The Atreq speed resistor resigned to increase your acceleration, anaerobic endurance (short bursts of strength or speed), and lower-body power. One person provides the load by holding back on the strap attached to the harness, while the runner sprints at maximum effort. When the speed resistor is released, you will be primed to move faster around the field. Challenge your muscles to develop increased levels of power in nature, athletic movements. Great for short sprints, lateral shuffles, and explosive forward and backward movements. Easy to use, lightweight and comfortable.