Speed sensors for sport Fair warning: I'm a newbie when it comes to Arduino, so if I'm not too great at describing things, let me know so I can learn!

I have recently built a fairly accurate laser timer to time sprinters through a section of a soccer pitch, giving a nice reading of their average speed through the zone.

The limitation is that we would love to be able to see their speed as a progressive measurement throughout the sprint.

My problem? I have NO idea where to start. Google has so far come up empty...

All I have is the following link, Best of the 2015 NHL All-Star Skills Competition, illustrating the sort of thing we would like to accomplish. The bit in question starts at around 0:35 when they are talking about sensors in the players' jerseys.

Any one able to point me in the right direction?
Kinovea is good but this would be post processing not live. You need record video and then you can track each runner on time. Another one is Typhon program but it involves programming and calibrating (then you can track live).