Thank you for this inspiring and educative article. Like yourself I love calisthenics. They helped me boost my mood and shape my body. I documented my experience in an article recently https://medium.com/sensible-biohacking-transhumanism/calisthenics-shaped-my-body-and-lifted-my-mood-for-decades-7aa9426b6571

Planks also helped an elderly friend to lower back pain.

https://medium.com/sensible-biohacking-transhumanism/audrey-eliminated-back-pain-and-transformed-her-appearance-dedicating-to-six-minute-planks-daily-63d481404317