Conway Katie A, Crudup Keyaira L, Lewek Michael D, Franz Jason R
Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC.
Division of Physical Therapy, Department of Allied Health Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC.
Med Sci Sports Exerc. 2021 Mar 1;53(3):574-580. doi: 10.1249/MSS.0000000000002500.
Aging and many gait pathologies are often characterized by deficits in push-off intensity (i.e., propulsive ground reaction forces and peak ankle moment and power output) during walking. Unfortunately, conventional interventions such as progressive resistance training, designed to enhance calf muscle mechanical output, generally fail to translate strength gains to functional improvements in habitual push-off intensity.
Horizontal impeding forces applied to the body's center of mass systematically augment the mechanical output required from muscle-tendon units spanning the ankle during the push-off phase of walking, which could convey long-term benefits via training. Therefore, the purpose of this study was to investigate the preliminary efficacy of a 6-wk horizontal impeding force training paradigm on improving habitual push-off intensity in 11 healthy but not physically active older adults (age = 76 ± 4 yr, 6 females and 5 males).
We found that older adults significantly (P < 0.05) increased measures of isometric strength by 18%, maximum walking speed by 10%, and 6-min walk test distance by 9% as a result of horizontal impeding force training. As a more clinically significant contribution of this work, we found that those subjects also increased habitual peak ankle moment and peak ankle power during push off after training by a significant 10% and 15%, respectively (P ≤ 0.036).
We conclude that the use of horizontal impeding forces in older adults improves their maximum muscular and walking capacities while encouraging access to newfound strength gains, thereby improving habitual push-off intensity during walking.
衰老以及许多步态病理状况通常的特征是步行过程中蹬离强度不足(即推进性地面反作用力、踝关节力矩峰值和功率输出)。不幸的是,旨在增强小腿肌肉机械输出的传统干预措施,如渐进性抗阻训练,通常无法将力量增长转化为习惯性蹬离强度的功能改善。
在步行蹬离阶段,施加于身体重心的水平阻力会系统性地增加跨越踝关节的肌肉-肌腱单元所需的机械输出,通过训练可能带来长期益处。因此,本研究的目的是调查为期6周的水平阻力训练模式对11名健康但缺乏身体活动的老年人(年龄 = 76 ± 4岁,6名女性和5名男性)习惯性蹬离强度改善的初步疗效。
我们发现,通过水平阻力训练,老年人的等长力量测量值显著增加(P < 0.05)18%,最大步行速度增加10%,6分钟步行试验距离增加9%。作为这项工作更具临床意义的贡献,我们发现这些受试者在训练后蹬离过程中的习惯性踝关节力矩峰值和踝关节功率峰值也分别显著增加了10%和15%(P ≤ 0.036)。
我们得出结论,在老年人中使用水平阻力可提高他们的最大肌肉力量和步行能力,同时促进获得新增加的力量,从而改善步行过程中的习惯性蹬离强度。