The start of the push. you can see that Jamia has thrown her entire body weight against the sled to get it moving. Shauna starts back at the line with Jamia so by the time she takes a step to get to her push bar which is sticking out of the side of the sled, the sled is already moving. Then you sprint down the ice, the driver gets in and the brakeman gets in behind her. These girls have a LOT of power in their legs.