If you look in your rearview mirror, you will see the still-diminishing era of steady-state cardio requirements. Gone are the days of “20 to 30 minutes of low-intensity” work on your go-nowhere treadmill.

High-speed, high-intensity work has become the norm, and for good reason. It gets you leaner in less time while preserving your hard-earned muscle mass. And yes, there are multiple ways to get your high-intensity interval training on, but for our money, sprinting provides a pretty high return on investment.

But if you’re not a sprinter by nature, where does one begin? We’ve outlined three starting points for you with a single requirement: Pack every ounce of effort you can muster into each sprint.