Next in the How-To Series comes a favorite exercise that targets the abdominal muscles: the sit-up.
Also known as the curl-up, the sit-up is an abdominal endurance exercise that strengthens the abdominal muscles. It has a larger range of motion when compared to the crunch. In order to execute proper form, you first must lie with your back on the floor with knees bent. Usually, arms are crossed across the chest or placed behind your head with elbows bent. This is meant to help with reducing loaded stress on the lower back muscles and lumbar spine. Then, you elevate both upper and lower vertebrae from the floor in a neutral position, using your abdominal muscles as guidance, into the sitting up position, as seen below:
Again, this is a targeted exercise specifically for your abdominals. If you do not have the correct form with keeping a neutral spine while sitting upright, then you may cause lower back strain or arc your back, further increasing lower back injury in the future. A rule of thumb to remember on how to execute a proper sit-up is to proper breathing technique. Exhale on your way sitting up; inhale on the way lying back down.
If you have lower back problems that prevent you from using the full range of motion, then the alternative–or modified–exercise would be an abdominal crunch.
The abdominal crunch is similar to a sit-up that targets the same muscle groups, but it also pinpoints the oblique muscles. However, you have a shorter range of motion in this isolation exercise, and your lower back stays on the floor. Arms stay behind your head like you would in a traditional sit-up. Since you keep the lower back on the floor, you do not engage the hip flexors.
As noted above, you can use exercise equipment to elevate the crunches, depending on what suits you best.