Horse Lunge Lines & Driving Lines - are used for basic groundwork and starting young horse. Many horse trainers start training for the horse with Lunge Lines, Long Lines and Ground Driving Reins. Lunging used for foundation work for the young horse and also way to maintain fitness of the horse. Lunging helps horses to warm up horses prior to being ridden and lunging a western horse is used as rehab after a layup. Lunge lines come in a variety of lengths and materials. Tack Warehouse recommends cotton as opposed to nylon because this material is easier on the riders hands.