of Sport and Health Sciences
      Tukholma, Stockholm, Sweden
  • 1978-2008
    • Karolinska Institutet
      • • Department of Neuroscience
      • • Department of Molecular Medicine and Surgery
      Solna, Stockholm, Sweden
  • 2002
    • Danderyds Sjukhus AB
      Tukholma, Stockholm, Sweden
  • 1999
    • Uppsala University
      Uppsala, Uppsala, Sweden
  • 1976
    • University of Jyväskylä
      • Department of Biology of Physical Activity
      Jyväskylä, Province of Western Finland, Finland
    • Boston University
      Boston, Massachusetts, United States
    • University of Baltimore
      Baltimore, Maryland, United States