Straight Spine Sit-Up
Keeping the spine fixed during a sit-up requires more strength and control. The longer the spine is the harder it is to control. In a standard sit-up people curl the spine which shortens the trunk lever. This reduces the workload. Keeping the spine fixed as a long lever, in your anatomical position, increases the challenge on the body. Building spine control and strength is the key to reducing or eliminating training related injuries. The more time you spend training your spine to be a controlling system vs. a moving system the better your training results will be. I have helped hundreds of athletes to eliminate or prevent injuries by introducing them to my column core training system.