I'm about ready to purchase an Apple Watch and have a question about how it tracks waling. I have two 70 lb. GSDs and take them on a 5K walk several times a week. I have read that the watch tracks walking/running by arm movement. I'd be wearing the watch on my left hand, but I also hold the leashes in my left hand. As a result, my left arm makes considerably less movement due to holding the leashes. Would this reduction in movement decrease the AW's ability to accurately record the distance of my walks?