Repeated sprinting on natural grass impairs vertical stiffness but does not alter plantar loading in soccer players
Repeated sprinting on natural grass impairs vertical stiffness but does not alter plantar loading in soccer players
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DOI：
10.1007/s00421-011-1884-5
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发表时间：
2011-10-01
影响因子：
3
通讯作者：
Brocherie, Franck
中科院分区：
文献类型：
--
作者：
Girard, Olivier;Racinais, Sebastien;Brocherie, Franck
本研究旨在确定在足球特定条件下重复冲刺引起的弹簧质量模型（SMM）特征、足底压力和肌肉活动的变化；也就是说，在天然草地上穿着足球鞋。13名足球运动员进行了6 x 20米短跑，中间穿插20秒的被动恢复。通过内底压力记录仪记录足底压力分布，分为9个区域进行分析。跨步时间参数允许估计SMM特征。监测股外侧肌、股直肌和股二头肌的表面肌电图活动。从第一次重复到最后一次重复，冲刺时间、接触时间和总步幅持续时间延长（+6.7、+12.9和+9.3%；均P < 0.05），而飞行时间、挥拍时间和步幅长度保持不变。跨步频率在重复中的下降接近显著性（-6.8%;P = 0.07）。最大力、平均力、峰值压力和平均压力均不受冲刺次数的主要影响，冲刺次数与足部区域之间无显著交互作用（均P < 0.05）。质心垂直位移随时间增加（P < 0.01），峰值垂直力和腿部压缩量不变（P < 0.05）。垂直刚度降低（-15.9%,P < 0.05），而腿部刚度变化不显著（-5.9%,P < 0.05）。三个测试肌肉的均方根活动在短跑重复中变化不显著。尽管穿着足球鞋的运动员在天然草地上反复冲刺会损害他们的腿弹簧行为（垂直刚度），但在肌肉激活水平或足底压力模式方面没有实质性的变化。
This study aimed to determine changes in spring-mass model (SMM) characteristics, plantar pressures, and muscle activity induced by the repetition of sprints in soccer-specific conditions; i.e., on natural grass with soccer shoes. Thirteen soccer players performed 6 x 20 m sprints interspersed with 20 s of passive recovery. Plantar pressure distribution was recorded via an insole pressure recorder device divided into nine areas for analysis. Stride temporal parameters allowed to estimate SMM characteristics. Surface electromyographic activity was monitored for vastus lateralis, rectus femoris, and biceps femoris muscles. Sprint time, contact time, and total stride duration lengthened from the first to the last repetition (+6.7, +12.9, and +9.3%; all P < 0.05), while flight time, swing time, and stride length remained constant. Stride frequency decrease across repetitions approached significance (-6.8%; P = 0.07). No main effect of the sprint number or any significant interaction between sprint number and foot region was found for maximal force, mean force, peak pressure and mean pressure (all P > 0.05). Center of mass vertical displacement increased (P < 0.01) with time, together with unchanged (both P > 0.05) peak vertical force and leg compression. Vertical stiffness decreased (-15.9%; P < 0.05) across trials, whereas leg stiffness changes were not significant (-5.9%; P > 0.05). Changes in root mean square activity of the three tested muscles over sprint repetitions were not significant. Although repeated sprinting on natural grass with players wearing soccer boots impairs their leg-spring behavior (vertical stiffness), there is no substantial concomitant alterations in muscle activation levels or plantar pressure patterns.