The Growth Hormone Hypertrophy Myth
By Mark Young
The common assertion in strength training literature (I use that term loosely) is that compound movements must be done (and short rest intervals used) to maximize the growth hormone output associated with training to accentuate muscle hypertrophy.
In simpler terms:
Big compound movements + Growth hormone release = Hyooge muscles (i.e., looking like Bret Contreras)
(editors note: Compliments go a long way in these parts!)
For years studies have demonstrated that training using compound movements and/or short rest intervals does indeed increase the output of anabolic hormones giving strength to this theory which would normally be considered a good thing. Sounds good right?
However, more recent research has demonstrated that although testosterone, growth hormone, and IGF1 do rise with when training the larger muscle groups, there is no difference in muscle protein synthesis (muscle building) or intracellular signaling when compared to a group training without these hormonal changes.
Of course, caution is always warranted when we’re looking at mechanistic studies where hypertrophy is not actually measured (as this is how we got in this mess in the first place) so a follow-up training study was conducted to demonstrate the effects of training in the presence or absence of these hormones on hypertrophy and strength.
In this study, 12 males trained their biceps using a unilateral arm curl for 15 weeks. However, one arm was trained on one day strictly performing curls (Low Hormone Group). The other arm was trained on a completely different day followed immediately by several leg exercises aimed at increasing hormone concentrations in the blood (High Hormone Group).
From weeks 1-6 each arm was trained once per week. From weeks 7-15 each arm was trained two times per week although 48 hours was always left after the arm only condition (Low Hormone Group) to make sure that they did not experience any influence of the additional anabolic hormones while still while their protein synthesis was still elevated from training the previous day.
For those who are interested, each arm workout consisted of 3-4 sets of 8-12 reps using 95% of their bicep curl 1 rep max. In addition, the high hormone group performed 5 sets of 10 reps of leg presses followed by 3 sets of 12 reps of a leg extension/leg curl superset after each arm workout.
At the end of each workout the subjects drank a beverage containing 18 grams of whey protein to facilitate maximal protein synthesis. Isometric strength, 1 repetition max, and 10 repetition max for the bicep curl were taken pre-training and at 15 weeks. MRI and muscle fiber biopsies were used to determine increases in muscle growth.
As it turns out, the high hormone condition did elicit greater responses in testosterone, growth hormone, and IGF1 than the low hormone condition. While both groups experiences increases in strength, fiber hypertrophy, and muscle cross sectional area, there were ABSOLUTELY NO SIGNIFICANT DIFFERENCES BETWEEN THE TWO GROUPS. In other words, training in the presence or absence of endogenous hormones didn’t make a lick of difference.
Criticisms of this study might include the fact that the subjects were novice lifters, that they didn’t have enough protein after training and that there were no dietary controls.
To these I offer a two considerations.
1 – Novice trainees will indeed make gains in response to almost anything. It is certainly harder to make gains with advanced lifters. For this reason I would argue that the differences would be LESS pronounced in people who were already trained since their gains are already limited.
2 – Whether or not the protein intake was actually sufficient (which THIS STUDY indicates that it is) or whether the diets were controlled doesn’t really matter because the study was a within subject design. In other words, because the study was comparing one arm to another instead of comparing between two separate groups means that each arm was subject to the same nutritional effects as the other arm since the belong to the same person. This minimizes the possible variability usually found in a between subject design (i.e., one group ate a lot of protein and calories and the other didn’t) and makes a within subject design more powerful. If there was a difference between methods, this type of design would have been the best suited to discover it.
All in all, the big picture is that training the larger muscle groups and shortening the rest intervals DOES increase the output of anabolic hormones. However, these hormones do NOT cause any additional hypertrophy.
That is not to say that you shouldn’t use the “big bang” exercises or that short rest intervals are useless. Heavy lifting taxes more muscle groups thereby increasing your chances of strength and growth. Short rests also make workouts quicker and more efficient (or possibly allow more training volume during a fixed amount of time).
It does mean though that you don’t HAVE to do the big exercises or maintain short rest intervals to elicit hypertrophy. For those who find it difficult to squat, deadlift, or bench due to an injury or condition, this should come as a welcome change to the usual “do the big 3 or be forever small” mantra. You have to load the muscles and you have to feed your body, but how you do it is up to you.
In the end, the anabolic hormone cascade is not going to do you any favors in terms of extra hypertrophy…because that is straight up bro science.
Consider That Myth Busted!
For those who want to reach Mark to bitch him out for shattering their dreams of becoming muscular and sexy as a result of endogenous hormone release you can visit his website at www.markyoungtrainingsystems.com