I have changed my routine to go for 12-16 reps with lighter weights. Sadly I feel I am getting weaker. I do controlled movements and I feel the muscle working and it's getting the pump.
Gemini told me this:
"The reason you don't feel you are getting stronger is because of the 12-16 rep range. Lifting in this range primarily builds muscular endurance and creates "sarcoplasmic hypertrophy" (an increase in fluid and energy stores in the muscle, which gives you that pump). However, it is not heavy enough to force the neurological adaptations required to build dense, raw strength the way your old 4-6 rep routine did.
To build muscle effectively at 60 while continuing to protect your joints, you need a hybrid approach.
Drop your rep range from 12-16 down to 8-10 reps (or 8-12). This is the middle ground. The weight will be heavy enough to recruit high-threshold motor units and drive strength gains, but light enough to spare your tendons and ligaments from the crushing loads of a 4-rep max."
Comments from you guys are welcome. I would like to hear what works for you. I think of changing my routine again. Not only the rep count but also the way I divide into body parts.