Lunges exercises specifically target the lower body muscles to increase strength and build muscles. Ball lunge with placing rear foot on stability ball is an effective variation to work on thighs, hips, legs and back simultaneously. Stability ball is a great exercising tool to offer variations and challenges in your workouts. The instability of stability ball adds challenge in ball lunge exercise to enhance the intensity of the workout that surely increases the benefits. It provides a deep stretch in all related muscles and builds and strengthens the muscles. You must focus on keeping your back straight and abs muscles tight throughout the exercise to get the maximum benefits from the workout.