DeVita P, Hortobagyi T
Biomechanics Laboratory, East Carolina University, Greenville, North Carolina 27858, USA.
J Appl Physiol (1985). 2000 May;88(5):1804-11. doi: 10.1152/jappl.2000.88.5.1804.
At self-selected walking speeds, elderly compared with young adults generate decreased joint torques and powers in the lower extremity. These differences may be actual gait-limiting factors and neuromuscular adaptations with age or simply a consciously selected motor pattern to produce a slower gait. The purpose of the study was to compare joint torques and powers of young and elderly adults walking at the same speed. Twelve elderly and fourteen young adults (ages 69 and 21 yr) walked at 1.48 m/s over a force platform while being videotaped. Hip, knee, and ankle torques and powers were calculated from the reaction force and kinematic data. A support torque was calculated as the sum of the three joint torques. Extensor angular impulse during stance and positive work at each joint were derived from the torques and powers. Step length was 4% shorter and cadence was 4% higher in elderly adults (both P < 0.05) compared with young adults. Support angular impulse was nearly identical between groups, but elderly adults had 58% greater angular impulse and 279% more work at the hip, 50% less angular impulse and 39% less work at the knee, and 23% less angular impulse and 29% less work at the ankle compared with young adults (t-test, all P < 0.05). Age caused a redistribution of joint torques and powers, with the elderly using their hip extensors more and their knee extensors and ankle plantar flexors less than young adults when walking at the same speed. Along with a reduction in motor and sensory functions, the natural history of aging causes a shift in the locus of function in motor performance.
在自选步行速度下，与年轻人相比，老年人下肢产生的关节扭矩和功率降低。这些差异可能是实际的步态限制因素以及随年龄增长的神经肌肉适应性变化，或者仅仅是为了产生较慢步态而有意识选择的运动模式。本研究的目的是比较以相同速度行走的年轻人和老年人的关节扭矩和功率。12名老年人和14名年轻人（年龄分别为69岁和21岁）在测力平台上以1.48米/秒的速度行走，同时进行录像。根据反作用力和运动学数据计算髋、膝和踝关节的扭矩和功率。计算支撑扭矩为三个关节扭矩之和。站立期伸肌角冲量和每个关节的正向功由扭矩和功率得出。与年轻人相比，老年人的步长缩短了4%，步频提高了4%（均P<0.05）。两组之间的支撑角冲量几乎相同，但与年轻人相比，老年人在髋关节处的角冲量增加了58%，功增加了279%；在膝关节处的角冲量减少了50%，功减少了39%；在踝关节处的角冲量减少了23%，功减少了29%（t检验，所有P<0.05）。年龄导致关节扭矩和功率的重新分配，老年人在以相同速度行走时，比年轻人更多地使用髋部伸肌，而较少使用膝部伸肌和踝部跖屈肌。随着运动和感觉功能的下降，衰老的自然过程导致运动表现功能位点的转移。
