Reliability and Validity of the Ground Reaction Force Asymmetric Index at Seat-Off as a Measure of Lower Limb Functional Muscle Strength: A Preliminary Study

This study examined the reliability of newly developed ground reaction force asymmetry index (GRF AI) at seat-off using a low-cost plate and validity this new test by comparing it with other muscle strength-measuring methods walking speed. was cross-sectional design in general hospital setting. A convenience sample 47 community-dwelling adults aged ≥40 years performed. GRF AI is measurement value obtained shifting weight to right left while performing sit-to-stand (STS). assessed data during an STS maximal shift side repeated 4 weeks later. Hip knee extensor strength were measured hand-held dynamometry; hand grip speed standardized method. Intrasessional intrarater Sessions 1 2 high (intraclass correlation coefficients [ICC] = 0.947 0.974; 0.931 0.970, respectively). In addition, intersessional single trial (ICC 0.911 0.930) mean three trials 0.965 0.979) also high. There low between right-side (r 0.268) left-side 0.316). No significant correlations found parameters. Although high, poor. To be clinically useful, should further refined modifying protocol.