What is the best way to create muscle mass? The long held belief was that lifting heavy weights, 80-90% 1RM (one rep max) was necessary in order to build strength and increased mass. Lifting lighter weights for more repetitions was only going to make you leaner and help tone muscle you already had.
Well new research coming out of McMaster University may have just blasted that old myth. It turns out that muscle mass can be increased by using lighter weight (the study used 30% of 1RM) and the key appears to be lifting to fatigue. The results published in the Public Library of Science (PLoS) indicates that lifting to muscle failure, not lifting heavy weights alone, is what is required in order to increase gains. It appears that lifting to fatigue triggers the body to increase muscle protein synthesis which means, more muscle.
This theory has merit aside from the new research. Consider this; if you were to bench press 200lbs for 3 sets of 5 reps you would essentially lift 3000lbs in one session at the gym. Now if you lift 150lbs for 3 sets for 15 reps that's 6750lbs! Over time you would be lifting more weight more consistently and that would lead to increased gains.
Does this mean you should stop lifting heavy weights and concentrate on lighter weights alone? Not exactly. The body responds to variation over time. Periodization will take effect in 4-6 weeks however this is good news for those with injuries that don't allow them to lift heavy weights or for those that don't want to worry about an injury in the future. I would recommend a day or week of relatively light work with high reps, 30-50% your 1RM for 15 - 20 reps. Then 75% with 8-10 reps the following week and a heavy week of 80 - 90% your 1RM for 4-6 reps. It is also wise to consider pyramid workouts, starting with a weight 80-90% 1RM and then working your way down by 10-15% of the weight each set until fatigue has burned the muscle out, that appears most appropriate for variation and to conform with this study for optimal results. Varying your workouts like this will keep it interesting and that is the key to getting back to the gym to be consistent.
I anticipate that this study will not resolve the age old debate about how to increase body mass or what the best way to lift is but this study does mean that you don't have to hurt your self in order to increase mass, just hit the gym knowing that pushing your body to fatigue may be all you need to increase size.