How long do you rest? By @smurray_32
Long rest intervals allow you to fully recover strength between sets and replenish as much ATP as possible which subsequently allows you to then train with more power/force in the following sets. Salles et al (2009) confirmed this, showing rest intervals of 3–5 minutes allowed for greater repetitions over multiple sets when training with loads between 50 & 90% of 1RM. As we know that progressive overload/mechanical tension (MT) is the number 1 key to hypertrophy, by being able to lift more in every set you can thus overload a muscle more & maximise hypertrophy. Now, although mechanical tension is maximized by long rest periods, metabolic fatigue (MF), which is another driver of hypertrophy (2nd most important imo) is compromised (Kraemer et al 1991) & this may then blunt anabolic drive & reducing the potential hypertrophic response.
This is where short rest periods come in as they have shown to generate significant metabolic stress & heighten anabolic processes associated with metabolite build-up (Goto et al 2004) such as alterations in anabolic hormones, cell swelling, free-radical production & an increased activity of growth-oriented transcription factors (Gordon et al 1994) BUT the body will fight back & though you may reap the anabolic benefits of MF, these benefits seem to be then counterbalanced by impairing muscular performance in your following sets (Pincivero et al 1997) thus making short rest intervals suboptimal for maximizing hypertrophic gains.
Practical implications: In order to achieve MAXIMUM hypertrophy you need to be able to produce significant amounts of MF while MAINTAINING a moderate degree of MT. Therefore, what I suggest is that for your compound movements, you rest a full 3-5mins in order to maximise MT but then on isolations, you work with shorter rest periods of 30-60s in order to maximise MF. This way you can reap ALL the benefits and make HELLA Gains!