dog pulling on coat

Question
I have a 2 year old Bernese Mountain Dog that has started grabbing our gloves or back of coat at the dog park and pulling and growling.  We know he thinks he is playing but at 120 lbs he can easily pull us off balance.  this behaviour happens in the winter, we did not see it during the summer months at all.  Some time it is our gloves he grabs (with our hands still in them) and commanding him 'down', 'off' or 'bad dog' does nothing but make him more excited.  He is normally a sweet obediant dog.  Any ideas?

Answer
It sounds like play behavior. I'd have another toy to distract him, and be sure you don't give him a lot of attention, trying to get him to release your clothes. Some dogs also don't understand when people have extra accessories and clothing. I'd have a toy available to redirect him. Sandy Case BFA MEd CPDT www.positivelycanine.com