停經後婦女在水中與陸地跳躍運動之動力學特徵

Integrated plyometric exercise, muscle strength and balance training are the exercise strategies to improve bone health. Although jumping in water can provide exercise benefits for older adults, the biomechanical characteristics of water jumping exercise in postmenopausal women are yet unclear. The purpose of this study was to compare the ground reaction forces of 2 types of jumps, in water and on land among postmenopausal women. We recruited 11 postmenopausal women for this study. Participants were randomly assigned to a cross over design to perform counter movement jump (CMJ), jumping with opening legs and arms (JOLA), and single leg jump (SLJ) in water or on land surfaces. The vertical ground reaction force data of each jump on land or in water were collected from a force plate. The study results showed that the peak concentric forces of CMJ, JOLA, and SLJ in water were significantly lower than those on land. However, there were no significant differences between the surfaces in the rate of force development and time to peak concentric force during the jumping phases. During the landing phase, the peak impact force and loading rate in water were significantly lower than those on land. The time to peak impact force was significantly prolonged when the participants jumped in water. We conclude that the landing impacts were reduced in water. The jump force development intensities in water were similar to those on land. Therefore, water jumping exercise may be an alternative approach to maintain the bone health among postmenopausal women.