Evaluation of Peak Power Output in Healthy Adults during Sit-to-Stand and Vertical Jump Assessments

Introduction Measuring maximal, or peak, power output (P-max ) through vertical jumps (VJ) may not be appropriate for all individuals; the sit-to-stand (STS) test could potentially be more functionally relevant for older adults. However, the reliability of measuring P-max in conjunction with STS and the relationships between P-max during STS and VJ are unknown. This study aimed to determine the reliability and relationships of P-max during VJ and STS assessments using a commercially designed testing device. Methods Sixteen healthy males (mean +/- standard deviation: age, 24 +/- 4 yr; height, 177 +/- 7 cm; mass, 86 +/- 19 kg) visited the laboratory on two occasions separated by 2-7 d. During each visit, participants performed three maximal STS tests from a table at knee flexions of 90 degrees (STS90) and 120 degrees (STS120) and three countermovement jumps (CMJ) and squat jumps (SJ) in randomized order. Reliability for P-max during STS and VJ were determined using intraclass correlation coefficients (ICC; model 2,1) and standard errors of the mean (SEM). Systematic variability was examined using separate one-way repeated-measures analyses of variance (ANOVA). Pearson correlation coefficients (r) examined relationships between P-max as measured during the STS and the VJ. Results ANOVA indicated no systematic variability in P-max across trials (P > 0.05). ICC and SEM expressed as percentages of the mean ranged from 0.958 to 0.978 and 5.586% to 6.396% for STS and from 0.924 to 0.974 and 4.025% to 6.534% for VJ, respectively. Significant positive relationships were observed between P-max as measured during STS90, STS120, CMJ, and SJ (r = 0.751-0.962, P <= 0.001). Conclusion Results indicate that commercially designed devices may be highly reliable for assessing P-max during STS and VJ. STS testing is potentially an effective alternative to VJ for assessing lower-body muscle power.