I have said it many times, Heavy is not how much is on the bar; Heavy is how much stress a muscle is under.
The former is an external cue that has no meaning in and of itself. The latter is an internal performance indicator that bears meaning short and long term. As experts and trainees we need to stop being so one dimensional in our thinking.
The second problem with this assumption is that somehow people then equate load with intensity. In other words, I get letters where people "assume" they're training hard because they're training with heavy loads.
Wrong! And there's also an expert bias that "strength training" is CNS training; hypertrophy training is myofibril training; and conditioning training is metabolic.
These are only categories of reference and they're not mutually exclusive. There exists this bias that high volume training is somehow lower intensity. This couldn't be further from the truth, just ask one of my clients.
Workload capacity can be improved to a point where tremendous volumes can be handled at high intensities. Once again, these need not be mutually exclusive, and thinking that way is to misrepresent research and decades of real life, in-the-trenches experience as well as scientific research.