This article originally appeared in Shape.
For people who despise spending a huge chunk of their free time on cardio machines at the gym, high-intensity interval training workouts can easily be considered a panacea. They improve your aerobic capacity, burn a ton of calories, flood you with mood-boosting endorphins — and do it all in less time than lower-intensity workouts.
No matter how much you love those jump squats and burpees, though, your body (or neighbors) might not be too pleased with the constant impact of these moves. “If you’re doing HIIT-style running or cardio movements that aren’t on a piece of equipment, like a bike, you can end up feeling really sore or get pain in your knees or in other joints,” says Ashley Davies, a certified group fitness instructor and former Flywheel cycling instructor.