Muscle Building: Isolation Exercise - Leg Tuck (Seated)

Sit on a bench sideways, grasping the edges for support. With knees bent, raise your legs slightly and then straighten them, leaning backward as balance requires. Now lift your knees up toward your chest, keeping your lower leg pointed downward, and flex your abs really hard. Keep continuous tension on the abs throughout this movement. This exercise works both upper and lower abs.