[danny_shank]

I think because of the way the left shoulder joint naturally works, the dog would never be left running in place (he'd run in circles - hinge action). The dog is the pull.

So I'd lean to saying you can't have too much extensor action. The "problem" of "too much extensor action", probably, in reality, is a left arm that is not properly left alone to be inert or a piece of rope. I'd say you need all the properly produced structure you can get (by stretching the left arm).

Wouldn't too much extensor action impede a player from swinging the left arm freely from it's socket?