You need a barbell for each hand. Line up single file. First in line is the engine-leader. Your feet move like cross ski and arms punch the water. The leader takes the train all over the pool---careful not to drown anyone :) The train moves fast going down hill or slow for up hill. I usually go fast 30-45 seconds then same for slow. Off and on intervals. After two minutes I have the engine take the caboose position, making second person in line the engine. After 10-15 minutes we work on legs or arms for our cool down.