We all know exercise is good for us—but what happens when your knees or hips start hurting? Do you stop squatting, running, or lifting altogether? Not necessarily. This is where isometric exercises  come in. According to the Cleveland Clinic, during an isometric exercise, “you hold a position that maintains the same muscle length, causing your muscles to fatigue.”  In other words, instead of doing multiple reps, you simply hold one position—no movement, just tension. These ho