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 (VO ₂ ) 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 VO ₂ measurements. Peak (Fz _peak ) and impulse of Fz were determined. In addition, VO ₂ percentages relative to maximal VO ₂ (VO _2max ) values obtained in each maximal test were expressed as %VO _2max . Data were analysed using two-way ANOVA with repeated measures ( α  = 0.05). As results, significant differences were found in Fz _peak and impulse between the water-based exercises, with similar VO ₂ and %VO _2max values between them for each cadence. In addition, with the increasing cadence, Fz _peak (0.20-0.80 BW), VO ₂ (5.3-9.4 ml kg ^{- 1}  min ^{- 1} ) and %VO _2max (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.