As long as there are no rabbits to chase on the course unless the rabbit runs straight to the finish, things to sniff, grass to pee on my dog would be a great assist! Though by about a mile he'd get bored and want to go off into the fields and see what other fun things he could do!
Also I ran with my lab at Emma Coburn's Elk run 5k in Crested Butte and she gave my dog Calvin a low five when we crossed the finish line. That was cool!
I have competed in many various different running races where I was legally required to complete the race as part of a team with another animal. Animals in these races were of 4 different species. I have raced as part of a team with other humans, burros, llamas and also dogs.
All of the above animals can be trained to provide significant assistance (pull) certain runners so that they would complete the race much faster than they could on their own. Depending on the relative abilities and training levels of the runner and other individual animals, those animals might either aid or inhibit the runner in a race.
Normally races that allow animal/runner teams have specific rules regarding how the team members must interact (such as pulling ok with leash/rope length limits, no riding, no pulling allowed, what and whose body part constitutes a team finish when crossing the finish line, mandatory vet checks, etc., etc.)
But your average local community running race (including some with prize money) likely has no documented defined rules about anything, including use of dogs, other people/pacers, shoe types, PEDs, outside assistance, taking a ride in a car, etc.
So competitive runners should consider getting pulled by a dog to be an unfair advantage in a running competition.
But it would only be an ethical complaint unless the race has rules in place that prohibit and/or define the use of dogs.
Also, racing with other animals presents many additional questions and grey areas in today's world. If a biologic female is teamed with a male dog, what division are they in? Are dogs neutered when very young still considered male dogs? What about female dogs that identify as male when they hump other dogs? Based upon those types of observed interactions, are there non-binary dogs? What age group should a 42-year-old runner and a 4-year-old dog be in?
I have competed in many various different running races where I was legally required to complete the race as part of a team with another animal. Animals in these races were of 4 different species. I have raced as part of a team with other humans, burros, llamas and also dogs.
If this is for real, I think the world is a weirder place than I had ever imagined and I also think it is wonderful.
It was a lab sized dog that was running the whole time, 10 mile race. We didn't realize she was 4th OA until her 1st in age group award came in the mail. Is this mechanical doping? Biological doping?
The size of the dog doesn't necessarily matter. I have a chihuahua mix I've raced several times with, all dog-friendly like a no-results Turkey Trot or dog-specific (ex: Doggie Dash). She definitely helped me run faster. Now I have her and another larger dog and have only raced once with them both so far, but it was an advantage. At the time, I was probably in 22ish min 5K shape and we ran like 20:02 including a brief leash trip-up. The key is to have them warm-up with you so they get all their bathroom business out of the way first. Once the race starts, they see all the people and stay focused running in the same direction, so squirrels and other potential distractions are mostly ignored.