| 1. |
- Andersson, Eva A, et al.
(author)
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Abdominal and hip flexor muscle activation during various training exercises.
- 1997
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In: European Journal of Applied Physiology and Occupational Physiology. - : Springer Science and Business Media LLC. - 0301-5548 .- 1432-1025 .- 1439-6319 .- 1439-6327. ; 75:2, s. 115-23
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Journal article (peer-reviewed)abstract
- The purpose of this study was to provide objective information on the involvement of different abdominal and hip flexor muscles during various types of common training exercises used in rehabilitation and sport. Six healthy male subjects performed altogether 38 different static and dynamic training exercises trunk and hip flexion sit-ups, with various combinations of leg position and support, and bi- and unilateral leg lifts. Myoelectric activity was recorded with surface electrodes from the rectus abdominis, obliquus externus, obliquus internus, rectus femoris, and sartorius muscles and with indwelling fine-wire electrodes from the iliacus muscle. The mean electromyogram amplitude, normalised to the highest observed value, was compared between static and dynamic exercises separately. The hip flexors were highly activated only in exercises involving hip flexion, either lifting the whole upper body or the legs. In contrast, the abdominal muscles showed marked activation both during trunk and hip flexion sit-ups. In hip flexion sit-ups, flexed and supported legs increased hip flexor activation, whereas such modifications did not generally alter the activation level of the abdominals. Bilateral, but not unilateral, leg lifts required activation of abdominal muscles. In trunk flexion sit-ups an increased activation of the abdominal muscles was observed with increased flexion angle, whereas the opposite was true for hip flexion sit-ups. Bilateral leg lifts resulted in higher activity levels than hip flexion sit-ups for the iliacus and sartorius muscles, while the opposite was true for rectus femoris muscles. These data could serve as a basis for improving the design and specificity of test and training exercises.
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| 2. |
- Andersson, Eva A, et al.
(author)
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Diverging intramuscular activity patterns in back and abdominal muscles during trunk rotation.
- 2002
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In: Spine. - : Ovid Technologies (Wolters Kluwer Health). - 1528-1159 .- 0362-2436. ; 27:6, s. E152-60
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Journal article (peer-reviewed)abstract
- STUDY DESIGN: An intramuscular electromyographic study was performed on trunk rotations during sitting and standing. OBJECTIVE: The aim was to provide new information on activation levels for deep trunk muscles in various unresisted and resisted trunk rotations. SUMMARY AND BACKGROUND DATA: Frequent daily trunk twisting and decreased maximal strength during trunk rotation have been associated with low back pain or sciatic pain. However, the involvement of deep trunk muscles during different trunk rotations is relatively unknown. METHODS: Ten healthy subjects participated. Fine-wire electrodes were inserted, under ultrasound guidance, into psoas, quadratus lumborum, the superficial medial lumbar erector spinae (ES-s, multifidus) and its deep lateral portion (ES-d, iliocostalis), iliacus, rectus abdominis, obliquus externus, and obliquus internus. RESULTS: The highest involvement for all muscles was observed on the ipsilateral side, in maximal trunk twists with shoulder resistance, except obliquus externus, which showed a dominant contralateral side, and rectus abdominis, which was little activated in all rotations. In contrast, maximal trunk twist without shoulder resistance, i.e., freely performed, resulted generally in lower levels for all muscles involved and in a shift of side dominance for the lumbar muscles quadratus lumborum, psoas, and ES-s. CONCLUSIONS: During trunk rotations the activity patterns for various trunk muscles could drastically change, and even be the opposite, between the two body sides, within the same type of task, depending on several factors such as initial position, effort level, sitting or standing, and external shoulder resistance.
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| 3. |
- Andersson, Eva A
(author)
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EMG and strength in trunk and hip muscles
- 1997
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Doctoral thesis (other academic/artistic)abstract
- The overall aim of this thesis was to study the myouelectric activity of all major muscles involved in the movements and stabilization of the trunk, pelvis and hips during training exercises, postures, motor tasks, maximal strength performance and locomotion. By use of ultra-sound, EMG electrodes could be guided safely and accurately into muscles situated even close to the spinal column, such as psoas, quadratus lumborum and deep parts of erector spinae. A task specific variation in activation levels were seen between muscle synergies, as well as between individual muscles within a synergy. Selective engagement of the abdominal muscles could be achieved in trunk flexion sit-ups, that is lifting only the upper trunk from the floor. An even higher activation of abdominal muscles was needed for static stabilization of the trunk and pelvis during hip flexion sit-ups, whereas single leg lifts were performed without involvement of the abdominal muscles. A selective activation of either the iliacus or psoas muscle was observed, for example in certain types of training exercises and in walking and running. Applying bending moments to the spine, resulted in a grading of the muscle activation response according to mechanical advantage, that is highest in the quadratus lumborum in lateral loading and in the superficial erector spinae in ventral loading. An exception was the most forward flexed position in standing where the superficial erector spinae "relaxed" but quadratus lumborum remained active. In general, the level of EMG in maximal efforts was maintained at the same high level irrespective of position in the range of motion, despite a marked variation in strength output. This position-dependency, as well as the strength values as such, varied in a specific way in groups of athletes, related to previous background. These data contribute to the understanding of muscle function and motor control of the trunk , pelvis and hips. They are also of relevance when evaluating and designing tests and training programs in rehabilitation and sport contexts as well as for improving biomechanical models of spinal loading.
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| 4. |
- Andersson, Eva A, et al.
(author)
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Intramuscular EMG from the hip flexor muscles during human locomotion.
- 1997
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In: Acta Physiologica Scandinavica. - 0001-6772 .- 1365-201X. ; 161:3, s. 361-70
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Journal article (peer-reviewed)abstract
- The purpose was to investigate the activation pattern of five major hip flexor muscles and its adaptation to changing speed and mode of progression. A total of 11 healthy subjects performed walking and running on a motor-driven treadmill at speeds ranging from 1.0 to 6.0 m s-1. Intramuscular fine-wire electrodes were used to record myoelectric signals from the iliacus, psoas, sartorius, rectus femoris and tensor fascia latae muscles. The basic pattern, with respect to number of activation periods, remained the same irrespective of speed and mode of progression. However, differences in the relative duration and timing of onset of activation occurred between individual muscles. Over the speed range in walking, a progressively earlier onset was generally seen for the activation period related to hip flexion. Changes in EMG amplitude were measured in the iliacus and psoas muscles and showed a marked increase and difference between walking and running at speeds above 2.0 m s-1. Thus, the alternating flexion-extension movements at the hip during locomotion appear to be governed by a rather fixed 'neural program' which normally only needs minor modulations to accomplish the adjustments accompanying an increase in speed of progression as well as a change from walking to running.
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| 5. |
- Andersson, Eva A, et al.
(author)
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Relative EMG levels in training exercises for abdominal and hip flexor muscles.
- 1998
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In: Scandinavian Journal of Rehabilitation Medicine. - : Informa UK Limited. - 0036-5505 .- 1940-2228. ; 30:3, s. 175-83
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Journal article (peer-reviewed)abstract
- The main purpose of our study was to compare systematically EMG levels in sub-maximal training exercises for the trunk and hip flexor muscles with those voluntarily attainable in corresponding situations. Six healthy subjects performed three types of standardized training exercises, whose static positions, movement velocity and range of motion were reproduced during maximal voluntary isokinetic strength tests. EMG was recorded with wire electrodes from the iliacus muscle and with surface electrodes from the rectus femoris, sartorius, rectus abdominis, obliquus externus and internus muscles. The relative EMG values demonstrated a task dependency which could differ between individual muscles. The maximal voluntary activation levels were relatively constant across conditions. Exceptions were present, particularly for the rectus femoris and iliacus muscles. These findings highlight the consequences of using different methods of normalizing EMG. The relative EMG values presented may serve as guidelines when selecting training exercises for specific trunk and hip flexor muscles in sports and rehabilitation.
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| 6. |
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| 7. |
- Andersson, Eva, et al.
(author)
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EMG activities of the quadratus lumborum and erector spinae muscles during flexion-relaxation and other motor tasks.
- 1996
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In: Clinical biomechanics (Bristol, Avon). - : Elsevier BV. - 1879-1271 .- 0268-0033. ; 11:7, s. 392-400
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Journal article (peer-reviewed)abstract
- OBJECTIVE: The aim of this study was to provide new information on the myoelectrical activation of the quadratus lumborum, the deep lateral and the superficial medial lumbar erector spinae, the psoas, and the iliacus muscles in various motor tasks. DESIGN: An intramuscular electromyographic study was performed. BACKGROUND: The contribution of individual deep trunk muscles to the stability of the lumbar spine is relatively unknown in different tasks, including the flexion-relaxation phenomenon. METHODS: Seven healthy subjects participated. Fine-wire electrodes were inserted with a needle guided by ultrasound. RESULTS: The highest activity observed for quadratus lumborum and deep lateral erector spinae occurred in ipsilateral trunk flexion in a side-lying position and for superficial medial erector spinae during bilateral leg lift in a prone position. Quadratus lumborum and deep lateral erector spinae were activated when the flexion-relaxation phenomenon was present for superficial medial erector spinae, i.e. when its activity ceased in the latter part of full forward flexion of the trunk, held relaxed and kyphotic. CONCLUSIONS: In general, the activation of the investigated muscles showed a high degree of task specificity, where activation of a certain muscle was not always predictable from its anatomical arrangement and mechanical advantage.
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| 8. |
- Andersson, Eva, et al.
(author)
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The role of the psoas and iliacus muscles for stability and movement of the lumbar spine, pelvis and hip.
- 1995
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In: Scandinavian Journal of Medicine and Science in Sports. - 0905-7188 .- 1600-0838. ; 5:1, s. 10-6
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Journal article (peer-reviewed)abstract
- 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.
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| 9. |
- Andersson, Eva, et al.
(author)
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Trunk muscle strength in athletes.
- 1988
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In: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 20:6, s. 587-93
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Journal article (peer-reviewed)abstract
- Maximal voluntary strength of the trunk muscles was measured in 57 male elite athletes (soccer players, wrestlers, tennis players, and gymnasts), 14 female elite gymnasts, and in a normal group of 87 conscripts. Mean ages in the different groups ranged from 18-22 yr. An isokinetic (constant velocity) technique was used to record maximal torque produced by trunk and hip muscles during flexion, extension, and lateral flexion over the range of motion. The constant angular velocities used were 15 deg.s-1 and 30 deg.s-1, respectively. Isometric strength was measured in a straight body position (0 deg. of flexion). The measurements were made with the subjects in a horizontal position with the pivot point at the hip and at the lumbar (L2-L3) level. All male athlete groups showed higher peak torque values than the normals. The differences were largest in hip extension and trunk flexion. The male gymnasts also showed significantly higher peak values in hip flexion as compared to all other categories. There was no difference in strength per kg body weight between female gymnasts and untrained males, except in trunk extension. The position for peak torque occurred earlier in the movements for the athletes, especially for the gymnasts in extension movements and for the tennis players in flexion movements. In isometric contractions essentially the same strength differences were present as in the slow isokinetic contractions. In lateral flexion wrestlers and tennis players showed significantly higher strength in movements toward the nondominant side. Thus, differences were present between the athletes and the normals, some of which appeared to be sport specific and related to long-term systematic training.(ABSTRACT TRUNCATED AT 250 WORDS)
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| 10. |
- Arndt, Anton, 1968-, et al.
(author)
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Non-uniform displacement within the Achilles tendon durig passive ankle joint motion.
- 2012
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In: Knee Surgery, Sports Traumatology, Arthroscopy. - : Springer Science and Business Media LLC. - 0942-2056 .- 1433-7347. ; 20:9, s. 1868-74
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Journal article (peer-reviewed)abstract
- PURPOSE:An initial step in the understanding of Achilles tendon dynamics is to investigate the effects of passive motion, thereby minimising muscle activation and reducing internal joint forces. Internal tendon dynamics during passive ankle joint motion have direct implications for clinical rehabilitation protocols after Achilles tendon surgery. The aim of this study was to test the hypothesis that tendon tissue displacement is different in different layers of the Achilles tendon during controlled passive ankle joint movements.METHODS:Ultrasound imaging was conducted on the right Achilles tendon of nine healthy recreationally active males. Standardised isokinetic passive dorsi-plantar-flexion movements were performed with a total range of motion of 35°. The tendon was divided into superficial, central and deep layers in the resulting B-mode ultrasound images viewed in the sagittal plane. A block-matching speckle tracking algorithm was applied post-process, with kernels for the measurement of displacement placed in each of the layers.RESULTS:The mean (SD) displacement of the Achilles tendon during passive dorsiflexion was 8.4 (1.9) mm in the superficial layer, 9.4 (1.9) mm in the central portion and 10.4 (2.1) mm in the deep layer, respectively. In all cases, the movement of the deep layer of the tendon was greater than that of the superficial one (P < 0.01).CONCLUSIONS:These results, achieved in vivo with ultrasonographic speckle tracking, indicated complex dynamic differences in different layers of the Achilles tendon, which could have implications for the understanding of healing processes of tendon pathologies and also of normal tendon function.
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| 11. |
- Askling, Carl, et al.
(author)
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A new hamstring test to complement the common clinical examination before return to sport after injury
- 2010
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In: Knee Surgery, Sports Traumatology, Arthroscopy. - : Springer-Verlag. - 0942-2056 .- 1433-7347. ; 18:12, s. 1788-1803
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Journal article (peer-reviewed)abstract
- PURPOSE: The aim was to introduce and evaluate the reliability and validity of an active hamstring flexibility test as a complement to common clinical examination when determining safe return to sport after hamstring injury. METHODS: Eleven healthy subjects (28 years) were tested on repeated occasions, and 11 athletes (21 years) with MRI-verified acute hamstring strain were tested when common clinical examination revealed no signs of remaining injury, i.e. there was no differences between the legs in palpation pain, manual strength tests, and passive straight leg raise. Flexibility, i.e. highest range of motion of three consecutive trials, was calculated from electrogoniometer data during active ballistic hip flexions and conventional passive slow hip-flexions in a supine position. A VAS-scale (0-100) was used to estimate experience of insecurity during active tests. RESULTS: No significant test-retest differences were observed. Intra-class correlation coefficients ranged 0.94-0.99 and coefficients of variation 1.52-4.53%. Active flexibility was greater (23%) than passive flexibility. In the athletes, the injured leg showed smaller (8%) active, but not passive, flexibility than the uninjured leg. Average insecurity estimation was 52 (range 28-98) for the injured and 0 for the uninjured leg, respectively. CONCLUSION: The new test showed high reliability and construct validity; furthermore, it seems to be sensitive enough to detect differences both in active flexibility and in insecurity after acute hamstring strains at a point in time when the commonly used clinical examination fails to reveal injury signs. Thus, the test could be a complement to the common clinical examination before the final decision to return to sport is made.
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| 12. |
- Askling, Carl, et al.
(author)
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Hamstring injury occurrence in elite soccer players after preseason strength training with eccentric overload.
- 2003
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In: Scandinavian Journal of Medicine and Science in Sports. - : Wiley. - 0905-7188 .- 1600-0838. ; 13:4, s. 244-50
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Journal article (peer-reviewed)abstract
- 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.
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| 13. |
- Askling, Carl
(author)
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Hamstring muscle strain
- 2008
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Doctoral thesis (other academic/artistic)abstract
- Background: Acute hamstring strains are common injuries in different sports. They are often serious, causing long rehabilitation times and a proneness for re-injury. Preliminary observations indicate that the injuries can be of at least two types, one occurring during high-speed running and the other during motions where the hamstring muscles reach extreme lengths.Aims: To investigate the possible existence of different types of acute hamstring strains in two specific athletic groups, namely sprinters and dancers, as well as the generality of these findings in other sports.Methods: In the first project, 18 sprinters and 15 dancers with acute first time hamstring strains were prospectively included. All subjects were examined, clinically and with magnetic resonance imaging (MRI), on 4 occasions after injury: at day 2-4, 10, 21 and 42. The follow-up period was 2 years. In the second project, 30 subjects from 21 different sports were prospectively included. All subjects were examined clinically and with MRI. The follow-up period lasted until the subjects returned to sport or finished their sport activity due to the injury.Results: All sprinters sustained their injuries during competitive high-speed running. In contrast, all dancers encountered their injuries during slow-speed stretching type of exercises. The initial loss of strength and flexibility was significantly greater in sprinters than in dancers. At 42 days after injury, both groups could perform more than 90% of the test values of the uninjured leg. All the sprinters’ injuries were primarily located in biceps femoris long head, whereas the dancers’ injuries were mainly (87%) involving the proximal free tendon of semimembranosus. For the sprinters, involvement of the proximal free tendon, as estimated by MRI, and proximity to the ischial tuberosity, as estimated both by palpation and MRI, were associated with significantly longer time to return to pre-injury level. In the dancers, there were no significant correlations between clinical or MRI parameters and time to return to per-injury level. The time to pre-injury level was significantly longer (median 50 weeks, range 30-76) for the dancers compared to the sprinters (16, 6-50). In the second project, all injuries occurred during movements reaching a position with combined extensive hip flexion and knee extension. They were all located close to the ischial tuberosity and 83% involved the proximal free tendon of semimembranosus. Fourteen subjects (47%) decided to end their sport activity and for the remaining 16 subjects the median time back to sport was 31 (range 9-104) weeks. There were no significant correlations between clinical and MRI parameters and time to return to sport.Conclusions: There seems to be a link between the injury situation and the two types of acute hamstring strain in sprinters and dancers with respect to clinical findings, injury location, muscles and tissues involved, and time to return to pre-injury level. Proximity of the injury to the ischial tuberosity, as estimated both by palpation and MRI, is associated with longer recovery time. Also in other sports, an injury situation where the hamstrings reach extensive lengths caused a specific injury to the proximal posterior thigh similar to that described in dancers. Due to the prolonged recovery time associated with this type of injury, correct diagnosis based on history, clinical and MRI investigation, and adequate information to the athletes are essential.
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| 14. |
- Askling, Carl M, et al.
(author)
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Acute first-time hamstring strains during high-speed running: a longitudinal study including clinical and magnetic resonance imaging findings
- 2007
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In: The American journal of sports medicine. - : SAGE Publications. - 0363-5465 .- 1552-3365. ; 35:2, s. 197-206
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Journal article (peer-reviewed)abstract
- Hamstring muscle strain is one of the most common injuries in sports. Still, knowledge is limited about the progression of clinical and magnetic resonance imaging characteristics and their association with recovery time in athletes. Hypothesis Knowing the anatomical location and extent of an acute first-time hamstring strain in athletes is critical for the prognosis of recovery time. Study Design Case series (prognosis); Level of evidence, 2. Methods Eighteen elite sprinters with acute first-time hamstring strains were prospectively included in the study. All subjects were examined, clinically and with magnetic resonance imaging, on 4 occasions after injury: at day 2 to 4, 10, 21, and 42. The clinical follow-up period was 2 years. Results All sprinters were injured during competitive sprinting, and the primary injuries were all located in the long head of the biceps femoris muscle. There was an association between the time to return to pre-injury level (median, 16; range, 6-50 weeks) and the extent of the injury, as indicated by the magnetic resonance imaging parameters. Involvement of the proximal free tendon, as estimated by MRI, and proximity to the ischial tuberosity, as estimated both by palpation and magnetic resonance imaging, were associated with longer time to return to pre-injury level. Conclusion Careful palpation during the first 3 weeks after injury and magnetic resonance imaging investigation performed during the first 6 weeks after injury provide valuable information that can be used to predict the time to return to pre-injury level of performance in elite sprinting.
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| 15. |
- Askling, Carl M, et al.
(author)
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Acute first-time hamstring strains during slow-speed stretching: clinical, magnetic resonance imaging, and recovery characteristics
- 2007
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In: The American journal of sports medicine. - : SAGE Publications. - 1552-3365 .- 0363-5465. ; 35:10, s. 1716-1724
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Journal article (peer-reviewed)abstract
- Hamstring strains can be of 2 types with different injury mechanisms, 1 occurring during high-speed running and the other during stretching exercises. Hypothesis A stretching type of injury to the proximal rear thigh may involve specific muscle-tendon structures that could affect recovery time. Study Design Case series (prognosis); Level of evidence, 2. Methods Fifteen professional dancers with acute first-time hamstring strains were prospectively included in the study. All subjects were examined, clinically and with magnetic resonance imaging, on 4 occasions after injury: at day 2 to 4, 10, 21, and 42. The clinical follow-up period was 2 years. Results All dancers were injured during slow hip-flexion movements with extended knee and experienced relatively mild acute symptoms. All injuries were located proximally in the posterior thigh close to the ischial tuberosity. The injury involved the semimembranosus (87%), quadratus femoris (87%), and adductor magnus (33%). All injuries to the semimembranosus involved its proximal free tendon. There were no significant correlations between clinical or magnetic resonance imaging parameters and the time to return to preinjury level (median, 50 weeks; range, 30-76 weeks). Conclusion Stretching exercises can give rise to a specific type of strain injury to the posterior thigh. A precise history and careful palpation provide the clinician enough information to predict a prolonged time until return to preinjury level. One factor underlying prolonged recovery time could be the involvement of the free tendon of the semimembranosus muscle.
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| 16. |
- Askling, Carl M, et al.
(author)
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Acute hamstring injuries in Swedish elite football : a prospective randomised controlled clinical trial comparing two rehabilitation protocols.
- 2013
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In: British Journal of Sports Medicine. - : BMJ. - 0306-3674 .- 1473-0480. ; 47:15, s. 953-9
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Journal article (peer-reviewed)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.
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| 17. |
- Askling, Carl M, et al.
(author)
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Acute hamstring injuries in Swedish elite sprinters and jumpers : a prospective randomised controlled clinical trial comparing two rehabilitation protocols.
- 2014
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In: British Journal of Sports Medicine. - : BMJ. - 0306-3674 .- 1473-0480. ; 48:7, s. 532-9
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Journal article (peer-reviewed)abstract
- BACKGROUND: Hamstring strain is a common injury in sprinters and jumpers, and therefore time to return to sport and secondary prevention become of particular concern.OBJECTIVE: To compare the effectiveness of two rehabilitation protocols after acute hamstring injury in Swedish elite sprinters and jumpers by evaluating time needed to return to full participation in the training process.STUDY DESIGN: Prospective randomised comparison of two rehabilitation protocols.METHODS: Fifty-six Swedish elite sprinters and jumpers with acute hamstring injury, verified by MRI, were randomly assigned to one of two rehabilitation protocols. Twenty-eight athletes were assigned to a protocol emphasising lengthening exercises, L-protocol, and 28 athletes to a protocol consisting of conventional exercises, C-protocol. The outcome measure was the number of days to return to full training. Re-injuries were registered during a period of 12 months after return.RESULTS: Time to return was significantly shorter for the athletes in the L-protocol, mean 49 days (1SD±26, range 18-107 days), compared with the C-protocol, mean 86 days (1SD±34, range 26-140 days). Irrespective of protocol, hamstring injuries where the proximal free tendon was involved took a significantly longer time to return than injuries that did not involve the free tendon, L-protocol: mean 73 vs 31 days and C-protocol: mean 116 vs 63 days, respectively. Two reinjuries were registered, both in the C-protocol.CONCLUSIONS: A rehabilitation protocol emphasising lengthening type of exercises is more effective than a protocol containing conventional exercises in promoting time to return in Swedish elite sprinters and jumpers.
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| 18. |
- Askling, Carl M, et al.
(author)
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Proximal hamstring strains of stretching type in different sports: injury situations, clinical and magnetic resonance imaging characteristics, and return to sport
- 2008
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In: The American journal of sports medicine. - : SAGE Publications. - 1552-3365 .- 0363-5465. ; 36:9, s. 1799-1804
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Journal article (peer-reviewed)abstract
- Hamstring strains can be of at least 2 types, 1 occurring during high-speed running and the other during motions in which the hamstring muscles reach extreme lengths, as documented for sprinters and dancers. Hypothesis Hamstring strains in different sports, with similar injury situations to dancers, also show similarities in symptoms, injury location, and recovery time. Study Design Case series (prognosis); Level of evidence, 4. Methods Thirty subjects from 21 different sports were prospectively included. All subjects were examined clinically and with magnetic resonance imaging (MRI). The follow-up period lasted until the subjects returned to or finished their sport activity. Results All injuries occurred during movements reaching a position with combined extensive hip flexion and knee extension. They were located proximally in the posterior thigh, close to the ischial tuberosity. The injuries were often complex, but 83% involved the semimembranosus and its proximal free tendon. Fourteen subjects (47%) decided to end their sports activity. For the remaining 16 subjects, the median time for return to sport was 31 weeks (range, 9-104). There were no significant correlations between specific clinical or MRI parameters and time to return to sport. Conclusions In different sports, an injury situation in which the hamstring muscles reach extensive length causes a specific injury to the proximal posterior thigh, earlier described in dancers. Because of the prolonged recovery time associated with this type of injury, correct diagnosis, based on history and palpation, and adequate information to the subject are essential.
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| 19. |
- Askling, Carl, et al.
(author)
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Self-reported hamstring injuries in student-dancers.
- 2002
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In: Scandinavian Journal of Medicine and Science in Sports. - : Wiley. - 0905-7188 .- 1600-0838. ; 12:4, s. 230-5
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Journal article (peer-reviewed)abstract
- 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.
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| 20. |
- Askling, Carl, et al.
(author)
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Sports related hamstring strains--two cases with different etiologies and injury sites.
- 2000
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In: Scandinavian Journal of Medicine and Science in Sports. - : Wiley. - 0905-7188 .- 1600-0838. ; 10:5, s. 304-7
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Journal article (peer-reviewed)abstract
- 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.
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| 23. |
- Bergh, U, et al.
(author)
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Maximal oxygen uptake and muscle fiber types in trained and untrained humans.
- 1978
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In: Medicine and science in sports. - 0025-7990. ; 10:3, s. 151-4
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Journal article (peer-reviewed)abstract
- Maximal oxygen uptake (Vo2 max) was determined in 138 male and 41 female human subjects and muscle fiber composition (gastrocnemius and vastus lateralis) in 53 of the males. Highest values for Vo2 max were 7.38 1 x min-1 and 4.341 x min-1 in males and females, respectively. In relation to body weight the highest values were 94 and 77 ml x (kg x min)-1. Athletes participating in endurance events had very high Vo2 max and predominantly slow twitch (ST) fiber populations whereas weight lifters attained rather low values for Vo2 max and had a higher percentage of fast twitch (FT) fibers. Among subjects with the same fiber composition, Vo2 max was higher in the athletes than in the moderately trained. All groups taken together demonstrated a positive relationship between Vo2 max and the relative number of ST fibers (r = 0.67). For endurance and strength athletes r = 0.72 and for the moderately trained r = 0.34, both correlation coefficients being significant.
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| 24. |
- Bjerkefors, Anna, et al.
(author)
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Deep and superficial abdominal muscle activation during trunk stabilization exercises with and without instruction to hollow.
- 2010
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In: Manual Therapy. - : Elsevier BV. - 1356-689X .- 1532-2769. ; 15:5, s. 502-7
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Journal article (peer-reviewed)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.
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| 25. |
- Bjerkefors, Anna, et al.
(author)
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Dynamic trunk stability is improved in paraplegics following kayak ergometer training.
- 2007
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In: Scandinavian Journal of Medicine and Science in Sports. - : Wiley. - 0905-7188 .- 1600-0838. ; 17:6, s. 672-9
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Journal article (peer-reviewed)abstract
- 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.
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