Exercising opposing muscle groups back-to-back (a superset) is a popular method for burning more fat. But a Journal of Strength and Conditioning Research study revealed that supersets did not burn away any more calories than traditional straight sets. The superset workouts were, however, shorter and burned more calories relative to the duration of the training. Bottom line: Keep doing supersets if you're looking for efficiency, but if you're trying to burn fat, running sprints plus cutting calories from your diet is still your best bet.
A recent study questions the benefits of this popular method