When working the core in long body Crunches, ensure that you are trying to move your ribs toward your hips, while pulling the belly button in and up toward the backbone. Rather than going higher, focus on your technique and feeling stable. Keep the elbows away from the ears and the neck long by gently tucking the chin.
For Leg Lifts and Lowers, keep a neutral spine, so you’re not imprinting the spine onto the floor, you keep just a small gap between the lower back and the Earth. Really pull the belly button toward the back bone.