The Phillips group is back at it again with another great muscle paper that just came out about hypertrophy (gaining muscle mass). It one is not nutrition oriented this time, but instead discusses the amount of weight necessary to stimulate an increase in muscle size.
Introduction: It has been shown that under an acute exercise bout, using 30% of a person’s 1 rep max (1RM) to the point of muscle fatigue (failure) was equally as effective at stimulating muscle protein synthesis in the muscle fibers as that of loads lifted at 90% of 1RM (also lifted to failure). This was shown previously by this same group. Even more intriguing, they found the 30%-1RM condition resulted in a more prolonged muscle protein synthetic response with a greater rise in muscle protein synthesis than the 90% 1RM group 24 hours post-exercise. Furthermore, other than a relative training load (weight), another important variable for resistance training is volume or the amount of work performed. The Phillips group also showed before that 3 sets at 70% of 1RM to failure led to greater and a more prolonged muscle protein synthetic rate in the fibers as compared to a single set condition. However, as I stated, these are all under short-term conditions. Thus, this new study wishes to see if these hold true under long-term conditions.
Methods: Eighteen healthy young men underwent 10 weeks of one leg knee extension resistance training where each leg was randomly assigned to one of the three training conditions: 1 set performed to voluntary failure at 80% of 1RM (80%-1), 3 sets performed to the point of fatigue at 80% of 1RM (80%-3), or 3 sets performed to the point of fatigue at 30% of 1RM (30%-3).
Results: After 10 weeks of training, quadriceps muscle volume increased significantly in all groups and average type I and type II muscle fiber area increased with training (irrespective of training condition with no significant differences between groups). All three groups also increased their 1RM but it was increased greatest in the 80%-1 & 80%-3 groups. Total work that could be completed with 80% of the subect’s 1RM increased in all groups and the number of reps that could be performed with 80% of their current 1RM increased in all groups.
Discussion: The main outcome from this paper is that there was no difference in the magnitude of quadriceps muscle hypertrophy (determined by MRI and muscle fiber area) between legs trained at 30% or 80% of 1RM after 10 weeks of knee-extensor exercise. Furthermore, there was no statistical difference in the degree of hypertrophy between the 80%-1 and 80%-3 group even though the 3 set group gained a little more volume than the 1 set group. More interestingly, the 80%-3 and 30%-3 showed more than double the average hypertrophy of the 80%-1 condition. This adds to the mounting evidence that lifting lighter loads, so long as fatigue is induced, induces roughly equal hypertrophy gains. It is important to note that both type I and type II fibers increased equally between the heavy and light loads meaning that both fiber types were recruited during the training to an almost equal amount.
My input: I can’t preach it enough or put it in bold enough; fatigue, fatigue, fatigue. Train your muscles till failure. Don’t worry about the weight on the bar or saving yourself for that last all out set. Take every set to muscle failure, even beyond with partial repetitions and forced repetitions (if you have a spotter). I have written it in the past but it needs reemphasized; when training for hypertrophy, the muscle does not “know” the weight on the bar, all it knows is fatigue. Check your ego, men. Women too, who use 5 lb dumbbells and do unlimited numbers of reps (you know who you are), aren’t accomplishing anything. I think it is also important to mention that this study pushes for a volume principle whereas the two groups that completed 3 sets instead of 1 had more muscle volume after the 10 weeks than the group that did only 1 set till failure. The next plausible step is to see if there is in fact a threshold where doing more sets than 3 will lead to an even greater increase in muscle size (future PhD thesis for anyone that wants to take it). I would also like to see this study repeated with subjects that are weight trained to eliminate the possibility of a first-time adaptive response to training (another future PhD thesis for anyone that wants to take it). That could have been the reason why the 1 set to failure condition saw an increase in muscle hypertrophy due to the fact they have not weight trained in over a year. On the strength side, it also lends to credence to specificity of training in that the leg conditions that used 80% of their 1RM increased their strength more than the group that used only 30%. If you want to solely increase your strength, focus on using heavier weight, duh. More long-term studies are needed because a lot of questions can still be asked, but this is already off to a great start when looking at chronic resistance training responses in muscle.
Mitchell et al J Appl Physiol. 2012 Apr 19.
“The last three or four reps is what makes the muscle grow. This area of pain divides the champion from someone else who is not a champion. That’s what most people lack, having the guts to go on and just say they’ll go through the pain no matter what happens.”