A training and swing exercise device with resilient resistance is used as a training apparatus for developing greater power and strength at impact when striking a ball. The device provides impact resistance to a golfer, baseball player's, hockey player's, field hockey player's and tennis player's swing...http://www.google.com.au/patents/US7993249?utm_source=gb-gplus-sharePatent US7993249 - Swing enhancement exercise device with resilient resistance
