Having started the KB Simple/sinister workout as a General phys performance program, and having grasped your centenarian Olympics model of physical health and performance, through the lens of min effective dose, kb seems to be a good alternative to a gym/garage full of specialized equipment and is time efficient. I am speaking as a healthy 57 y/o active guy with good metabolic markers. What are your thoughts on KB use as THE primary strength/aerobic fitness tool ? Downsides?