For comparision, Is it possible to get 6 packs(body build) in my 40s, 50s? Yes it is possible but extremely unlikely.
1. Ageing degrade muscle more in 50s than 20s,
2. Testosterone (hormore required for building muscles ) in 50s is much less 20s.
So, someone in 20s can get 6 packs by doing exercises 1 hour by day meanswhile 50s require 4-6 hours per day.
Similar question in chess, a guy can still be a master in his 50s but amount of studies and hard work must be three fold or six fold than 20s.
I think Lyudmil is a strong player, much stronger than he was 10 years ago, perhaps between 2300 and 2500, but much stronger when playing against engines.