Powerstroke Bungee Mk2 Surfers Paddling Training Aid New MK2 model with Latex cords and handle paddles for improved performance. - Work 95 Cant get to the pool or ocean but dont want to loose your surf fitness - The Power stroke system is a resistance training tool for improving all upper body strength for surfing. If used regularly it will improve all the major muscles involved in paddling out back and into waves A major part of any surf session. - The Power stroke bungee cords can be attached almost any where for a surfing work out. The powerstroke bungee will also improve your aerobic surfing fitness and major muscles for surfing paddle power works if your a beginner or a seasoned pro. Works on - Latissimus doris major muscles along side the back - Trapezius muscles that help support the head above the shoulder blades - Triceps back of the arms