ORIGINAL RESEARCH article
Front. Sports Act. Living
Sec. Biomechanics and Control of Human Movement
Volume 7 - 2025 | doi: 10.3389/fspor.2025.1558784
This article is part of the Research TopicAdvancing Performance: Biomechanics in Paralympic and Adapted SportsView all 5 articles
Muscle fascicle length adaptations to high-velocity training in young adults with cerebral palsy
Provisionally accepted
- 1University of Calgary, Calgary, Canada
- 2Mount Royal University, Calgary, Alberta, Canada
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In 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. Purpose: To determine the effects of HVT on changes in MG muscle fascicle length and that impact on changes to MG muscle forcelength-velocity-power characteristics in young adults with CP. Methods: 12 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 10m 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. Results: HVT resulted in a significant increase in fascicle length in CP-T (+1.92 ± 3.21mm, p<0.005) compared to a significant decrease in CP-NT (-1.63 ± 3.00mm, 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. Conclusion: HVT 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.
Keywords: sarcomerogenesis, Neurological Disorder, power, sprint agility, Force-length, Force-velocity, Para sport
Received: 11 Jan 2025; Accepted: 23 Apr 2025.
Copyright: © 2025 Gallinger, Macintosh and Fletcher. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Tessa Gallinger, University of Calgary, Calgary, Canada
Jared R Fletcher, Mount Royal University, Calgary, T3E 6K6, Alberta, Canada
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