Human Performance Laboratory, University of Calgary, Calgary, AB, Canada T2N 1N4.
J Exp Biol. 2012 Dec 15;215(Pt 24):4314-21. doi: 10.1242/jeb.073833. Epub 2012 Sep 12.
Compared with running straight, when human runners sprint along a curve, the ability of the inside leg to generate force is compromised. This decreased force generation has been suggested to limit the overall performance of the runner. One theory for this force loss is that the large non-sagittal plane joint moments of the inside leg reach their operating limits, thus prohibiting further generation of the performance-related sagittal plane joint moments. We investigated the inside leg force generation and the ankle and knee joint moments when 13 subjects sprinted with and without an additional mass of 12.4 kg along a curve of 2.5 m radius. The increase in the subjects' mass evoked a significant increase in the resultant ground reaction force. The peak non-sagittal plane moments increased significantly for both the ankle and knee joints. This observation suggests that when sprinting normally with maximum effort, the non-sagittal plane joint moments are not operating at their limits. The large increases in ground reaction force were associated with greater extension moments generated at the knee joint. In contrast, the peak ankle plantarflexion moment remained unchanged across conditions. It is possible that for the specific joint configuration experienced, the overall ability to generate plantarflexion moment reaches the limit. Future studies with interventions increasing the ability of the muscle-tendon units to generate plantarflexion moment may provide an experimental opportunity to further examine this speculation.
与直线奔跑相比，人类在曲线上冲刺时，内腿产生力量的能力会受到影响。这种力量的减弱被认为限制了跑步者的整体表现。造成这种力量损失的一个理论是，内腿的大矢状面关节力矩达到了其工作极限，从而阻止了与性能相关的矢状面关节力矩的进一步产生。我们研究了 13 名受试者在以 2.5 米半径的曲线上分别以和不带有 12.4 千克附加质量的情况下冲刺时的内腿力产生情况和踝关节与膝关节力矩。受试者的质量增加引起地面反作用力的显著增加。踝关节和膝关节的峰值非矢状面力矩均显著增加。这表明，当以最大努力正常冲刺时，非矢状面关节力矩并未达到其极限。地面反作用力的大幅增加与膝关节产生的更大伸展力矩有关。相比之下，各条件下的峰值踝关节跖屈力矩保持不变。对于所经历的特定关节结构，产生跖屈力矩的整体能力可能达到了极限。未来的研究可以通过干预措施增加肌肉-肌腱单元产生跖屈力矩的能力，为进一步检验这一假设提供实验机会。
