Designed to mimic the motion and feedback of a traditional rope, this system helps you build rhythm, speed, and arm endurance without the risk of tripping or whip marks. The weighted balls create resistance and even make a whistle sound at high speeds, giving you the real rope feel—minus the rope. Useful for: * Practicing double unders & speed jumping rhythm and coordination. * Improving arm endurance for competitive jumpers (most coaches know that it isn't the legs that wear out; it's the arms). * Improving coordination between arms. Many jumpers have a difficult time using both hands equally, which causes the rope to turn too close to their feet. The result is misses! Speed training with this system helps increase coordination and strength in the "weaker" hand. The result: fewer misses and faster scores. Perfect for competitive jumpers, beginners building confidence, or anyone who wants a portable, no-impact workout. From hotel rooms to practice sessions, it’s your go-to tool for refining technique, increasing stamina, and keeping your workouts frustration-free. For "no jumping" workouts: The Jump Rope Trainer is also a great tool for those who are unable to jump well. The balls will turn with little or no jumping. Use for a fun workout.