Changes in muscular strength following nine weeks of high- or low-load resistance training

Traditional resistance training schemes often utilize higher loads for strength gains and lower loads for muscular endurance or hypertrophy. This study aimed to investigate muscular strength adaptations after nine weeks of high- or low-load resistance training.

Seventeen recreationally-trained male lifters were recruited for this study (age 20.4±2.7 years) and split into high-load (85% 1-RM; N.=8) or low-load (30% 1-RM; N.=9), completing three whole-body training sessions per week for nine weeks. Each session included three working sets of repetitions to failure. At baseline and every three weeks after, knee extension/flexion were tested using an isokinetic dynamometer. Participants completed three 5-s MVIC and isokinetic muscle actions at 60°/s and 120°/s, with the highest torque value used in analysis. Predicted 1-RM testing was at baseline and end of training program. ANCOVAs were conducted to analyze changes in strength, with significance set at P<0.05.

This study demonstrated similar MVIC and peak torque values for both isokinetic speeds, although there were nonsignificant decreases largely driven by the 30% group. The high-load group showed greater increases in 1-RM following the training program.

This study suggests training with lighter loads may be detrimental for long term isokinetic strength, whereas heavier loads could result in maintenance and greater increases in 1-RM despite performing repetitions to failure.