Per IWPA rules, either freight or sled harness is acceptable.

Pull long and light, my 85 pound male pulls approximately 55 pounds for One and a half miles and back again with only one or two stops to rest. I keep adjusting this weight, for instance when we first started he only pulled 30 pounds this way, then to 40, to 45, etc. Eventually I want him to pull his bodyweight this way. Do this low weight long pull twice a week.

Pull short and heavy, that same male pulls 130 pounds for maybe 50 feet or so a couple of times, then we rest just long enough to drop weight, drag the lower weight for another 50 feet etc... usually pull till he balks a few times and then I ask for one more pull. The lowest weight I will let him pull is his body weight when pulling this way. Do this short and heavy weight pull once a week.

Then I let him walk on a long leash, (no weights) for about 5 to 10 minutes and then we go to the river for a swim... he loves the river.