The IRIS Resistance Trainer with shoulder Harness is not just for runners. By incorporating it into your regular training . It will improve your athletic performance for any sport you participate in. The harness design makes it a breeze to keep your posture in proper alignment as you run. Learning to properly run with resistance makes you that much faster and stronger when the resistance is eventually reduced or removed. If done properly with mindful form, the harness takes the pressure off of your knees and enables you to run with resistance without fear of joint distress.