Cross-education effects of isokinetic eccentric plantarflexor training on flexibility, strength, and muscle–tendon mechanics
Document Type
Journal Article
Publication Title
Medicine and Science in Sports and Exercise
Volume
56
Issue
7
First Page
1242
Last Page
1255
Publisher
Wolters Kluwer
School
Centre for Human Performance / School of Medical and Health Sciences
RAS ID
71492
Abstract
KAY, A. D., A. J. BLAZEVICH, J. C. TYSOE, and B. A. BAXTER. Cross-Education Effects of Isokinetic Eccentric Plantarflexor Training on Flexibility, Strength, and Muscle–Tendon Mechanics. Med. Sci. Sports Exerc., Vol. 56, No. 7, pp. 1242- 1255, 2024. Introduction: Large increases in joint range of motion (ROM) have been reported after eccentric resistance training; however, limited data exist describing the associated mechanisms or potential cross-education effects in the contralateral limb. Therefore, the effects of a 6-wk isokinetic eccentric plantarflexor training program were examined in 26 participants. Methods: Before and after the training program, dorsiflexion ROM, plantarflexor strength, and muscle–tendon unit (MTU) morphology and mechanics were measured in control (n = 13) and experimental (n = 13) young adult groups. Training consisted of 5 sets of 12 maximal isokinetic eccentric plantarflexor contractions twice weekly on the right limb. Results: Significant (P < 0.05) increases in dorsiflexion ROM (4.0–9.5°), stretch tolerance (40.3–95.9%), passive elastic energy storage (47.5–161.3%), and isometric (38.1–40.6%) and eccentric (46.7–67.0%) peak plantarflexor torques were detected in both trained and contralateral limbs in the experimental group. Significant increases in gastrocnemius medialis and soleus thickness (5.4–6.1%), gastrocnemius medialis fascicle length (7.6 ± 8.5%), passive plantarflexor MTU stiffness (30.1 ± 35.5%), and Achilles tendon stiffness (5.3 ± 4.9%) were observed in the trained limb only. Significant correlations were detected between the changes in trained and contralateral limbs for dorsiflexion ROM (r = 0.59) and both isometric (r = 0.79) and eccentric (r = 0.73) peak torques. No significant changes in any metric were detected in the control group. Conclusions: Large ROM increases in the trained limb were associated with neurological, mechanical, and structural adaptations, with evidence of a cross-education effect in the contralateral limb being primarily driven by neurological adaptation (stretch tolerance). The large improvements in ROM, muscle size, and strength confirm that isokinetic eccentric training is a highly effective training tool, with potential for use in athletic and clinical populations where MTU function is impaired and current therapies are ineffective.
DOI
10.1249/MSS.0000000000003418
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Comments
Kay, A. D., Blazevich, A. J., Tysoe, J., & Baxter, B. A. (2024). Cross-education effects of isokinetic eccentric plantarflexor training on flexibility, strength, and muscle-tendon mechanics. Medicine & Science in Sports & Exercise. https://doi.org/10.1249/MSS.0000000000003418