Any golfer who drives the ball really far, regardles of their size (or shape) has the physical attributes to do so. The other factor is they also have the coordination to use those physical attributes to maximum efficiency. 

Most golfers physically have what it takes for longer than average drives. The difference in the long/short hitters is because those physical attributes have either not been strengthened, or are not used properly. I think between these two factors, not properly using those physical attributes for maximum distance is most prevalent. 

The easier answer is with all things being equal, some golfers have, and properly use what it takes, some don't. 

I am sure there are other factors involved. I used to golf with a guy with huge, visable  muscles from top to bottom. He worked out everyday. He could easily lift  several hundred pounds. His drives only went, on average, 220-230 yards. In his case, I would guess his physical attibutes were not geared for a long distance golf swing. 

I think a vast majority of golfers (self included) release the club too early. Some more than others. If you stop and listen, you can hear where the whoosh sound is compared to the collision with the ball. Good players tend to have a tighter whoosh that happens at impact versus a more drawn out whoosh that happens before contact. 

I have an old friend from college who is a very fit 5’6”, i.e., by no account tall or big, and drives the ball in the 250 range, and occasionally much further. He has told me the key is tempo (and for what it’s worth, suggested I study Ernie Els). 

If strength was the determining factor, we all would be able to out drive most of the women on the LPGA.   Lexi Thompson averages around just under 280.   Not many men hit the ball as far as her.   I'm sure athleticism comes into play but do you remember seeing Craig Statler?  He would have had trouble running up a steep incline but could hit the ball very well.  John Daly is another.   How many push ups do you think he can do?   We see you kids that weigh a dime, soak and wet, that can hit the ball over 200 yards.  

It's about club head speed and technique.  

Is it possible that people small in stature grow up playing clubs that are proportionally longer?  Just a stray thought; but there could be some merit in the idea that a shorter golfer learns to handle the longer clubs at an earlier age.  Could be nonsense.  

When I was in college I had a math class with our kicker (who was up for the Groza Award that year) and I recall him saying that kicking was about leg speed, not leg strength "otherwise they'd have running backs kicking field goals".

I assume the same principles apply for golf.

Keep in mind that while an athlete may be shorter or lighter than average, they most likely have above average physical strength or speed to go along with their world-class mechanics and skill.

Tim Lincecum, Kirby Puckett, Spud Web, Muggsey Bogues, Ben Hogan, Barry Sanders, Mike Singletary are/were  good examples of undersized athletes who excelled in their sport. I don't know that their success was 100% due to technique.

Then you have sports such as boxing and weightlifting which are divided into weight classes. When I watch a boxer such as Manny Pacquiao fight, or look up women's olympic weightlifting records, I suddenly don't feel as bad about Justin Thomas or even Lydia Ko (ranked 126th in driving distance among LPGA) outdriving me by as much as they do.

Yes, technique is a huge part of it. But even if I were young and had perfect swing mechanics, I doubt I would have ever been able to hit the ball consistently as far as 5'4" Sadena Parks.

It's obvious that combo of swing sequencing and club path is probably darn near perfect. But still not sure how some can pour more focused speed that others (even in pro ranks). I guess training + genetics.

If you look at JT's 12,000 fps slow mo swing, one thing is clear - 'ground reaction forces' are not much of a contributor, if any. They seem to fire pretty hard with an open upper right body.

https://www.youtube.com/watch?v=pIebmK1xyuw

Because I seriously doubt the average golfer trains nearly as hard as the guys on the PGA tour, not just on their swing but their fitness.
 

1 hour ago, Slowcelica said:

Because I seriously doubt the average golfer trains nearly as hard as the guys on the PGA tour, not just on their swing but their fitness.

I don't think Bubba trains like this at all, if he does, he just started doing it. Bubba figured his power out all on his own. Strength training only mildly changes distance. Distance deals more with leverage and creating momentum, aka lag.

It is talent, technique and timing.

Talent to do the second two, talent also allows you to recognize what gives you your power and repeat it. I am far from long but I do utilize what I have pretty well and can feel where the power is in my body. I know I have more in the tank because there are times the planets align right and I hit it another 20 yards more than my longest drives. If I could only repeat this...

Technique in knowing what makes that power and utilizing them all in your swing so nothing is "left on the table".

Timing to make sure that all power points are all hit at the right time. These "smaller" guys just have the ability to generate power, have be coached to optimize their talent and practiced it a lot.

I think a big part of the schism in people’s minds about this game is they still think about “hitting” the ball in a conventional sense, where strength and size should provide an advantage – as it does with most sports. I’m no physicist, but if you hold out your wedge and think about how heavy it is, that is a considerable amount of force delivered at speed. What is the common refrain? “Let the club do the work”. There is so much mechanical advantage in a golf swing, even a smaller person can hit the ball really far with proper technique. It’s also probably worth noting golf clubs are fit to people, to optimize their swing.

I think we are conditioned to seeing the bigger kids bully and win everything starting at around age 12 on up through college. It makes sense the biggest kid in class should also be good at golf, because that follows form – bigger kids are better at sports. Except that golf is not a team sport. It’s more like running a 5k or throwing darts. There is no playing of defense, no physical intimidation involved.

2 hours ago, Valleygolfer said:

I don't think Bubba trains like this at all, if he does, he just started doing it. Bubba figured his power out all on his own. Strength training only mildly changes distance. Distance deals more with leverage and creating momentum, aka lag.

It is talent, technique and timing.

Talent to do the second two, talent also allows you to recognize what gives you your power and repeat it. I am far from long but I do utilize what I have pretty well and can feel where the power is in my body. I know I have more in the tank because there are times the planets align right and I hit it another 20 yards more than my longest drives. If I could only repeat this...

Technique in knowing what makes that power and utilizing them all in your swing so nothing is "left on the table".

Timing to make sure that all power points are all hit at the right time. These "smaller" guys just have the ability to generate power, have be coached to optimize their talent and practiced it a lot.

I'm not at all saying technique has nothing to do with it, hitting the golf ball a long way is all about speed, you cannot swing the club fast if your body cannot handle that speed or don't know how to produce that speed. Watson may have that "natural" ability that athletes just have or he may have more quick twitch muscle fibers in his body. He also may train his tail off just like others. You can train speed, that involves learning the proper technique, but also you need to have flexibility and the fitness to do so.

Tyler the guy in the video that I posted is not much bigger than me, but is in way better shape, he is probably a few inches taller. But he has a driver swing speed of around 140 mph measured on Trackman.