Wow! That is super inspiring to me--to think it is possible to look that good at 55 years old--a time when most men look like utter shit. Just wow.
Most guys, once they get to around that age, no matter how much muscle they maintain/build or how lean they get, begin to take on an aged appearance. The skin loses its elasticity and starts to look more worn, loosing its youthful tone and texture. The muscles themselves start to lose their roundness, while taking on a less seperated, more blurred together appearance. This is generally apparent everywhere, but especially in the legs. Basically, the entire physique shows signs of aging by this point in life.
Gary is he first man I have seen at this age, at least in this pic, where a man's physique is indistinguishable from that of a 20-30 year old in terms of youthful appearance. I can't see any convincing, visible signs of aging anywhere on his body--not in this shot. Just amazing.