Getting Weak Isn’t Aging. It’s Disuse.
Almost everything we know about losing muscle with age comes from studying people who stopped moving. When researchers scanned athletes aged 40 to 81 who never stopped, muscle mass held, and the strength drop came late and then levelled off.
Runners Get Less Back Pain, Not More
The received wisdom is that pounding the pavement wrecks your back. A systematic review of nineteen studies found back pain is less common in runners than in the general population, not more.