I have not contributed for a while but this has been on my mind...
This is a question that some have pondered and experimented with in their workouts. Recently I had the same question with my own workouts. Having a limited time to train due to professional and personal commitments, I found myself asking me how to get 10 pounds of shit out of a 5 pound paper bag! Time and recovery is a problem.
I began experimenting with alternating single exercises for each body-part so that I would have variation but still fall withing a abbreviated 2-3 exercise workout. I remember Marty Gallagher talking about pro power lifters training once per week, all 3 lifts. Ed Coan was one of them:
https://www.ironcompany.com/blog/once-a-week-strength-training-part-1
At almost 66, I need more recovery as the intensity rises. I am usually a pile of dog heap the day I train and up to 2 days after.
What I did to solve this problem is I chose 10 exercises, split them up into 2 split workouts and alternated exercises per workout. For instance I would train Chest Back and Triceps one workout and the next Biceps and Legs. Using mainly compound exercises I constructed the workouts. I did not do any direct shoulder work as I found in chasing a big bench, the shoulders are trained enough with other movement and direct usually causes them to be over-trained. Unless you are using some gear which dramatically helps your recovery ability.
I employed forced reps, partial reps, rest pause etc to go to failure and beyond, but sometimes just go to failure. The only twist is with rest pause, I used a higher rep scheme and with that scheme, I used a 30-40 second rest pause with a maximum of rest pause sets.
The rep range is also kept higher, usually edging into this workout for the first time, I use a lighter weight where I can get almost 30 perfect reps, which helps the joints and tendons by putting a lot of blood into them. As I get stronger and add weight, I bring that threshold down to 20 reps, adding weight as I break the 20 barrier i.e. 22-24 reps. I add weight again, trying to go no lower than 15 reps. Believe me, you end up using weight you previously did 8-12 reps on.
Here is an example workout:
Wo 1
Decline Bench
Barbell Row
Reverse or Close Grip Bench
Wo 2
Barbell Curls
Squats or Leg Presses
(No I do not work caves, I get a ton of stimulation from these exercises, especially when you are doing 20-30 reps)
With Legs I usually breath through them. I go to failure, take a couple of breaths, failure then another couple til I can not do anymore.
Wo 3
Dips
Partial High Pulls
Kaz Extensions
Wo 4
Hammer Dumbbell Curls
Squats or Leg Presses
Today I am not doing deads but I do throw them in on occasion, usually trap bar. I will probably end up throwing a deadlift workout in between the first 2 and the last 2 workouts in the near future.
I started with 2 days rest between workouts and quickly ended up now with 4 or more days. As I am getting stronger I find I need more rest and I and my training partner get stronger each and every workout by reps and weight or both.
I find that compound exercises are best but do throw in some sissy exercises here an there.
Give it a try if you need a change or are stuck. The higher reps are working very well.
Another point. When doing rest pause, say I get 20 reps or under, I rest 30-40 reps or 15 deep breaths and take another set to failure, rest again and then another set to failure. This is a most productive set as you will see the next time you train. With forced reps a couple of forced reps and negatives following a straight set works great. And sometimes, just a set to failure.
I hope this helps give you some ideas. As I go into the next decade I find that it is necessary to do less but make it count and then get enough rest to make it count.
To your strength, health and happiness,
Bill Sahli