Internal mechanical work and maximum subtalar joint pronation in different gradients

Abstract Introduction: Some authors have described the importance of physiological intensity in the behavior of the biomechanical aspects of running (for example, subtalar pronation), but the complex relationships between these variables are not yet well understood. Objective: This study investigated the influence of positive gradients on internal mechanical work (Wint) and maximum subtalar pronation at a submaximal running speed. Method: Sixteen male, trained long-distance runners (age: 29 ± 7 yr; stature: 1.72 ± 0.07 m; body mass: 72.1 ± 10.6 kg), performed four running economy tests (gradients: +1%, +5%, +10% and +15%, respectively) for four minutes at a same submaximal running speed to quantify the maximum values of subtalar pronation and predict the Wint values. Data were analyzed using descriptive statistics, Student’s T-test, and one-way repeated-measures (ANOVA) along with the Statistical Package for the Social Sciences (SPSS) version 20.0. Results: Wint increased according to the gradient (p &lt; 0.05). However, no significant differences were observed in the maximum values of maximum subtalar pronation corresponding to each gradient. Conclusion: Results show the maximum subtalar pronation during submaximal running depends on the speed rather than intensity of effort.引言：已有学者阐述了生理强度在跑步生物力学行为（如距下关节旋前（subtalar pronation））中的重要性，但上述变量间的复杂关联尚未得到充分阐释。研究目的：本研究旨在探究亚最大跑速下，正向坡度对内部机械功（Wint）及最大距下关节旋前角度的影响。研究方法：选取16名经过系统训练的男性长跑运动员（年龄：29±7岁；身高：1.72±0.07m；体重：72.1±10.6kg），在固定亚最大跑速下完成4组跑步经济性测试，测试坡度分别为+1%、+5%、+10%、+15%，每组持续4分钟，以量化距下关节最大旋前角度并预测内部机械功（Wint）数值。数据分析采用描述性统计、学生t检验、单因素重复测量方差分析（ANOVA），并借助社会科学统计软件包（Statistical Package for the Social Sciences, SPSS）20.0版本完成。研究结果：内部机械功（Wint）随坡度递增呈显著升高趋势（p<0.05）。但不同坡度对应的最大距下关节旋前角度未出现显著组间差异。研究结论：结果表明，亚最大跑速下的最大距下关节旋前角度取决于跑步速度，而非运动强度。