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1000 Kcal per day (weight loss thread)
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I am currently 30lbs out of racing weight (5' 11" and 200lbs). I have bought the book "racing weight" and I am trying to follow as many of the ideal eating patterns as possible. I have also set a goal beginnng today to burn 1000kcal per day though exercise 6 of the 7 days per week.

I have noticed my Sunto watch and powertap are within 5% for the reported caloric expenditure at high zone 2 intensities. When my HR goes up the predicted values on my watch are lower then the measured power tap values.
Not sure what running/skiing would be like, but it is cool that the watch prediction is fairly accurate with one type of execise at the zone I spend most of my time training.
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Re: 1000 Kcal per day (weight loss thread) [FTDA] [ In reply to ]
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Running in zone 13 will burn way more calories.
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Re: 1000 Kcal per day (weight loss thread) [nickwhite] [ In reply to ]
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I really like running in zone 5(squared) massive calories burned.
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Re: 1000 Kcal per day (weight loss thread) [FTDA] [ In reply to ]
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I have noticed my Sunto watch and powertap are within 5% for the reported caloric expenditure at high zone 2 intensities. When my HR goes up the predicted values on my watch are lower then the measured power tap values.
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it is cool that the watch prediction is fairly accurate with one type of execise at the zone I spend most of my time training.

What do you mean by "predicted values" vs. "measured values?" (i.e why is your watch "predicting" while your powertap is "measuring?" Does your HR strap report to the PT head unit and not the watch? If so, on what basis is your watch predicting your HR? If the suunto is simply reading your mind then that's pretty cool.

Depending on what the watch is reading to determine your calorie expenditure running/skiing could either be pretty accurate or not accurate at all. For instance, if your suunto is doing HR-based calorie calculations then it's going to be pretty accurate. If it's simply taking a couple of parameters like age, weight, height, etc and combining that data with pace then it'll probably be fairly close in running, but will vastly overestimate calorie expenditure in skiing if it doesn't have a dedicated skiing mode. I mean, let's be honest...gravity is doing most of the work--skiing isn't really that hard when compared with running or biking until you start getting into Olympic intensity, in which case it's probably ridiculous how many calories it burns.

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Re: 1000 Kcal per day (weight loss thread) [ZackC.] [ In reply to ]
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predicted based on HR, weight , intensity.

Xc skiing is rather difficult, I would like to see how well you stack up to a competitive xc skier : )
Last edited by: FTDA: Nov 28, 11 7:08
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Re: 1000 Kcal per day (weight loss thread) [FTDA] [ In reply to ]
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FTDA wrote:
predicted based on HR, weight , intensity.

Xc skiing is rather difficult, I would like to see how well you stack up to a competitive xc skier : )

"skiing isn't really that hard when compared with running or biking until you start getting into Olympic intensity"

I got a kick out of that too....




Steve

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Re: 1000 Kcal per day (weight loss thread) [FTDA] [ In reply to ]
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Why do you say that the powertap is "measuring" your kcal expended? How could the PT possibly know how many kcal you've expended?

If your suunto is using HR and weight to determine kcal burned, I'd say that counts as a measurement. If your suunto is set up properly for you (i.e correct height/weight/age etc.) you're not going to get a much more accurate figure than that unless you go to a lab.

I can ski uphill in regular skis and boots without poles, my aerobic fitness is trick...I'm fairly confident I could be a competitive xc skiier. I'm pretty handy with a gun too. If I lived in a colder climate I'd probably take up biathlon instead of triathlon. That said, I don't believe you originally specified XC skiing (I was thinking you were planning on doing some downhill skiing for exercise, which wouldn't be all that effective in terms of rate of calorie expenditure).

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Re: 1000 Kcal per day (weight loss thread) [ZackC.] [ In reply to ]
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I was under the impression that it measures Kjoules, which due to a mathematical quirk with typical efficiencies of humans while biking can be equated to Kcal.

I did not specify xc skiing, I apologize on being ambiguous.
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Re: 1000 Kcal per day (weight loss thread) [FTDA] [ In reply to ]
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The powertap isn't any better at "measuring" than your watch is. In fact, neither "measures" your calorie expenditure in the strictest sense of the word--both take one or more input parameters (which is not calorie expenditure), do some math (which may or may not be based specifically on you and your body type and energy expenditure rates), then give you a number. I'm not sure what data you had to plug into the powertap, but if the answer is "none" then I'd take the data from the suunto over the PT any day. In fact, if the PT isn't using HR to calculate expenditure, then I'd say the data is about as useful as a poopoo flavored lollipop. A small fraction of the rider's total energy expenditure and time rate of energy expenditure (power) is accounted for by the rear wheel power, with the remaining majority spent simply venting heat through your skin to the air, heating up your internals, etc. Obviously, using some sort of "typical efficiency" figure would attempt to sort out the fractions, and extrapolate how many calories you burn overall, but I would have serious doubts about the accuracy of this method because of the extent to which the correlation between rear-wheel power output and net power output is related to your own body. What I'm trying to get at is the HR-based calculation is a lot more direct, and I would sooner use that as my "accepted value" than the PT number.

Either way, it would be more correct to say that the two numbers are within 5% of each other, rather than saying that one is predicted and the other is measured. Not trying to be a stickler, but I think it will help you in the long run to understand the distinction. Just thinking about this you probably burned 500 cal.

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Re: 1000 Kcal per day (weight loss thread) [ZackC.] [ In reply to ]
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leaving the semantics, I found it comforting that the two "predictions" were so close. I feel much more comfortable using my Suunto as a guide in the future to track caloric expendature.

I should have stated the predicted Kcal from the measured Kjoules~!
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Re: 1000 Kcal per day (weight loss thread) [FTDA] [ In reply to ]
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for the powertap use kj to equal calories burned
for running use cal= distance traveled (km) x your weight (kg)
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Re: 1000 Kcal per day (weight loss thread) [ZackC.] [ In reply to ]
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ZackC. wrote:
The powertap isn't any better at "measuring" than your watch is.


You don't know what you're talking about. You do sound incredibly authoritative, which makes me think you're either very young or very idiot.

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Re: 1000 Kcal per day (weight loss thread) [Paulo Sousa] [ In reply to ]
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I'm just trying to understand why the OP would trust the PT calorie data but be dubious of the suunto calorie data.

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Re: 1000 Kcal per day (weight loss thread) [FTDA] [ In reply to ]
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If your not going to write peer reveiwed paper, use either. The goal is to lose weight, what you describe will work fine if you stick to it and don't fudge. Good luck

Styrrell
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Re: 1000 Kcal per day (weight loss thread) [Paulo Sousa] [ In reply to ]
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well he said he can ski uphill without poles so could probably race competitively at it, but then I thought that was one of the better ways to learn xcountry skiing, ie without poles

I am going with young to give the benefit of a doubt. we older folks will take idiot when we say such things
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Re: 1000 Kcal per day (weight loss thread) [ZackC.] [ In reply to ]
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ZackC. wrote:
I'm just trying to understand why the OP would trust the PT calorie data but be dubious of the suunto calorie data.


the powertap data is POWER= very accurate KJ measurements

kj is roughly equal to kcal.

suunto= HR which means a very inaccurate guess.
Last edited by: SeasonsChange: Nov 28, 11 8:09
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Re: 1000 Kcal per day (weight loss thread) [Paulo Sousa] [ In reply to ]
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Neither device has a mechanism for directly measuring calorie expenditure, that is a given. Both have some sort of built in model for correlating a measured input parameter to your calories burned. I'm just trying to make the point that one is bound to be better than the other because it uses a better model or the model is better calibrated using data from the user. I think it would be hard for you to make the case that a model based on rear-wheel power only (assuming the PT isn't collecting HR data) is better than one that takes into account HR, height, weight, etc., but I'm simply interested in the truth, so if you know something I don't, feel free to enlighten me.

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Re: 1000 Kcal per day (weight loss thread) [ZackC.] [ In reply to ]
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ZackC. wrote:
Neither device has a mechanism for directly measuring calorie expenditure

wrong.
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Re: 1000 Kcal per day (weight loss thread) [ZackC.] [ In reply to ]
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ZackC. wrote:
Neither device has a mechanism for directly measuring calorie expenditure, that is a given.

Wrong.

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Both have some sort of built in model for correlating a measured input parameter to your calories burned.

Wrong.


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t I'm simply interested in the truth, so if you know something I don't, feel free to enlighten me.

I am not going to do your homework for you. But hopefully you're able to use The Google.

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Re: 1000 Kcal per day (weight loss thread) [SeasonsChange] [ In reply to ]
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the powertap data is POWER= very accurate KJ measurements
kj is roughly equal to kcal.

Dude. If your powertap told you how many kcal you burned based only on the power you expend to turn the pedals then the value will be off by a VERY large percentage. I certainly hope you're not trying to tell me that your body doesn't burn calories generating heat, etc, and that there is no need to take this into account.

Here's the deal, without HR data, your PT has to solve the following problem to get total calorie expenditure:
Calories expended to do mechanical work over time at the rear wheel hub (about 10-15% of your body's total calorie expenditure)
+
Account for "other" calories expended by your body, in the form of heat, work done on other parts of your body (a la out of saddle sprints where you move your torso), biological processes etc. (about 85-90% of your body's total calorie expenditure)
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Net calories

My point is simply that the PT isn't some gold standard for measuring calorie expenditure because it is extrapolating the 85-90% based on the 10-15%.

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Re: 1000 Kcal per day (weight loss thread) [Paulo Sousa] [ In reply to ]
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Just because it puts out a number that says "calories" doesn't mean it's directly measuring that. Good God you are stupid.

Until a Suunto or PT can directly assess the heat output from your body and sum that with your mechanical work output it is NOT, AND I REPEAT, NOT measuring your calorie expenditure.

Fuck off PS, you're dumber than you think you are.

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Re: 1000 Kcal per day (weight loss thread) [ZackC.] [ In reply to ]
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im not sure if youre extremely narrow minded or just ignorant.

im going to just go with you not knowing physics.

http://en.wikipedia.org/wiki/Muscle#Efficiency
Last edited by: SeasonsChange: Nov 28, 11 8:29
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Re: 1000 Kcal per day (weight loss thread) [ZackC.] [ In reply to ]
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ZackC. wrote:
Fuck off PS, you're dumber than you think you are.

We will meet one day. Have a nice day.

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Re: 1000 Kcal per day (weight loss thread) [SeasonsChange] [ In reply to ]
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How are you not getting this? Anything other than basically putting the human being inside a calorimeter is an indirect measurement of calorie expenditure, and requires some sort of conversion to get calories out of work done.


Read the link you sent:

For example, a manufacturer of rowing equipment shows burned calories as four times the actual mechanical work, plus 300 kcal per hour



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Re: 1000 Kcal per day (weight loss thread) [ZackC.] [ In reply to ]
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http://www.competitivecyclist.com/pdf/power_v1.pdf

you are not understanding ~1kj= ~1kcal or that HR doesnt really tell you that much.
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