There are some fitness maxims you just can't argue with, one of which is that in order to reach your goals, you have to be willing to work for them.

That being said, if you want next summer (or even next winter) to be your fittest yet, prepare to put the time in at the gym. But, the last thing you want to do is waste your effort. Instead, you want to make sure that every pound you lift, every second you run, and every step you take provides you with the maximum return on your fitness investment.

The first way to help ensure max ROI is to incorporate interval training into your workout. Research from Laval University in Canada found that 15 weeks of high-intensity interval training shed nine times more fat than 20 weeks of steady, moderate-intensity exercise.

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