1Department of Podiatry, School of Health, Medical and Applied Science, Central Queensland University, Rockhampton, Queensland Australia.
2Physical Education and Sports Science Academic Group, National Institute of Education, Nanyang Technological University, Singapore, Singapore.
J Foot Ankle Res. 2019 Apr 23;12:24. doi: 10.1186/s13047-019-0334-1. eCollection 2019.
Flat-footed individuals are believed to have poorer jump performance compared to normal-arched individuals. Foot orthoses are commonly used to support the deformed foot arch, and improve normal foot function. However, it is unclear if foot orthoses use affects jump performance in athletes. Our study aims to investigate if foot type and/or foot orthosis influence countermovement jump (CMJ) and standing broad jump (SBJ) performance and lower limb biomechanics.
Twenty-six male basketball players were classified into normal-arched ( = 15) or flat-footed ( = 11) groups using the Chippaux-Smirak index, navicular drop test, and the resting calcaneal angle measurement. They performed jumps with and without prefabricated foot orthoses. We measured jump height and distance for CMJ and SBJ, respectively. Hip, knee and ankle joint angles, angular velocities, moments and powers during take-off were also measured.
For CMJ, the flat-footed group exhibited less ankle plantarflexion ( = 8.407, = 0.008, = 0.259 large effect) and less hip joint power ( = 7.416, = 0.012, = 0.244 large effect) than the normal-arched group. Foot orthoses reduced ankle eversion in both groups ( = 6.702, = 0.016, = 0.218 large effect). For SBJ, the flat-footed group produced lower peak hip angular velocity ( = 7.115, = 0.013, = 0.229 large effect) and generated lower horizontal GRF ( = 5.594, = 0.026, = 0.189 large effect) than the normal-arched group. Wearing foot orthoses reduced ankle eversion ( = 5.453, = 0.028, = 0.185 large effect), peak horizontal GRF ( = 13.672, = 0.001, = 0.363 large effect) and frontal plane ankle moment ( = 4.932, = 0.036, = 0.170 large effect).
Foot type and the use of foot orthoses influence take-off biomechanics, but not actual CMJ and SBJ performances in basketball players. Compared to the normal-arched individuals, flat-footed athletes generated smaller propulsion GRF and lower hip flexion velocity and power, which suggests possible compensatory movement strategies to maximise jump performance. Future studies may investigate whether these altered biomechanics, taking into consideration their respective magnitude and effect sizes, may have implications on lower limb injuries. The use of foot orthoses resulted in biomechanical changes in both the normal-arched and flat-footed groups but does not enhance jumping performance.
扁平足的人被认为比正常足弓的人跳跃表现更差。足部矫形器常用于支撑变形的足弓，改善正常足部功能。然而，目前尚不清楚足部矫形器的使用是否会影响运动员的跳跃表现。我们的研究旨在调查足型和/或足部矫形器是否会影响反跳式（CMJ）和站立式跳远（SBJ）的表现以及下肢生物力学。
使用 Chippaux-Smirak 指数、舟骨下降测试和跟骨休息角测量，将 26 名男性篮球运动员分为正常足弓（n=15）或扁平足（n=11）组。他们在使用和不使用预制足部矫形器的情况下进行跳跃。我们分别测量了 CMJ 和 SBJ 的跳跃高度和距离。还测量了起跳时髋关节、膝关节和踝关节的角度、角速度、力矩和功率。
对于 CMJ，扁平足组的踝关节跖屈（ = 8.407， = 0.008， = 0.259 大效应）和髋关节功率（ = 7.416， = 0.012， = 0.244 大效应）小于正常足弓组。足部矫形器减少了两组的踝关节外翻（ = 6.702， = 0.016， = 0.218 大效应）。对于 SBJ，扁平足组的髋关节峰值角速度（ = 7.115， = 0.013， = 0.229 大效应）和水平 GRF（ = 5.594， = 0.026， = 0.189 大效应）均低于正常足弓组。穿足部矫形器可减少踝关节外翻（ = 5.453， = 0.028， = 0.185 大效应）、水平 GRF（ = 13.672， = 0.001， = 0.363 大效应）和额状面踝关节力矩（ = 4.932， = 0.036， = 0.170 大效应）。
足型和足部矫形器的使用会影响起跳的生物力学，但不会影响篮球运动员的实际 CMJ 和 SBJ 表现。与正常足弓的人相比，扁平足运动员产生的推进力 GRF 较小，髋关节屈曲速度和力量较低，这表明可能存在补偿运动策略来最大程度地提高跳跃表现。未来的研究可能会研究这些改变的生物力学特性，同时考虑它们各自的幅度和效应大小，是否会对下肢损伤产生影响。足部矫形器的使用在正常足弓和扁平足组都导致了生物力学的变化，但不会提高跳跃表现。
