Stand on a treadmill. Set an incline and walking pace that is comfortable for you. Try starting at 4% incline and 2.5 miles per hour and go from there. Start walking with an upright posture and eyes forward. Strike gently through the heel and roll your weight forward through the ball of your foot while letting your arms swing freely.
A commercial level treadmill that folds up for easy storage. Automatic incline and decline, plus a large screen make this a great treadmill for your home gym.