We have one at our Elementary School. The kids walk twice per week during lunch recess from Sept. to Nov. and then from End of Mar. to June (weather dependent). It is optional but we try to do different incentives for the kids to participate. For every 40 laps walked (1 mile) we give the kids a toe token on a metal chain (like a fan pull chain) that they put on their shoes and then at the end of the year we award prizes (donated from the YMCA - frisbees, cups, water bottles, pedometers, T-Shirts) for certain levels of participation. We are trying to increase participation. 1st & 2nd grades have a lot of participants but the level goes down for grades 3-5. We are considering a guest walker program (teachers, principal, local sports mascots) and ordering personalized prizes (items with our school name on them).
We have a group of about 12 parents with 4 volunteers required for each recess (11:30-1:30), we have lists of names by grade in alphabetical order. We hand out tongue depressors for each lap then 5 minutes before the end of each recess we have the kids count the sticks and then we record the number of laps and one person puts that information into a spreadsheet to track it.
Hope this is helpful.