You’re planning on jumping back into a regular fitness routine right after the new year begins. What type of training is going to provide the biggest return on your investment in gym time? A study published in the journal Medicine and Science in Sports and Exercise shows what 42 inactive male subjects in their mid-20s accomplished.

These volunteers performed either 5 minutes of sprint interval training (SIT), 13 minutes of high intensity interval training (HIIT) or 40 minutes of steady state aerobics 5 days a week for a total of 8 weeks. All subjects significantly increased their capacity for exercise, with the greatest gains seen in the HIIT group.

True Strength Moment: If calorie burning is your goal, the SIT group sweated out 100 calories per session while HIIT burned up an estimated 180 calories per gym visit. Steady state cardio was the calorie-burning champion at 360 per session, so if time isn’t an issue that might be your best approach. In terms of time efficiency, it’s hard to top HIIT.