Department of Kinesiology, University of New Hampshire, Durham, NH, USA.
Gait Posture. 2011 Apr;33(4):668-72. doi: 10.1016/j.gaitpost.2011.02.022. Epub 2011 Apr 1.
The purpose of this study was to determine how lower-limb strength in older women affected gait speed, supportive forces, spatial, and temporal aspects of walking gait. Twenty-four women between 65 and 80 yr performed maximal voluntary isometric contractions for the knee extensors (KE), knee flexors (KF), ankle plantarflexors (PF) and ankle dorsiflexors (DF) and were separated into low strength and normal strength groups using a KE torque threshold of 1.5 Nm kg(-1). They walked at both a standard speed of 0.8 m s(-1) and at a self-selected maximal speed on an instrumented treadmill that recorded vertical ground reaction forces (vGRF) and spatiotemporal gait measures. Older women with low strength had 30% lower KE maximal torque, 36% lower PF maximal torque, 34% lower KE rate of torque development (RTD) and 30% lower KF RTD. Low strength women demonstrated slower maximal walking speeds (1.26±0.20 m s(-1) vs. 1.56±0.20 m s(-1)), lower vGRF during weight acceptance (1.15±0.10 BW vs. 1.27±0.13 BW), lower weight acceptance rates (11.3±0.5 BW s(-1) vs. 17.0±5.5 BW s(-1)), slower stride rates, shorter stride lengths, and longer foot-ground and double-limb support times (all P<0.05). Maximal gait speed was strongly correlated to peak vGRF and rate (r=0.60-0.85, P<0.01) and moderately related to lower-limb strength (r=0.42-0.60, P<0.05). In older women with low strength, diminished peak vGRFs were associated with slower walking speeds putting them at risk for mobility limitation, disability, poor health, and loss of independence.
本研究旨在确定老年女性下肢力量如何影响步态速度、支撑力、行走步态的空间和时间方面。24 名 65 至 80 岁的女性进行了最大自主等长收缩的膝关节伸展肌（KE）、膝关节屈肌（KF）、踝关节跖屈肌（PF）和踝关节背屈肌（DF），并使用 KE 扭矩阈值为 1.5 Nm kg(-1)将其分为低强度组和正常强度组。她们在仪器化跑步机上以标准速度 0.8 m s(-1)和自我选择的最大速度行走，该跑步机记录垂直地面反力（vGRF）和时空步态测量值。下肢力量较弱的老年女性的 KE 最大扭矩降低了 30%，PF 最大扭矩降低了 36%，KE 扭矩发展率（RTD）降低了 34%，KF RTD 降低了 30%。低强度女性的最大行走速度较慢（1.26±0.20 m s(-1)比 1.56±0.20 m s(-1)），在承受体重时的 vGRF 较低（1.15±0.10 BW 比 1.27±0.13 BW），承受体重的速度较低（11.3±0.5 BW s(-1)比 17.0±5.5 BW s(-1)），步速较慢，步长较短，足地和双支撑时间较长（均 P<0.05）。最大步态速度与峰值 vGRF 和速度高度相关（r=0.60-0.85，P<0.01），与下肢力量中度相关（r=0.42-0.60，P<0.05）。在下肢力量较弱的老年女性中，峰值 vGRF 降低与行走速度较慢有关，使她们面临活动受限、残疾、健康状况不佳和丧失独立性的风险。
