Metabolic cost, mechanical work, and efficiency during walking in young and older men
Metabolic cost, mechanical work, and efficiency during walking in young and older men
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DOI：
10.1111/j.1748-1716.2006.01522.x
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发表时间：
2006-02-01
影响因子：
6.3
通讯作者：
Minetti, AE
中科院分区：
文献类型：
--
作者：
Mian, OS;Thom, JM;Minetti, AE
目的：研究机械功、效率和拮抗肌共同激活，以更好地了解老年人步行代谢成本 (C-W) 升高的原因。方法：对体重和腿长相同的健康年轻人（YOU；n = 12，年龄 = 27 +/- 3 岁）和老年人（OLD；n = 20，年龄 = 74 +/- 3 岁）步行进行代谢、机械和肌电图测量 在跑步机上以四种速度（范围从 0.83 到 1.67 m s(-1)）进行测试。结果：通过间接量热法测定的净（高于静息状态）C-W 在 OLD 中高出 31%（不同速度的平均值）（P < 0.05）。 OLD 中保持了被动摆的完整性，例如质心机械能交换（COMB），这是一种节能机制。此外，根据 COMB 和身体各节相对于 COMB 的机械能波动确定的总机械功在 OLD 中并未显着升高。这导致 OLD 效率较低（-17%，P < 0.05）。根据肌电图记录进行的时间量化，大腿拮抗肌的 OLD 中的共激活高出 31%（P < 0.05）。在三种速度下，大腿共激活与 C-W 呈中度相关（r = 0.38-0.52，P < 0.05）。结论：无步态障碍的健康七十多岁老人的 C-W 升高，这不能用全身机械功的升高来解释。拮抗肌共同激活的增加（可能是为了确保足够的关节稳定性而进行的适应）可能为 C-W 升高提供部分解释。
Aim: To investigate mechanical work, efficiency, and antagonist muscle co-activation with a view to better understand the cause of the elevated metabolic cost of walking (C-W) in older adults.Methods: Metabolic, mechanical and electromyographic measurements were made as healthy young (YOU; n = 12, age = 27 +/- 3 years) and older (OLD; n = 20, age = 74 +/- 3 years) men of equivalent body mass and leg length walked on a treadmill at four speeds (ranging from 0.83 to 1.67 m s(-1)).Results: Net (above resting) C-W, determined by indirect calorimetry was 31% higher (average across speeds) in OLD (P < 0.05). The integrity of the passive pendulum like interchange of mechanical energies of the centre of mass (COMB), an energy-saving mechanism, was maintained in OLD. Furthermore, total mechanical work, determined from fluctuations in mechanical energy of COMB and of body segments relative to COMB, was not significantly elevated in OLD. This resulted in a lower efficiency in OLD (-17%, P < 0.05). Co-activation, temporally quantified from electromyography recordings, was 31% higher in OLD for antagonist muscles of the thigh (P < 0.05). Thigh co-activation was moderately correlated with C-W at three speeds (r = 0.38-0.52, P < 0.05).Conclusion: Healthy septuagenarians with no gait impairment have an elevated C-W which is not explained by an elevation in whole body mechanical work. Increased antagonist muscle co-activation (possibly an adaptation to ensure adequate joint stability) may offer partial explanation of the elevated C-W.