Department of Kinesiology and Health Education, 2109 San Jacinto Blvd, D3700, University of Texas at Austin, Austin, TX 78712, USA.
J Biomech. 2021 Mar 5;117:110251. doi: 10.1016/j.jbiomech.2021.110251. Epub 2021 Jan 13.
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.
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.
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.
Smaller trunk flexion angles with greater activation of the hip abductor and adductor muscles in TO contributed to improving postural stability during the STS.
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.
由于与年龄相关的神经肌肉力量和协调性下降，老年人进行坐站（STS）可能是一项具有挑战性的任务。我们研究了不同初始足部位置（IFP）对年轻和老年成年人在 STS 期间运动学、肌肉激活模式和平衡控制的影响。
10 名年轻和 10 名健康的老年人参加了这项研究。研究了四种对称的 IFP：（1）参考（REF），（2）脚尖朝外，脚跟并拢（TOHT），（3）脚尖朝外（TO）和（4）宽。测量了矢状面和额状面的下肢肌肉激活模式以及动力学和运动学数据。
在两组中，上升时躯干前倾角度和髋关节伸展扭矩在 TO 和 Wide 时较小。在上升完成后，后足姿势摆动和压力中心摆动面积最小，两组之间无差异。与其他 IFP 相比，TO 中的内收肌和臀中肌活动更大，并且老年人的活动程度大于年轻人。
TO 中较小的躯干弯曲角度和更大的髋关节外展和内收肌激活有助于改善 STS 期间的姿势稳定性。
STS 训练采用脚尖朝外的足部位置可能是一种有效的老年康复策略，可增强控制 STS 期间中-侧平衡所需的髋关节肌肉。
