If you want to get the most benefit, with the least wasted effort and the least risk of injury, from performing resistance exercise, you SHOULD avoid unproductive and inefficient exercises. Therefore, you should either have the guidance of someone who KNOWS biomechanics, or you should learn it yourself.
Do not be fooled by “trainer” who appear to have a well developed muscular physique. Do not assume they understand biomechanics. The question is not, “How do I develop a muscular physique?”. The question is, “How do I develop a muscular physique without wasting time and effort, and risking injury?”. You can drive on a bumpy and muddy road, and arrive at your destination, or you can drive on a smooth, clear road and arrive there also. The difference is how much effort and how much “wear and tear” (injury) it will take to arrive.
Doug provides simplified explanations to complex human mechanics, which allow non-academics to understand biomechanical principles and how to apply them in their workouts. The Brignole method is a shortcut to success—the best results, as quickly and easily as possible, without injury.