Objective

The purposes of this study were to investigate the combined effects of age and obesity on gait and to analyze the relationship between age and obesity on ankle muscle activities during walking.

Materials and methods

4 groups; the young non-obese control group (CG, n = 50, age = 31.8 ± 4.5 years; BMI = 21.4 ± 2.2 kg/m²), the young obese group (OB, n = 30, age = 35.4 ± 4.1 years; BMI = 38.6 ± 3.5 kg/m²), the non-obese older adults group (OA, n = 20, age = 76.1 ± 3.5 years; BMI = 24.4 ± 1.1 kg/m²) and the obese older adults group (OBOA, n = 20, age = 79.6 ± 5.7 years; BMI = 35.5 ± 2.7 kg/m²) walked on an instrumented gait analysis treadmill at their preferred walking speed. Spatiotemporal parameters, walking cycle phases, Vertical ground reaction force (GRFv) and center of pressure (CoP) velocity were sampled from the treadmill software. Electromyography (EMG) activity of the gastrocnemius medialis (GM), the soleus (SOL) and tibialis anterior (TA) were also collected during the walking test. A forward stepwise multiple regression analysis was performed to determine if body weight or age could predict ankle muscle activities during the different walking cycle phases.

Results

Compared to OB, OBOA walked with higher CoP velocity, shorter stride, spending more time in support phase (p < .05). These manifestations were associated with higher TA and SOL activities during the 1st double support (1st DS) and higher TA activity during the single support (SS) (p < .05). Compared to OA, OBOA walked with lower GRFv, shorter and wider stride and spend more time in SU (p < .05). Moreover, SOL, TA and GM activities of OBOA were higher compared to OAG during 1st DS, SS and 2nd Double support (2nd DS), respectively (p < .05). During the 1ST DS, the stepwise multiple regression revealed that age accounted for 87% of the variance of TA activity. The addition of age contributed a further 16% to explain the variance TA activity. During the SS, age accounted for 64% and 46% of the variance of SOL and TA activity respectively. The addition of the body weight added further 15% and 66% of the variation of SOL and TA activity respectively. During the 2nd DS, body weight accounted for 86% of the variance and the addition of the body weight added a further 17% to explain the high level of GM.

Conclusion

Age in obese adults and obesity in older adults should be considered separately to evaluate neuromuscular responses during walking and, subsequently, optimize the modality of treatment and rehabilitation processes in obese individuals in order to reduce and/or prevent the risk of falls.

中文翻译：

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肥胖与年龄相关的相互作用对步态和跨踝关节肌肉活动的影响。

目的

这项研究的目的是调查年龄和肥胖对步态的综合影响，并分析年龄和肥胖对步行过程中脚踝肌肉活动的关系。

材料和方法

4组；非肥胖的年轻对照组（CG，n  = 50，年龄= 31.8±4.5岁； BMI = 21.4±2.2 kg / m ²），年轻的肥胖组（OB，n  = 30，年龄= 35.4±4.1岁； BMI = 38.6±3.5 kg / m ²），非肥胖老年人组（OA，n  = 20，年龄= 76.1±3.5岁； BMI = 24.4±1.1 kg / m ²）和肥胖老年人组（OBOA） ，n = 20，年龄= 79.6±5.7岁； BMI = 35.5±2.7 kg / m ²）以他们喜欢的步行速度在仪器化步态分析跑步机上行走。时空参数，步行周期阶段，垂直地面反作用力（GRFv）和压力中心（CoP）速度均从跑步机软件中采样。步行测试期间还收集了腓肠肌（GM），比目鱼（SOL）和胫骨前（TA）的肌电图（EMG）活性。进行了逐步逐步回归分析，以确定体重或年龄是否可以预测不同步行周期阶段的脚踝肌肉活动。

结果

与OB相比，OBOA以更高的CoP速度，更短的步幅行走，在支持阶段花费更多的时间（p  <.05）。这些表现与第一个双支持（1st DS）期间较高的TA和SOL活性以及单支持（SS）期间较高的TA活性相关（p <.05）。与OA相比，OBOA行走时GRFv较低，步幅更短且更宽，并且在SU中花费更多的时间（p <.05）。此外，在第一个DS，SS和第二个双重支持（第二个DS）期间，OBOA的SOL，TA和GM活性分别高于OAG（p <.05）。在1ST DS期间，逐步多元回归显示年龄占TA活动差异的87％。年龄的增加进一步贡献了16％，以解释方差TA活性。在SS期间，年龄分别占SOL和TA活性差异的64％和46％。体重的增加分别增加了SOL和TA活性变化的15％和66％。在第二次DS中，体重占差异的86％，体重的增加又增加了17％，以解释高水平的GM。

结论

肥胖成年人的年龄和老年人的肥胖应该分开考虑，以评估步行过程中的神经肌肉反应，并随后优化肥胖个体的治疗和康复过程的方式，以减少和/或预防跌倒的风险。