When it comes to aging and training I have to keep coming back to my man Clarence Bass. While he is definitely showing signs of aging in his muscle tone and presumably other aspects of his metabolism, the guy is a beast, and has been for years.
He might be an aberration but if so I suspect it is his capacity for and ability to manage high intensity protocols, and not anything to do with genetics.
Peak Shape - at 60
==As detailed in The Lean Advantage 3, Lovelace Foundation for Medical Education and Research in Albuquerque, New Mexico, measured my maximum heart rate for the first time in 1977, when I was a few months short of 40. It was 180, exactly in accordance with the standard formula (220 - 40 = 180). Interestingly, that was a few years after I began doing regular high-intensity aerobics.
Since then, my maximum heart rate has been measured in a laboratory setting seven times -- at ages 44, 47, 50, 51, 55, 60 and 62 – and has consistently exceeded the predicted rate by an ever widening margin. In June of this year, the Cooper Clinic in Dallas recorded my maximum heart rate at 182. Confounding the formula, my maximum heart rate has remained 180 or higher for 22 years. Why have I been able to defy the rule? Am I an aberration?==
and
==Evans and Rosenberg and their colleagues at the U.S. Department of Agriculture's Human Nutrition Center on Aging at Tufts University have found that "the muscles of elderly people are just as responsive to weight training as those of younger people." Startlingly, an 8-week program of strength training by 87- to 96-year-old women confined to a nursing home resulted in a tripling of strength and a muscle-size increase of ten percent.==