If you examine your favorite items of clothing closely enough, you may start to ask questions like: Why are shirt buttons on different sides for men and women? (Because, historically, women didn't dress themselves.) Or why do my jeans have a tiny pocket? (To hold your pocket watch, of course.) Both of the clothing quirks mentioned above are relics of a different time, but if you look at your sneakers, you'll find a commonly-ignored detail that can be useful to your daily life.
Most sneakers have an extra set of holes above the laces that are often left empty. The holes may not line up exactly with the rest of the laces, indicating that they're there to serve a special purpose. For many situations, ignoring this pair of holes is totally fine, but if you're tying up your shoes before a rigorous run or hike, you should take advantage of them.
The video below from the company Illumiseen illustrates how to create a heel lock with these extra holes. Start by taking one lace and poking it through the hole directly above it to create a loop, and then do the same with the lace on the other side. Next, take the ends of both laces and pull them through the opposite loops. Tighten the laces by pulling them downwards rather than up. After creating the heel lock, secure it with a regular bow tie.
What this method does is tighten the opening of your shoe around your ankle, thus preventing your heel from sliding against the back of it as you run. It also stops your toe from banging against the front of your shoe. The heel lock is especially handy for long runs, walks, and other activities that often end with heel blisters and bruised toes. Even if you aren't slipping on your shoes for exercise, lacing up those extra holes can make a loose-fitting sneaker feel more comfortable.
Of course, the trick only works as long as your laces stayed tied—which even the most expertly-tied knot can't guarantee. Here's some of the science behind why your shoes often untie themselves.