背景:研究神经和肌肉的形态适应以评估运动训练对老年人的影响很重要。
目的:本研究旨在探讨家庭体重深蹲训练对老年人神经肌肉适应的影响。
方法:将25名社区居住的老年人(77.7±5.0岁)分配到下蹲(SQU)或对照组(CON)。SQU组的人每天进行100次体重深蹲,CON组的其他人仅进行4个月的日常活动。评估了次最大收缩期间的最大膝关节伸展扭矩和高密度表面肌电图。确定了单个运动单位(MU),并将其分为相对较低或较高的招募阈值MU组。计算每个MU组的射击率。使用超声评估大腿外侧的肌肉厚度和回声强度。作为物理测试,通常的步态速度,计时并进行测试,握力,并进行了五次椅子站立测试。
结果:虽然肌肉力量没有改善,肌肉厚度,回波强度,或在任何一组中都注意到物理测试,干预后,SQU组相对低招募阈值MU的放电率显著下降.
结论:这些结果表明,即使进行高重复和高频运动,低强度的家庭深蹲训练也不能显着改善肌肉力量或身体功能,但可以稍微调节社区居住的老年人的神经激活。
BACKGROUND: It is important to investigate neural as well as muscle morphological adaptations to evaluate the effects of exercise training on older adults.
OBJECTIVE: This study was aimed to investigate the effects of home-based bodyweight squat training on neuromuscular adaptation in older adults.
METHODS: Twenty-five community-dwelling older adults (77.7 ± 5.0 years) were assigned to squat (SQU) or control (CON) groups. Those in the SQU group performed 100 bodyweight squats every day and the others in the CON group only performed daily activities for 4 months. Maximum knee extension torque and high-density surface electromyography during submaximal contraction were assessed. Individual motor units (MUs) were identified and divided into relatively low or high-recruitment threshold MU groups. Firing rates of each MU group were calculated. The muscle thickness and echo intensity of the lateral thigh were assessed using ultrasound. As physical tests, usual gait speed, timed up and go test, grip strength, and five-time chair stand test were performed.
RESULTS: While no improvements in muscle strength, muscle thickness, echo intensity, or physical tests were noted in either group, the firing rate of relatively low recruitment threshold MUs significantly decreased in the SQU group after intervention.
CONCLUSIONS: These results suggest that low-intensity home-based squat training could not improve markedly muscle strength or physical functions even if high-repetition and high frequency exercise, but could modulate slightly neural activation in community-dwelling older adults.