Want Bigger Guns? Train Legs Before Arms!

It is quite obvious that an elevation of testosterone and growth hormone facilitates muscle gains by jacking up protein synthesis and ameliorating protein breakdown. Now, intense leg training is famous for increasing both, testosterone as well as growth hormone levels of trainees. It is thus quite logical that Ronnestad et al. found (Ronnestad. 2011) that your arms grow faster, if you train them right after your legs.

The study design the scientists used is quite awkward, but clever. They had 9 (unfortunately) untrained subjects perform 4 workouts per week. On two of the occasions the subjects trained legs + one arm (L + A) on the other two occasions they only trained the other arm. Thus, Ronnestad et al. made sure that "both conditions have the same nutritional and genetic environment".

Figure 1: Plasma testosterone and growth hormone  measured before the strength training session (T-0), immediately after the leg exercises in the L ? A session (T-1), immediately after the arm exercises for both the L + A and A session (T-2), and 30 min after the arm exercises in both L + A and A session (T-3). (Ronnestad. 2011)

As can be seen in figure 1, only leg + arm, but not arm training alone produced measurable elevations of testosterone and growth hormone. Yet, although the cross sectional surface area (CSA, measured by MRA) of the biceps increased in both conditions, the major finding of the study was that...

only L + A increased the elbow flexors’ CSA at the two middle sections where the CSA of elbow flexors was largest.

In other words, the peak of your biceps, this hallmark, every bodybuilder is looking for, comes from training your legs (prior to your biceps).