How do I perform marching lying on my back?

Lie on your back with your knees bent, keep your feet flat on the floor and your toes pointing straight ahead. Gently draw-in your navel towards your spine and contract your glutes. Slowly lift one foot off the floor with control, hold in the air for a few seconds and lower your foot back to the floor. Repeat with the other foot.

Lie on your back with your knees bent and feet flat on the floor. Toes are pointing straight ahead and arms are on the floor in a position that is comfortable for you. Draw your abs in and lift one foot off the floor (keeping the knee bent) as high as you can control. Hold the position for 1-2 seconds then slowly lower the foot back to the starting position. Repeat the movement with the other foot. Continue alternating sides for the required number of repetitions.