Intra-rater reliability and minimal detectable change of vertical ground reaction force measurement during gait and half-squat tasks on healthy male adults

Background: The understanding of vertical ground reaction force (VGRF) during walking and half-squatting is necessary and commonly utilised during the rehabilitation period. The purpose of this study was to establish measurement reproducibility of VGRF that reports the minimal detectable changes (MDC) during walking and half-squatting activity among healthy male adults. Methods: 14 male adults of average age, 24.88 (5.24) years old, were enlisted in this study. The VGRF was assessed using the force plates which were embedded into a customised walking platform. Participants were required to carry out three trials of gait and half-squat. Each participant completed the two measurements within a day, approximately four hours apart. Results: Measurements of VGRF between sessions presented an excellent VGRF data for walking (ICC Left = 0.88, ICC Right = 0.89). High reliability of VGRF was also noted during the halfsquat activity (ICC Left = 0.95, ICC Right = 0.90). The standard errors of measurement (SEM) of VGRF during the walking and half-squat activity are less than 8.35 Nm/kg and 4.67 Nm/kg for the gait and half-squat task respectively. Conclusion: The equipment set-up and measurement procedure used to quantify VGRF during walking and half-squatting among healthy males displayed excellent reliability. Researcher should consider using this method to measure the VGRF during functional performance assessment