We’ve written before at HuffPost UK about the surprisingly gross reason there’s a “v” stitched under your sweater’s collar, as well as what that tiny jeans pocket is really for.
But what about that second hole behind the top eyelet of some trainers? I’ve never used mind before, and frankly had no idea they had a purpose.
Well, according to Dr. Rob Kominiarek D.O., FACOFP, who spoke to Good Housekeeping about the topic, they do ― it helps to prevent blisters.
How?
“These holes fit the sneaker more securely to your foot,” the doctor shared with the publication.
“And this helps prevent slippage, a common problem which can result in irritation and blisters.”
For that reason, a lacing method that uses the extra eyelet is sometimes referred to as a “heel lock.”
But if, like me, you’re still not sure how you’re meant to use them, a YouTube video from Business Insider has answers.
You simply thread the end of your lace (no need to cross them over) through the eyelet, they say, creating a loop.
Then, you pull the ends of the lace to tighten the lock and tie your bow through those lace loops rather than on top of the shoe’s tongue.
The method is also known as a “lace lock” or “racer’s loop.”
How exactly does that prevent blisters?
As Dr Kominiarek said, it helps to prevent friction.
You might not notice much chafing over a short walk, but if you’re running at speed or for a long distance, little changes to your shoes can make the difference between healthy feet and a red-raw sole.
Indeed members of Reddit’s r/RunningShoeGeeks swear by the method, with a podiatrist writing in the comments: “I recommend a heel lock lacing pattern usually a minimum of 5 times a day to my patients, with many of them runners.”
Of course, the method isn’t just for athletes.
Shoe company Asics says you may need to adapt the technique if you notice “Heel blisters or excessive wear in the back of your shoes are common signs of heel slippage.”