The influence of internal (movement focus) and external (outcome focus) attentional-focusing instructions on muscular endurance were investigated using three exercise protocols with experienced exercisers. Twenty-three participants completed a maximal repetition, assisted bench-press test on a Smith's machine. An external focus of attention resulted in significant (p less than 0.05) improvements in performance compared to the internal focus of attention, but not the control condition. Seventeen participants completed repetitions to failure at 75% 1-RM on free bench-press and squat exercises. In both tasks, externally focused instructions resulted in significantly greater repetitions to failure than control and internal focus conditions (p less than 0.05). These results support previous research showing beneficial effects of externally focused instructions on movement efficiency.