In a marching bridge with your back resting on the yoga ball and your feet on the ground, start by lying on your back with your knees bent and feet flat on the floor. Place the yoga ball underneath your lower back and hips for support. Lift your hips off the ground to create a bridge position, keeping your back firmly against the ball. Alternate lifting one knee towards your chest while maintaining stability and balance on the ball, engaging your core and lower body muscles throughout the movement. This exercise targets your glutes, hamstrings, and core while also challenging your balance and stability.