The disconnect between how I think I swim and how I actually swim never ceases to amaze me. Phil, the manager of our local pool kindly allowed us to video our stroke after the pool emptied. The purpose was to show a physiotherapist treating shoulder pains we both occasionally experience.
But once we started looking at our techniques we found all sorts of 'faults'. Presumably these crept in over the summer when we'd been focusing on distance not technique.
For just one example, watch at my left arm. It's going in the water bent and crossing my centre-line. That will have implications for my subsequent catch. (Although, given the photo above was taken last June, perhaps this has been a long standing issue!)
Either way we now have new focus for our visits to the pool.