Supplementary information files for "How humans run faster: the neuromechanical contributions of functional muscle groups to running at different speeds

Supplementary files for article "How humans run faster: the neuromechanical contributions of functional muscle groups to running at different speeds"<br><br>How the neuromechanics of the lower limb functional muscle groups change with running speed remains to be fully elucidated, with implications for our understanding of human locomotion, conditioning, and injury prevention. This study compared the neuromechanics (ground reaction and joint kinetics, kinematics and muscle activity) of middle-distance athletes running on an instrumented treadmill at six wide-ranging speeds (2.78–8.33 m·s⁻¹). Ground reaction forces and kinematics were analyzed using inverse dynamics to calculate flexor and extensor joint torques, and positive and negative work done by these torques. Contributions of each functional muscle group to the total positive and negative work done by the limb during stance, swing, and the whole stride were quantified. During stance, the ankle plantar flexors were the major energy generator and absorber (&gt;60%) at all speeds, but their contribution to whole stride energy generation and absorption declined with speed. Positive work by the hip extensors rose superlinearly with speed during stance (3-fold) and especially during swing (12-fold), becoming the biggest energy generator across the whole stride at &gt;5 m·s⁻¹. Knee flexor and extensor negative work also rose superlinearly with speed during swing, with the knee flexors becoming the greatest energy absorber over the whole stride at &gt;7.22 m·s⁻¹. Across speeds, plantar flexor peak moment and positive work accounted for 97% and 96% of the variance in step length, and swing hip extension peak moment and positive work accounted for 98% and 99% of the variance in step frequency. There were pronounced speed, phase (stance/swing), and work (positive/negative) dependent contributions of the different functional muscle groups during running, with extensive implications for conditioning and injury prevention.<br><br>© The Author(s), CC BY 4.0

论文《人类如何跑得更快：不同跑步速度下功能性肌群的神经力学贡献》补充材料<br><br>下肢功能性肌群（functional muscle groups）的神经力学（neuromechanics）如何随跑步速度改变，这一科学问题尚未得到完全阐明，其研究成果对人类运动、体能训练与损伤预防的认知均具有重要参考价值。本研究针对中长跑运动员在测力跑台（instrumented treadmill）上以六种跨度较大的速度（2.78–8.33 m·s⁻¹）跑步时的神经力学指标（包括地面反作用力、关节动力学、运动学与肌电活动）开展了对比分析。研究通过逆动力学分析法对地面反作用力与运动学数据进行处理，计算了关节屈肌与伸肌的力矩，以及该力矩所做的正负功，并量化了各功能性肌群在支撑相（stance）、摆动相（swing）及完整步周期（stride）内，对下肢总正负功的贡献占比。<br><br>在支撑相中，所有测试速度下的踝关节跖屈肌（ankle plantar flexors）均为主要的能量产生与吸收结构（占比超60%），但其在完整步周期中的能量产生与吸收贡献占比随速度提升而下降。髋伸肌（hip extensors）所做的正功在支撑相内随速度呈超线性增长（增幅达3倍），在摆动相内增幅尤为显著（达12倍）；当跑步速度超过5 m·s⁻¹时，髋伸肌成为完整步周期内最大的能量产生结构。摆动相内膝关节屈肌（knee flexor）与膝关节伸肌（knee extensor）的负功同样随速度呈超线性增长；当速度超过7.22 m·s⁻¹时，膝关节屈肌成为完整步周期内最大的能量吸收结构。<br><br>在所有测试速度范围内，跖屈肌的峰值力矩与正功可分别解释步长（step length）97%与96%的变异度；摆动相髋伸肌峰值力矩与正功则可分别解释步频（step frequency）98%与99%的变异度。跑步过程中，不同功能性肌群的能量贡献存在显著的速度、运动相（支撑/摆动）及功性质（正/负）依赖性，该发现对体能训练与损伤预防均具有广泛的指导意义。<br><br>© 作者，CC BY 4.0 许可协议