as the video goes on, you can see the weigh is increased. also in some of the clips you may be able to see the marker attached to the back of the sled, it has distance marked on it. they will add weight until the horses can not pull the full distance and see who does the best.
Very cool. What are the rules exactly? We do horse pull a little different here in Estonia. A fixed weight over a long distance and measure time.
as the video goes on, you can see the weigh is increased. also in some of the clips you may be able to see the marker attached to the back of the sled, it has distance marked on it. they will add weight until the horses can not pull the full distance and see who does the best.