I would agree that low t is an issue also, low gh. Attitude is the biggest motivator. I have been body building for 29 years now and refuse to let age get me. I will use HRT as needed, my cycles as needed to achieve my goals. The biggest thing to remember is to lift smarter, not harder. Find what level of lifting works for you, light weights lots of reps, heavy weights low reps. I'm the heavy and low group. We do tend to ache a bit more, but with HRT, that should go away or diminish to acceptable levels. Once you think your old and believe it your done. Never give in to age, make it earn every bit of your life until its your time.
I like this saying from the movie 13th Warrior:
"The stain of your life has already been written. Go hide in a hole if you want, you won't live 1 second longer."