In curling, sweeping is critical. As the shooter propels the stone down the ice, the path of the stone may be further influenced by two sweepers with brooms while escorting it down the sheet. Naomi does just that. Her purpose is to alter the state of the ice in front of the stone in order to manipulate the path of which the stone's delivered.
Shout out to the guys at www.stevescurling.com. First-class service.