Lace Locking refers to the many different ways to tie laces and depending on your foot type, some will suit wide feet and others narrow, high arch, low arch etc . Laces coming undone in an event is annoying and dangerous, practice your lace tying before the day, so you know what works for you.
Here is a link for 55 ways to tie a lace https://www.fieggen.com/shoelace/
Lace locking is equally important as if the laces are loose around the ankle area then the foot can move forward in the shoe and also out of the back of the shoe causing shear then blisters at the heel, toes and under the ball of the feet.
Check out this great infographic and get more detail from https://runrepeat.com/top-10-running-shoe-lacing-techniques
Material and shape of laces needs to be a consideration too, round laces tend to slip more than flat laces. An absorbent material like cotton will soak up more water and become heavier and can flap around on the skin causing problems, polyester, nylon and Kevlar may be a better option but they can con come loose if not secured correctly. Easy laces and lock laces are stretchy laces that have a locking device where the bow should be, a lot of athletes like this mechanism of laces but there can be downside to them, if you have feet that swell during an event then there is less control of adjusting the laces over a hot spot of pressure on the top of the foot during an event. Whatever lace and type you choose, make sure the lace loops and lace ends are either cut to size or secured away in the lacing crossings so they don’t snag or pick up surrounding debris.
Who would have thought the humble lace could present so many choices!!