Crunch (exercise)
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The crunch or curl-up is an abdominal exercise that works the rectus abdominis muscle. Crunches use the exerciser's own body weight to strengthen muscle and are recommended by some experts, despite ne
Performing the crunch
Sit-up
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The sit-up is an abdominal endurance training exercise to strengthen, tighten and tone the abdominal muscles. It is similar to the curl-up, but sit-ups have a fuller range of motion and condition addi
Crunch (exercise)
…Research has shown that both sit-ups and crunches are mediocre strength-building exercises and have injured many people. In a crunch, unlike a sit-up, the lower back stays on the floor. This is said to eliminate any involvement by the hip flexors, and make the crunch an effective isolation exercise…
Sit-up form
Seabees conduct a situp variation