In the short term it makes no difference whether you pump iron in the morning or afternoon. But if you can choose, then probably in the long term it’s better to train in the afternoon, write sports scientists from the Finnish University of Jyvaskyla in the Journal of Strength & Conditioning Research.
There’s something magical about doing power training early in the morning. Pumping iron while the rest of the city is still asleep sounds special. But is it more effective? Do you really build more muscles if you train at seven o’clock in the morning than at, say, six o’clock in the evening? The Finns tried to answer this question by doing an experiment with 24 men whose average age was 30.
Eight men did nothing at all; they were the control group. Sixteen others trained their legs, doing squats, jump-squats, leg-presses and leg-extensions. For the first 10 weeks they all trained late in the afternoon to perfect their training, then the sixteen were split into two groups. Nine men trained for 10 weeks between 7 and 9 o’clock in the morning. Seven men trained for 10 weeks between 5 and 7 o’clock in the evening. Morning and afternoon athletes followed the same programme.
After 20 weeks the researchers measured the growth in the quadriceps muscle in the test subjects’ legs. They saw that the leg muscles of the afternoon group showed a greater increase in volume than the quads of the morning group. The difference between the morning and afternoon groups was not significant. Compared to the men in the control group, who had done no exercise, both groups had gotten bulkier muscles.
The researchers also measured the subjects’ increase in strength. Here the difference between the morning and afternoon groups was negligible. The weight at which the morning group just managed 1 rep with the squat increased during the 20 week period by 46 kilograms. In the afternoon group the figure was 45 kilograms. The men’s training scheme wasn’t actually aimed at strength, but was designed to achieve hypertrophy.
The researchers conclude that for a period of 2-3 months it doesn’t matter whether you train in the morning or afternoon. If you are training to build up strength, it doesn’t matter at all. But if you’re training because you want to develop larger muscles, then in the long term training in the afternoon is perhaps more effective.
An American sports scientist already published the results of a study in which bodybuilders who trained after 6 o’clock in the evening built up more muscle mass and lost more fat mass than bodybuilders who trained before 10 o’clock in the morning. Theoretically it is not so unlikely that doing strength training in the early evening is more effective. There are fundamental studies which show that you are at your strongest in the evening. What’s more, the balance between steroid hormones like testosterone and growth hormone and the catabolic hormone cortisol is better in the evening than in the morning.
Effect of time-of-day-specific strength training on muscular hypertrophy in men.
The purpose of the present study was to examine effects of time-of-day-specific strength training on muscle hypertrophy and maximal strength in men. A training group underwent a 10-week preparatory training (wk 0-wk 10) scheduled between 17:00 and 19:00 hours. Thereafter, the subjects were randomized either to a morning or afternoon training group. They continued with a 10-week time-of-day-specific training (wk 11-wk 20) with training times between 07:00 and 09:00 hours and 17:00 and 19:00 hours in the morning group and afternoon groups, respectively. A control group did not train but was tested at all occasions. Quadriceps femoris (QF) cross-sectional areas (CSA) and volume were obtained by magnetic resonance imaging scan at week 10 and 20. Maximum voluntary isometric strength during unilateral knee extensions and half-squat 1 repetition maximum (1RM) were tested at week 0, 10, and 20 at a randomly given time of day between 09:00 and 16:00 hours. The QF average CSA and volume increased significantly (p < 0.001) in both the morning and afternoon training groups by 2.7% and 3.5%, respectively. The 0.8% difference between the training groups was not significant. The entire 20-week training period resulted in significant increases in maximum voluntary contraction and 1RM of similar magnitude in both training groups (p < 0.001 and p < 0.01, respectively) as compared with the control group. In conclusion, 10 weeks of strength training performed either in the morning or in the afternoon resulted in significant increases in QF muscle size. The magnitude of muscular hypertrophy did not statistically differ between the morning and afternoon training times. From a practical point of view, strength training in the morning and afternoon hours can be similarly efficient when aiming for muscle hypertrophy over a shorter period of time (<3 mo).
PMID: 19910830 [PubMed - indexed for MEDLINE]