proof

Callouses at the base of each finger, another one in the middle of the hand, below the middle finger. Torn skin near the base of the thumb, between thumb and first finger...pull-ups on the pull-up bar. Kung-Fu sit-ups on the pull-up bar. WIDE grip on the pull-up bar. Keeping the thumbs over when gripping the pull-up bar.
Six sets of ten pull-ups on the pull-up bar. (Today a new record, FIVE pull-ups successful on the first set!) Six sets of nine Kung-Fu sits on the pull-up bar.
Feeling the burn on the pull-up bar.
Failing on the pull-up bar.
Leaving little bits of me on the pull-up bar.
Taking some of it with me from the pull-up bar.
Like Yoda says: "Try not. Do or do not, there is no try."