20min vs 45min of weight lifting...

It depends on your program but it certainly could. Part of the reason for between sets rest is to allow for ATP recovery so that you get the most benefit from the next set. Why the rush?

Not sustainable for very long.

At some point, you'll need the rest. It's best to practice resting before you get to that point.

"Opting to get all 16 sets done in about 20min rather than 45min, by cutting rest between sets."

If your goal is to lift heavy, I believe you are doing yourself a disservice. Since you able to do all your reps/sets without rest, you are not lifting as heavy as you could and, maybe, should. If your goal is to lift lighter with more reps, it's probably fine, but, you may not be getting the reps you would if resting between sets.

Mr_Healthy_Habits wrote: »

If my volume is the same, 16 sets, does the duration matter?

Opting to get all 16 sets done in about 20min rather than 45min, by cutting rest between sets.

Able to do almost the same volume, with the same weight, and trying to build up to the same volume as a 45min workout within 20min...

If you're able to recover enough to condense 45 minutes to 20 you're probably slacking

Essentially, there is a point to test duration, cutting it means that you're diminishing your available capacity so you're not going to get the same effect in a shorter time.

I superset with exercises that work different muscles, as I generally try and fit my workouts into my lunch break.
My trainer's helped set up the supersetting so that it doesn't impact on my big lifts, and it seems to be working well for me and getting me results.

I used to do SL 5x5, and found the proscribed rest times felt really long, and that I could be doing something more useful with the time! I get that my legs need to rest between sets of squats, but I don't see why I can't use that time to do a set of bench press or whatever.
(Apart from making sure there's space in the gym to do it, I'm not blocking anyone's use of equipment, and I'm letting people work in!)

Mr_Healthy_Habits wrote: »

If my volume is the same, 16 sets, does the duration matter?

Opting to get all 16 sets done in about 20min rather than 45min, by cutting rest between sets.

Able to do almost the same volume, with the same weight, and trying to build up to the same volume as a 45min workout within 20min...

I agree with others that simply cutting down on rest is doing yourself a disservice, but that entirely depends on your goal as well. To little rest, and your body may be too worn down for any progression to occur. You may not notice it the first week or the second week, but it usually catches up in time.

That said, as a full-time working mom of 4, I totally get the need for making my workouts as efficient as possible. Which is why I'm a huge fan of supersetting my workouts. Supersets allow you to move from one exercise to the next without rest, as each exercise works different muscle groups, so muscle group one is actually resting while muscle group two is being worked. I take my 2 min rest between supersets, but I actually take no rest between sets during each superset. It allowed me to take a 1hr full body workout and shrink it down to 30 mins.

In your case, since your current workout only focuses on one muscle group a day, you may not be able to shorten the 45 min session, but rather, you can combine day 1 and day 2 into a single 45 min workout and give your son the time you no longer need for your day 2 workout.

Freischuetz wrote: »

to save time , why not a HIT workout? (not HIIT)

you can either do it full body, or split it as you wish. you need much more time for recovery - so more time for family!

it is mentaly pretty heavy to force yourself between 5-8 reps until your muscel give up. in your case at least worth to try

If you are talking about reps then you may not understand what HIIT really is. If your talking about barbell complex intervals then you are in the neighborhood. But they are not HIIT.

Mr_Healthy_Habits wrote: »

chaotic work schedule and a 5yr old who craves attention, so any extra time I could create in a day is a blessing...

when i saw '5yo' and then 'burpees and jacks' in your next post, my first thought was: why are you wasting those in the gym? first-graders are probably the only critters on earth who probably think burpees are fun

i don't know anything about the programme you picked and it would be rude for me to criticize it anyway. but i am wondering how wedded to it you are, because 16 sets is a LOT for anybody who's watching a clock. have you looked at any of the simpler 'strength' programmes that use compound lifts, like starting strength, stronglifts or wendler 5/3/1? wendler in particular is almost stupidly quick, if all you do is the 'main' lift of the day.

and if you like the volume work for its own sake, i had a great little patch for a while where i'd stagger the lifts so i'd have one that i was doing 5/3/1 style and the other one in 5x10 style. i found i could superset those with pretty minimal rest. if i was on a tear i could get in and get out in an hour including the time needed for things like shoe change. however, i tend to like my actual workouts to be extremely simple, and isolated 'body part' stuff makes me fidget and itch like i'm stuck in traffic. [brain yell: because INEFFICIENT AGGAH AGHH]. so maybe it isn't your thing if you're enjoying doing a range of different things every time you go in.

Still sore and feel that tightness afterwards, and in some respects feel like I've gotten a better workout...

i hope this won't sound condescending. i don't mean it that way and it's not like i'm any kind of guru. but one of the things i really like about lifting is i don't feel like i have to worry about the destination so much any more. i just concentrate on liking the individual workout each time, in the sense of having an assignment and going in there to do the assignment and then assessing how i feel about the doing it, once it's done. the 'did i work hard enough' part and the 'is this going to make me stronger' . . . i don't think much about that anymore. kind of hte point of a programme is that you climb on and let it take care of that side of things.