Test-retest Reliability And Concurrent Validity Of An In-shoe Pressure System During Two Landing Maneuvers

Abstract

In-shoe pressure sensor systems have been used to measure vertical ground reaction forces (GRFs) during functional tasks in clinical settings. However, no study has evaluated their reliability and validity during functional tasks in healthy soccer players. PURPOSE: To determine the test-retest reliability of the peak plantar pressure measured by an in-shoe pressure system during landing from long-jump (LLJ) and landing from heading-jump (LHJ) performed by healthy soccer players. A second purpose was to evaluate the concurrent validity of the peak plantar pressure in relation to the peak vertical GRFs obtained using a force plates system as a criterion reference during both landing maneuvers. METHODS: Ten healthy soccer players (age: 25.6 ± 2.67; BMI: 22.74 ± 2.33) participated in this study. LLJ included jumping forward and landing on the force plates, whereas LHJ included jumping forward to head a soccer ball and landing on the force plates. Each participant performed five trials of each landing maneuvers. Within three days from initial testing, participants were asked to perform the same five trials of each landing task. Peak plantar pressure and peak vertical GRFs were measured during the landing phase (from initial contact to maximum bilateral knee flexion). Intra-class correlation coefficients [ICC (3,2)] were used to determine test-retest reliability. Pearson product-moment coefficient of correlations (r) were calculated to compare the peak plantar pressure with the peak vertical GRFs. RESULTS: Test-retest reliability exhibited good reliability for peak pressure during LLJ (ICC = 0.96) and LHJ (ICC = 0.89). Peak plantar pressure and peak vertical GRFs showed a significant good-to-excellent positive correlation (r = 0.80, p < 0.001) during the LLJ, whereas a significant moderate-to-good positive correlation (r = 0.67, p = 0.03) was observed during the LHJ. CONCLUSION: The present findings indicate that the in-shoe pressure system is reliable and valid during both landing maneuvers in healthy soccer players. Therefore, this system could be a useful tool to evaluate vertical GRFs in field and laboratory settings since it does not restrict participants to step or land on the force plates, thus allowing them to perform a more natural functional task.