When it comes to exercise, gravity is your friend — though it may not feel that way when you're working against it. That's why the incline board, also known as "slant board," is a time-honored accessory in the quest for fitness. An incline board is an adjustable bench that can be raised at the foot end to increase its angle. In gyms, they usually have padded braces at the high end for securing the feet and ankles.
Doing sit-ups, curl-ups or crunches on an incline board increases the amount of resistance the muscles must overcome to raise the torso. When you do sit-ups or other exercises on an incline board, you're increasing the amount of gravity you're bringing into the equation. Doing sit-ups at angles activates the muscle fibers in a different way and adds intensity your sit-ups.
When using an incline board, proper form is more important than ever. This goes double for sit-ups, which already carry a high risk of injury to the lower back. Some exercise specialists actually discourage doing them at all. Once your shoulders are off the ground, the abdominals give way and the hip flexors do the work. Even bent-knee sit-ups with the feet braced — frequently offered as the safe alternative — aren’t without risk. They can also pressurize the lumbar area, making disc injury a risk.
Form is Everything
"The form is the same as doing sit-ups horizontally, but it's definitely going to put all the more stress on the lower back," says Los Angeles-based personal trainer David Knox, author of "Body School: A New Guide to Improved Movement in Daily Life." "But you're going to be all the more tempted to pull on your neck, which can cause you to pull neck muscles," he adds.
Placing your hands behind your head adds resistance to the exercise, but it's important to remember that your hands are there to support the neck, not to pull your torso forward. This can cause neck train. If you're just starting out, you may find it easier to cross your arms over your chest. It's important to lower your back all the way down the surface because otherwise the abdominal muscles don't engage. If the neck is sensitive, it should be remain in a neutral position with space between the chin and breast bone.
Hip Flexors Need Love, Too
Although one of the main criticisms of sit-ups is the aforementioned fact that the hip flexor rather than the abdominal muscles complete the movement, this isn't necessarily a bad thing — if your abdominal muscles are strong enough to counter the flexor muscles' pull on the lower spine. Sit-ups on an incline board allow you to exercise both the abdominal muscles and the hip flexors at the same time. According to the sports medicine web site ExRx.net, sit-ups on an incline board can be performed safely for those with adequate abdominal conditioning.