1. Lie on your back with knees bent and feet flat on the floor. 2. Hold a weight (plate, dumbbell, or similar) behind your head with both hands. 3. Engage your core and lift your upper body toward your knees in a crunch motion. 4. Exhale as you crunch up, keeping the weight stable behind your head. 5. Slowly lower back down with control to the starting position.
Log your weighted crunch (behind head) sets in 1RM.fit and watch your estimated 1RM update automatically as you get stronger.