Centile charts show the position of a measurement compared to a reference population. They are useful for comparing measurements that change with growth and time for an individual or a group. The time to run 550 m was measured as the time taken to run five times around an oval track (26.5m by 42.5m).

We have developed gender-specific time to run 550m centile charts from measurements of 5059 children aged 6 to 12 years. The calculations that underpin the graphical representation of these charts have been embedded in the attached excel spreadsheet. For a child, or group of children of the same gender the age and run time in years, minutes and seconds may be entered in the unprotected cells and the point will be plotted on the gender-specific chart and the z score determined. For example for a group of 6 year old girls the median age will be 6.5 years and the median run time of the group may be entered. In this way changes in run time over time may be assessed or different children and groups compared with and without intervention and accounting for gender and age.