Skeletal muscle fiber type, resistance training, and strength-related performance.

The research goal was to attempt to clarify the consequences of increased strength on performance at submaximal exercise intensities. Eight subjects (4 males, 4 females) completed a 3-d.wk-1, 16-wk resistance training regimen. After training, upper (bench press, BP) and lower (parallel squat, PS) extremity strength were increased by 23% and 37%, respectively. Performance at the same absolute work rates as before training was increased by 30-159% following training depending on intensity and type of exercise. Performance at the same relative work rates (80%, 60%, 40%) remained unchanged by the training for both exercises. Prior to training, PS repetitions at 40% were correlated (r = 0.69, P < 0.05) with the percentage of slow-twitch (ST) fibers in the vastus lateralis muscle. There were similar relationships at 40% (r = 0.73) and at 60% (r = 0.83) for the PS exercise after training. However, the resistance program did not result in greater relative submaximal performance in individuals with a higher percentage of ST fibers. We conclude that strength improvement of up to 40% does not produce a strength-related performance deficit, when training and testing procedures are identical. Yet, these data do not rule out the potential of a strength-related repetition performance deficit. When subjects were equally divided by strength levels, those tested at the highest absolute resistance had significantly lower bench press repetition performance at 60% and 40% of the 1-RM than the subjects tested at the lowest absolute resistance.