I tend to buy shoes that are half a size too big anyway compared to day-to-day shoes, seems to be a better fit, but you can tighten the fit around the top of the shoe by lacing them differently. There should be an extra lace hole which isn't used at the top of the shoe, if you thread the lace from the same side back through that hole to make an extra loop on both sides, then thread whats left through that loop. little hard to explain, but like this:
I was under the impression it meant running a short distance with exagerated long strides, so running faster would be more a side effect than the actual aim. Usually do them as part of a warm up just to loosen the legs up.
Thanks for the link, I'll look into that. I'd be surprised if it was glutes, they get plenty of regular exercise at the gym, but maybe I need to try some different exercises. The pictures in that article definitely looked like they'd kicked their other leg too, mine looked more like a vertical scrape.
As for puddles, it wasn't puddle-y mud, more sticky mud. I'm not concerned about injury as such, more just curious. I can find plenty of stuff about foot position with regards to where you strike or pronation, but not much about the actual angle between the direction you're running and the direction your feet point when they hit the ground.
Its probably nothing worth worrying about, just made me a bit curious.