Assigns a percentual value to a time you ran on a certain distance. Data via Alan Jones. This percent enables you to compare yourself to someone of a different age or gender. In essence this value is the ratio of your time to the world record (or expected world record) for someone in your category.
The way I understand it, this does not mean that a value of 70% indicates you are in the top 30% of the world. The value is only there to compare with the values of other people.
h m s
This predicts your time in one race based on your time in a previous one. Formula devised by Pete Riegel in the 70s.
h m s
Pete Pfitzinger Heart Rate Zones
Using the numbers and categories in Faster Road Racing. Good book, go get it.