They increase time under tension for your muscles—something important for building muscle—since they must stay engaged the entire time. The Exercises Glute bridge with abduction Side-Lying Leg Raise Squat Clock Tap Glute Kickback Lat Pull-Down Plank Jacks Overhead Press Single-Arm Row Shoulder External Rotation Standing Single-Leg Tap Out Quadruped Leg Extension How to do it: Start …