It’s tough to escape the treadmill when the weather starts to turn. And while cruising through an easy run with entertainment is one thing, locking into intense speed intervals while staring at the same console is another. Without fresh scenery or a crew of training partners to pull you along, speedwork on the belt can test your focus before it tests your fitness.

Even professional runners know the feeling. When weather or logistics reroute a key workout indoors , they adapt and find ways to make the session productive, fast, and even fun.

Here, eight pros share the treadmill workouts they rely on to turn indoor interval sessions into serious gains.

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