Sylvia Õunpuu - Academia.edu (original) (raw)

Papers by Sylvia Õunpuu

Handbook of Human Motion, 2016

Journal of Biomechanics, 2006

Journal of Applied Biomechanics, 2012

Documentation of the lower extremity motion patterns of adolescent pitchers is an important part ... more Documentation of the lower extremity motion patterns of adolescent pitchers is an important part of understanding the pitching motion and the implication of lower extremity technique on upper extremity loads, injury and performance. The purpose of this study was to take the initial step in this process by documenting the biomechanics of the lower extremities during the pitching cycle in adolescent pitchers and to compare these findings with the published data for older pitchers. Three-dimensional motion analysis using a comprehensive lower extremity model was used to evaluate the fast ball pitch technique in adolescent pitchers. Thirty-two pitchers with a mean age of 12.4 years (range 10.5–14.7 years) and at least 2 years of experience were included in this study. The pitchers showed a mean of 49 ± 12° of knee flexion of the lead leg at foot contact. They tended to maintain this position through ball release, and then extended their knee during the follow through phase (ball release...

Gait & Posture, 2013

A better understanding of gait dysfunction for children and youth with Charcot-Marie-Tooth (CMT) ... more A better understanding of gait dysfunction for children and youth with Charcot-Marie-Tooth (CMT) will assist in developing appropriate treatments and understanding prognosis for ambulation. The purpose of this retrospective study was to document the typical gait patterns in children and youth (12±4 years) with CMT using motion analysis and relate these findings back to the clinical assessment at the ankle. All patients underwent a motion analysis as a component of treatment decision-making. Lower extremity kinematics and kinetics were evaluated in comparison to a typically developing age-matched reference control group collected in the same gait laboratory. Three patient subgroups were defined based on peak ankle dorsiflexion in terminal stance: greater than typical (n=23), within typical range (n=30) and less than typical (n=13). The three subgroups showed statistically significant differences (p<0.004) in degree of impairment for ankle plantar flexor and dorsiflexor weakness and ankle plantar flexor contracture. Patients with excessive dorsiflexion in terminal stance had the greatest ankle plantar flexor weakness (median 2) and the greatest dorsiflexor weakness (median 4). Patients with less than typical dorsiflexion in terminal stance were the only patients with a plantar flexor contracture (-2±9°). Delayed peak dorsiflexion in stance was the most common kinematic finding and consistent with ankle plantar flexor weakness. All patients showed significantly less (p<0.001) peak ankle moments and power generation in terminal stance than the typically developing controls. We concluded that children and youth with CMT present differently in terms of impairment and associated gait issues which therefore require patient specific treatment strategies.

Developmental Medicine & Child Neurology, 2015

Orthopaedic Journal of Sports Medicine, 2014

Sports Biomechanics, 2014

Current pitching literature focuses primarily on the elbow and glenohumeral joints. This has led ... more Current pitching literature focuses primarily on the elbow and glenohumeral joints. This has led to a paucity of information regarding the forearm and wrist, and the limited data available are inconsistent. Therefore, this article seeks to provide a comprehensive description of the kinematics and kinetics of the wrist and forearm for the fastball, curveball, slider/cutter, and change-up for college-level baseball pitchers. Thirty-six collegiate pitchers were evaluated using motion analysis techniques. Results indicated that pitching the curveball generated the greatest forearm supination (16 ± 13°) compared with the other three pitch types (p < 0.05). The curveball and slider/cutter were pitched with less wrist extension and greater ulnar deviation compared with the fastball and change-up. The curveball was found to produce the greatest ulnar moment (7.3 ± 2.2 Nm) and was significantly different from the moments noted when pitching the fastball and change-up (5.1 ± 1.9 and 4.9 ± 1.9 Nm, respectively; p < 0.05). These results indicate that it may be possible to objectively determine pitch type from kinematic data of the wrist and forearm. It may also be possible that coaches may be able to identify abnormal pitching mechanics from more proximal segments by understanding the motion of the wrist.

Journal of applied biomechanics, 2012

Documentation of the lower extremity motion patterns of adolescent pitchers is an important part ... more Documentation of the lower extremity motion patterns of adolescent pitchers is an important part of understanding the pitching motion and the implication of lower extremity technique on upper extremity loads, injury and performance. The purpose of this study was to take the initial step in this process by documenting the biomechanics of the lower extremities during the pitching cycle in adolescent pitchers and to compare these findings with the published data for older pitchers. Three-dimensional motion analysis using a comprehensive lower extremity model was used to evaluate the fast ball pitch technique in adolescent pitchers. Thirty-two pitchers with a mean age of 12.4 years (range 10.5-14.7 years) and at least 2 years of experience were included in this study. The pitchers showed a mean of 49 ± 12° of knee flexion of the lead leg at foot contact. They tended to maintain this position through ball release, and then extended their knee during the follow through phase (ball release...

Orthopaedic journal of sports medicine, 2013

There are a number of studies showing that fastball pitches place greater loads on the shoulder a... more There are a number of studies showing that fastball pitches place greater loads on the shoulder and elbow than the curveball; however, the results of these studies are inconsistent, especially in collegiate-level pitchers. There is also discussion that sliders may produce substantially greater loads than other breaking pitches, but there is little scientific evidence to support this claim. The curveball and slider/cutter produce greater moments on the shoulder and elbow compared with the fastball and change-up. Descriptive laboratory study. Thirty-six collegiate pitchers were evaluated using motion analysis techniques. All subjects pitched a fastball and a change-up, 29 pitched a curveball, and 20 pitched a slider/cutter. Kinematic data were collected, and kinetic (joint moment) data were computed using standard protocols. A random-intercept, mixed-model regression analysis was used to assess differences in joint moments between pitch types. The greatest glenohumeral and elbow momen...

There are a number of studies showing that fastball pitches place greater loads on the shoulder a... more There are a number of studies showing that fastball pitches place greater loads on the shoulder and elbow than the curveball; however, the results of these studies are inconsistent, especially in collegiate-level pitchers. There is also discussion that sliders may produce substantially greater loads than other breaking pitches, but there is little scientific evidence to support this claim. The curveball and slider/cutter produce greater moments on the shoulder and elbow compared with the fastball and change-up. Descriptive laboratory study. Thirty-six collegiate pitchers were evaluated using motion analysis techniques. All subjects pitched a fastball and a change-up, 29 pitched a curveball, and 20 pitched a slider/cutter. Kinematic data were collected, and kinetic (joint moment) data were computed using standard protocols. A random-intercept, mixed-model regression analysis was used to assess differences in joint moments between pitch types. The greatest glenohumeral and elbow moments were found when pitchers were pitching the fastball (mean ± standard deviation: 80.8 ± 15.5 and 79.2 ± 16.9 N·m, respectively) and the lowest when pitching the change-up (73.2 ± 14.5 and 71.6 ± 15.0 N·m, respectively). The moments produced by the slider/cutter and curveball were similar (74.9 ± 16.4 and 75.6 ± 15.5 N·m at the elbow, respectively) and significantly lower than the moments produced by the fastball (P < .0001). Results also indicate that the change-up produced the lowest joint moments compared with other pitch types. This study shows that the fastball and not the curveball or slider/cutter produced the greatest moments on the college pitcher's glenohumeral and elbow joints, as previously believed. The study also shows that the change-up may be the safest of the 4 pitch types analyzed. There is a long-held belief that throwing breaking pitches, specifically the slider and curveball, places additional stresses on the shoulder and elbow of skeletally mature pitchers. However, these results show that pitching breaking pitches may not be as detrimental to a college-aged pitcher as currently believed.

Medicine and science in sports and exercise, 2007

Document the biomechanics of the pitching motion to help provide insight about the etiology of co... more Document the biomechanics of the pitching motion to help provide insight about the etiology of common injuries seen in adolescent baseball pitchers. Kinematic and kinetic data for the upper and lower extremities, thorax, and pelvis were collected from 24 adolescent pitchers, using modern three-dimensional computerized motion-analysis techniques. Original information regarding forearm and wrist motion was reported in this study and were consistent with expected motions for the fastball pitch. Average excursion of motion was: pronation/supination 63 +/- 15 degrees, wrist flexion/extension 44 +/- 14 degrees, and ulnar/radial deviation 12 +/- 4 degrees. Explosive forearm motion occurred between ball release (BR) and maximal glenohumeral internal rotation (GH-MIR) with a peak pronation velocity of 2051 +/- 646 degrees.s(-1). The majority of internal/external and abduction/adduction shoulder motion was attributed to the glenohumeral motion. Internal glenohumeral rotation range of motion w...

Pediatric clinics of North America, 2015

Heritable diseases of the peripheral nerves (Charcot-Marie-Tooth disease [CMT]) affect the motor ... more Heritable diseases of the peripheral nerves (Charcot-Marie-Tooth disease [CMT]) affect the motor units and sensory nerves, and they are among the most prevalent genetic conditions in the pediatric patient population. The typical clinical presentation includes distal muscle weakness and atrophy, but the severity and progression are largely variable. Improvements in supportive treatment have led to better preservation of patients' motor functions. More than 80 genes have been associated with CMT. These genetic discoveries, along with the developments of cellular and transgenic disease models, have allowed clinicians to better understand the disease mechanisms, which should lead to more specific treatments.

Gait & posture, 2015

Multilevel surgical intervention is a common approach for the correction of gait abnormalities in... more Multilevel surgical intervention is a common approach for the correction of gait abnormalities in children with cerebral palsy (CP). The short-term outcomes for the combination of rectus femoris transfer, hamstring lengthening and gastrocnemius lengthening have been well documented using three-dimensional motion analysis. However, the impact of time, growth, and puberty on these short-term outcomes of this combination of procedures is not well understood. The purpose of this study was to evaluate the long-term outcomes of these procedures on gait in patients with CP. Twenty-two patients underwent rectus femoris transfers, medial hamstring lengthenings and gastrocnemius lengthenings in combination with a selection of other soft tissue and/or bony procedures of the lower limb. All patients had a pre-operative motion analysis and post-operative analysis one and 11 years following surgery. Significant changes in both clinical and gait variables from pre to 1 year post surgery confirmed ...

Developmental Medicine & Child Neurology, 2015

The aim of this study was to examine differences in gait kinematics and spatiotemporal parameters... more The aim of this study was to examine differences in gait kinematics and spatiotemporal parameters in ambulatory children and adolescents with bilateral spastic cerebral palsy (BSCP) among Gross Motor Function Classification System (GMFCS) levels I-III. A retrospective review was conducted of individuals with BSCP who had three-dimensional motion analysis (3DGA) at one of seven pediatric hospitals. Means and standard deviations of each gait parameter were stratified by GMFCS levels (I-III) and for a typically developing comparison group. Data from 292 children and adolescents with BSCP (189 males, 103 females; mean age 13y) were compared to a typically developing comparison group (24 male, 26 female; mean age 10y 6mo). Gait patterns differed from typically developing in all GMFCS levels, with increasing deviation as GMFCS level increased in 21 out of 28 parameters. Despite significant differences in selected mean kinematic parameters among GMFCS levels such as knee angle at initial contact of 24°, 29°, and 41° in GMFCS levels I, II and III respectively, there was also substantial overlap among GMFCS levels. GMFCS levels cannot be identified using specific gait kinematics. Treatment decisions should be guided by comprehensive 3DGA that allows measurement of gait impairments at the joint level for each individual.

The American journal of sports medicine, Jan 11, 2015

The incidence of upper extremity injuries in baseball pitchers is increasing. Over the past decad... more The incidence of upper extremity injuries in baseball pitchers is increasing. Over the past decade there has been a great deal of research attempting to elucidate the cause of these injuries, focusing mainly on the mechanics of the pitching arm with no examination of other key segments, such as the trunk. This is surprising, as coaches will often comment on trunk position in an effort to improve pitching outcomes. To determine the association between contralateral trunk lean and ball velocity and the moments about the elbow and glenohumeral joint. Descriptive laboratory study. A total of 99 pitchers were recruited for this study and underwent a pitching analysis using 3-dimensional motion analysis techniques. A random intercept mixed-effects regression model was used to determine if statistically significant associations existed between contralateral trunk lean (away from the pitching arm side) and ball velocity, as well as the elbow varus moment and glenohumeral internal rotation m...

Children with crouch gait frequently walk with improved knee extension during the terminal swing ... more Children with crouch gait frequently walk with improved knee extension during the terminal swing and stance phases following hamstrings lengthening surgery; however, the mechanisms responsible for these improvements are unclear. This study tested the hypothesis that surgical lengthening enables the hamstrings of persons with cerebral palsy to operate at longer muscle-tendon lengths or lengthen at faster muscle-tendon velocities during walking.

Sports Health: A Multidisciplinary Approach, 2013

Medicine & Science in Sports & Exercise, 2010

Medicine & Science in Sports & Exercise, 2007

Handbook of Human Motion, 2016

Journal of Biomechanics, 2006

Journal of Applied Biomechanics, 2012

Documentation of the lower extremity motion patterns of adolescent pitchers is an important part ... more Documentation of the lower extremity motion patterns of adolescent pitchers is an important part of understanding the pitching motion and the implication of lower extremity technique on upper extremity loads, injury and performance. The purpose of this study was to take the initial step in this process by documenting the biomechanics of the lower extremities during the pitching cycle in adolescent pitchers and to compare these findings with the published data for older pitchers. Three-dimensional motion analysis using a comprehensive lower extremity model was used to evaluate the fast ball pitch technique in adolescent pitchers. Thirty-two pitchers with a mean age of 12.4 years (range 10.5–14.7 years) and at least 2 years of experience were included in this study. The pitchers showed a mean of 49 ± 12° of knee flexion of the lead leg at foot contact. They tended to maintain this position through ball release, and then extended their knee during the follow through phase (ball release...

Gait & Posture, 2013

A better understanding of gait dysfunction for children and youth with Charcot-Marie-Tooth (CMT) ... more A better understanding of gait dysfunction for children and youth with Charcot-Marie-Tooth (CMT) will assist in developing appropriate treatments and understanding prognosis for ambulation. The purpose of this retrospective study was to document the typical gait patterns in children and youth (12±4 years) with CMT using motion analysis and relate these findings back to the clinical assessment at the ankle. All patients underwent a motion analysis as a component of treatment decision-making. Lower extremity kinematics and kinetics were evaluated in comparison to a typically developing age-matched reference control group collected in the same gait laboratory. Three patient subgroups were defined based on peak ankle dorsiflexion in terminal stance: greater than typical (n=23), within typical range (n=30) and less than typical (n=13). The three subgroups showed statistically significant differences (p<0.004) in degree of impairment for ankle plantar flexor and dorsiflexor weakness and ankle plantar flexor contracture. Patients with excessive dorsiflexion in terminal stance had the greatest ankle plantar flexor weakness (median 2) and the greatest dorsiflexor weakness (median 4). Patients with less than typical dorsiflexion in terminal stance were the only patients with a plantar flexor contracture (-2±9°). Delayed peak dorsiflexion in stance was the most common kinematic finding and consistent with ankle plantar flexor weakness. All patients showed significantly less (p<0.001) peak ankle moments and power generation in terminal stance than the typically developing controls. We concluded that children and youth with CMT present differently in terms of impairment and associated gait issues which therefore require patient specific treatment strategies.

Developmental Medicine & Child Neurology, 2015

Orthopaedic Journal of Sports Medicine, 2014

Sports Biomechanics, 2014

Current pitching literature focuses primarily on the elbow and glenohumeral joints. This has led ... more Current pitching literature focuses primarily on the elbow and glenohumeral joints. This has led to a paucity of information regarding the forearm and wrist, and the limited data available are inconsistent. Therefore, this article seeks to provide a comprehensive description of the kinematics and kinetics of the wrist and forearm for the fastball, curveball, slider/cutter, and change-up for college-level baseball pitchers. Thirty-six collegiate pitchers were evaluated using motion analysis techniques. Results indicated that pitching the curveball generated the greatest forearm supination (16 ± 13°) compared with the other three pitch types (p < 0.05). The curveball and slider/cutter were pitched with less wrist extension and greater ulnar deviation compared with the fastball and change-up. The curveball was found to produce the greatest ulnar moment (7.3 ± 2.2 Nm) and was significantly different from the moments noted when pitching the fastball and change-up (5.1 ± 1.9 and 4.9 ± 1.9 Nm, respectively; p < 0.05). These results indicate that it may be possible to objectively determine pitch type from kinematic data of the wrist and forearm. It may also be possible that coaches may be able to identify abnormal pitching mechanics from more proximal segments by understanding the motion of the wrist.

Journal of applied biomechanics, 2012

Documentation of the lower extremity motion patterns of adolescent pitchers is an important part ... more Documentation of the lower extremity motion patterns of adolescent pitchers is an important part of understanding the pitching motion and the implication of lower extremity technique on upper extremity loads, injury and performance. The purpose of this study was to take the initial step in this process by documenting the biomechanics of the lower extremities during the pitching cycle in adolescent pitchers and to compare these findings with the published data for older pitchers. Three-dimensional motion analysis using a comprehensive lower extremity model was used to evaluate the fast ball pitch technique in adolescent pitchers. Thirty-two pitchers with a mean age of 12.4 years (range 10.5-14.7 years) and at least 2 years of experience were included in this study. The pitchers showed a mean of 49 ± 12° of knee flexion of the lead leg at foot contact. They tended to maintain this position through ball release, and then extended their knee during the follow through phase (ball release...

Orthopaedic journal of sports medicine, 2013

There are a number of studies showing that fastball pitches place greater loads on the shoulder a... more There are a number of studies showing that fastball pitches place greater loads on the shoulder and elbow than the curveball; however, the results of these studies are inconsistent, especially in collegiate-level pitchers. There is also discussion that sliders may produce substantially greater loads than other breaking pitches, but there is little scientific evidence to support this claim. The curveball and slider/cutter produce greater moments on the shoulder and elbow compared with the fastball and change-up. Descriptive laboratory study. Thirty-six collegiate pitchers were evaluated using motion analysis techniques. All subjects pitched a fastball and a change-up, 29 pitched a curveball, and 20 pitched a slider/cutter. Kinematic data were collected, and kinetic (joint moment) data were computed using standard protocols. A random-intercept, mixed-model regression analysis was used to assess differences in joint moments between pitch types. The greatest glenohumeral and elbow momen...

There are a number of studies showing that fastball pitches place greater loads on the shoulder a... more There are a number of studies showing that fastball pitches place greater loads on the shoulder and elbow than the curveball; however, the results of these studies are inconsistent, especially in collegiate-level pitchers. There is also discussion that sliders may produce substantially greater loads than other breaking pitches, but there is little scientific evidence to support this claim. The curveball and slider/cutter produce greater moments on the shoulder and elbow compared with the fastball and change-up. Descriptive laboratory study. Thirty-six collegiate pitchers were evaluated using motion analysis techniques. All subjects pitched a fastball and a change-up, 29 pitched a curveball, and 20 pitched a slider/cutter. Kinematic data were collected, and kinetic (joint moment) data were computed using standard protocols. A random-intercept, mixed-model regression analysis was used to assess differences in joint moments between pitch types. The greatest glenohumeral and elbow moments were found when pitchers were pitching the fastball (mean ± standard deviation: 80.8 ± 15.5 and 79.2 ± 16.9 N·m, respectively) and the lowest when pitching the change-up (73.2 ± 14.5 and 71.6 ± 15.0 N·m, respectively). The moments produced by the slider/cutter and curveball were similar (74.9 ± 16.4 and 75.6 ± 15.5 N·m at the elbow, respectively) and significantly lower than the moments produced by the fastball (P < .0001). Results also indicate that the change-up produced the lowest joint moments compared with other pitch types. This study shows that the fastball and not the curveball or slider/cutter produced the greatest moments on the college pitcher's glenohumeral and elbow joints, as previously believed. The study also shows that the change-up may be the safest of the 4 pitch types analyzed. There is a long-held belief that throwing breaking pitches, specifically the slider and curveball, places additional stresses on the shoulder and elbow of skeletally mature pitchers. However, these results show that pitching breaking pitches may not be as detrimental to a college-aged pitcher as currently believed.

Medicine and science in sports and exercise, 2007

Document the biomechanics of the pitching motion to help provide insight about the etiology of co... more Document the biomechanics of the pitching motion to help provide insight about the etiology of common injuries seen in adolescent baseball pitchers. Kinematic and kinetic data for the upper and lower extremities, thorax, and pelvis were collected from 24 adolescent pitchers, using modern three-dimensional computerized motion-analysis techniques. Original information regarding forearm and wrist motion was reported in this study and were consistent with expected motions for the fastball pitch. Average excursion of motion was: pronation/supination 63 +/- 15 degrees, wrist flexion/extension 44 +/- 14 degrees, and ulnar/radial deviation 12 +/- 4 degrees. Explosive forearm motion occurred between ball release (BR) and maximal glenohumeral internal rotation (GH-MIR) with a peak pronation velocity of 2051 +/- 646 degrees.s(-1). The majority of internal/external and abduction/adduction shoulder motion was attributed to the glenohumeral motion. Internal glenohumeral rotation range of motion w...

Pediatric clinics of North America, 2015

Heritable diseases of the peripheral nerves (Charcot-Marie-Tooth disease [CMT]) affect the motor ... more Heritable diseases of the peripheral nerves (Charcot-Marie-Tooth disease [CMT]) affect the motor units and sensory nerves, and they are among the most prevalent genetic conditions in the pediatric patient population. The typical clinical presentation includes distal muscle weakness and atrophy, but the severity and progression are largely variable. Improvements in supportive treatment have led to better preservation of patients' motor functions. More than 80 genes have been associated with CMT. These genetic discoveries, along with the developments of cellular and transgenic disease models, have allowed clinicians to better understand the disease mechanisms, which should lead to more specific treatments.

Gait & posture, 2015

Multilevel surgical intervention is a common approach for the correction of gait abnormalities in... more Multilevel surgical intervention is a common approach for the correction of gait abnormalities in children with cerebral palsy (CP). The short-term outcomes for the combination of rectus femoris transfer, hamstring lengthening and gastrocnemius lengthening have been well documented using three-dimensional motion analysis. However, the impact of time, growth, and puberty on these short-term outcomes of this combination of procedures is not well understood. The purpose of this study was to evaluate the long-term outcomes of these procedures on gait in patients with CP. Twenty-two patients underwent rectus femoris transfers, medial hamstring lengthenings and gastrocnemius lengthenings in combination with a selection of other soft tissue and/or bony procedures of the lower limb. All patients had a pre-operative motion analysis and post-operative analysis one and 11 years following surgery. Significant changes in both clinical and gait variables from pre to 1 year post surgery confirmed ...

Developmental Medicine & Child Neurology, 2015

The aim of this study was to examine differences in gait kinematics and spatiotemporal parameters... more The aim of this study was to examine differences in gait kinematics and spatiotemporal parameters in ambulatory children and adolescents with bilateral spastic cerebral palsy (BSCP) among Gross Motor Function Classification System (GMFCS) levels I-III. A retrospective review was conducted of individuals with BSCP who had three-dimensional motion analysis (3DGA) at one of seven pediatric hospitals. Means and standard deviations of each gait parameter were stratified by GMFCS levels (I-III) and for a typically developing comparison group. Data from 292 children and adolescents with BSCP (189 males, 103 females; mean age 13y) were compared to a typically developing comparison group (24 male, 26 female; mean age 10y 6mo). Gait patterns differed from typically developing in all GMFCS levels, with increasing deviation as GMFCS level increased in 21 out of 28 parameters. Despite significant differences in selected mean kinematic parameters among GMFCS levels such as knee angle at initial contact of 24°, 29°, and 41° in GMFCS levels I, II and III respectively, there was also substantial overlap among GMFCS levels. GMFCS levels cannot be identified using specific gait kinematics. Treatment decisions should be guided by comprehensive 3DGA that allows measurement of gait impairments at the joint level for each individual.

The American journal of sports medicine, Jan 11, 2015

The incidence of upper extremity injuries in baseball pitchers is increasing. Over the past decad... more The incidence of upper extremity injuries in baseball pitchers is increasing. Over the past decade there has been a great deal of research attempting to elucidate the cause of these injuries, focusing mainly on the mechanics of the pitching arm with no examination of other key segments, such as the trunk. This is surprising, as coaches will often comment on trunk position in an effort to improve pitching outcomes. To determine the association between contralateral trunk lean and ball velocity and the moments about the elbow and glenohumeral joint. Descriptive laboratory study. A total of 99 pitchers were recruited for this study and underwent a pitching analysis using 3-dimensional motion analysis techniques. A random intercept mixed-effects regression model was used to determine if statistically significant associations existed between contralateral trunk lean (away from the pitching arm side) and ball velocity, as well as the elbow varus moment and glenohumeral internal rotation m...

Children with crouch gait frequently walk with improved knee extension during the terminal swing ... more Children with crouch gait frequently walk with improved knee extension during the terminal swing and stance phases following hamstrings lengthening surgery; however, the mechanisms responsible for these improvements are unclear. This study tested the hypothesis that surgical lengthening enables the hamstrings of persons with cerebral palsy to operate at longer muscle-tendon lengths or lengthen at faster muscle-tendon velocities during walking.

Sports Health: A Multidisciplinary Approach, 2013

Medicine & Science in Sports & Exercise, 2010

Medicine & Science in Sports & Exercise, 2007