Hey man … I’m no expert, but I am over 35 (45), lol
Also did the “one body part a week” thing for years … About 5 years ago started to break things up so I’m hitting each body part twice per week, but the total number of sets during each workout is reduced. I’ve also experimented with pull ups every day, push ups every day, and currently doing delt side raises 3 x per week to work more shoulders in. All of that extra work is high reps and never to failure.
For example:
M- legs (squats, LP, hacks) 10-12 sets
- hammies 3 sets of whatever
- back (BB rows, cable rows) 8-10 sets
- bi’s (barbell curls, concentration curls) 8 sets
-
- side laterals, 3 x 15-30 *
T - chest (FB, incline hammer) 10-12 sets
- Tri’s ( dips, machine extensions, push downs ) 10-12 sets
W- Delts (OHP, BNP) 10-12 sets
TH - legs (squats only, higher reps and light) 5 sets
- back (DL, pull-ups, hammer rows) 10-15 sets
- hammies, 3 sets of whatever
F - tri’s ( CGBP, dips) 10 sets
- chest (decline BP, 3 sets 10-15 reps)
- bi’s (hammer curl, machine preacher) 8 sets
-
- side laterals, 3 x 15-30 *
This set up isn’t ideal … I don’t like working delts after chest and tris, and don’t like hitting biceps after back day, but it keeps me from hitting the gym on the weekends, which is more important for me at the moment.
Just an idea of how you can structure in extra workouts for each body part … Try to take advantage of the “bleed over” from similar work … For example, CGBP hits chest as well as tris, so I do that on Fridays workout rather than Tuesdays to hit a little more chest.
At the end of the day you’re halving a 15-20 set one body part day into 2 workouts within a seven day period (or longer if your schedule permits)
Clear as mud? Lol