Vertical ground reaction force in a water-based exercise performed by women: age effects

Abstract

Background: Increasing knowledge about the forces that act in different aquatic exercises in women of different ages is important for a more effective and individualized prescription.

Goals: To compare the vertical ground reaction force during the water-based frontal kick exercise performed at different cadences between young and postmenopausal women.

Method: Twenty-four participants, twelve young (23.7 ± 3.6 years) and 12 postmenopausal women (57.3 ± 2.6 years), voluntarily completed a session with frontal kick performance in the aquatic environment (cadences 80, 100, and 120 b.min^-1) to determine peak and impulse of vertical ground reaction force. Repeated measures two-way ANOVA was used (α = 0.05).

Results: The peak vertical ground reaction force increased from 80 b.min-1 to the higher cadences (p < 0.001). In addition, young showed greater peak vertical ground reaction values than the postmenopausal women (p = 0.012), revealing that postmenopausal women presented 78-82% of peak vertical ground reaction values observed for young women during water-based frontal kick exercise. Moreover, it was observed a reduction in impulse with the increasing cadence (p < 0.001), with similar values between young and postmenopausal women (p = 0.835).

Conclusions: These findings highlight the safety of the water-based exercise for postmenopausal women since lower peak vertical ground reaction (0.65-0.75 BW) and similar impulse (94-133 N·s) values were observed in comparison to the young ones, considered as low odds for musculoskeletal injuries, regardless the cadence of performance.