Benefits: This exercise is good for postural control, and it involves the rectus abdominis, transversus abdominis, and obliques. The exercise simulates and exaggerates the rotational movements of running. Balancing on one leg challenges the muscles that respond to the instability that is present during running (when running, you only have one foot on the ground at a time). The crunch itself also compresses the trunk and makes inhaling more challenging.
IMT loading level: light to moderate
Duration: 30 repetitions
Sets: 2 sets
Procedure: Stand upright with your BMT in your mouth, your right hand behind your head (elbow in line with your shoulder), and your left hand resting on your hip (a). Rotate and crunch your body to bring your right elbow toward your left knee (don’t flex your elbow forward to meet your knee; keep your elbows level with your shoulders) (b). As you crunch, inhale forcefully through your BMT, exhaling as you return to upright. Then swap sides, bringing your left elbow toward your right knee.
Variations: You can add difficulty by standing on balance cushions or a Bosu.