You know those extra little shoelace holes at the top of your running shoes? It turns out that those holes serve quite an important function.

They're intended to be used as a "heel lock" or a "lace lock," a knot that is used to keep the ankle and heel area nice and tight without having to tighten the whole shoe.

If you're tired of getting blisters on your heels when you go running, walking, or hiking, then this video is just for you.

(source Illumiseen)