Flexibility man. That's about the only defense for an ankle. All tied together though. Most kids, especially boys, have super tight hamstrings. Affects the knee, calf, ankle...pretty much anything on the lower half. But there's a happy middle ground in there too. Need flexibility, but too much flexibility limits the load you can carry (weight you can push/pull/drag...you get it). I coach HS hoops. We do ankle walks daily. I beg our strength and conditioning guy to work on ankle mobility in the weight room too. (Knocking on wood) We don't have big issues with ankles. Idk if it's a coincidence or not.