To take a high volume approach, you would focus on getting many, many high quality reps into your session, but you wouldn’t train until failure.
If you prefer the high intensity method, you wouldn’t be overly concerned with the number of repetitions, instead you would focus your energies intently on only one work-set, and you’d push as close to muscular failure on that one set as you could. The goal is one intense experience per exercise.
There are pros and cons to each approach.
If you need to practice a particularly demanding skill, find something easier you can practice in order to increase your cardiovascular capacity, your work capacity, and then when you come back to the difficult skill in some time, you’ll be well conditioned enough that fatigue won’t be so much of an issue. You do need a degree of aerobic conditioning to be capable of practicing a physical skill for reps over time. If you rely on skills training to also provide aerobic conditioning, training can get a bit muddy, and you might find you constantly fatigue sooner than you would like. This is why athletes of various technically demanding sports practice jogging and the like so much, so that they are fit enough to be able to practice the techniques of their sport well.
On the other hand, a high intensity approach is useful if you wish to increase your ability to work hard, but you’re not trying to master a complicated technique, or you’re already satisfied with your degree of skill.
So when would you use one method or the other? Firstly, if you always train in the same way, training plateaus are inevitable. Of course, regardless of how you train, plateaus are inevitable anyway, so there is certainly that! Sometimes I think you’ll be stuck until your body is damn well ready to progress, and it’ll do so in its own time, but changing your training methods does seem to help stimulate the body to adapt and develop. So it’s useful to employ either method at different times in your training.
If you’re learning a new skill, clearly the high volume method will give you more opportunities to practice the technique, and since coordination is mostly a repetition game, the high volume approach is great for beginners.
After you’ve built up some degree of familiarity with the technique, and enough strength that you’re capable of practicing the given technique for a reasonable number of reps, then the high intensity approach may become more useful.
And to be capable of training at a high level of intensity, within close proximity to your maximum capacity, you need to be well-conditioned anyway. That doesn’t happen immediately, or automatically.
So if you’re at the point where you can practice a given exercise well for ten to twenty repetitions, then the high intensity approach may be useful. Do a couple of warm-up sets, where you stay well away from failure – or work with reduced loading parameters, such as training push-ups with your hands on a raised surface rather than flat on the ground – at this point in time, you’re just waking up the body and the central nervous system, so to speak.
There’s a bit of a common misnomer out there, that proponents of the high intensity method don’t do warm-ups. This is untrue. Of course they do warm-ups and preparatory sets, when they talk about training one intense set only, they mean that they only practice one work-set, and they take that set as far as they can.
So of course, then when you’re properly ready you’ll train your one high intensity work-set. It’s a max-effort set, where you attempt as many reps as you can, assuming a reasonable target.
But it’s not always appropriate to practice the high intensity method either.
If you’re only capable of doing three or four reps of a given exercise, sometimes you can attempt max-effort sets, but I generally prefer a volume-based approach.
Let’s say you’re trying to get to the point where you can do full push-ups from your toes, with your hands on the ground. Attempting a high intensity set when you can’t really rep-it-out, as they say, often doesn’t lead to progress.
A better option would be to regress the technique a bit, elevate the hands a shade, make it difficult enough that if you were really pushing yourself, you could do four or so reps.
Then, rather than take that approach, do like ten singles or something. Sets of one. So you’d do one rep, then rest as long as you need, and go again. Or maybe a set of two if you like. This way, you’re keeping well away from failure, you’re practicing good movement patterns, and you’ll get a high number of total reps in. Twice or three times as many reps as you would if you took the high intensity approach.
And after some weeks or months, you may wish to test your max again, and see if you’re ready to progress to a more challenging version of the exercise. Do not mistake the testing method for the training method.
This approach has worked very well for me in the past, when I’ve had to focus on building up my chin-ups again, after injuries or lay-offs. If you can only do three or four reps, adding a fifth may require an extra 20 or 30% of your total. It’s a big ask, that high number isn’t going to come from nowhere. So expecting to train intensely and add more reps over time – it doesn’t always work out that way. If you’re doing something for fifteen reps however, an extra rep only requires a small percentage of additional work. That’s reasonable.
I hope that makes sense, I’m not sure if that’s literally why it’s so hard to progress exercises that you can’t do for many reps, but that’s how it feels.
Instead of pushing it to failure all the time, just do sets of one, even if you’re capable of two or three. The reps will feel better, you’ll be less exhausted, but you’ll get a lot of good work into the muscles, and you’ll get in a decent amount of good quality practice of the technique.
And then, in future, go high intensity again. The tendency is to believe that the thing we’re doing now, the thing that works for us now, is the best method. That it’s better than the methods we tried in the past. But all methods grow stale, all people plateau, and most approaches have some degree of merit. What worked for you in the past may not work for you in future, and what did not work for you in the past may one day become useful.