The two key Tim Ferriss Abs exercises in his Four Hour Body 6-Minute Abs workout are:
- The Myotatic Crunch: a slow sit-up on a stability ball with arms straight overhead.
- Cat Vomit Exercise: Get on your hands and knees, inhale to exercise your lower abdominals and hold it.
The Myotatic Crunch
1. Sit on a stability ball or the floor.
2. Raise arms straight overhead. Keep your arms next to your ears for the entire movement.
3. Slowly lean backward for 4 seconds until your ﬁngers are parallel to the ﬂoor. Keep arms outstretched.
4. Pause at the bottom for 2 seconds.
5. Rise slowly and pause in the up position for 2 seconds. Stop when your arms are perpendicular to the ground.
6. Do 10 reps. If you can do 10, add weight.
The Cat Vomit Exercise
1. Get on your hands and knees. Look directly down.
2. Exhale until your lugs are empty. Contract your abs while exhaling. Gravity provides the resistance while you contract your transverse abdominals.
3. Hold your breath and pull your belly button upward toward your spine as hard as you can for 10 seconds.
4. Inhale fully after the hold.
5. Take one breath cycle of rest, then repeat 10 times.