ExRx.net

nelson · n00b Joined: 05 Feb 2008 Posts: 3

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

shaf_43 · Rookie Joined: 04 Feb 2008 Posts: 24 Location: Norfolk, NE

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?

KPj · Veteren Member Joined: 02 Mar 2006 Posts: 2385

I can't answer your question, but it made me think of a previous discussion on here. It actually wasn't really on power, but it almost got hijacked by some, erm, debating which is why it seems a bit all over the place. but there's some great info,

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=4143&postdays=0&postorder=asc&start=15

Hope that helps

KPj

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

stuward

huwwaters · n00b Joined: 12 Dec 2007 Posts: 4 Location: Wales

stuward · Posted: Tue Feb 12, 2008 5:36 pm Post subject:

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/vertical-jump-power.htm

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

huwwaters · n00b Joined: 12 Dec 2007 Posts: 4 Location: Wales

nelson · n00b Joined: 05 Feb 2008 Posts: 3

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.

tostig · Apprentice Joined: 23 Dec 2007 Posts: 100

Why don't you try running up several flights of stairs instead (say all the way up a 12 story building)?

Power is the change in potential energy (your weight x total height obtained) over time (the time it took to climb all those stairs).

It's all legs - just like jumping.

Jungledoc · Posted: Sun Apr 06, 2008 9:37 pm Post subject:

Nelson--What are you using the calculation for? Comparing one athlete with another? Measuring your own progress over time? I'd think that if it's not for some scientific study where precision is essential, that you could just pick a method and use it consistently.

TimD · Posted: Mon Apr 07, 2008 5:50 am Post subject:

JD, I think you are right. I've seen this topic on the vertical come up many times. Most often, what is recommended are fairly heavy squats, to estblish a strength base in the hips/glutes/quads, followe by some OL pulling motions from the floor, and some 2nd pull variations. The 2nd pull is basiclly kicking the hips in combined with a jump shrug with a heavy barbell. This works pretty well. However, when it comes to Vertical Jumps for basketball stuffing, LOL, the best method I've ever seen came from a women's Basketball coach, and she went and bought one of those adjustable hoops, and then had the gals stuff at a given hieght, and then slowly raised the bar = so to speak. She didn't worry, or care, about scientific studies, she just got her ladies out there and adapting to the height increases.
Tim

nelson · n00b Joined: 05 Feb 2008 Posts: 3

Jungledoc

Thanks for the response. I am really just trying to motivate myself to improve. I just got curious how the math and physics worked and figured there would be a precise calculation.