One-legged squat hanging fitness. Facing the door handle, fix the strap so that the arm bends and the elbow reaches the waistline. Lift your left leg straight in front of you and let all your center of gravity be on your right foot. Bend your right knee and sit down as if you were sitting in a chair. Keep the center of gravity on the heel and try not to "hang" backwards. Exercise calf muscles through heel. Repeat 15-20 times on the right, and then switch to the left.