I've had my huaraches for a while now but they are getting more use recently because of sore knees. Wearing regular (10 oz) trainers tends to exacerbate the knee problems. Why? Because they have heels, causing my foot to land wrong. Because they are heavier, thus slowing down turnover, thus causing me to push with greater force. I just got back from a 10 mile road run and feel quite a bit better than I did yesterday after running 12 on the track in (7 oz) flats. That's partly because I ran when it was cooler today.
I just recently trimmed the end of the strap so that it isn't so long. Between that and just getting in better shape, I can run better and faster in my huaraches now. I think getting rid of the extra will also result in less sand, etc getting in between the sandals and my feet.
In the middle of today's run, my right ankle was sore and my lower legs were hurting a little. But this went away and I was really cooking toward the end. The ball of my right foot can get sore too but this sort of stuff recovers pretty quickly.