“Assistance” Exercises – What do They Assist?

by Mark Rippetoe | August 16, 2023

The time-honored dogma of barbell training holds that the major exercises must be supplemented by more isolated single-joint muscle group exercises, which we refer to as Assistance Work. (I know that the Blue Book refers to “assistance exercises” as partial versions of the primary barbell exercises, but for this article the term will be used as it is in the broader fitness industry.) The theory is that your squats – at 455 x 5 x 5 – just didn't get enough quad work, so you need to do some leg extensions too. And that the leg extensions thereby contribute to your 460 x 5 x 5 next week. This is bodypart-thinking, a holdover from bodybuilding. And I'm now going to ask you to think critically about this, because it really doesn't make any sense. My thinking on it has changed, and yours should too.

First, the squat actively uses about 90% of the muscle mass of the body – if it's done correctly. Quite literally everything is in contraction, and most of it contributes to the work done on the bar. Everything that is not actually moving the bar is in isometric contraction providing support for that which is moving the bar. And as the weight on the bar increases, the strength of all the contracting muscle mass increases along with it – because it has to.

So the idea that working the quads – the vastus lateralis, intermedius, and medialis, and the rectus femoris, by themselves – is going to strengthen the whole squat ignores the obvious facts that 1.) the quads are already working at their anatomically-determined level of participation within the entire kinetic chain, 2.) that when you add 5 pounds to the squat, you add 5 pounds to the quads too, and 3.) adding extra work to this separate muscle group that's already working at capacity cannot benefit the entire movement pattern unless you somehow change it to favor stronger quads, which then affects the other components of the kinetic chain in a way that makes them less efficient participators in the movement. If we have correctly analyzed the movements and their kinetic chains – and we have – the way we teach them utilizes the component muscle mass in the most efficient way possible, and any change would represent reduced efficiency.

Here's a better question: if I do leg extensions for 6 weeks and go from 90 to 130, does that make my squat go up, or if I take my squat up 5 pounds per workout from 185 to 365 x 5, what happens to my leg extension? If you've had any experience with this, you know that leg extensions do not drive the squat up, and that squats do in fact drive up the leg extension. And this is true of any single-joint assistance exercise. They don't actually “assist” the primary barbell exercises – the barbell exercises “assist” the isolation exercises. So which ones are the Assistance Exercises?

Here's another question: Do you know anybody that got their squat unstuck by doing leg extensions and leg curls? Bulgarian split squats or weighted lunges? Or calf raises? Do you know anybody that got their bench unstuck with dumbbell tricep kickbacks or French presses? You know why? Because you cannot get stronger doing single-joint assistance exercises – they cannot be trained. If they made you stronger, all the gym bros doing them would be strong, and they're not. You already know this.

Now, if you're going to the gym for purposes other than getting stronger, do what you want to and have fun. People do assistance exercises for the way they make them feel. But let's not pretend that the Pec-Deck or dumbbell flyes improve your bench, or that single-arm dumbbell presses do anything for your press, or that dumbbell rows drive your deadlift. The basic lifts done for sets of 5 reps, and sometimes sets of 3 reps, with regular programmed incremental increases make you stronger, and everything else is merely recreational. There's nothing wrong with recreation, as long as you are honest with yourself about what you're doing.