Made specifically for the fitness minded, the Sport is back and better than ever with the new 4th Generation (G4). The same famous style now with upgraded components for an even smoother and faster ride. Adjustable handlebars let you focus on different muscle groups. Hybrid tires are smooth on top for speed, and knobby on the sides for control and traction through turns and loose footing. Perfect for cross-training, Kickbiking works all the same muscles as running and biking combined, with practically zero impact, leaving you loose and stretched, not stiff and sore. There is now a fantastic 3rd option to running and cycling!