It's not okay for dogs to be jumping you. Rocky is addressing rude dog behaviour.
Your best option is to avoid those dogs (the owners will not change their ways). Don't go in, leave the dog park, or if inside the dogpark, gain distance, keep moving, walk (don't run) away and do all this in a cheerful and pleasant manner.
Edit: ugh. I just reread your post properly. Horrible dog park--dogs should not be jumping and knocking people over. Play groups, running dogs accidently colliding with people okay--people need to watch out too, but this sounds like very rude dogs and owners.
Your dog is now expecting the worst (I don't blame him). My advise remains the same, but more. Avoid those dog that jump up on you as much as possible.
Your best option is to avoid those dogs (the owners will not change their ways). Don't go in, leave the dog park, or if inside the dogpark, gain distance, keep moving, walk (don't run) away and do all this in a cheerful and pleasant manner.
Edit: ugh. I just reread your post properly. Horrible dog park--dogs should not be jumping and knocking people over. Play groups, running dogs accidently colliding with people okay--people need to watch out too, but this sounds like very rude dogs and owners.
Your dog is now expecting the worst (I don't blame him). My advise remains the same, but more. Avoid those dog that jump up on you as much as possible.