# Human Energy, Work Done and Declining results

• flebber
In summary: /index.asp which may be a better starting point as it looks at how the body performs in relation to the environment.
flebber
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.

There are no simple laws of physics that allow you to determine how fast you can run the last km in your example. This is mostly to do with human physiology and training. For example a trained sprinter might run the last km faster than a trained marathon runner just because their muscles are different.

You need to talk to a sports scientist. As I understand it sports scientists estimate work done by measuring oxygen consumption. I believe they can tell how fast you should run so you don't build up an energy deficit (eg that might affect your speed over the final km.)

Example: http://www.livescience.com/5359-perfect-running-pace-revealed.html

flebber
CWatters said:
There are no simple laws of physics that allow you to determine how fast you can run the last km in your example. This is mostly to do with human physiology and training. For example a trained sprinter might run the last km faster than a trained marathon runner just because their muscles are different.

You need to talk to a sports scientist. As I understand it sports scientists estimate work done by measuring oxygen consumption. I believe they can tell how fast you should run so you don't build up an energy deficit (eg that might affect your speed over the final km.)

Example: http://www.livescience.com/5359-perfect-running-pace-revealed.html

I guess if I could get enough data of people running at set distances at various speeds/intervals you could derive an expectation of decline or increase in speed of those who ran quick early vs mid vs late and see if there a common thread.

Interestingly about the 8.3 mph optimum speed in the article you linked it doesn't delve into whether that pace allows recuperation to occur.

Edit seems the field I am looking for is Biomechanics http://www.bases.org.uk/biomechanics

## 1. What is human energy and why is it important?

Human energy refers to the physical and mental effort that a person puts into accomplishing a task. It is important because it is required for any type of work and without it, tasks cannot be completed efficiently.

## 2. How is human energy measured?

Human energy is measured in units of work, such as joules or calories. It can also be measured in terms of power, which is the rate at which work is done.

## 3. What factors contribute to declining results in human energy?

There are several factors that can contribute to declining results in human energy. These include physical fatigue, mental exhaustion, lack of motivation, and poor nutrition or hydration.

## 4. How can declining results in human energy be prevented?

To prevent declining results in human energy, it is important to take breaks and rest when needed, maintain a healthy diet and exercise regularly, and find ways to stay motivated and engaged in tasks.

## 5. How does human energy relate to work done?

Human energy is directly related to work done, as without the physical and mental effort put into a task, work cannot be completed. The amount of human energy put into a task can also affect the quality and efficiency of the work done.

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