Train with a high volume to build muscle and lose weight—more total repetitions will always be superior for a better body composition. By lifting more reps to muscle failure with limited rest, you will trigger greater muscle development and elevate growth hormone for significant fat loss.
A new study in the Journal of Applied Physiology shows that training with a high volume is the most important factor for muscle building. It’s possible to gain muscle with fairly light loads (in the 30 percent of the 1RM range) as long as you train to failure and lift a high volume. In contrast, if strength gains are your sole priority, a heavy load is necessary to increase neural adaptations—greatest gains will still come from a greater volume, but that volume must be broken down into many sets with only a few reps per set.
This study compared the effect of the following three leg extension protocols on muscle hypertrophy and maximal strength gains in the lower body : 3 sets at 30 percent of the 1RM to failure, 1 set at 80 percent of the 1RM to failure, and 3 sets at 80 percent of the 1RM to failure. Results showed that the greater volume used in both of the 3-set protocols (at 30 and 80 percent 1RM) produced greater muscle hypertrophy than the small volume used in the 1 set at 80 percent 1RM protocol—no real surprise there.
Statistically, both the 30 percent and the 80 percent loads performed for 3 sets produced equal growth in the quadriceps muscles. But, at closer examination, the 3-set at 80 percent protocol triggered slightly more growth in the quadriceps than the other two conditions—again no real surprise.
The mechanism by which a light 30 percent load can be nearly as effective at producing gains in hypertrophy follows the “size principle” of motor unit activation that states that motor units are recruited in an orderly fashion from smallest to largest. When lifting a light load to failure, the smallest motor units that were initially recruited will fatigue, producing less force or ceasing to fire completely, at which point larger motor units will be recruited to sustain the lifting movement. Theoretically, nearly all motor units will be recruited, trained, and hypertrophied. This study shows that by lifting to failure with at least a passable number of sets (3), light and heavy loads are equally effective for building muscle.
Researchers also measured the activity of anabolic muscle signaling and found that with the lighter 30 percent load, the muscle building response was not elevated until nearly 4 hours after the workout, whereas for the 80 percent load it was elevated to a large degree at 1 hour post-workout. Although more research is necessary, this suggests that If you intend to build muscle with lighter loads, the timing of nutrition may need to be manipulated for best results—consider taking BCAAs or protein post-workout and a few hours after to training to sustain protein synthesis.
If your goal is to lose fat and build muscle for summer, be sure to train a high volume—if you decide to use lighter loads, be sure to recruit more motor units by lifting to failure. Heavier loads with a high volume will be most effective, and short rest periods will elevate growth hormone the most to burn a lot of fat fast.
Mitchell, C., Churchward-Venne, T., et al. Resistance Exercise Load Does Not Determine Training-Mediated Hypertrophic Gain in Young Men. Journal of Applied Physiology. 2012. Published Ahead of Print.