>>289014259
> I'd be scared a rubber band or a strap or whatever would snap while I'm kicking/moving my leg

they weigh 80 grams and have no moving parts, you're not gonna throw them loose or break a band with the force on them unless you screwed something up. You're more likely to lose your shoe.

>>289014482
You do one corner around the first loop at the toes and two corners around the ends before you tie the knot, at most you'll have to relace your shoes once so you have some slack at the bottom.