Clothing is also different for time trialling. One-piece skinsuits that do not flap in the wind are common; tight lycra shoe covers help improve airflow over buckles and straps; long pointed helmets channel air down the riders back (the position of the helmet above the rider's back is crucial, it must be as close to the body as possible; too high and the air will just flow underneath the helmet. This is often hard to achieve as the rider moves his head due to the suffering endured during a hard race).