Jack LaLanne, legendary fitness promoter, did several exhibitions from his 40s into his 70s in which he swam and towed boats while in hand restraints. He also performed public feats of strength with weights and in bodyweight exercises such as chin-ups. It wasn’t all for show, though – he actively worked to encourage women, the elderly, and the disabled to take advantage of the health benefits of exercise.
His own “conversion” came in his teens after hearing a lecture about nutrition and deciding to clean up his junk-heavy, sugary diet. He went on to build an empire of gyms, design specialized resistance equipment (including the much-reviled Smith Machine, which he envisioned as an introductory device), host a television show, and tirelessly promote better health through activity and nutrition.