This is one of those topics that bro-s like to talk about a lot... and it turns out, they maybe weren't wrong ????.
There's always been this idea around the fact that bodybuilders tend to have a "bigger look" and they don't necessarily have the strength to back it up (greater sarcoplasmic hypertrophy due to more "pump work"), and they also seem to end up losing the gains very fast after a period of non-training (and no I'm not talking about PEDs).
While instead strength trainees, such as PLers or WLers, show a denser ,yet "smaller" look (greater myofibrillar hypertrophy due to a more performance-oriented training regime), and also seem to maintain a greater portion of the size after a period of de-training.
While body fat% will most definitely play a role, let's see what science has to say;
..we know that light, moderate and heavy weight training are all able to produce the same hypertrophic results , as long as we reach the same proximity to failure with each training style (matched volume).
In fact, it is generally accepted to believe that both myofibrillar & sarcoplasmic hypertrophy occur in tandem/at the same time, more or less when working within a different rep range/intensity & overall volume.
A new study from Haun et al. (2019) however, has been able to show this not to be always the case. In their group study, in fact, they used a high volume training routine with a moderately heavy weight (60% of 1RMs) and noticed that sarcoplasmic volume increased, contrary to the myofibrillar one. Sets were not even taken to failure (~4RIR) but hypertrophy occurred regardless.
Although there's definitely not enough data around the topic, this is an interesting study nonetheless, which gives me (us) a potentially better understanding of how different rep ranges/intensities & proximities to failure can work differently when hypertrophy is the goal.