Inch Worm

Start from a push up position with a neutral spine. Slowly and carefully walk the hands past your head (tight core) to your ability (knowing they could slide out). Then from that extended position, tip toe up slowly keeping the legs straight and dropping the heels holding that position for a second or two (as high as your flexibility allows) . Repeat by walking the hand out again in sequence. To increase difficulty add a push up with hands out.

Work on walking the hand further out, and getting the legs further in, as your upper body strength and flexibility increases.

Great stretch of posterior chain, core and upper body strength.