I got back into cycling at 50, peaked at 63. "They say" it takes 7 years to peak. Took me a little longer. Any training program works, but some work better than others, depending on the individual and their goals. Main thing is to stick with a program for long enough to see how it works, say a year. I'm 68 and I can still put on muscle, leg sled 4X bodyweight, etc.