Department of Kinesiology, University of New Hampshire, 124 Main Street, Durham, NH 03824, USA.
J Electromyogr Kinesiol. 2010 Jun;20(3):482-8. doi: 10.1016/j.jelekin.2009.08.004. Epub 2009 Sep 25.
The objective of this study was to compare reaction time, joint torque, rate of torque development, and magnitude of neuromuscular activation of lower-extremity muscles in elderly female fallers and nonfallers. Participants included 11, elderly, female fallers (71.3+/-5.4 years) and twelve nonfallers (71.3+/-6.2 years) who completed a fall risk questionnaire. Then, maximal, voluntary, isometric contractions of the knee and ankle muscles were performed in reaction to a visual cue to determine joint torque, rate of torque development, reaction time, and nervous activation of agonists and antagonists. Results indicated that significantly more fallers reported "dizziness upon rising", "use of balance altering medications", "stress or depression", "not enough sleep", "arthritis in lower body", "chronic pain in lower body", and "tiring easily while walking" (all P<0.05). Normalized dorsiflexion and plantarflexion strength scores (summation of peak torque, rate of torque development and impulse) were lower in fallers than in nonfallers (P<0.05). When summed across lower-extremity muscle groups, fallers demonstrated 19% lower peak torque and 29% longer motor time (P<0.05). In conclusion, comprehensive fall risk screening and prevention programs should address both neuromuscular and non-muscular factors, and, weakness of the ankle dorsiflexors and plantarflexors should be further studied as potential contributors to falls in older adults.
本研究旨在比较老年女性跌倒者和非跌倒者下肢肌肉的反应时间、关节扭矩、扭矩发展速率和神经肌肉激活程度。参与者包括 11 名老年女性跌倒者（71.3+/-5.4 岁）和 12 名非跌倒者（71.3+/-6.2 岁），他们完成了跌倒风险问卷。然后，通过视觉提示对膝关节和踝关节肌肉进行最大、自愿等长收缩，以确定关节扭矩、扭矩发展速率、反应时间以及激动剂和拮抗剂的神经激活程度。结果表明，跌倒者更多地报告“起床时头晕”、“使用影响平衡的药物”、“压力或抑郁”、“睡眠不足”、“下半身关节炎”、“下半身慢性疼痛”和“行走时容易疲劳”（均 P<0.05）。跌倒者的背屈和跖屈力量评分（峰值扭矩、扭矩发展速率和脉冲的总和）低于非跌倒者（P<0.05）。当跨下肢肌肉群总和时，跌倒者的峰值扭矩降低了 19%，运动时间延长了 29%（P<0.05）。总之，全面的跌倒风险筛查和预防计划应同时考虑神经肌肉和非肌肉因素，并且应该进一步研究踝关节背屈肌和跖屈肌的无力是否是老年人跌倒的潜在原因。
