Strength athletes can reduce their fat percentage by doing trisets instead of traditional sets, sports scientists at the San Antonio Catholic University of Murcia in Spain have discovered.
The Spanish researchers used 33 health men as their subjects. They divided the men into three groups: a control group, a group that trained in the traditional way [TS] and a group that did trisets training [HRC].
The TS group did their strength training in the way that most bodybuilders do. They did sets of each exercise, and when they had completed these they started on the next exercise. Between sets they rested for three minutes. Each training session the men did six exercises, at a weight with which they could do a maximal six reps.
The HRC group did trisets. They started with one set of exercise 1, and almost immediately followed that with one set of exercise 2, directly followed by one set of exercise 3. After that the men did another set of exercise 1, and so on. The researchers had worked out an exercise scheme in such a way that it was possible to train with minimal rest periods.
After eight weeks the men in the TS and the HRC group had made equal progression in strength. The HRC group had gained 1.5 kg lean mass; the TS group 1.2 kg. The difference was not significant.
The table above shows that the fat percentage of the TS group dropped by 1.1 percent – not a statistically significant drop. But the fat percentage of the HRC group dropped by 1.5 percent – and this was statistically significant.
"Both groups were able to complete the same work and achieve the same strength increases but the HRC group did so in less time", the Spaniards conclude. "Thus, the HRC was more efficient and might therefore be useful for individuals who perceive that a lack of time available for training is a substantial exercise deterrent."
The researchers do not speculate about why workouts with trisets result in more fat burning as their results suggest, so we'll do that for them: it's because of the EPOC effect. The shorter the rest periods between sets, the higher EPOC after strength training.
J Strength Cond Res. 2011 Sep;25(9):2519-27.