To all clients, 
Ensure that you follow your specific stretch programme and do not deviate into other stretches.
Please make sure that you watch the guidance video before watching the stretching videos.

Swiss ball size guidance
Height                   Ball Size
Under 5'2"               45cm
5'2" - 5'7"                 55cm
5'8" - 6'2"                 65cm
Over 6'2"                  75cm