Is it worthwhile to "randomly" do sets when I feel I have the energy?

Question

I'm sort of a beginner to weight training. Often I find I can't fit in everything I want to do in my workouts given my time constraints - I can work out at most 5 times a week for about 1.5 hours, and I want to hit chest/arms/shoulders/back twice per week, and legs once per week (maybe twice if I can fit it in). Typically I do chest/arms on one day, then back/shoulders, then legs.

I typically start with chest, and by the time I get to arms, my triceps are exhausted, and I'd need a much longer break than is practical to move the same weight around as I normally could. For instance, when I'm well rested I can do 4 sets of 12 dumbbell skullcrushers with 25lbs, but after chest I can only do 4 sets of 6-8 with 22.5lbs.

Recently, I started doing sets "whenever I feel like I have the energy." I have a dumbbell set at home, so whenever I'm bored I'll do 4x12 dumbbell skullcrushers, or 4x12 dumbbell concentration curls with 30lbs, or 4x10 dumbbell shoulder presses with 50lb dumbbells, etc. The point is that these numbers are often astronomically better than what I can put out in the gym after the first half of my workout. I feel like I'm limiting my capacity for growth doing 4x8 skullcrushers with 22.5lbs when I know I could be doing 4x12 with 25lbs.

Is there just as much benefit to doing exercises "at random times throughout the day" as there is to doing them all in a single workout? Part of me thinks "it all counts as volume, what's the difference between whether I do this in the gym at a scheduled time, or at home throughout the day?" Another part of me thinks something is "wrong" about this approach - my gut says it wouldn't be as effective to do 5 different exercises spaced out over a 12 hour day as it would be to do those same 5 exercises in an hour window. Perhaps something about the shorter rest times contributes to greater muscle damage/hypertrophy. Is my gut right or wrong?

If there truly is no benefit doing exercises at "random times throughout the day", and I'm just wasting my time, then what can I do as a beginner to increase my weekly volume without dramatically increasing my rest times/workout lengths? Should I just do each of chest/arms/shoulders/back once a week on a separate day, so that I can push the most amount of weight on each day? I wish I could do two muscle groups on a single day, but my body just isn't ready for that kind of fatigue I guess.

Answer 1

Is there just as much benefit to doing exercises "at random times throughout the day" as there is to doing them all in a single workout?

Yes, as long as the exercises are similarly difficult.

I.e. Say you were working with a weight that you could lift for an absolutely maximum of 10 reps before complete failure.

• If you did sets of 8 with that weight, resting for 3 minutes between each set and pretty much fully recovering, then it would not matter whether you did your sets in a single workout vs spaced out throughout the day, because the sets are individually challenging.
• If you would normally train almost to failure, with a moderately short 1 minute rest between sets, reducing the number of reps each set as fatigue build such that you might do a set of 9, then a set of 8, then 7, then only 5, then when splitting these sets out across a day, you would probably find that you could instead do 4 sets of 9 due to the increased rest opportunity.
• Whereas if you were doing a large number of sets of 4 reps with the same weight and only 30 seconds rest between sets, so that the individual sets are easy but you are relying on fatigue to accumulate between sets in order to make the later sets difficult, then spacing them out throughout the day would be completely different, because then you're missing the accumulating fatigue and instead it's just a bunch of easy sets.

Perhaps something about the shorter rest times contributes to greater muscle damage/hypertrophy.

Metabolite buildup is a driver of hypertrophy (though only secondary to muscle tension), and shorter rest times contribute to this, but really only if the individual sets are not sufficiently challenging if you take long rest periods between them.

That said...

Often I find I can't fit in everything I want to do in my workouts given my time constraints - I can work out at most 5 times a week for about 2.5 hours

If five 2.5 hour sessions per week are not enough for you to fit in everything you want to do, then you are doing something egregiously wrong.

From the small amount of your program described, it sounds like you're doing a tonne of junk volume (volume that generates so much fatigue so a significant part of the workout you're no longer capable of moving enough weight to actually drive progress), and also trying to isolate body parts in an impractical way (given that your "chest" training is fatiguing your triceps). From this description it seems as though you're trying to cram both a once-per-week chest day and a once-per-week arm day from a traditional "bro split" program into a single workout, so you can train chest and arms twice in a week. That's not how higher frequency training (working muscle groups multiple times per week) works. If, as a starting point, you had a bro split which had you doing 16 sets of chest on Monday, 16 sets of arms on Tuesday, and other body parts the other days of the week, then an equivalent program that would train your chest and arms twice weekly would have you doing 8 sets of chest work and 8 sets of arm work on Monday, and then another 8 sets of each on another day during the week. You definitely don't try to cram 16 sets of chest and 16 sets of arms into Monday.

I'd strongly recommend hiring a coach to write a proper program for you, or failing that then at the very least reducing the volume of your workouts by 50% and not aiming to complete all the exercises aimed at a single body part before moving on to another body part.

Answer 2

There's really no relevant time constraints here, 5 times per week, 2.5 hrs is more than enough time to train, if you can't fit in all your sets in that time you need to take a long hard look at your routine.