If you begin to notice that traditional supine bridges are getting too easy, then use the "marching" version as a progression. The marching supine bridge is the perfect exercise for the glutes! This version of the supine bridge is similar to the original. When marching steps come into play, the exercise becomes more difficult because you briefly have to support your body weight on one leg. You will definitely feel this one working. Instructions for this exercise are listed below:

Lie supine (on your back) on an exercise mat. Bend your knees and place your hands by your sides. Elevate your hips as high as you can. Slowly lift each leg off the ground one at a time, as if to march in place. Your head and shoulders should always remain affixed to the workout mat.