Exercise intensity of head-out water-based activities (water fitness)

The aims of this study were: (i) to measure the exercise intensity (EI) of the most common water-based exercises (WE) at different movement frequencies (f1 = 1.8–2.0 Hz; f2 = 2.0–2.2 Hz; f3 = 2.2–2.4 Hz) and at a standardize movement’s amplitude; (ii) to measure EI during a combination (MIX) of these WE. Five WE were selected: “running raising the knees high” (S); “jumping moving the legs sideways” (SJ); “jumping moving the legs backward and forward” (FJ); “alternate forward kicks” (FK); “alternate sideways kicks” (SK). Twelve physically active women were asked to perform these WE at the three frequencies, as well as a combination (MIX) of the WE. EI increased significantly (p < 0.01) with increasing frequency; as an average, for all WE: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \dot{V}_{{{\text{O}}_{2} }} $$\end{document} ranged from 18 to 25 ml kg−1 min−1, HR from 102 to 138 bpm, RPE from 9.8 to 14.4 (at f1 and f3, respectively). In terms of % \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \dot{V}_{{{\text{O}}_{2\max } }} $$\end{document}, EI ranged from 37 to 54% for S, was similar for SJ and FJ (31–43%) and for FK and SK (47–63%) at f1 and f3, respectively. Thus, a given EI can be attained either by changing the type of exercise and/or the frequency of the movement. The combination of exercises did not change (in terms of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \dot{V}_{{{\text{O}}_{2} }} $$\end{document}, HR and RPE) the intensity of each exercise performed separately. These data can be utilized to control, in terms of exercise type and frequency, the intensity of a proposed water-based activity.