Aging induces fast and relevant decrements in muscle power (MP), reducing autonomy and quality of life. The authors' aim was to determine reliability data in a new, simple protocol for muscle power using a previously individualized load. The authors evaluated 18 healthy young adults (12 women), unaccustomed to strengthening exercises. Initially, 1-RM was determined with simultaneous measurement of velocity and MP (Fitrodyne, Bratislava) in an upright row exercise, performed up to mesosternal level in standing position, and measurement of load in which MP was obtained. In the following week, they returned in five consecutive days to perform 2x2 reps in four days and in one day 10x2 reps (3 s interval between reps), using maximal velocity in the concentric phase. Comparing best results by repeated measures ANOVA-Bonferroni t-tests, PM did not differ - mean values ranging from 262 to 267 W (p = .69). Looking for individual data variability, values of 3 and 8% were found, respectively, for coefficient of variation (CV) and for the mean range of scores divided by the mean value (M-m/X) (maximum minus minimum score divided by the subject's mean value). Analyzing intraday reliability in the 10 consecutive sets - mean results (ranging from 242 to 263 W) - significant differences were only found between set 1 and 4 and 6 (p < .05). If set 1 data were excluded (5 of the 18 subjects performed very low values in this set), the differences disappeared (p = .13). Individual variability data showed 6 and 20%, respectively, for CV and M-m/X in the 10 consecutive sets. The authors concluded that MP obtained in this simple test presents high intraday and interday reliability with relatively low variability, comparable to that often observed in other measurements usually used in exercise sciences. This test can be recommended for MP assessment in health and fitness facilities, where utilization of more sophisticated devices and protocols are either inappropriate or unsuitable.
Maximal muscle power; Muscle power test; Strength training; Resistance training; Inter and intraday reliability
