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Abstract
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BACKGROUND.: Stair climb power is an important clinical measure of lower-extremity power. The stair climb power test (SCPT) was validated by requiring individuals to climb a full flight of stairs. A four-step SCPT (4SCPT) would be more clinically feasible and easier to perform, yet its reliability and validity is unknown.
OBJECTIVE.: To evaluate reliability, validity, and minimal detectable change of 4SCPT among community-dwelling older adults. DESIGN.: A cross-sectional analysis of baseline data from a clinical trial.
METHODS.: Fifty older adults ≥ 65 years, at risk for mobility decline, were consented to participate in this ancillary study. Test-retest reliability was derived from two measurements within each participant measured by a single assessor. Pearson correlation analyses among leg power measures (4SCPT, SCPT, single leg press power at 40% and 70% of the one-repetition maximum (SLP40, SLP70) were performed. Separate multivariate linear regressions were conducted evaluating the associations between each leg power measure and two mobility outcomes, the Short Physical Performance Battery (SPPB) and habitual gait speed (HGS). Minimal detectable change was based on a 90% confidence interval (MDC 90 ).
RESULTS.: The 4SCPT had excellent test-retest reliability (ICC(2,1) = 0.951), and strong correlation with SCPT, SLP40 and SLP70 (r = 0.85-0.96). The 4SCPT explained a greater amount of variance in the SPPB (R 2 = 0.31) than other leg power measurements (R 2 = 0.23-0.25). The 4SCPT (R 2 = 0.41) and SCPT (R 2 = 0.42) described equivalent amounts of variance in HGS, and greater than that with SLP40 (R 2 = 0.28) and SLP70 (R 2 = 0.30). The MDC 90 for 4SCPT was 44.0 watts. LIMITATIONS.: This was a cross-sectional analysis within a small, non-representative sample. Inter-rater reliability was not evaluated.
CONCLUSIONS.: The 4SCPT shows scientific promise as a valid and reliable leg power measurement among community-dwelling older adults.
Language: en |