Oli Glaser wrote:

> On 18/04/2011 18:11, V G wrote:
>> But maybe the power output isn't linear over that time. Maybe the
>> power output was maximum at the first millisecond and decreased for the =
rest
>> of the second.
>=20
> This was my point - I'm wondering how accurately they measure the=20
> instantaneous power.
> For instance, if the power was 10kW for a millisecond then drops to 100W=
=20
> for 999ms, but you were only averaging the power over every second then=20
> you will have a reading of ~110W, and never know about the 10kW peak.

That's sort of basic measurement theory. The stronger the filter, the
more stable the reading but you also get less data -- which is the
objective :) If you want to see 1 ms peaks, you can't use a 1 s filter
-- but you'd have to be prepared for the much higher data rate.

> Or a weightlifter could lift in very small increments, taking a rest
> in between each one. As Gehard also pointed out, with other types of
> lift one usually uses the weight of the body and trades energy with
> the weight to be lifted, making it harder to calculate the
> instantaneous power.

We're only talking about simple, abstract mechanical power here. While
holding 500 kg at a height of 1 m doesn't cost any abstract mechanical
power, we probably can agree that most of us would have to expend more
"biological power" than we have at our disposal in doing so for longer
than a few milliseconds.

The actual energy expended is something else, higher, and the
relationship between the energy expended and the effect would be an
interesting figure.

Gerhard
--=20
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