Image of woman biking. Computer graphic of her breathing patterns and expansion of lungs. Prolonged CU of her heart monitor and results. Next scene, two children racing on a track - shot of girl crossing the finish line and breaking the ribbon. Computer graphic of a boy and girl running. Scene of two other people racing - boy winning this time. Computer graphic of four people running. Image of a group of children racing. CU of two boys at front of the pack. Computer graphic of average speeds for boys and girls. Scene of a large group of people racing. Several CUs of runners. Back to computer reenactment of runners to work out average speed of test group - worked out a bell curve for both male and female runners