plenty of crap coaches are very successful because they have the money, influence and facility thus they draw the best athletes...success often has very little to do with competency but id often precipitated by wealth and luck
I believe the heavyweights DID improve with the training experience in Thailand
however it sill holds that a heavyweight athlete is ALWAYS better with a heavyweight trainer because its such a unique weight class and I suggest they would have been EVEN MORE IMPROVED if they had heavweight coaches not tiny little Thais
I for instance had a rough time sparring at the muay thai gym because I was required to waste 5 rounds jumping rope and my legs were already hurt by the time we strapped on the shin guards...especially the ankles and feet
the VERY SAME guys [when they came to my MMA club] were easy to handle in muay thai because I hadent beat the crap out of my legs jumping rope
Thai training is designed by small coaches for small fighters and is a GREAT EXAMPLE how the one size fits all training protocols FAIL the biggest athletes
The larger European athletes even kick differently then the tiny thais
I have a very detailed argument on this thread
https://forums.sherdog.com/threads/tippy-toes-a-no-no-a-better-way-to-kick.3894957/