Lying on your back (supine) tuck your tailbone, squeezing your legs and glutes tightly. Lift your shoulder blades off the ground by pressing your ribs down and engaging your upper abs. Holding this dish shape, begin to rock front and back. Think of initiating the rock upwards with the legs by pulling the pelvis off the ground, then the upper body rock by pushing the chest forward.
Starting lying flat on your back, put your hands at your side, palms down on the floor. Lifting both legs together bring them as far overhead as you can. This is the plow position – hold for a second to increase your pike flexilibility. Then send your feet up towards the ceiling, squeezing your glutes and core to stabilize. Bend your knees tight into your chest and roll down slowly trying to keep your back on the ground as you return to your starting position.
Seated on the ground with your legs straight and together (piked), put one hand on the ground on either side of your legs. Keeping your back straight lift both legs off the ground repeatedly keeping the legs straight (no knee bend). To increase the challenge walk your hands closer to your knees / feet. To decrease the challenge, put your hands on the ground behind your back so that you are not so closed / piked at the hip.