From Ergo Log
The research that Tim Scheett did at the University of Southern Mississippi has not been published in a peer reviewed journal. In fact, his research might never be published. Nevertheless we suspect you might be interested to know the conclusion – that bodybuilders make more progression if they train in the evenings than if they train early in the morning.
Training in the evening gives you more muscles, more definition
Fundamental studies have shown that the time at which training is done can have an effect on your progression. The balance between muscle building testosterone and muscle destroying cortisol is more favourable in the evening. You’re also slightly stronger in the evening. But are these effects so strong that you also build up more muscle mass and strength if you train in the evening? This is the question that Scheett set out to answer.
So he did an experiment with 16 trained bodybuilders. He got them to train four times a week for a period of ten weeks. The test subjects trained each large muscle group twice a week using weights. They did three-quarters of an hour weight training each workout, followed by three-quarters of an hour of cardio training.
Half of the test subjects trained in the mornings before 10 o’clock. This was the AM group. The other half of the test subjects, the PM group, trained after 6 o’clock in the evening.
When the ten weeks were up, Scheett looked at what had happened to the body composition of the bodybuilders in the two groups.
The differences were not statistically significant. This is because the group of athletes that Scheett used for the experiment was too small.
Both groups achieved the same amount of progression in terms of muscle strength.
Scheett refers to the effects that he observed as ‘small’, and did not regard them as big enough to discourage bodybuilders from training in the morning. “You should train at a time that is most convenient to you and at a time which feels comfortable”, stresses Scheett. “Only if it doesn’t matter to you when you train, could you consider doing those bench presses in the evening. Or if you’ve already been training for a while in the morning, but have noticed that you don’t react well to this.”
Scheett did not investigate how these effects arise. He speculates that the body’s metabolism usually declines in the evening. As a result you use less energy. But if you train at that moment, your metabolism starts to work even harder. If you train in the evenings, you burn more energy over the whole day. That might explain why the subjects in the PM group became drier. And the more favourable testosterone-cortisol ratio may also help explain why the PM group also built up more muscle mass.
Scheett presented his findings in a poster during the annual National Strength and Conditioning Association Conference in Las Vegas, Nevada, 2005. The full title was Effect of training time of day on body composition, muscular strength and endurance.
Flex, Feb 2009. [Offline]