Is this good?

This is what the elliptical at the gym said I was pushing, and that was my average heart-rate. A guy at the gym told me 220 watts is "quite good" but I don't really have a clue.

The machine also said I burned 420 calories in 30 minutes at that rate.. and I told this to a co-worker who's an engineer (I work for a big computational fluid dynamics engineering firm as their IT guy).

I told him I wouldn't trust the caloric burn on those machines. He told me, "Why not? That number is mathematically pulled by the watts you push, and simply calculated as work-effort.. so I'm sure it's pretty accurate."

If it had come from anyone else, I would have blown it off.. but not one of our engineers that designs (and improves) turbines.
Is this accurate?!?!?!

I've had the same thought. If the manufacturer is reputable, there's no reason to believe their computers would just make these numbers up.

Still, I'd be curious to know if anyone familiar with the nitty gritty of these things has anything to say about this.

Is this good?

This is what the elliptical at the gym said I was pushing, and that was my average heart-rate. A guy at the gym told me 220 watts is "quite good" but I don't really have a clue.

The machine also said I burned 420 calories in 30 minutes at that rate.. and I told this to a co-worker who's an engineer (I work for a big computational fluid dynamics engineering firm as their IT guy).

I told him I wouldn't trust the caloric burn on those machines. He told me, "Why not? That number is mathematically pulled by the watts you push, and simply calculated as work-effort.. so I'm sure it's pretty accurate."

If it had come from anyone else, I would have blown it off.. but not one of our engineers that designs (and improves) turbines.
Is this accurate?!?!?!

As an engineer, I also had a problem with this. After all, the calorie counter should just be a measure of the work that the machine is doing, which you are doing to it. So it should be pretty accurate. Well I discovered that he is right and he isn't. The thing that can't really be counted in a machine like that is momentum and inertia. That old newton's law thing that says that a body in motion will stay in motion and a body at rest will stay at rest unless acted upon by an external force. Once you get your ellyptical machine up to speed, it takes less effort to keep it at that speed than it did to get it there initially. So even though the machine may be calculating an energy expenditure, you are actually using less energy to keep it going. Hence the output that the machine says isn't necessarily the energy that your body is expending.

However this explanation also bothers me, because the machine should be able to calculate the actual power being generated by the machine, and even though it is easier after you have it going, it should be able to still calculate your energy expenditure, becuase you are the only one keeping it going. So anyone else have a better explanation?

i always thought it calculated cals burned strictly on your weight, age, resistance and speed, which i guess all goes into how many watts you are outputting...?

Is this good?

IMO, yes quite good, at that level of resistance, to me at least, it might as well be considered a leg excersise and not cardio.

On machines like a concept2 i would think that the conversion would be pretty good as the weight and distribution of load make very little difference. It is purely how much kenetic energy you transfer to the handle that is measured.

Runners and elipticals are a whole different ball game. A couple of things that spring to mind that will effect the energey used are:
The machine has to guess your technique.(long strides on a runner reduces the energy used when on the flat in my experience).
How much of your weight is actually being lifted. (Support rail Grabbers beware !)
How good your trainers are (Yes a good pair of trainers role you forward into the next stride)
How much you balance youself using the rails (balancing takes afew extra muscles and more energy if you dont hold the rails)
etc...

Widers

Ohh and is this fasted cardio ? If it is then i think it would be pretty good if not then its probebrly just good.
Widers

On machines like a concept2 i would think that the conversion would be pretty good as the weight and distribution of load make very little difference. It is purely how much kenetic energy you transfer to the handle that is measured.
Yay for concept II ergs!:claphigh:

And I agree with Widerbeast (and others)...inertia of machines like an elyptical, treadmill, bike, etc have the "keep it moving" quality (inertia), and thus the final wattage output isn't a great indicator...

unless the machine figures wattage based on a per-stride basis (taking into account the wattage of your last stride, including inertia)...did that make sense?

Yay for concept II ergs!:claphigh:

And I agree with Widerbeast (and others)...inertia of machines like an elyptical, treadmill, bike, etc have the "keep it moving" quality (inertia), and thus the final wattage output isn't a great indicator...

unless the machine figures wattage based on a per-stride basis (taking into account the wattage of your last stride, including inertia)...did that make sense?

Yes, it makes sense. I think we're all in agreement: it comes down to how good the computer is at accounting for all the variables in the mechanics at work in the machine.

Might be worth an email to a manufacturer or two.

Yay for concept II ergs!:claphigh:

And I agree with Widerbeast (and others)...inertia of machines like an elyptical, treadmill, bike, etc have the "keep it moving" quality (inertia), and thus the final wattage output isn't a great indicator...

unless the machine figures wattage based on a per-stride basis (taking into account the wattage of your last stride, including inertia)...did that make sense?

Yes it does... also I was thinking about it this morning as I was on the ellyptical machine at the gym. The total calories per hour reported on the machine goes up for me as my heart rate increases, even though the resistance stays the same and the rpm's stay the same. That means that is has some formula that takes into account my heart rate into calculating the number of calories burned. This means that it is based on an average for most people, based on their heart rate, and so will not be completely accurate for me individually. I keep that machine pumping out about 280 watts for an hour at right around 75% of my mhr and it says I use about 1200-1300 calories in that timespan. I know that it also factors in weight too, becuase I have noticed that it is much harder to get to these high calorie amounts now than it used to be when I was 40 pounds heavier. So added uncertainty comes from your weight too, as people who weigh the same but have differen body fat percentages would be using different amounts of energy, but the machine would say that they use the same.