It's pretty easy to develop muscle imbalances. Athletes can overdevelop the muscles they use most often in their sports. Bodybuilders and lifters tend to favor certain exercises while neglecting others (usually the ones they're not that good at.) The result: injuries.
But imbalances can be quickly corrected if you're willing to perform the right exercises. Here's one most lifters need to be doing.
The vastus medialis (VMO) is the tear-drop shaped muscle on the inside of the knee. Unless prioritized and specifically targeted in training, it commonly falls behind in strength compared to the well-developed lateral (outside) muscles.
The heel-elevated step-up will keep the VMO from lagging behind. It's something all athletes should be doing at some point during their training session. Not doing so leaves you vulnerable to knee problems (jumper's knee) and future injury (ACL tears).
Once you build up a baseline of strength, add this exercise into your dynamic warm-up so it remains strong year-around. You should also find a way to incorporate backwards sled drags, hack squats, split squats, and side step-ups, all of which also target the VMO.