Jump test performance and sarcopenia status in men and women, 55 to 75 years of age.

BACKGROUND AND PURPOSE: Jumping mechanography uses maximal countermovement jumps to test obtain such as jump power (JPow). Recently, it has been shown to be a safe method for assessing muscle function in older adults; however, little is known about the relationships between JPow, muscle strength, and sarcopenia status. The purpose of this study was to examine jump performance, muscle strength, and sarcopenia status in older adults.

METHODS: This was a cross-sectional study that included men (n = 27) and women (n = 33) (55-75 years) recruited from the general community. Participants completed health status and physical activity questionnaires. Body composition, including appendicular skeletal muscle mass (ASM), bone free lean body mass, and relative skeletal muscle mass index, were assessed by total body dual-energy x-ray absorptiometry scans. The criteria for sarcopenia were relative skeletal muscle mass index values less than 7.26 kg/m2 for men and less than 5.45 kg/m2 for women. Three vertical jumps on a jump mat were performed to assess JPow, jump velocity (JVel), and jump height (JHt). Muscle strength was measured by 1RM testing for leg press (LP) and right and left hip abduction isotonic resistance exercises.

RESULTS: Sarcopenia was found in 20% (12/60) of the participants. Jump power was significantly lower (P = .001) in the sarcopenia group than in the normal group, 651.1 (41.7) W versus 851.0 (27.4) W, respectively. Jump power and JHt were significantly (P < .01) positively correlated (r = 0.54-0.77) with ASM and bone free lean body mass. Significant (P < .01) positive correlations (r = 0.43-0.70) were also reported between jump test variables (JPow, JVel, JHt) and muscle strength (LP, right and left hip abduction).

DISCUSSION: The jump test protocol was conducted safely with no injuries or balance issues. Our finding of lower JPow in sarcopenic individuals adds new information to the existing literature on age-related declines in muscle power.

CONCLUSION: Community-dwelling individuals classified as sarcopenic had significantly lower JPow but not muscle strength compared with their counterparts with normal amounts of muscle mass. Jump test variables were positively correlated with lean tissue and lower body muscle strength. Based on our findings, JPow may be useful for sarcopenia screening in the middle-aged and older adults; however, more research is needed to determine the utility of this method in clinical populations.