Hi,

Please reference how "it is an established fact that pre-exercise stretching is a must".

If you mean warming up, then yes. But stretching can actually diminish performance. Ask a professional weightlifter if they stretch before a competition lift - they don't because shortened muscle fibres generate more power.

Raising the core temperature of the body is a wise and smart thing to do. Then doing some dynamic exercises / "stretches" in a functional way would also be wise.

Pre-exercise stretching, in my opinion - and i am happy to be wrong - is not an established fact. Maybe an established routine / ritual / belief...