These lifts strengthen the rectus abdominis. Using a chair allows you to keep your legs bent at a right angle, which will protect your lower back from injury.
Lie on your back, put your shins on a chair, hands at your temples or stretch along your body. Raise the body, trying to transfer the maximum load to the abdominal muscles.
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Level 1 – 3 sets of 10 reps. Rest between sets – 1 minute.
Level 2 – 4 to 16, rest – 45 seconds.
Level 3 – 5 to 26, rest – 35 seconds.
Level 4 – 6 to 34, rest – 30 seconds.