What is the purpose of the camber in sports wheelchairs?

The camber provides greater stability to the wheelchair, especially when turning.
A positive camber angle (greater width at the base) makes the wheelchair more stable and the propulsion more efficient.
A negative camber angle (less width at the base) makes the wheelchair less stable during turns and requires the arms to be propelled further apart.
The recommended camber angle is between 6º and 12º.