Water-based exercises in postmenopausal women: Vertical ground reaction force and oxygen uptake responses.

The purpose of the present study was to analyse vertical ground reaction force (Fz) and oxygen uptake (VO2) responses in six different water-based exercises performed at different cadences by postmenopausal women. Twelve postmenopausal women (57.3 ± 2.6 years, 158.1 ± 6.9 cm, 69.1 ± 10.9 kg) voluntarily took part in the study. Participants completed six sessions corresponding to maximal tests for each water-based exercise. Then, two sessions were performed for the experimental protocols, which comprised the performance of three exercises at three cadences (80, 100 and 120 b min-1), with Fz and VO2 measurements. Peak (Fzpeak) and impulse of Fz were determined. In addition, VO2 percentages relative to maximal VO2 (VO2max) values obtained in each maximal test were expressed as %VO2max. Data were analysed using two-way ANOVA with repeated measures (α = 0.05). As results, significant differences were found in Fzpeak and impulse between the water-based exercises, with similar VO2 and %VO2max values between them for each cadence. In addition, with the increasing cadence, Fzpeak (0.20-0.80 BW), VO2 (5.3-9.4 ml kg-1 min-1) and %VO2max (32.1-57.6%) values increased, while impulse (0.20-0.07 N.s/BW) values were reduced. Therefore, for a same physiological intensity, postmenopausal women experience different Fz loads during different water-based exercises.