Muscle fascicle length adaptations to high-velocity training in young adults with cerebral palsy

IntroductionIn individuals with Cerebral Palsy (CP), both muscle cross-sectional area and fascicle length are reduced, contributing to decreased muscle strength, muscle shortening velocity and muscle mechanical power output, particularly in the plantarflexor muscles. A proposed mechanism to target i...

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Main Authors: Tessa L. Gallinger, Brian R. MacIntosh, Jared R. Fletcher
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-05-01
Series:Frontiers in Sports and Active Living
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Online Access:https://www.frontiersin.org/articles/10.3389/fspor.2025.1558784/full
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author Tessa L. Gallinger
Tessa L. Gallinger
Brian R. MacIntosh
Jared R. Fletcher
Jared R. Fletcher
author_facet Tessa L. Gallinger
Tessa L. Gallinger
Brian R. MacIntosh
Jared R. Fletcher
Jared R. Fletcher
author_sort Tessa L. Gallinger
collection DOAJ
description IntroductionIn individuals with Cerebral Palsy (CP), both muscle cross-sectional area and fascicle length are reduced, contributing to decreased muscle strength, muscle shortening velocity and muscle mechanical power output, particularly in the plantarflexor muscles. A proposed mechanism to target increased muscle mechanical power output is to incorporate high velocity training (HVT) in these individuals, to increase fascicle length via sarcomerogenesis. To determine the effects of HVT on changes in MG muscle fascicle length and that impact on changes to MG muscle force-length-velocity-power characteristics in young adults with CP.Methods12 young adults with CP (GMFCS I or II, 22.8 ± 6.0 years) were randomly allocated (some crossover) to no training (CP-NT, n = 8), or training (CP-T, n = 8). 10 recreationally trained healthy adults (HA, 22.5 ± 2.8 years) served as controls. CP-T performed 10-week training of biweekly sessions consisting of progressive intensity 10 m sprints, plyometrics and agility tasks. Triceps surae muscle force-power-velocity relationships were quantified with isokinetic dynamometry and ultrasound imaging. Data are expressed relative to pre-intervention values.ResultsHVT resulted in a significant increase in fascicle length in CP-T (+1.92 ± 3.21 mm, p < 0.005) compared to a significant decrease in CP-NT (−1.63 ± 3.00 mm, p < 0.013). While HVT did not result in significant changes in maximal shortening velocity (Vmax) or maximal peak power output (Pmax), a large effect size for vmax following training in CP-T was seen (+45.2 ± 76.4%, d = 0.909, p = 0.452), in contrast to CP-NT (+2.9 ± 70.5%, d = 0.059, p = 1.00). HVT also resulted in a very large effect for Pmax in CP-T (+35.0 ± 49.1%, d = 1.093, p = 0.232), but only a small effect was observed in CP-NT (+7.8 ± 49.1%, d = 0.245, p = 1.00). HA had significantly greater Pmax (p < 0.001), longer resting and active fascicle lengths (p < 0.001) and greater muscle force (p < 0.001), compared to CP-T.DiscussionHVT is a feasible training intervention to increase triceps surae muscle fascicle length in individuals with CP. HVT can partially mitigate losses in Pmax in CP compared to healthy adults. Longer HVT programs may be required to increase muscle mechanical power output in CP to levels observed in HA.
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spelling doaj-art-87981a39ea174654a3727cbd5bfc36c22025-08-20T03:52:48ZengFrontiers Media S.A.Frontiers in Sports and Active Living2624-93672025-05-01710.3389/fspor.2025.15587841558784Muscle fascicle length adaptations to high-velocity training in young adults with cerebral palsyTessa L. Gallinger0Tessa L. Gallinger1Brian R. MacIntosh2Jared R. Fletcher3Jared R. Fletcher4Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, CanadaCanadian Paralympic Committee, Ottawa, ON, CanadaHuman Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, CanadaHuman Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, CanadaDepartment of Health and Physical Education, Mount Royal University, Calgary, AB, CanadaIntroductionIn individuals with Cerebral Palsy (CP), both muscle cross-sectional area and fascicle length are reduced, contributing to decreased muscle strength, muscle shortening velocity and muscle mechanical power output, particularly in the plantarflexor muscles. A proposed mechanism to target increased muscle mechanical power output is to incorporate high velocity training (HVT) in these individuals, to increase fascicle length via sarcomerogenesis. To determine the effects of HVT on changes in MG muscle fascicle length and that impact on changes to MG muscle force-length-velocity-power characteristics in young adults with CP.Methods12 young adults with CP (GMFCS I or II, 22.8 ± 6.0 years) were randomly allocated (some crossover) to no training (CP-NT, n = 8), or training (CP-T, n = 8). 10 recreationally trained healthy adults (HA, 22.5 ± 2.8 years) served as controls. CP-T performed 10-week training of biweekly sessions consisting of progressive intensity 10 m sprints, plyometrics and agility tasks. Triceps surae muscle force-power-velocity relationships were quantified with isokinetic dynamometry and ultrasound imaging. Data are expressed relative to pre-intervention values.ResultsHVT resulted in a significant increase in fascicle length in CP-T (+1.92 ± 3.21 mm, p < 0.005) compared to a significant decrease in CP-NT (−1.63 ± 3.00 mm, p < 0.013). While HVT did not result in significant changes in maximal shortening velocity (Vmax) or maximal peak power output (Pmax), a large effect size for vmax following training in CP-T was seen (+45.2 ± 76.4%, d = 0.909, p = 0.452), in contrast to CP-NT (+2.9 ± 70.5%, d = 0.059, p = 1.00). HVT also resulted in a very large effect for Pmax in CP-T (+35.0 ± 49.1%, d = 1.093, p = 0.232), but only a small effect was observed in CP-NT (+7.8 ± 49.1%, d = 0.245, p = 1.00). HA had significantly greater Pmax (p < 0.001), longer resting and active fascicle lengths (p < 0.001) and greater muscle force (p < 0.001), compared to CP-T.DiscussionHVT is a feasible training intervention to increase triceps surae muscle fascicle length in individuals with CP. HVT can partially mitigate losses in Pmax in CP compared to healthy adults. Longer HVT programs may be required to increase muscle mechanical power output in CP to levels observed in HA.https://www.frontiersin.org/articles/10.3389/fspor.2025.1558784/fullsarcomerogenesisneurological disorderpowersprint agilityforce-lengthforce-velocity
spellingShingle Tessa L. Gallinger
Tessa L. Gallinger
Brian R. MacIntosh
Jared R. Fletcher
Jared R. Fletcher
Muscle fascicle length adaptations to high-velocity training in young adults with cerebral palsy
Frontiers in Sports and Active Living
sarcomerogenesis
neurological disorder
power
sprint agility
force-length
force-velocity
title Muscle fascicle length adaptations to high-velocity training in young adults with cerebral palsy
title_full Muscle fascicle length adaptations to high-velocity training in young adults with cerebral palsy
title_fullStr Muscle fascicle length adaptations to high-velocity training in young adults with cerebral palsy
title_full_unstemmed Muscle fascicle length adaptations to high-velocity training in young adults with cerebral palsy
title_short Muscle fascicle length adaptations to high-velocity training in young adults with cerebral palsy
title_sort muscle fascicle length adaptations to high velocity training in young adults with cerebral palsy
topic sarcomerogenesis
neurological disorder
power
sprint agility
force-length
force-velocity
url https://www.frontiersin.org/articles/10.3389/fspor.2025.1558784/full
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