Neuromuscular and Functional Responses Among Males Trained with Free Weights vs. Machines: Implications for Injury Prevention

The purpose of this study was to compare balance, functional performance and isometric hip strength muscle among males practitioners of resistance training (RT) with Free-weights and Machines. Thirty males were recruited and separated into two groups: Free-weights (n = 15) and Machines (n = 15). Free-weights group showed a routine of RE that engaged the whole body with resistance bands, free-weights, dumbbells, and medicine balls. Conversely, machine group trained only exercises on machines. All participants underwent three tests to assess balance, functionality, and isometric muscle strength. All tests were performed in a single assessment session in the following order: Y Balance test; functional performance testing; and maximal isometric hip strength, respectively. The two-way ANOVA yielded main effects for group in the anterior (F1,22= 12.11, p < .002), posteromedial (F1,22= 16.87, p < .0005), posterolateral (F1,22= 15.97, p < .0006) and composite (F1,22= 21.39, p < .0001) in performance during YBT between free-weight vs. machines group for both legs. Single leg step down (SLSD) and Single leg hop (SLH) test demonstrating better functional performance in the free-weight group for both legs (p<.001). Isometric muscle strength of hip abduction and extension showed lower in the machines when compared to free-weight group for both legs. This study showed greater balance, functional performance and isometric muscle strength of hip abduction and extension in males trained with Free-weight. Males trained with machine showed lower functional performance, balance and bilateral asymmetry of the hip extensor muscles strength and risk of injuries.