I've been photographing some practice sessions for our local roller derby team. I have to say it's a great experience. Their practice sessions are a great place for me to practice action shots, working with bad light and working with people that love to have pictures taken. I highly recommend it.
Anyway, I took this last Monday and have been playing with it. The original shot was ISO400, f/5, 1/25 sec. and more or less 100mm on a cropped sensor. I say more of less because I zoomed in during the exposure. There was some good motion blur near the edges of the frame, but I decided to crop in close. There's still some motion blur on her elbows, but it is minimal.
I don't know if you can see it, but there's just the tiniest bit of post-processing.
Basically these images have 3 layers. From top to bottom those are
1) A transparent layer with just the edges rendered.
2) The skater posterized to about 20 colors.
3) The background, posterized and then converted to B/W.
derby20140224 001 copy - Version 2 by picsfrommt, on Flickr
I found the skater in the background distracting, so cloned her out of the picture. I also cropped it to a square format and got this
Pretty (tough) in Pink by picsfrommt, on Flickr