SpencoÂ® PolySorbÂ® Cross Trainer Insoles For aerobics, court sports, running, weight training, racquet sports and walking. Special cushioning in both the heel strike zone and the forefoot area for outstanding performance. Helps turn any athletic shoe into a cross training shoe. Best combination of shock absorption and energy-return. Proven cushioning and support improves athletic performance and prolongs the life of your shoes. Low Price - Click Now!