That’s a big inference that the beginners are shy. Why not worried they will break the bar if they pull too hard? Or maybe they feel the need to experiment with different approaches in order to learn for themselves what the pros already know. Or maybe they are not completely comfortable with the new action that feels foreign to them. Or maybe they don’t want to be embarrassed (but I wouldn’t equate that with being shy, either). Or maybe they are uncertain of all the motions they need to go through and need to be walked through step-by-step to counter this uncertainty.
What it sounds like is that people need to get comfortable with all the steps in the process — even seeing what can go wrong at the various steps — before they start.
Shy just seems like the wrong word here. Hesitant, maybe. Uncertain. That’s another great word. Shy? Not so much.