We’ve all been there: holding at the bottom of a squat or plank, feeling your legs start to quiver like crazy. Congrats—you’ve experienced the burn of an isometric hold. These strength-boosting pauses ...

If you’ve ever held a plank, paused at the bottom of a squat or pressed your palms together in front of your chest, you’ve done an isometric exercise. Ta-da! These holds might look simple — after all, ...