469 Official Journal of ICAPA www.JAPA-Journal.com ORIGINAL RESEARCH Journal of Aging and Physical Activity, 2012, 20, 469-1 © 2012 Human Kinetics, Inc. Bento, Pereira, and Rodacki are with the Section of Biological Sciences, Federal University of Parana, Parana, Brazil. Ugrinowitsch is with the School of Physical Education and Sport, São Paulo University, São Paulo, Brazil. The Effects of a Water-Based Exercise Program on Strength and Functionality of Older Adults Paulo Cesar Barauce Bento, Gleber Pereira, Carlos Ugrinowitsch, and Andre L.F. Rodacki Objective: To analyze the effects of a water-based exercise program on peak torque (PT) and rate of torque development (RTD) during maximal voluntary ballistic isometric contractions of the lower limb muscles and the performance of a number of functional tests in the elderly. Method: Thirty-seven elderly were randomly assigned to water-based training (3 d/wk for 12 wk) or a control group. Extensor and fexor PT and RTD of the ankle, knee, and hip joints and functional tests were evaluated before and after training. Results: PT increased after training for the hip fexors (18%) and extensors (40%) and the plantar-fexor (42%) muscles in the water-based group. RTD increased after training for the hip-extensor (10%), knee-extensor (11%), and ankle plantar-fexor (27%) muscles in the water-based group. Functional tests also improved after training in the water-based group (p < .05). Conclusion: The water-based program improved PT and RTD and functional performance in the elderly. Keywords: elderly, aging, physical activity Aging is characterized by neuromuscular changes that include a marked decline in the net joint torque (Delmonico et al., 2009; Frontera et al., 2000), power-pro- duction capacity (Candow & Chilibeck, 2005), and resistance to fatigue (Petrella, Kim, Tuggle, Hall, & Bamman, 2005). In general, the muscle-capacity reductions are related to a decrease in the number of fast-twitch fbers and their cross-sectional area (Lexell & Taylor, 1991). Furthermore, some authors have suggested that the ability of older individuals to perform a number of daily tasks (e.g., standing up and climbing stairs) is closely related to the torque-production capacity of the lower limb joints (Hortobágyi, Mizelle, Beam, & DeVita, 2003; Misic, Rosengren, Woods, & Evans, 2007; Narici, Maganaris, Reeves, & Capodaglio, 2003). Decreases in the muscles’ ability to generate torque around a joint have been associated with a greater risk of falls in the elderly. Indeed, one in three elderly over 70 years of age experience at least one fall per year (Hill & Schwarz, 2004;