Whats watt

[Primal Scream]

My gym has a new machine a Scifit, the display tells me I am producing 80 watts, I understand speed, bpm, calories and distance but watts is new to me.

Any explanation of its relevance please.

 

[lukesdad]

A measure of power.

 

[Primal Scream]

A measure of power.

Being from an electrical engineering background I sort of knew that however I cannot work out its relevance in this situation, I dont even know how to reference it on a poor to good scale.

 

[subaqua]

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

might help you get head round it. TBH I am not overly bothered by it but the race teams are as they work on getting an average watt output from the riders.

 

[amaferanga]

Many pro cyclists can maintain >400W for an hour. 80W is quite modest even for a recreational rider, but it could be that the numbers on your gym bike are inaccurate and/or imprecise.

 

[VamP]

Many pro cyclists can maintain >400W for an hour. 80W is quite modest even for a recreational rider, but it could be that the numbers on your gym bike are inaccurate and/or imprecise.

This.

I occasionally use gym bikes when on business trips, and the watt numbers are all over the place. I remember a particularly demoralising session of 2x20 in a hotel in Germany, where try as I might I could not hold more than about 120 watts. My usual 20 minute power is 300.

So unless you have some means of calibrating the machine, the watt number is meaningless.

 

[Ningishzidda]

kW = ( Torque ( Nm ) x speed (RPM) ) / 9549.3

Torque ( Nm ) = kgf x g x distance ( m )

A cyclist of 0.5 m^2 area and 1.0 Cd will require 80 Watts to ride at 12.4 ( 20 kmh ) on the flat thru still air at 20 C.

 

[Primal Scream]

Thank you for the replies.