Pimentel Richard E, Feldman Jordan N, Lewek Michael D, Franz Jason R
Applied Biomechanics Laboratory, Joint Department of BME, UNC, and NCSU, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
Human Movement Science Laboratory, Division of Physical Therapy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
Front Sports Act Living. 2022 Sep 9;4:942498. doi: 10.3389/fspor.2022.942498. eCollection 2022.
Walking speed is a useful surrogate for health status across the population. Walking speed appears to be governed in part by interlimb coordination between propulsive (F) and braking (F) forces generated during step-to-step transitions and is simultaneously optimized to minimize metabolic cost. Of those forces, F generated during push-off has received significantly more attention as a contributor to walking performance. Our goal was to first establish empirical relations between F and walking speed and then to quantify their effects on metabolic cost in young adults. To specifically address any link between F and walking speed, we used a self-paced treadmill controller and real-time biofeedback to independently prescribe walking speed or F across a range of condition intensities. Walking with larger and smaller F led to instinctively faster and slower walking speeds, respectively, with ~80% of variance in walking speed explained by F. We also found that comparable changes in either F or walking speed elicited predictable and relatively uniform changes in metabolic cost, together explaining ~53% of the variance in net metabolic power and ~14% of the variance in cost of transport. These results provide empirical data in support of an interdependent relation between F and walking speed, building confidence that interventions designed to increase F will translate to improved walking speed. Repeating this protocol in other populations may identify other relations that could inform the time course of gait decline due to age and disease.
步行速度是衡量整个人群健康状况的一个有用指标。步行速度似乎部分受步间转换过程中产生的推进力（F）和制动力（F）之间的肢体间协调性的控制，同时被优化以将代谢成本降至最低。在这些力中，蹬离过程中产生的F作为步行表现的一个影响因素受到了更多关注。我们的目标是首先建立F与步行速度之间的实证关系，然后量化它们对年轻人代谢成本的影响。为了具体探究F与步行速度之间的联系，我们使用了一个自定步速的跑步机控制器和实时生物反馈，在一系列运动强度条件下独立设定步行速度或F。分别以较大和较小的F行走会本能地导致较快和较慢的步行速度，步行速度约80%的差异可由F解释。我们还发现，F或步行速度的可比变化会引起代谢成本可预测且相对一致的变化，二者共同解释了净代谢功率约53%的差异和运输成本约14%的差异。这些结果提供了实证数据，支持F与步行速度之间存在相互依存关系，增强了这样一种信心，即旨在增加F的干预措施将转化为步行速度的提高。在其他人群中重复此方案可能会发现其他关系，这些关系可为因年龄和疾病导致的步态衰退的时间进程提供信息。
