Effects of Inspiratory Muscle Training on Exercise Capacity and Spontaneous Physical Activity in Elderly Subjects: a Randomized Controlled Pilot Trial - Aznar-Lain, S; Webster, A L; Cañete, S; San Juan, A F; López Mojares, L M; Pérez, M; Lucia, A; Chicharro, J L (International Journal of Sports Medicine, 2007)