Thank you! That was actually one of my main worries about this: that as it changed, the animal slowed down as it evolved to run??? That doesn't make sense, but it's too late to redo it now @.@
Nay, it actually makes sense. With each evolution every stride becomes more efficient, which means he spends less energy to cover the same distance, while keeping the same speed. Evoultion at its finest: doing the same thing better and at a lesser cost.