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Effects of foot orthosis on ground reaction forces and perceived comfort at moderate to fast running speeds in flat-footed athletes
Author
Ng, Jun Wei
Supervisor
Kong, Pui Wah
Abstract
Flatfoot is a flattening of the foot medial arch. This condition places athletes on higher risk of running-related injuries from sporting movement consisting of repetitive high loading on the foot. Immediate and conservative treatments such as a foot orthosis (FO) were found to benefit flatfooted individuals during standing, walking and running at submaximal speeds. In the current literature, there is a gap in the use of FO on flatfooted athletes at faster running speeds that reflect the nature of many sprint-based sports. Therefore, the present study aimed to examine the effects of a prefabricated FO for flatfooted male athletes during fast running. It was hypothesised that a prefabricated FO may benefit flatfooted male athletes during fast running speeds in reducing the vertical impact force and loading rate while increasing perceived comfort. A randomised crossover repeated measures experiment was conducted to compare within-group differences between FO and sham orthosis (control) for effects of FO. Adult male athletes (n=20) with flatfoot participating in sprint-based sports were recruited for running trials on an instrumented treadmill at three running speeds (5m/s, 6 m/s, 7 m/s). The force plates and visual analogue scale (VAS) were used to measure ground reaction force (GRF) and perceived comfort respectively. Two-way analysis of variance (ANOVA) with repeated measures were performed on the GRF variables while paired sample t-tests were used to analyse the perception data. Results showed that FO use increased vertical impact force (p = .005) and vertical loading rate (p = .001); increased propulsive force variability (p = .038) and loading rate variability (p = .019) across all speeds; reduced all perceived forefoot cushioning (p = .001), perceived heel cushioning (p = .002), and perceived comfort (p = .008) but increased perceived arch support (p = .001). It was discussed that increased GRF variables may be related to increased joint stiffness to reduce rearfoot overpronation in flatfooted gait, while the effect in perception and gait variability variables associated with FO use may be related to material hardness and perceived novelty, respectively. It was concluded that a prefabricated FO alters both kinetic and perception variables of flatfooted athletes during fast running. Future work can further investigate on the effect of FO on joint kinematics and on reducing risk of running-related injuries.
Date Issued
2019
Call Number
GV1061 Ng