Primary Muscle Group: Gluteus Maximus
Muscle Groups Worked in This Exercise: Gluteus Maximus, Quadriceps (Rectus femoris, vastus lateralis, vastus medialis and vastus intermedius)
Preparation: Begin with the ball on your right side. Rest your hand on top and take a big step forward with your left leg.
Breathing: Inhale as you bend, exhale as you straighten your leg.