Come into an all fours position on an exercise mat with your hands directly under your shoulders and your knees directly under your hips. Maintaining a 90 degree bend at the knee and without rounding your back, slowly move it outwards until it’s almost parallel to your hip. Keeping the knee there, slowly rotate the hip inwards until your foot is pointing towards the sky. Try not to over-arch the back at this point in the exercise. Gradually, and with control, drive the leg back, keeping the knee at a right angle and level with the rest of the body. Slowly drive the knee forward to return to the start position. Then repeat the steps above in reverse. This counts as one rep. Repeat for the recommended number of reps (or time).