Effect of Time of Day and Concentric or Eccentric Strength Training on Muscle Strength

To determine the time of day (morning/evening), which is best for strength training to yield maximum strength gains? Apart from this, which is the type of exercise (concentric/eccentric) that should be done at that particular time to produce maximum benefits in strength?

34 healthy boys (16.6 +1.2 yr) were randomly divided into 4 groups. Two groups trained their elbow flexors in the mornings for 2 days per wk, one group using eccentric (ME) and the other using concentric (MC) contractions. Similarly the other two groups EE and EC trained in the evenings. Dynamic strength (1-RM) was measured pre training, at the intervals of 2 wks, 4 wks and post training (after 6 weeks) for comparisons.

The results indicate that evening eccentric exercise leads to maximum dynamic strength gains. The dynamic strength of EE, EC, ME and MC groups improved by 28.53% ±4.35%, 23.34% ±3.27%, 22.91% ±4.01% and 20.82% ±4.43% respectively. The gain in dynamic strength of EE group was maximum when inter group comparisons were done.

It was concluded that it is possible to have better strength gains with eccentric exercise training than concentric exercise training even if done at relatively same exercise load in terms of percentage of 1-RM. This difference becomes remarkable when the eccentric exercise is done in the early part of the evening.