Abstract
BACKGROUND: The aim of the study was to examine the feasibility for postmenopausal women of a bone-strengthening jumping intervention, which has been previously successful for premenopausal women. MATERIALS AND METHODS: Forty-nine participants (mean ± standard deviation [SD] age = 57.8 ± 4.3 years) were randomized into either an exercise intervention or sham-control group in a double-blinded fashion. The intervention consisted of 10 maximal, rest-inserted countermovement jumps, performed three times a week on a hard surface without shoes for 8 months. Sham-control participants performed unilateral balance exercises of equivalent duration. RESULTS: The jumps were well tolerated, with women in the jumping group completing 95% of the prescribed exercise. Of the participants who completed the study (n = 23 intervention, n = 16 control), there were no significant differences in broadband ultrasound attenuation (BUA) using quantitative ultrasound (QUS) of the calcaneum within and between groups (mean ± SD BUA = 64.9 ± 7.3 and 66.6 ± 6.5 dB/MHz for intervention pre- and post-trial, respectively, versus mean ± SD BUA = 63.6 ± 4.2 and 64.4 ± 4.5 dB/MHz for sham-controls pre- and post-trial, respectively) or for any QUS parameters, although there was a 3% increase in BUA for intervention participants. CONCLUSIONS: Recruitment and participation rates were feasible for this duration of study and the exercise was acceptable. For a future study of this nature, 48 participants would be required to ensure adequate power, especially as lifestyle variations and post-menopausal hypoestrogenism prevent substantial gains in bone strength with high-impact exercise.