Jeon Woohyoung, Whitall Jill, Griffin Lisa, Westlake Kelly P
Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, United States; University of Maryland School of Medicine, Department of Physical Therapy & Rehabilitation Science, Baltimore, MD, United States.
University of Maryland School of Medicine, Department of Physical Therapy & Rehabilitation Science, Baltimore, MD, United States.
Gait Posture. 2021 May;86:292-298. doi: 10.1016/j.gaitpost.2021.03.025. Epub 2021 Mar 24.
Stand-to-sit (StandTS) movement is an important functional activity that can be challenging for older adults due to age-related changes in neuromotor control. Although trunk flexion, eccentric contraction of the rectus femoris (RF), and coordination of RF and biceps femoris (BF) muscles are important to the StandTS task, the effects of aging on these and related outcomes are not well studied.
What are the age-related differences in trunk flexion, lower extremity muscle activation patterns, and postural stability during a StandTS task and what is the relationship between these variables?
Ten younger and ten older healthy adults performed three StandTS trials at self-selected speeds. Outcomes included peak amplitude, peak timing, burst duration, and onset latency of electromyography (EMG) activity of the RF and BF muscles, trunk flexion angle and angular velocity, whole body center of mass (CoM) displacement, center of pressure (CoP) velocity, and ground reaction force (GRF).
There were no age-related differences in weight-bearing symmetry, StandTS and trunk flexion angular velocity, or BF activity. In both groups, EMG peak timing of RF was preceded by BF. Compared to younger adults, older adults demonstrated shorter RF EMG burst duration, reduced trunk flexion, and reduced stability as indicated by the longer duration in which CoM was maintained beyond the posterior limit of base of support (BoS), greater mean anterior-posterior CoP velocity and larger standard deviation of CoM vertical acceleration during StandTS with smaller vertical GRF immediately prior to StandTS termination. Trunk flexion angle and RF EMG burst duration correlated with stability as measured by the duration in which the CoM stayed within the BoS.
Decreased trunk flexion and impaired eccentric control of the RF are associated with StandTS instability in aging and suggest the importance of including StandTS training as a part of a comprehensive balance intervention.
从站立到坐下（StandTS）的动作是一项重要的功能活动，由于神经运动控制方面与年龄相关的变化，对老年人来说可能具有挑战性。尽管躯干屈曲、股直肌（RF）的离心收缩以及RF和股二头肌（BF）肌肉的协调对StandTS任务很重要，但衰老对这些以及相关结果的影响尚未得到充分研究。
在StandTS任务期间，躯干屈曲、下肢肌肉激活模式和姿势稳定性方面与年龄相关的差异是什么，以及这些变量之间的关系是什么？
10名年轻健康成年人和10名年长健康成年人以自我选择的速度进行了三次StandTS试验。结果包括RF和BF肌肉的肌电图（EMG）活动的峰值幅度、峰值时间、爆发持续时间和起始潜伏期、躯干屈曲角度和角速度、全身质心（CoM）位移、压力中心（CoP）速度以及地面反作用力（GRF）。
在负重对称性、StandTS和躯干屈曲角速度或BF活动方面，没有与年龄相关的差异。在两组中，RF的EMG峰值时间都早于BF。与年轻成年人相比，年长成年人表现出RF的EMG爆发持续时间更短、躯干屈曲减少以及稳定性降低，这表现为CoM维持在支撑面（BoS）后限之外的时间更长、StandTS期间CoP的平均前后速度更大以及CoM垂直加速度的标准差更大，且在StandTS终止前垂直GRF更小。躯干屈曲角度和RF的EMG爆发持续时间与通过CoM停留在BoS内的持续时间衡量的稳定性相关。
躯干屈曲减少和RF的离心控制受损与衰老过程中StandTS的不稳定性相关，并表明将StandTS训练作为综合平衡干预的一部分的重要性。
