That is why heavy weights are so effective for gaining muscle. They do a great job of activating the largest muscle fibers in our bodies without wasting any time. However, due to the Size Principle, a similar effect can be achieved by lifting lighter weights closer to failure. During a maximal set of 20 reps, the smaller muscle fibers are capable of moving the load for about the first 10-12 reps, but eventually they will become fatigued, and the body will be forced to activate the larger and stronger muscle fibers to continue lifting the weight. This is exactly what we want.
At this point, some of you might be asking why you should care. Everyone who lifts heavy frequently enough has gained plenty of muscle. These people probably figure that if their program works, why fix it?
How can we take advantage of this new information? We can devise a training strategy that utilizes both heavy and light weights to maximize growth. If you currently bench and squat heavy twice a week, I suggest adding a third session with low weight (think sets of 20-30 reps), and push close to failure on this day. The light weights will spare your joints and nervous system from excessive strain, while giving the muscles a great workout and stimulating growth.
Don’t be afraid to schedule your lift sessions within 24 hours of your heavier work. The lighter loads are not capable of causing much muscle damage, and therefore do not produce a lot of soreness or inflammation. Research shows that muscles grow faster the more often you train them, so don’t shy away from light days if you want to reach your full potential. In case you forgot, here is my fabulous article on training frequency.
Maik & Kieran