This post actually came from the insistence of Li-Ann, who has been observing my habitual exercises lately. I have been doing these exercises regularly for the past 1.5 years or so, on advice by my physiotherapist and podiatrist.
Apart from my flat feet, another contributing factor to the risk of me getting injured is the weak muscles in my... erm, posterior. Gluteus. Buttock. Backside. Call it what you like. I supposed it's obvious from my (very) flat rear. And sadly, after doing these exercises for so long, I don't think I have gained any mass in that area. But I would do anything to prevent injury, hence, I try my best to do this every other day, if not everyday.
So how would having stronger butt muscles help prevent injury, you'd ask? Well, as endurance athletes, we tend to neglect certain muscles and overuse other muscles and joints to compensate for these weak muscles. Prolonged overcompensation will strain these muscles and joints, increasing the risk of injury.
I'm no sports scientist, but it made sense to me. And I believe this exercise does help. Here's one of the exercises that helps strengthen the butt muscles. I am sure there are many more, and you can easily Google search them. Enjoy!