With a sit-up, you move your torso to a sitting position, whereas in a crunch, you only lift slightly off the ground to raise your upper back. Sign up to get the BEST of Tom's Guide direct to your ...

Perform the sit-up with perfect form with expert advice and guidance plus the best sit-up alternatives and 10 best ... Simultaneously lift your knees and torso off the floor into the v-sit position.

If your abdominal muscles are not strong enough to do good sit-ups, begin with crunches (partial sit-ups). Assume the sit-up position as described, but slowly raise only the head and shoulders off ...

Strengthen your core without putting too much strain on your neck using this abs workout that avoids sit-ups and crunches.

FBI applicants must pass a physical fitness test that consists of sit-ups, push-ups, a 300-meter sprint and a 1.5-mile run. A candidate demonstrates proper sit-up form here.

Your baby may be able to sit up as early as 6 months old, with a little help getting into the position. Sitting independently is a skill that many babies master between 7 to 9 months of age.

Generally, the sitting position that puts the least pressure on the back and shoulders is best for lower back pain. Typically, this involves placing the feet on the ground and using back support.