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Postural stability of athletes is commonly tested with single-leg stance (SLS) tests. However, for this population, these tests are insufficiently challenging to achieve high sensitivity. Therefore, a new dynamic SLS test based on standardized translational surface perturbations was developed. This study aimed to assess reliability, sensitivity to learning effects, and internal and concurrent validity of this novel test.Healthy soccer players (21 females, 21 males) performed 2 test sessions. Each session consisted of 2 trials. For one trial, the participant performed a 30-seconds, unperturbed SLS on each leg, followed by 12 platform perturbations per leg.Intraclass Correlation Coefficients (ICC) and correlations between outcomes were calculated for the Center of Pressure speed (CoPs) and Time To Stabilization (TTS). ANOVA was used to assess learning effects. CoPs and TTS showed a fair reliability between sessions (ICC = 0.73–0.76). All variables showed improvement over time within and between sessions (all p < 0.01) and were moderately correlated with CoPs during unperturbed SLS (r = 0.39–0.56).Single-leg dynamic postural stability testing through standardized horizontal platform perturbations yielded sufficiently reliable CoPs and TTS outcome measures in soccer players. The moderate correlations with unperturbed SLS support concurrent validity, but also indicates that the new test captures aspects of postural stability that differ from the conventional, unperturbed SLS test.

Objective: The aims of this study were to identify the most appropriate indicator to assess the balance in the sudden perturbation test conditions. Methods: In this study, 13 freestyle national wrestlers at the age of 20.5±2.4 and 13 normal subjects with average age of 23.5±1.4 were used recruited. Balancing test was carried out under two conditions: standing with the guard (guard) and stand feet shoulder width apart (standing). To measure the balance parameters, the RS-scan system was used, and for external perturbation movable plant with weights equal to 12% of the mass was used. The independent t-test for statistical analysis in each direction between the two groups was used. Results: Center of pressure (CoP) travel distance in the anterior, posterior and external directions, wrestlers were more than those in normal individuals in both positions; for guard position (p = 0.01, p = 0.01, p = 0.5) and (p = 0.2, p = 0.5, p = 0.01) in stand position. The COP average speeds in the anterior, posterior and external directions in both conditions were more in wrestlers than that normal group, (p = 0.01, p = 0.08, p = 0.01) in the guard position and (p = 0.27, p = 0.1, p = 0.01) in the stand position. The wrestlers were able to get stable as soon as possible in both positions and in four direction (p=0.001). Conclusion: Athletes in sudden perturbation want to reach equilibrium and stability in shorter time by increasing speed CoP. Thus it seems, time to stability can be a good indicator for balance evaluating.

Postural stability of athletes is commonly tested with single-leg stance (SLS) tests. However, for this population, these tests are insufficiently challenging to achieve high sensitivity. Therefore, a new dynamic SLS test based on standardized translational surface perturbations was developed. This study aimed to assess reliability, sensitivity to learning effects, and internal and concurrent validity of this novel test. Healthy soccer players (21 females, 21 males) performed 2 test sessions. Each session consisted of 2 trials. For one trial, the participant performed a 30-seconds, unperturbed SLS on each leg, followed by 12 platform perturbations per leg. Intraclass Correlation Coefficients (ICC) and correlations between outcomes were calculated for the Center of Pressure speed (CoPs) and Time To Stabilization (TTS). ANOVA was used to assess learning effects. CoPs and TTS showed a fair reliability between sessions (ICC = 0.73-0.76). All variables showed improvement over time within and between sessions (all p < 0.01) and were moderately correlated with CoPs during unperturbed SLS (r = 0.39-0.56). Single-leg dynamic postural stability testing through standardized horizontal platform perturbations yielded sufficiently reliable CoPs and TTS outcome measures in soccer players. The moderate correlations with unperturbed SLS support concurrent validity, but also indicates that the new test captures aspects of postural stability that differ from the conventional, unperturbed SLS test., Competing Interests: The authors declare no conflict of interest., (© 2021 The Author(s).)