“A repetitive motion that rubs, tugs, or stretches in a minor way multiplied enough times can do actual damage to muscle tissue, connective tissue, even bone. Such injuries usually send advance warning of danger ahead. A pain will typically start small, eventually growing larger and louder until it demands attention.”
Runner’s World Guide to Injury Prevention, Dagny Scott Barrios
As I’ve said elsewhere, Wing Chun can do a job on your shoulders if you are not careful. Careful means slowly and properly learning alignment and proper technique. Keep the humerus (upper arm bone) sucked up into the socket. Don’t let it float around! Feel the arms always bracing against the body as you move the arms. The upper body and the lower body should linked at the waist, so you have access to the ground.
This warning about repetitive motion applies to many aspects of training. If you are doing it wrong and then develop a training habit, doing it wrong, disaster will ensue! This is why it is crucial as a beginner to ask lots of tiny detailed questions about the movements and forms and make sure you have it right. Then you can put a bunch of miles on the movement and it will become more and more available in a solid bio-mechanically sound form. Techniques will just pop out of you!
And then someday, if you train enough, especially Chi Sao / Gwoh Sao – the movements will become something other than a technique. They will become an expression of your mind.
“I have already stated that attack is the trump suite in boxing, and have also pointed out that attack does not necessarily mean rushing or charging at or after your opponent. Attack, indeed, commences earlier than hitting. For the ideal punch, or perhaps it would be better to say the best punch, the most effective one, is a good, stiff counter, to a ducked, brushed aside, or otherwise evaded lead.