Inacio Mario, Creath Rob, Rogers Mark W
University of Maryland School of Medicine, Baltimore, MD, USA.
University of Maryland School of Medicine, Baltimore, MD, USA.
Clin Biomech (Bristol). 2018 Dec;60:127-133. doi: 10.1016/j.clinbiomech.2018.10.018. Epub 2018 Oct 13.
Age-related neuromuscular changes in the hip abductor-adductor muscles lead to reduced performance, especially in the rate of force development and power production. These alterations may impair weight transfer control and lateral balance recovery through protective stepping. This study compared the effects of eight weeks of low-dose hip abductor-adductor power and strength training on the performance of isometric maximal voluntary contractions, and lateral balance recovery at different initial weight-bearing conditions in older individuals.
Eighteen healthy older adults (71.3 (0.9) years) underwent eight weeks of low-dose hip abductor-adductor exercise training involving either power training (n = 10) or lower velocity strength training (n = 8). Outcomes were assessed for hip abductor-adductor isometric maximal voluntary contractions and lateral waist-pull balance perturbations with three initial stepping limb-load conditions (50%, 65%, or 80% body mass).
Power training increased isometric maximal voluntary contractions abductor-adductor peak torque (14%-18%, p < 0.05), rate of torque development (31%-39%, p < 0.05) and rate of neuromuscular activation (37%-81%, p < 0.05). During lateral balance recovery, power training increased the incidence of stabilizing single lateral steps at 80% body mass pre-load (by 43%, p < 0.05), reduced step lift-off time by 27 ms at 50% body mass (p < 0.05) and decreased downward momentum of the body center of mass at 80% body mass (32%, p < 0.05). Power training also increased in task hip abductor net joint torque (49%-61%, p < 0.05), power (21%-54%, p < 0.05), and abductor-adductor rate of neuromuscular activation (17%-62%, p < 0.05).
Low-dose hip abductor-adductor power training was more effective than strength training at eliciting improvements in maximal neuromuscular performance and enhanced medio-lateral balance recovery.
髋外展肌和内收肌与年龄相关的神经肌肉变化会导致运动能力下降，尤其是在力量发展速度和功率产生方面。这些改变可能会通过保护性跨步损害体重转移控制和侧向平衡恢复。本研究比较了为期八周的低剂量髋外展肌-内收肌功率和力量训练对老年人等长最大自主收缩性能以及不同初始负重条件下侧向平衡恢复的影响。
18名健康老年人（71.3（0.9）岁）接受了为期八周的低剂量髋外展肌-内收肌运动训练，包括功率训练（n = 10）或较低速度的力量训练（n = 8）。评估了髋外展肌-内收肌等长最大自主收缩以及在三种初始跨步肢体负荷条件（50%、65%或80%体重）下的侧向腰部牵拉平衡扰动情况。
功率训练增加了髋外展肌-内收肌等长最大自主收缩的峰值扭矩（14%-18%，p < 0.05）、扭矩发展速度（31%-39%，p < 0.05）和神经肌肉激活速度（37%-81%，p < 0.05）。在侧向平衡恢复过程中，功率训练增加了在80%体重预负荷下稳定单侧侧向跨步的发生率（增加43%，p < 0.05），在体重50%时将跨步离地时间缩短了27毫秒（p < 0.05），并在80%体重时降低了身体重心的向下动量（降低32%，p < 0.05）。功率训练还增加了任务中髋外展肌的净关节扭矩（49%-61%，p < 0.05）、功率（21%-54%，p < 0.05）以及髋外展肌-内收肌的神经肌肉激活速度（17%-62%，p < 0.05）。
低剂量髋外展肌-内收肌功率训练在改善最大神经肌肉性能和增强中外侧平衡恢复方面比力量训练更有效。
