1. The document discusses how physical abilities like flexibility, strength, and oxygen capacity naturally decline with age due to physiological changes in the body. 2. It notes that most sports organize competitive divisions by age to group athletes of similar physical maturity and ability levels together, since older athletes generally recover more slowly from injuries and have greater risk of health issues. 3. Examples given of age-divided sports competitions include junior Wimbledon, England football under 21s, and English schools athletics.