Using Peak of Action is one method of getting a sharper image. The easiest example I can think of is when you drop a ball onto a hard wood floor. At the moment the ball is at the highest point and just before it comes down again is the peak of action. At that exact moment the ball is entirely still, no upward or downward motion.
Now, apply this do dogs. Lots of dogs. Dogs which are racing as fast as they can. The larger the dog team the harder it is to capture an image where every dog (and if you’re lucky, the musher) is at its peak of action.
When applied in this fashion you want the dogs ears and skin to be up in the air and not down. Because the dogs are fresh near the beginning of the race it is easier to get “up” shots but near the finish line it is obvious that they just don’t have the energy they once did.
Look at these images and determine which dogs and mushers are at their peak of action.
mytoesarecold gallery series
Above: Some of the dogs are, not the musher.
mytoesarecold gallery series
Above: the Lead dogs are, not the musher.
mytoesarecold gallery series
Above: Lead dogs are, dog on right is, musher is too.
mytoesarecold gallery series
Above: All dogs are, musher is not.
mytoesarecold gallery series
Above: None of the dogs are, the musher sure is though, just look at that foot above the head!
This sport is so fast that without a fast frame per second rate it would be nearly impossible to capture peak of action shots. The D90 shoots at 4.5 fps which is borderline for this sort of shooting. Something like the D300(S), D700, or the D3(S) would be much better suited.