Alive is terrific for kids and teens. So far I have used it primarily with 11 to 16 year-olds. With other systems, I could never get an accurate heart rate signal from many younger children because they were so wiggly, and I often had to have very short training sessions because of their short attention span. With Alive, these children sit quietly and don't want to stop, even after 55 minutes. To quote one young boy who caught on immediately: "I have to stay calm even when things get hard."