“People use pre-exhaustion to ‘burn’ their muscles out as much as possible. But compound moves are usually the most effective strength building moves, so I don’t think you should go into them already fatigued,” says Eni.

In fact, doing so can reduce the total volume you lift throughout your workout, because the muscles will be so worn down. In a 2016 study published in the Journal of Strength and Conditioning, researchers reported a “significantly greater number of repetitions for the compound exercise when it was not preceded by an isolation exercise”. The less tired the muscles are, the more they will be able to lift over the course of your session, leading to greater muscle and strength gains. Could pre-exhaustion actually be a pointless endeavor?

The same study, which was looking at chest and triceps activation during bench press, also reported no significant differences in strength gains between pre-exhaustion and straight sets. Researchers found that “the muscles utilised within upper-body pressing movements, such as bench press and chest press, are already maximally active for that movement.” Going into the exercise with an already fatigued chest actually only further loaded the triceps in the study, as the chest couldn’t take on anymore weight – the opposite of what was intended.

That doesn’t mean the technique is totally pointless. They could be motivating for you if you love to feel your muscles really taking on a challenge. Plus, if you have some areas you find particularly hard to engage it could be helpful to activate them before you do a big lift, says Eni: “I think the best way to use pre-exhaustion is for the glutes. As these are commonly under-used muscles it is good to ‘switch them on’ before a compound lift. But I wouldn’t recommend going to failure with your glute isolation, as you’ll then struggle when it comes to lifting the big weights.”

“Don’t forget that there’s always a place for isolation exercises in your training,” according to Eni. But for most people, isolation exercises work better after you’ve completed your toughest compounds.

Pre-exhaustion in strength training: does it really work?