Sit on ground with legs out in front of you. Put your hands on the ground at your sides and lift your hips up off the ground. Keeping yourself up with your hands and legs, move forward going feet first, or backward going hands first. Measure reps in distance covered.
You can also perform this exercise stationary, as a Crab Toe Touch. Get in same position for the Crab Walk. Keeping your glutes and butt off the ground, raise your left leg to straighten the knee out and reach with your right arm to touch the left toe. Keep yourself supported with your opposite hand/leg. Return the leg and hand to original position and repeat with the other side. Can count each movement or one full cycle as one repetition.