Want to Cut Down on Your Finish Time at Your Next Race?  Try Cutting Corners: Running Tangents

This is not cheating. The only race courses which are "guaranteed" to be accurate are those which are "certified". In this country, courses are certified by the USATF, (USA Track & Field) to meet international standards set by the IAAF. (International Amateur Athletic Federation)  The IAAF and USATF require that courses be measured over the shortest route open to the runners. This means that the course is measured on a route that cuts all corners as closely as possible to the inside apex, usually within six inches of the road edge.

You are cheating yourself if you do not cut the corners as the course was measured. If you run down the center of the road, each right angle turn will cost you one or two seconds in your finish time and extends the distance you will have to run. To further ensure that courses are not short, the USATF recommends all courses be set up to be 0.1% long, about 50 yards or 8-16 seconds in a marathon.

To run the shortest route, keep as close as possible to the inside edge of the road on all turns, and as you come out of the turn, assume a straight line route to the inside of the next turn. Practice doing this in your training on roads or trails that are traffic free.

Road Racing Strategies by By Warren Finke