Some animation on him (e.g. fluttering clothing) would really help this, I think. An animated background that suggests "speed" is at odds with a perfectly still foreground.
The highlights on his arms are confusing and don't read like anything, so they just look like noise. Try to avoid having shadows and highlights that are only 1px thick when you can avoid it. Larger shapes can usually convey volume/form much better, using lines tends to make things flat and/or noisy.
Thanks for the suggestions!