This exercise primarily builds isometric strength and endurance in glutes, calves, quadriceps, hamstrings, and adductor muscles. This also is good for people who do sports.
Stand about 10-12 inches from the wall and lean back so that your back is flat against the wall. Your feet should be shoulder width apart and firmly planted on the ground. Slowly slide down the wall until your knees are bent at a right angle. Your knees should be directly above your ankles and your back should be touching the wall at all times. Hold this position for 20 seconds then slowly rise to the starting position. You should feel a burn in your quadricep muscles. If you feel any knee pain, you should stop the exercise.