Thanks Stew ... I don't lift any heavy weights anymore ... just a lot of TRX and calisthenics for all body parts ... getting as I get older and hopefully a little smarter, I'm not going to injure myself with lifting heavy. I'll continue to look at your and other TRX videos ... I can always can learn more about what others are doing with the TRX. What are you thoughts on intense quick aerobic runs / stair stepper vs longer runs, and stair stepper workouts where the heartbeat is approx. 60 to 80%?