Stair Ramp Leg Power Validation Study

Abstract

The performance of daily tasks, such as stair climbing or lifting an object, requires both muscle strength and power. Age-associated reductions in strength and power can affect an older adult's ability to complete daily tasks such as standing up from a chair or lifting a grandchild (Miszko et al., 2003) and may decrease independence and increase falls. Currently, there are few tests for people over the age of 50 that can assess lower body power and quantify power accurately (Signorile et al., 2007). PURPOSE: The purpose of this study was to validate a new lower body power field test and compare this to a valid field test known as the Margaria-Kalamen stair climbing test using younger adults to initially prove the validity of the new test. METHODS: A one shot case study design was selected for this study. Subject (n = 9) characteristics (mean ± SD) included age (20-40 ± 2.7 yrs), gender (6 female/3 male), height (63.5 ± 1.3 in.), and weight (140 ± 4.5 lbs). A newly designed uphill step ramp method vs. regular stairs was utilized to determine power (force × distance/time). College students were used to reduce the risk of injury during this beta test. All subjects were weighed on a calibrated healthometer scale to determine accurate body weight before a 5 minute specific neuromuscular warm-up began. Once a neuromuscular warm up was performed, participants lined up 3 meters from the first step and sprinted up the stair ramp at full effort. Each subject was given 3 trial attempts, with 2-3 minutes of rest in-between to restore ATP-PC levels. The subjects performed the Margaria-Kalamen stair climbing test within an hour and obtained 3 power scores in watts (W), resting 2-5 minutes between each attempt. RESULTS: An intra-class correlation was selected to determine any variation between subjects' times during their 3 trials. Based on the results, the step ramp method is a reliable test to assess lower body power (r =.995). A Pearson Product Moment Correlation (r =.861) was conducted to determine differences in the best trial power (W) score (mean ± SD) between the Margaria-Kalamen Stair Test (618 ± 119 W) and the modified stair-ramp test (634 ± 119 W). CONCLUSION: Based upon this beta test, the step ramp power test -seems to be a reliable and reasonably good method for determining lower body power in young adults.