Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America.
Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America.
PLoS One. 2020 Nov 13;15(11):e0242454. doi: 10.1371/journal.pone.0242454. eCollection 2020.
The ability to balance on one foot for a certain time is a widely used clinical test to assess the effects of age and diseases like peripheral neuropathy on balance. While state-space methods have been used to explore the mechanical demands and achievable accelerations for balancing on two feet in the sagittal plane, less is known about the requirements for sustaining one legged balance (OLB) in the frontal plane.
While most studies have focused on ankle function in OLB, can age and/or disease-related decreases in maximum hip abduction strength also affect OLB ability?
A two-link frontal plane state space model was used to define and explore the 'feasible balance region' which helps reveal the requirements for maintaining and restoring OLB, given the adverse effects of age and peripheral neuropathy on maximum hip and ankle strengths.
Maintaining quasistatic OLB required 50%-106% of the maximum hip abduction strength in young and older adults, and older patients with peripheral neuropathy. Effectiveness of a 'hip strategy' in recovering OLB was heavily dependent on the maximum hip abduction strength, and for healthy older women was as important as ankle strength. Natural reductions of strength due to healthy aging did not show a meaningful reduction in meeting the strength requirement of clinical OLB. However deficits in hip strength typical of patients with peripheral neuropathy did adversely affect both quasistatic OLB and recoverable OLB states.
The importance of hip muscle strength has been underappreciated in the clinical OLB test. This is partly because the passive tissues of the hip joint can mask moderate deficits in hip abduction strength until it is needed for recovering OLB. Adding a follow up OLB test with a slightly raised pelvis would be a simple way to check for adequate hip abductor muscle strength.
单脚平衡一定时间的能力是一种广泛用于评估年龄和周围神经病变等疾病对平衡影响的临床测试。虽然状态空间方法已被用于探索矢状面双脚平衡的力学需求和可实现的加速度，但对于维持单脚平衡（OLB）在额状面的要求知之甚少。
虽然大多数研究都集中在 OLB 中的踝关节功能上，但年龄和/或与疾病相关的最大髋关节外展力量下降是否也会影响 OLB 能力？
使用双链接额状面状态空间模型来定义和探索“可行平衡区域”，该区域有助于揭示在最大髋关节和踝关节力量对年龄和周围神经病的不利影响下维持和恢复 OLB 的要求。
维持准静态 OLB 需要年轻人和老年人以及患有周围神经病的老年患者的最大髋关节外展力量的 50%-106%。“髋关节策略”在恢复 OLB 中的有效性严重依赖于最大髋关节外展力量，对于健康的老年女性，其重要性与踝关节力量一样。由于健康衰老导致的自然力量下降并没有在满足临床 OLB 的力量要求方面表现出有意义的降低。然而，周围神经病患者典型的髋关节力量不足会对准静态 OLB 和可恢复 OLB 状态产生不利影响。
在临床 OLB 测试中，髋关节肌肉力量的重要性被低估了。这部分是因为髋关节的被动组织可以掩盖髋关节外展力量的中度缺陷，直到需要恢复 OLB 时才会显现出来。添加一个稍微抬高骨盆的后续 OLB 测试将是检查足够的髋关节外展肌力量的简单方法。
