Ahead of his bid at Royal St George’s to become just the seventh player to win the US Open and The Open back-to-back, the Spaniard revealed that “physical limitations” had effectively shaped the sort of truncated backswing that you expect to see at club level but not necessarily at the top of the game.
“I'm tired of hearing that the reason why I have a short swing is that I have tight hips,” said Rahm in dismissing that theory. “If you know anything about golf, that is the stupidest thing to say.
“I was born with a club foot on my right leg, which means my right leg down to the ankle was straight but my foot was 90 degrees turned inside and basically upside down.
“So , they pretty much broke every bone in the ankle and I was casted within 20 minutes of being born from the knee down.
“I think every week I had to go back to the hospital to get recast, so from knee down my leg didn't grow at the same rate. So I have very limited ankle mobility in my right leg. It's a centimetre-and-a-half shorter, as well.”
Rahm was speaking about the matter for the first time since turning professional in 2016, having racked up an impressive 13 victories in that short spell.
“My right ankle doesn't have the mobility or stability to take it,” he added of how he now swings a golf club.
“So I learned at a very young age that I'm going to be more efficient at creating power and be consistent from a short swing. If I take a full swing to parallel, yeah, it might create more speed, but I have no stability.
“My ankle just can't take it. Now, also, my wrists don't have much mobility. That's why I also naturally turn to bow my wrist to create power in every single sport I do.
"It's little things that I think a lot of people can learn. Let your body dictate how you can swing. Simple as that.”