Resistance training intensity and volume affect changes in rate of force development in resistance-trained men.

Abstract

To compare the effects of two different resistance training programs, high intensity (INT) and high volume (VOL), on changes in isometric force (FRC), rate of force development (RFD), and barbell velocity during dynamic strength testing. Twenty-nine resistance-trained men were randomly assigned to either the INT (n=15, 3-5RM, 3-min rest interval) or VOL (n=14, 10-12RM, 1-min rest interval) training group for 8weeks. All participants completed a 2-week preparatory phase prior to randomization. Measures of barbell velocity, FRC, and RFD were performed before (PRE) and following (POST) the 8-week training program. Barbell velocity was determined during one-repetition maximum (1RM) testing of the squat (SQ) and bench press (BP) exercises. The isometric mid-thigh pull was used to assess FRC and RFD at specific time bands ranging from 0 to 30, 50, 90, 100, 150, 200, and 250ms. Analysis of covariance revealed significant (p<0.05) group differences in peak FRC, FRC at 30-200ms, and RFD at 50-90ms. Significant (p<0.05) changes in INT but not VOL in peak FRC (INT: 9.2±13.8%; VOL: -4.3±10.2%), FRC at 30-200ms (INT: 12.5-15.8%; VOL: -1.0 to -4.3%), and RFD at 50ms (INT: 78.0±163%; VOL: -4.1±49.6%) were observed. A trend (p=0.052) was observed for RFD at 90ms (INT: 58.5±115%; VOL: -3.5±40.1%). No group differences were observed for the observed changes in barbell velocity. Results indicate that INT is more advantageous than VOL for improving FRC and RFD, while changes in barbell velocity during dynamic strength testing are similarly improved by both protocols in resistance-trained men.