Both are techniques used to target a specific bodypart and both are mainly used with hypertrophy in mind. Both involve the use of a compound/’big’ movement and an isolation/specific movement.
The names are pretty self-explanatory really. To use the pre-exhaust technique you would do a set or more to failure (or close to failure) of an isolation movement for the bodypart you’re targeting before moving on to a compound movement that uses that bodypart without allowing the muscles to fully recover between the two movements.
For example, this might involve doing a couple of sets of rope pushdown before doing bench press in order to target the triceps. To use post-exhaust you’d do the rope pushdowns after the bench press.
Pre Vs Post?
Both techniques have their place; which one is more valuable to you will depend on your training age. When you first start out in the gym and for several months, if not years, I think the focus should be getting strong and therefore on putting weight on the bar (I guess this never really changes, but things become less black and white in this respect). For that reason, I’d never recommend the pre-exhaust technique to a beginner – it allows you to use less weight on your main movements and is such holding you back.
However, the post-exhaust technique is pretty nifty for beginners, even if it is solely for them to feel like they ‘worked’ the bodypart that they wanted to. Add to that it might give them more hypertrophy in that bodypart and it’ll almost definitely improve the work capacity of that bodypart (maybe of the trainee as a whole).
I’ve never really been that sure of the pre-exhaust technique up until recently – I always just wanted to get weight on the bar for my main movements and because it hurt this process I rejected it.
However, I do think the method has merit for someone with a bit of training experience – after a couple of years of good training you should have decent all round strength, but you may also have a couple of weak bodyparts to go with that (I use the term weak not just to describe strength but also size relative to the rest of your body).
Some bodyparts just don’t grow like others despite getting strong on movements that should in theory work them hard – or maybe now you have a decent base of size and strength you want some specific hypertrophy so that you can look like that image you have in your head. Either way, I think using pre-exhaust might help you with bodyparts you’ve not been successful with in the past.
I’d add the caveat that you probably shouldn’t use pre-exhaust every time you train a certain main movement – if you want to do pushdowns before bench press, don’t do it every time you bench.
To the nuts and bolts of how I think you should use the techniques. Post-exhaust is pretty simple I think (another reason it’s good for less-advanced trainees): do your main movement, then as quickly as is practical after your last set, get set up and do the relevant isolation movement (I’d suggest in a higher rep range than the main movement).
The number of sets and reps is up to you really. Pre-exhaust is a bit more variable in nature, so I’ll just describe the way I do it (using bench and pushdown as an example): as I’m working up to my top set on bench I’ll do a few sets of a pushdowns between my bench warm-up sets. I’ll go close to failure on all of them so that by just before my top set of bench I’m struggling to get the reps I was to begin with.
Then I’ll do a set of bench (normally to failure), rest a little bit and do another set of pushdowns before doing my second set of bench at a lower weight. Equally good, but less time-conscious is just doing a few sets of pushdowns before starting bench press. Either way, locking out weights that would normally be comfortable becomes inhumanly difficult and the triceps get some serious work.
To get you started on pre-exhaust (remember – only if you have a bit of training under your belt), here are a few combinations of exercises that I’d recommend:
Quads: leg extension and back squat
Hamstrings: leg curl/hyperextension and back squat
Chest: flyes and bench press
Triceps: any extension-based triceps exercise and bench press
Shoulder Width: lateral raise and overhead press (barbell)
Rear Delts: face pull and barbell row
Lats: dumbbell or cable pullover and chin-ups