Centre for Physical Activity and Life Sciences, Faculty of Art, Science and Technology, University of Northampton, Northamptonshire, UNITED KINGDOM.
Centre for Human Performance (CHP), School of Medical and Health Sciences, Edith Cowan University, Joondalup, AUSTRALIA.
Med Sci Sports Exerc. 2024 Jul 1;56(7):1242-1255. doi: 10.1249/MSS.0000000000003418. Epub 2024 Mar 4.
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.
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.
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.
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.
已报道在进行离心抗阻训练后，关节活动范围（ROM）会大幅增加；然而，关于相关机制或对侧肢体的潜在交叉教育效应的数据有限。因此，本研究检测了 26 名参与者进行 6 周的等速离心足底屈肌训练计划的效果。
在训练计划之前和之后，在对照组（n=13）和实验组（n=13）的年轻成年人组中测量背屈 ROM、足底屈肌力量以及肌肉-肌腱单元（MTU）形态和力学特性。训练包括右侧肢体每周 2 次、每次 5 组、每组 12 次最大等速离心足底屈肌收缩。
实验组中，双侧训练和对照侧的背屈 ROM（4.0-9.5°）、拉伸耐受度（40.3-95.9%）、被动弹性储能（47.5-161.3%）、等长（38.1-40.6%）和离心（46.7-67.0%）峰值足底屈肌扭矩均显著增加（P<0.05）。仅在训练侧观察到比目鱼肌和腓肠肌内侧厚度（5.4-6.1%）、比目鱼肌内侧肌束长度（7.6±8.5%）、被动足底屈肌 MTU 硬度（30.1±35.5%）和跟腱硬度（5.3±4.9%）的显著增加。在训练和对照侧之间，背屈 ROM（r=0.59）和等长（r=0.79）和离心（r=0.73）峰值扭矩的变化之间检测到显著相关性。对照组中没有检测到任何指标的显著变化。
训练侧的 ROM 大幅增加与神经、机械和结构适应有关，对侧肢体的交叉教育效应的证据主要由神经适应（拉伸耐受度）驱动。ROM、肌肉大小和力量的大幅改善证实了等速离心训练是一种非常有效的训练工具，对于 MTU 功能受损且当前治疗方法无效的运动和临床人群具有潜在应用价值。
