What's the deal with exercise variations, for hypertrophy?

A lot of people are getting more familiar with the idea of throwing in different exercise variations to better stimulate certain parts of the muscle, and that makes sense, as we know that muscles can benefit from different biomechanical stimuli due to the anatomical structures that they each may target.

But is it actually important? And if so, how much?

Like every question, it depends. Exercise variation is definitely important if we want to maximize growth, because biomechanically different exercises, different contractions or even ranges of motion can target some muscle areas "more effectively" compared to others.

We can see that example with a squat + a leg extension machine with slow eccentrics for example, or a flat bench press + an incline one, or different variations of a Rowing machine to target back muscles differently, and so on... Some benefits may also be psychological, where doing different movements can help with adherence, by making the routine more fun, or maybe more enjoyable for some... but we have to keep in mind that when hypertrophy is the goal, fundamental rules still apply.

Doing the *right amounts of work* to ensure progression, and not provide excessively varied (or reduntant) stimulus, will likely be a better option. This can be achieved with a handful exercises per body part (1-2 up to 3 exercise variations at max can be a great way to progress long term).

So, when picking exercises for your muscle building goal, make sure you don't overdo it, and based on the tension they experience, see which exercise targets which area specifically. Importantly, make sure you're also choosing movements that you enjoy and/or want to learn/get stronger at.