Bryan Johnson's ongoing dunk training at age 49 highlights the steep athletic demands of generating sufficient vertical leap, explosiveness, and coordination for a regulation 10-foot rim with a full-size basketball. Recent sessions show incremental gains, advancing from a 9'8" rim with a smaller ball in mid-October to 9'9.5" days later, yet he remains several inches short while noting the added height and palming challenges of a standard ball. His baseline 23-inch running vertical, combined with age-related declines in power output and elevated injury risk from high-impact landings, creates substantial barriers despite dedicated plyometric and strength work. Trader consensus favoring "No" at 70.5% reflects these persistent gaps and the limited remaining window before 2027, even as consistent practice continues.