For stronger biceps, train your legs

The best way to develop more strength in your arms is to train them together with a large muscle groups such as the legs. This theory was put forward by sports scientists at Odense University, Denmark, in the Scandinavian Journal of Medicine & Science in Sports. Training large muscle groups results in anabolic hormone peaks that the smaller muscle groups also benefit from.

The Danes got fourteen students do weight training for nine weeks. One group of students trained only their biceps, at sixty percent of the weight at which they could make one more rep. This was group A. The other group also trained their biceps, but followed this with six sets of ten reps on the leg press. This was group LA.

The students only trained one arm. But the LA group trained both legs.

The bar chart below shows students’ progress in building up strength. AT stands for the trained biceps, AC for the untrained biceps. Both AT and AC refer to the students who only trained their biceps.

LAT = the trained biceps of the students who also trained their legs. LAC = the untrained biceps of the same group.


The white bars represent the progression of the test subjects during the first half of the experiment. The black bars show the progression during the second half.

As you can see, the biceps that the students did not train also became stronger. This is partly due to the hormonal effect of training the other biceps, and partly probably to a mental-neuromuscular effect. It sounds crazy, but muscles also get stronger even if all you do is to think about training those muscles.

Training the legs after training sessions in which you only train a small muscle group therefore speeds up the process of the small muscle group. The Danes think that training large muscle groups induces the body to make more anabolic hormones like testosterone and growth hormone.

The graph below shows the effect of the two different types of training on the production of growth hormone. And when the scientists looked at the concentration of testosterone in the bodybuilders’ bodies, the results were about the same.


Pre stands for the first training the students did, post for the last training.

A test group of fourteen students is small, so the scientists would like to see their research results confirmed in a large study. But despite this the Danes did come up with a recommendation for bodybuilders. “When practising strength training in order to increase strength of the arm muscles, it can be recommended to include training of large muscle groups in order to induce a greater anabolic hormonal response and thereby influence muscle strength to a greater extent”, they write in the conclusion of their publication. “Thus, when using a split routine during strength training, it may be an advantage to combine smaller muscle groups (arms, shoulders etc.) with larger muscle groups (chest, back, thighs etc.) to optimise the training effect.”

The idea that an optimal strength training should raise your anabolic hormone level as much as possible is no longer confined to the realms of scientific theory. Researchers in New Zealand have already shown that bodybuilders make the most progress on a training schedule that raises their testosterone concentrations most.

The effect of short-term strength training on human skeletal muscle: the importance of physiologically elevated hormone levels.


The effect of strength training and endogenously elevated hormone levels (plasma testosterone, growth hormone (GH) and cortisol) was studied in 16 young untrained males, divided into an arm only training group, A, and a leg plus arm training group, LA, in order to increase circulating levels of anabolic hormones. Both groups performed the same one-sided arm training for 9 weeks, twice a week. Group A trained only one arm (AT), the contralateral arm serving as control (AC), whereas group LA additionally trained their legs following the training of the one arm (LAT), with the contralateral arm serving as control (LAC). In spite of the attempt to match the two groups, the initial isometric arm strength was 20-25% lower for group LA compared to group A (significant for the arm to be trained). Isometric strength increased significantly in LAT and LAC by 37% and 10%, respectively, while the 9% and 2% increases in AT and AC, respectively, remained insignificant. Isokinetic strength increased at one out of three velocities tested for the trained arm relative to the untrained arm in both group A and group LA (P<0.05). Functional strength increased significantly by 20% in LAT, 18% in LAC, 19% in AT, and 17% in AC. Hormonal responses were monitored during the first and last training sessions. Resting hormone levels remained unchanged for both groups. However, during the first training session plasma testosterone as well as plasma cortisol increased significantly in group LA but not in group A. Plasma GH rose in all exercise tests, except during the last test in group LA, but was significantly higher in group LA than in group A in the first training session. In conclusion, a larger relative increase in isometric strength was found in the group having the highest hormonal response. However, due to the initial difference in isometric strength caution must be taken with the interpretation of this finding, which may only indicate a possible link between anabolic hormones and muscle strength with training.

PMID: 11782267 [PubMed – indexed for MEDLINE]