Force, velocity and power relationship of ankle plantar flexors and ankle dorsiflexors in the elderly

本研究旨在探讨老年人踝关节足底屈肌和踝关节背屈肌的受力特点、速度和力量关系。实验对象为15名老年男性（G-aged）和15名大学生（G-young），采用专门设计的仪器测量了足背屈肌的力、速度和合力输出，并根据Hill公式（F+a）(V+b)=(Fmax+a)b计算力-速度关系。通过超声仪测得的下肢肌肉厚度的平方估计下肢前、后横截面积（CSA-ante, CSA-poste）。CSA-ante在两组间无显著差异，但g -age组CSA-ante明显低于G-young组。最大功率值在Pmax、Fmax和Vmax上有显著差异（g -age < G-young）。与G-young相比，g -age组的跖屈肌Pmax（69.1%）和Vmax（82.8%）下降幅度大于Fmax(69.5%)，背屈肌Pmax（69.4%）下降幅度大于Fmax（81.8%）和Vmax（78.9%）。大鼠跖屈肌Fmax/CSA-poste、Pmax/CSA-poste、Vmax/下肢长度比值均显著低于幼鼠。背屈肌Famx/CSA-poste和Pmax/ CSA-poste Vmax/下肢长度比值在g -age组与G-young组比较差异无统计学意义。g -age的力-速度曲线趋于低于G-young。背屈肌的Vmax、V_<10>、V_<20>、V_<30>、V_<45>和V_<60>在g -age和G-young之间存在显著差异，而在不同的%Fmax负荷下，跖屈肌的Vmax在g -age和G-young之间无显著差异。足背屈肌激动剂和拮抗剂的iEMG和%iEMG在g -age和G-young之间无显著性差异。这些结果表明，随着年龄的增长，肌肉力量的发展能力可能比神经因素更机能性地下降。少

The present study aimed to investigate the characteristics of force, velocity and power relations of ankle plantar flexors and ankle dorsiflexors in elderly. The subjects were 15 elderly men (G-aged) and 15 college male students (G-young) Using specially designed apparatus, the force, velocity and resultant power output by the plantar-and dorsi-flexors muscles were measured, and the force-velocity relations were calculated according to Hill's equation: (F+a)(V+b)=(Fmax+a)b. Ante and post cross-sectional area (CSA-ante, CSA-poste) of the lower limb was estimated from the square of the muscle thickness measured by an ultrasonic apparatus. In CSA-poste, no significant difference was observed between the two age groups, however, the CSA-ante was significantly lower in G-aged than in G-young. The maximal power values were significant differences (G-aged < G-young) in Pmax as well as in Fmax and Vmax. Compared with G-young, G-aged showed a greater reduction in Pmax (69.1%) than Fmax (69.5%) … More and Vmax (82.8%) of the plantar-flexors, and also showed a greater reduction in Pmax (69.4%) than Fmax (81.8%) and Vmax (78.9%) of the dorsi-flexors. The ratios of Fmax/CSA-poste, Pmax/CSA-poste and Vmax/lower limb length of the plantar-flexors were significantly lower in G-aged than in G-young. However the ratios of Famx/CSA-poste and Pmax/Csa-poste Vmax/lower limb length of the dorsi-flexors were no significant in G-aged than in G-young. The force-velocity curves of G-aged tended to be lower than that of the G-young. There were significant differences among G-aged and G-young for Vmax, V_<10>, V_<20>, V_<30>, V_<45> and V_<60> in the dorsi-flexors, however, not for under various %Fmax load in the plantar-flexors. The iEMG and %iEMG of agonist and antagonist for the plantar-and dorsi-flexors were no significant between G-aged and G-young.From these results, it was suggested that the ability to develop muscular power may be reduced more functionally than neural factor with increasing age. Less