That one is a little small, a bit smaller than mine, but it is supposed to be a 50/50 activity. My dog will slack off if I'm too slow for a while he actually heels better with me on skates than walking
A lot of the sled dogs are only 35-45lbs, although larger pointer mixes seem to dominate single dog races of the skiing variety for several reasons, only one being size.
The problem is... my dog is afraid of my bike! Its going to take a while for that to work out