The PhysEdder RU-vid channel is where Phys Ed teachers and Coaches go to find Physical education minor games and resources. The games and resources are explained through easy to follow videos. You will also find videos identifying the critical components of Fundamental Motor Skills, information based on the Victorian Department of Education's Fundamental Motor Skills - A manual for classroom teachers. This channel was created by Dr. Brad Beseler, Lecturer at Federation University Australia.
I wouldn't use it to time the whole race, I would time with a stop watch to get the first person across the line and also record the finish on this app. Then you can figure out the other placings by combining the info on the app and the time on the stop watch