Hopefully someone can help me! I've been having this problem off and on for quite a while and it was a nuisance but manageable but just recently it has got considerably worse it even happens just walking.
About 2-3 miles into a run I feel like I'm losing control over my left leg, and if I try to run through it, my foot eventually starts audibly "slapping" the ground, and my leg seems to swing outward. It's incredibly frustrating, because it forces me to walk, even though the rest of my body could go on for much longer. I usually walk for a minute or two, then start running again (only to repeat the process).