If I recall correctly Cooper had a similar problem with calisthenics and discussed it in the book. That training doesn't help your cardiovascular capacity as mu

If I recall correctly Cooper had a similar problem with calisthenics and discussed it in the book. That training doesn't help your cardiovascular capacity as much as he wants, which is what's most important for your health and longevity. (I don't think calisthenics was given any points in his system.) He probably would also disagree about what's most straightforward. I recall him recommending running in the book because it doesn't require any special equipment or training, in contrast to cycling, weight lifting, swimming, calisthenics, etc. To be clear, I do think strength training is important as you age to avoid sarcopenia. But I suspect that running or cycling would provide enough resistance to slow sarcopenia for your lower body, making other exercise more important for your upper body and core.