踝关节力量生物反馈可减弱老年人远端至近端的重新分布。
Ankle power biofeedback attenuates the distal-to-proximal redistribution in older adults.
机构信息
Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC, USA.
Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC, USA.
出版信息
Gait Posture. 2019 Jun;71:44-49. doi: 10.1016/j.gaitpost.2019.04.011. Epub 2019 Apr 11.
BACKGROUND
Compared to young adults, older adults walk slower, with shorter strides, and with a characteristic decrease in ankle power output. Seemingly in response, older adults rely more than young on hip power output, a phenomenon known as a distal-to-proximal redistribution. Nevertheless, older adults can increase ankle power to walk faster or uphill, revealing a translationally important gap in our understanding.
RESEARCH QUESTION
Our purpose was to implement a novel ankle power biofeedback paradigm to encourage favorable biomechanical adaptations (i.e. reverse the distal-redistribution) during habitual speed walking in older adults.
METHODS
10 healthy older adults walked at their preferred speeds while real-time visual biofeedback provided target increases and decreases of 10 and 20% different from preferred ankle power. We evaluated the effect of changes in ankle power on joint kinetics, kinematics, and propulsive ground reaction forces. Pre and post overground walking speed assessments evaluated the effect of increased ankle power recall on walking speed.
RESULTS
Biofeedback systematically elicited changes in ankle power; increasing and decreasing ankle power by 14% and 17% when targeting ±20% different from preferred, respectively. We observed a significant negative correlation between ankle power and hip extensor work. Older adults relied more heavily on changes in ankle angular velocity than ankle moment to modulate ankle power. Lastly, older adults walked almost 11% faster when recalling increased ankle power overground.
SIGNIFICANCE
Older adults are capable of increasing ankle power through targeted ankle power biofeedback - effects that are accompanied by diminished hip power output and attenuation of the distal-to-proximal redistribution. The associated increase in preferred walking speed during recall suggests a functional benefit to increased ankle power output via transfer to overground walking. Further, our mechanistic insights allude to translational success using ankle angular velocity as a surrogate to modulate ankle power through biofeedback.
背景
与年轻人相比，老年人行走速度较慢，步幅较短，踝关节输出功率特征性降低。似乎是为了应对这种情况，老年人比年轻人更依赖髋关节输出功率，这种现象被称为远端到近端的重新分布。然而，老年人可以增加踝关节力量来走得更快或上坡，这揭示了我们理解中的一个重要的转化差距。
研究问题
我们的目的是实施一种新的踝关节力量生物反馈范式，以鼓励老年人在习惯性的日常行走中进行有利的生物力学适应（即逆转远端重新分布）。
方法
10 名健康的老年人以他们喜欢的速度行走，同时实时视觉生物反馈提供了 10%和 20%的目标增加和减少，与踝关节力量的偏好值不同。我们评估了踝关节力量变化对关节动力学、运动学和推进地面反作用力的影响。在地面行走速度评估之前和之后，评估了增加踝关节力量回忆对行走速度的影响。
结果
生物反馈系统地引起了踝关节力量的变化；当目标值与偏好值相差±20%时，分别增加和减少 14%和 17%的踝关节力量。我们观察到踝关节力量与髋关节伸肌做功之间存在显著的负相关。老年人更依赖于踝关节角速度的变化而不是踝关节力矩来调节踝关节力量。最后，老年人在回忆增加踝关节力量时，地面行走速度几乎提高了 11%。
意义
老年人能够通过有针对性的踝关节力量生物反馈增加踝关节力量——这些效果伴随着髋关节输出功率的降低和远端到近端的重新分布的衰减。在回忆过程中，偏好行走速度的增加表明通过生物反馈使用踝关节角速度作为替代来调节踝关节力量具有功能性益处。此外，我们的机制见解暗示了使用踝关节角速度作为替代来通过生物反馈调节踝关节力量的转化成功。
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