Everything that is tought in Billiards is about balance and finding the proper corrections for your body's fault.
For me, the backstroke is about finding the balance and speed, establishing the exact aim point and consistency. I observe how the cue will move/change in my forward motion. A longer stroke also relaxes the pressure of sudden acceleration and grip and I can hit the CB rather relaxed.
High speed shots are only possible with a longer stroke due to physical limits in accelerating your cue.
Also a longer stroke helps with developing dynamics.
You might try to adjust for a game or two or when playing on your own.
Stick to it for a whole game no matter the outcome.
Don't play on 8 for 7 ft tables (they ruin everything!) and also pick slower cloth. This will help, too.
Don't go for a long stroke, but just a bit longer than usual.
Yang's stroke sure is not nice to watch.
He's also hitting the CB just a moment before he's hitting his body with right hand; the CB contact is not at the most relaxed point in the movement, but near the end and approaching the uneasy part of the movement.
That doesn't leave him with a lot of dynamics, too.
If you watch closely you'll see he's not having good speed control, but every shot more or less looks the same in CB speed:
https://www.youtube.com/watch?v=Gbvh7d3RoxI
That's not something you want to achieve.
Shaun Murphy is very nice:
https://www.youtube.com/watch?v=EgJXm65jaUs
Cheers,
M
Cheers,
M