I’m sure there is some truth to this. I just can’t picture an 80 year old man continuing to get bigger and stronger on a
However, there have been a lot of people who have reached their peak conditioning in their 50’s. Powerlifting guru,
Louie Simmons, has hit his personal best lifts in his 50’s (i.e. 600 lb. bench press, 900+ lb. squat, and 700+ deadlift).
Masters Mr. Olympia winner Robbie Robinson has gotten into his best contest shape ever in his 40’s and 50’s.
So you can certainly continue to make solid gains in muscular size and strength well into your 50’s.