Biomechanical Comparison of Countermovement Jumps Performed on Land and in Water: Age Effects.
The aquatic environment provides a low impact alternative to land-based exercise and rehabilitation in older adults.OBJECTIVE
Evaluate the biomechanics of older adults and young adults performing jumping movements on land and in water.DESIGN AND SETTING
Cross-sectional, mixed-factorial experiment; adjustable-depth pool at sports medicine research facility.PARTICIPANTS
Fifty-six young adults (22.0 ± 3.9years) and twelve healthy older adults (57.3 ± 4.4years).INTERVENTIONS
Each participant performed six maximal effort countermovement jumps. Three jumps were performed on land. Three jumps were performed with participants immersed in chest-deep water.MAIN OUTCOME MEASURES
Using data from the amortization and propulsive phases of jumping, we computed the following kinetic and kinematic measures: Peak and mean mechanical power, peak force, amortization time and rate, unweighting and propulsive times, and lower-extremity segment kinematics.RESULTS
Mechanical power outputs were greater in younger adults (Peak: 7322 ± 4035W) versus older adults (Peak: 5661.65 ± 2639.86W) and for jumps performed in water (Peak: 9387 ± 3981W) versus land (Peak: 4545.84 ± 1356.53W). Peak dorsiflexion velocities were greater for jumps performed in water (66 ± 34°/s) versus land (4 ± 7 °/s). Amortization rate was 26% greater in water versus land. Amortization time was 20% longer in older adults versus young adults.CONCLUSIONS
Countermovement jumps performed in water are mechanically specific from those performed on land. Older adults jumped with longer unweighting times and increased mechanical power in water. These results suggest that aquatic-based exercise and rehabilitation programs that feature jumping movements may benefit older adults.