The Effect of Training Intensity on Voluntary Isometric Strength Improvement

Abstract

The effect of different training intensities on maximum voluntary isometric contraction (MVIC) strength was examined in a three week voluntary isometric exercise programme. Eighteen healthy university students were randomly assigned to one of three training groups: Low Intensity (LI), High Intensity (HI) and Maximal Effort (ME) groups. The LI and HI groups trained by producing voluntary isometric knee extension torques equivalent to 25% and 50% of MVIC strength, respectively. The ME group produced maximal effort contractions during training. Only the HI and ME groups demonstrated significant (p <.05) isometric strength gains. The HI group produced the greatest strength gain (45.8% of MVIC), followed by the ME group (31.3%) and the LI group (22.3%). No significant strength retention, cross transfer or isokinetic strength improvement were seen in any group. The strength improvements were of the same magnitude as those previously obtained using electro-motor stimulation at equivalent training intensities.