not sure if 7.5 times is correct, I’m not that good with math according to the GMAT.
But as the watts increase in a linear manner the physiological response increases exponentially.
That’s not terrible except for these points
- Does an ex equipment company have an incentive to overstate calories burned? Yes they do “OMG Becky I burned 1000 calories on that machine and I hardly sweated at all.”
- Do they have any incentive to understate calories burned? None that I can see
- Is anyone verifying that their stated calories burned are accurate? No, no one is checking that.
Well, I have, at least on 7 commercially available devices. Life Fitness bikes are very, very close.
What? A guy averaging 400W for an hour did twice as much work as a guy who did 200W for an hour. Work done in kJ is close enough to the number of Calories burned. How did you get 7.5 times?
You missread Tunaboo was comparing 400 watts to 200 calories so apples to oranges.
Since a watt per hour is 3.6kj doing 400 watts for a whole hour would burn ~ 14,400 Calories vs the 200 at 200 Calories/hour Oh burning 200 Calories per hour only requires outputting 200/3.6= 55.6 watts
TunaBoo wrote:
Didn’t realize this. So guy going 400 watts for an hour literally burned double the calories of the guy going 200 calories for an hour?
No.
That’s ~7.5 times the energy metabolised by a guy who burns 200 Cal for a hour.
Whoops, you’re right. I even read that a few times.
What? A guy averaging 400W for an hour did twice as much work as a guy who did 200W for an hour. Work done in kJ is close enough to the number of Calories burned. How did you get 7.5 times?
That’s not what the OP said.
They were comparing riding at 400W for an hour with someone who burned 200 Cal (kcal).
400W x 3600 seconds / 0.225 efficiency / 4.184 joules per cal = 1,530,000cal =1,530kcal
1530/200 = 7.65, which is ~7.5
Given efficiency could be in a range of say 0.19 - 0.24, then it could be anywhere from 7-9 times the energy metabolised by the 200 Calorie guy.
If they meant to compare with a 200W rider, then the energy metabolised will be roughly double, depending on the relative efficiency of each rider.
I think kJ may be one of the most under utilized metrics, if not the most underutilized metric that a LC triathlete could monitor.
IMO it’s way more important to know kJ in a IM or half then what TSS your attaining.
This ^^^^
One of the few studies I have seen published on elliptical trainers and energy consumption was a Navy study comparing models because they wanted to adjust the calorie burn numbers if necessary. I suppose since they are used shipboard.
I think kJ may be one of the most under utilized metrics, if not the most underutilized metric that a LC triathlete could monitor.
IMO it’s way more important to know kJ in a IM or half then what TSS your attaining.
This ^^^^
Agreed. A single days TSS score is of little use. For a single day it will just quantify how hard/how long you worked out but you can gauge that pretty closely with RPE. Too many people don’t realize that daily TSS is a long term accumulating metric.
On race day kJ is an important and often forgotten metric. We are all far too busy trying to hit a power target 
One of the few studies I have seen published on elliptical trainers and energy consumption was a Navy study comparing models because they wanted to adjust the calorie burn numbers if necessary. I suppose since they are used shipboard.
Well…sort of. It gets complicated. We are using them for fitness testing. The test consists of max calories burned in 12 minutes. So the equipment has to meet calorie accuracy standards. I have tested a bunch myself. The Life Fitness bikes are great. I also tested the accuracy of the wattage display on the Life Fitness bikes and found them to be spot on. Incidentally, with the right button push sequence you can get the Life Fitness bikes to display watts continuously. you have to download the instrucction manual to figure it out.