Really there is not much difference. Wrestlers that are bigger would have a clear advantage...but the weight class is established for safety in wrestling,
In running ...we do not do weight classes cause safety is not a factor. But imagine if they had weight classes. Then you would see teams try and get like a 300 pounder to run a 5k in like 40 minutes...lol....
Then all you super fast runner dudes here would be nothings...because youd all be in the same weight class and only a few would prevail. More attention would be given to the fat dudes that can run semi well.
Some of these 180 pound dad bod hobby joggers would also be legit!
I am serious here...