While the coaches are perfectly capable of spotting technical mistakes, they use a high speed camera to look for bits they miss or teach their athletes to see the limitation in their technique.
This is just ONE of the many sport schools around China. This isn't even the provincial team and definitely not the national team. In my country, this sort of facilities are only to the top athletes. On Friday, (Which i missed) my host showed me a video of 145 snatch, 175 cnj at 77kg at 15 years old. It's quite absurd.
For me, my back was naturally slimmer but my thighs were large. Use that. My flat foot on the right causes a collapse and lack of flexibility. He told me either to massage the foot back up or use inserts. He said for me, there is no future in using my back as my legs were naturally stronger. For me, my base were my legs.
You should click on my instagram link to read more about what they think of my shoes.