## Vertical Jump - Mean Power Calculation

**Moderators:** Ironman, Jungledoc, parth, stuward

### Vertical Jump - Mean Power Calculation

Does anyone know how mean power is calculated for the vertical jump calculator in exrx.net.

### It's physics

The fine people use the information that you supply and do something similar to what is described by this:

http://en.wikipedia.org/wiki/Power_(physics)

I don't know exactly either?

http://en.wikipedia.org/wiki/Power_(physics)

I don't know exactly either?

Really, your looking for the discussions about power with Kenny Croxdale, who is very knowledgeable on the subject :-)

http://exrx.net/forum/viewtopic.php?t=4 ... c&start=15

Hope that helps

KPj

p,s some good links in that thread, too.

### Re: Vertical Jump - Mean Power Calculation

I can't speak for the actual calculation used in the calculator, butnelson wrote:Does anyone know how mean power is calculated for the vertical jump calculator in exrx.net.

power=work/time or forcexdistance/time

In this case, force is equal to your weight, distance is the height of the jump and time is calculated from the height and gravity.

Stu

### Re: Vertical Jump - Mean Power Calculation

As mentioned here, to calculate power in Watts in a physical way:stuward wrote:I can't speak for the actual calculation used in the calculator, butnelson wrote:Does anyone know how mean power is calculated for the vertical jump calculator in exrx.net.

power=work/time or forcexdistance/time

In this case, force is equal to your weight, distance is the height of the jump and time is calculated from the height and gravity.

Stu

Power is energy dissipated per second.

Energy is work done.

Work done is force x distance.

Force is your body-weight in kilograms multiplied by upward acceleration.

Upward acceleration would need to be in excess of 9.81m/s/s.

You could work out the minimum power produced by:

Multiplying body-weight by 9.81 then multiply by change in height. With this answer divided by the time taken.

To get the absolute power you would need to know your final upward velocity.

A simple although not entirely accurate way would be to calculate the gain in potential energy, which is the (change in height) x (acceleration due to gravity) x (body-weight). Then divide the potential energy by the time taken to produce the change in height.

Example: Person of weight 100 kg. Gravity is 9.81m/s/s. Change in height 1m. Time taken 0.5s.

100 x 9.81 x 1 = 981 Joules

981 / 0.5 = 1962 Watts

I found this site:

http://www.topendsports.com/testing/ver ... -power.htm

They had 4 different calculations, all gave different answers and all were different than the calculator.

What I said was a raw theoretical analysis. Calculate the power by working out the change in potential energy and dividing that by the time taken to do so. It does not take other factors into consideration such as momentum, air resistance etc.stuward wrote:I had to plug your numbers into the calculator to see if it gave the same answer. It didn't. It gave 2401.

I found this site:

http://www.topendsports.com/testing/ver ... -power.htm

They had 4 different calculations, all gave different answers and all were different than the calculator.

### Vertical Calculation

Thanks for the responses.

I tried to calculate the power using potential energy or using kinetic energy, but my calculations were way off what was in ExRx.net.

I though if I found it on the internet it must be true.

I tried to calculate the power using potential energy or using kinetic energy, but my calculations were way off what was in ExRx.net.

I though if I found it on the internet it must be true.

Tim