Effect of home-based resistance training performed with or without a high-speed component in adults with severe obesity

The objectives of this study were to: (a) evaluate the effects of walking and home-based resistance training on function, strength, power, anthropometry, and quality of life (QoL) in adults with severe obesity, and (b) assess whether performing resistance exercises with maximal concentric velocity provides additional benefits compared with traditional slow-speed resistance training. Adults with a body mass index of >= 40 kg/m(2) were randomized to slow-speed strength training (ST; n = 19) or high-speed power training (PT; n = 19). Both groups completed a walking intervention and home-based resistance training (2x per week for 6 months). The PT group performed resistance exercises with maximal intended concentric velocity, whereas the ST group maintained a slow (2-seconds) concentric velocity. At 6 months, weight loss was similar to 3 kg in both groups. Both groups significantly improved function (g(z) = 1.04-1.93), strength (g(z) = 0.65-1.77), power (g(z) = 0.66-0.85), contraction velocity (g(z) = 0.65-1.12), and QoL (g(z) = 0.62-1.54). Between-group differences in shoulder press velocity (-0.09 m.s(-1), g(s) = -0.95 [-1.63, -0.28]) and 6-minute walk test (-16.9 m, g(s) = -0.51 [-1.16, 0.13]) favored the PT group. In conclusion, home-based resistance training and walking lead to significant improvements in functional and psychological measures in adults with severe obesity. In addition, considering the between-group effect sizes and their uncertainty, performing resistance exercises with maximal concentric speed is a simple adjustment to conventional resistance training that yields negligible negative effects but potentially large benefits on walking capacity and upper-limb contraction velocity.