This has actually been over the last couple of days.
Since my knee replacement, I've been learning to walk correctly all over again. One thing has been being conscious of stepping heel to toe, with my foot pointing forward, instead of outward. (I walked that way for decades because of how bowed my leg was).
It's been difficult, and I felt like I was kind of stomping. Uncomfortable and unnatural. My physical therapist said it was probably because my sneakers were 20 years old and weren't condusive (sp.?) to a natural stride.
So, yesterday, I went and bought a pair of walking shoes.
Oh, man! The difference was immediate. It feels smooth, no lurching or hitching.
Plus, I'm walking a lot faster, without even thinking about it.