Validação instrumental do aplicativo Power Frail para avaliação da potência muscular de membros inferiores de adultos jovens

Abstract

Introduction: Recently, the sit-to-stand test (STS) has been proposed to assess lower limb muscle power using instruments such as force platforms and linear position transducers. However, factors such as portability, calibration requirements, and economic constraints of these instruments hinder the feasibility of this assessment in clinical settings. In order to overcome these barriers, smartphone applications such as PowerFrail have been developed. Objective: To evaluate the validity of a smartphone application compared with the Wii Balance Board platform, NintendoTM (WBB), for assessing lower limb muscle power in young adults during the five-repetition sit-to-stand test (5 STS). Proposed Methodology: Twenty-eight young adults (21 women) with a mean age of 22.8 ± 2.17 years participated in this study. For instrumental validation, the PowerFrail application and the WBB platform were used. Relative and allometric muscle power were assessed using the 5 STS. The statistical methods applied included linear regression, intraclass correlation coefficient, Cronbach’s alpha test, and the Bland–Altman method. Results: Relative muscle power showed reasonable agreement (consistency ICC = 0.543; agreement ICC = 0.539) and moderate correlation (r = 0.54; p = 0.003; r2 = 0.30). The level of agreement assessed using the Bland–Altman method was moderate, as was Cronbach’s alpha (0.704). Allometric muscle power demonstrated excellent agreement (consistency ICC = 0.888; agreement ICC = 0.883), high correlation (r = 0.91; p = 0.001; r2 = 0.83), and high levels of agreement according to the Bland–Altman method. Cronbach’s alpha was excellent (0.94). Conclusion: The PowerFrail application is valid for assessing allometric muscle power in healthy young adults.