Hi I am having trouble locating resources for a topic as I do not know exactly what it is called, and I am looking for assistance. If you wanted to look at human performance and calculate the various ways a human could perform a task and how this would affect outcome by including "work done" energy consumed and used is there a known formula or calculation for this? As an example if I had a runner and he/she ran in a 5km race if they ran at an increased rate for the first kilometer measured by speed and heart rate, how would I be able to predict their speed over the last kilometer if they reduced their speed for the middle 3 kilometers? I assume there is an optimization formula that would exist but searching "maths physics work done" yields one good result that leads me to think I may be searching the wrong thing http://www.physicsclassroom.com/class/energy/Lesson-1/Definition-and-Mathematics-of-Work . It doesn't seem to relate to human achievement or potential energy as an athlete but rather using my size and motion direction to calculate work.