Training Distribution and the Acquisition of Maximal Isometric Elbow Flexion Strength

Twenty-six sedentary, college-aged females were matched and randomly assigned to one of two groups. The massed group («=13) completed 15 maximal isometric elbow flexion strength trials in one session, while the distributed group («=13) performed five such contractions on three successive days. After a two-week and three month rest interval, both groups returned to perform another five maximal isometric elbow flexion strength trials to assess retention of any potential strength gains. Elbow flexion torque and surface electromyography (SEMG) of the biceps and triceps were monitored concurrently. There was a significant (P < 0.05) increase in strength in both groups from block one (first five contractions) to block four (first retest) and from block one to block five (second retest). Both groups exhibited a similar linear increasing (P < 0.05) trend in biceps root-mean-square (RMS) SEMG amplitude. A significant (P < 0.05) decrease in triceps RMS SEMG amplitude was found between block one and block four for the distributed group. However, a significant (P < 0.05) increase was then found between block one and five for the massed group, and between blocks four and five for distributed group. These results suggest that there is flexibility in resistive exercise schedules. An increase in neural drive to the agonist muscle continued throughout testing. This was accompanied by a reduction in antagonist co activation that was a short-term (two weeks) training effect, dissipated over the longer rest interval (three months).