The SVJ is just a showing of potential to recruit muscle quickly, which is helpful when swinging a golf club.I am not knowledgeable about fitness, but I have to agree with this. I've always had a weaker than normal upper body. While some of the athletic kids in HS could bench press maybe 1 1/2 time their body weight, I was doing well to do my body weight. But I could clean and jerk the same amount of weight because that lift involves technique and the lower body - where I had above average strength.
This is why I think the correlation between vertical jump and distance is a bit dependent on those who have lower body strength/explosiveness also having that in the arms and upper body as well - which I believe is typically the case with a lot of folks.
I also believe strength doesn't always show up in physique. A tour player might look average, but be stronger/quicker than average to go along with flexibility and an incredibly efficient swing.
Again, just uneducated opinions.
It's why the SVJ is tested at the NFL