It looks like they are using longer leashes too. For years, I used a 12 foot big wave leash (distance is your friend and thicker too, for no slingshot effect). There are things you could do to further reduce the slingshot because you can feel where and what the board is doing behind you. I get hit in the head by my board WAY more without the leash.
Without the leash, the board beats me downwind and sometime beats me to the beach. If it doesnt run me over in the process.