Magnitude of vertical ground reaction force during water-based exercises in women with obesity

Individuals with obesity are recommended to practice physical activity with reduced weight bearing, such as water-based exercises. However, the magnitude of the vertical ground reaction force (Fz) during these exercises is unknown in this population. This study aimed to verify the magnitude of peak Fz (Fz_peak) in women with obesity during different exercises performed in water and on land and at different intensities. Ten adult women with obesity class 1 (body mass index: 31.6 ± 0.57 kg·m^-2) completed two randomised sessions, one performed on land and other in water, composed by three exercises (stationary running, frontal kick, butt kick) performed at cadences of 80 b·min^-1, 100 b·min^-1 and maximal. Fz_peak value was determined in each situation. Data were analysed using repeated-measures three-way ANOVA (α = 0.05). Significant lower Fz_peak values were observed in water (p < 0.001), with no significant differences between the exercises. A significant difference in the Fz_peak was verified between maximal cadence and 80 b·min^-1 (p = 0.01). Water-based exercises performed by women with obesity revealed a Fz_peak reduction from land to water corresponding to 41-67%. Also, the three water-based exercises resulted in similar Fz_peak values, while an increase was observed 80 b·min^-1 to the maximal cadence.