The increase in weight-lifting performance after resistance training is greater than the increase seen in maximal voluntary isometric contraction (MVC). This discrepancy has been attributed to learning and coordination. The purpose of the present study was to look into the contribution of joint angle specificity, and the specificity of the movement at various speeds in explaining the disproportionate increase in weightlifting strength compared to isometric strength. Eighteen participants completed the study. The quadriceps muscle group of each individual was trained unilaterally on a leg extension machine. Participants performed four sets of ten lifts at a steady pace. A load of 80% of the maximum load (1RM) was prescribed. The MVC of the quadriceps was measured on a strength-testing chair. The length-tension relationship was measured isometrically at 600, 750, 900, and 1050 of knee flexion. Measurement of isokinetic strength at velocities of 450/s, 1800/s and 300/s were made. All measurements were made before and after the training. The eight weeks training resulted in a 33% increased in weights lifted (p < 0.05) that was significantly greater than the gain in isometric MVC (6%). Significant gains in isometric strength were seen at all the joint angle but with no evidence of length specificity. Although there were significant gains in strength at higher velocities, they were not sufficient to explain the increased weight-lifting performance and, in any case, similar gains were seen with the untrained leg where no improvement in weight-lifting
performance was seen. From the findings it is concluded that angle and velocity specificity could not fully account for the discrepancy between gains in weight-lifting performance compared to isometric strength.