Background

Performing a sit-to-stand (STS) can be a challenging task for older adults because of age-related declines in neuromuscular strength and coordination. We investigated the effects of different initial foot positions (IFPs) on kinematics, muscle activation patterns, and balance control during a STS in younger and older adults. Methods: Ten younger and ten older healthy adults participated in this study. Four symmetric IFPs were studied: (1) reference (REF), (2) toes-out with heels together (TOHT), (3) toes-out (TO), and (4) Wide. Lower-extremity muscle activation patterns and kinetic and kinematic data in the sagittal and frontal planes were measured. Results: The trunk forward-tilt angle and hip extension torque during uprising were smaller in TO and Wide for both age groups. Postural sway and center of pressure sway area were smallest in TO after completion of uprising with no difference between age groups. Adductor longus and gluteus medius activity was greater in TO than in the other IFPs, and older adults activated these muscles to a greater degree than younger adults. Conclusion: Smaller trunk flexion angles with greater activation of the hip abductor and adductor muscles in TO contributed to improving postural stability during the STS. Significance: STS training with a toes-out foot position could be an effective rehabilitation strategy for older adults to strengthen hip muscles that control medio-lateral balance required for balance during a STS.

中文翻译：

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年轻人和老年人坐着站立时不同初始脚位置对运动学，肌肉激活模式和姿势控制的影响

背景

坐着站立（STS）对于老年人而言可能是一项艰巨的任务，因为与年龄相关的神经肌肉力量和协调能力下降。我们调查了在年轻人和老年人中进行STS期间，不同的初始足部位置（IFP）对运动学，肌肉激活模式和平衡控制的影响。方法：十名年轻和十名健康的成年人参加了这项研究。研究了四个对称IFP：（1）参考（REF），（2）脚跟并拢（TOHT），（3）脚跟（TO）和（4）宽。测量了矢状和额面的下肢肌肉激活模式以及动力学和运动学数据。结果：在两个年龄段的起义期间，躯干前倾角和髋部伸展扭矩在TO和Wide中均较小。起义完成后，姿势摆动和压力摆动中心的面积在TO中最小，各年龄组之间无差异。TO中的Adductor longus和臀中臀肌活动比其他IFPs大，并且老年人比年轻人更能激活这些肌肉。结论：较小的躯干屈曲角度以及TO中髋部外展肌和内收肌的更多激活有助于改善STS期间的姿势稳定性。意义： STS训练时，脚趾外伸可能是老年人增强髋部肌肉的有效康复策略，以控制STS期间平衡所需的中外侧平衡。