Depending on the individual, regular athletes or gym enthusiasts may have a personal preference to lift light or heavy weights. Whichever way you prefer training, I’m sure you have heard contradictory claims on light or heavy loads where one may be superior over the other to enhance muscle growth. Although it’s been debated for quite some time, recent evidence has shed some light on the advantages of each style of training.
A recent study with 30 resistance trained men, completed two gym sessions a week for a 12-week period training at a 20%, 40% or 80% 1RM with volume equated.
What did the results show?
Resistance training with intensity ranging 20 to 80% 1RM are effective to increase strength and muscle hypertrophy. However, low intensity (20% 1RM) was suboptimal for maximizing muscle hypertrophy. Training at 40% 1RM produced equal muscle gains (when training close to failure) as training at 80% 1RM; therefore, a wide spectrum of intensities, from 40 to 80% 1RM, are viable options to increase muscle mass.
It is feasible that employing combinations of these intensities may enhance hypertrophic results, as well as allow for better recovery by alleviating joint related stresses from continuous heavy-load training.
Although both groups produced equal muscle hypertrophy, there are differences in strength. If maximizing strength gains over the long-term training is a primary goal, it is necessary to employ higher training intensities.
More recent work shows different loads may activate different muscle fiber types, whereby low loads target type I fibers and high loads target type II fibers. Although data may be conflicting on this topic, it may be best practice that to fully enhance muscle hypertrophy, it is necessary to train at different intensities.
Steve O'Mahony BSc MSc
Muddle TWD. 2018. Effects of fatiguing, submaximal high- versus low-torque isometric exercise on motor unit recruitment and firing behavior. Physiol Rep. 6(8):e13675. doi: 10.14814/phy2.13675.
Thiago Lasevicius, 2018. Effects of different intensities of resistance training with equated volume load on muscle strength and hypertrophy. ISSN: 1746-1391. 1536-7290