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Vivienne
09-22-2011, 11:45 AM
.....and anyone else, of course.

I'm including it in the Keiser section as a sort of follow on from yumipon's recent posts as much as anything....... and it'll be obvious why., I hope.

I'm trying to guesstimate the average power output I'd need to generate in order to "burn 500 Cals in an average Spinning class". I put it in quotes because this is the sort of thing you hear out of the mouths of Trainer Bob etc. on TBL. I think that, in a similar discussion ages ago, you mentioned something in the region of 230 Watts (even if that's not exact, I'll use it in the context of this question) More specifically, I'm trying to get a handle on what the perceived exertion(s) for this effort might be over a range of folk who might attend an IDC class.

I think yumi might be some sort of cyber "lightening rod" here as, after my morning class yesterday a few of us GRRRLZ were discussing what exercise can do for weight management and whatnot (in truth, *they* were telling me why stuff "doesn't work" and I was trying to counter with the U R DOIN' IT RONG stance......thankfully not in a narsty ole locker room)

Since I've gotten something of a clue for what sustaining an effort of 200+Watts actually feels like, if you keep it up for any length of time, I'm wondering what sort of RPE number a gen-U-ine athlete such as yourself might put on a "500 Cals in an average Spinning class" workout. For me......and I don't think I'm at the lower level of fitness in my classes.....it'd represent something that's pretty close to the sort of butt-kicking training workout that'd have me making a big adjustment for the rest of the day. Not necessarily eating a load more calories but certainly resting up some to compensate.

So, my thinking is, even if folk are burning 500 Cals in class (as evidenced by their huffing and puffing and shaking hands with Mr. Pukey) there's a good chance that this doesn't ultimately represent an increase of 500Cals in daily energy expenditure .....or the caloric deficit they need to lose the proverbial 1lb of fat for 3500 Cals (and I'm not even talking about theincrease in appetite)

Vivienne

Todd S
09-22-2011, 01:13 PM
The rough rule of thumb is 1 kilojoule of exercise equates to about 1 Calorie (capital C). (1 kilojoule = 0.239 kilocalories which just happens to be pretty close to most folks metabolic efficiency.)

Therefore, 1000 kilojoules (roughly equivalent to the magic 1000 Calories in an hour) requires an average of about 278 watts for an hour. 500 Calories in an hour would require the rider to average about 139 watts.

Gears&Guts
09-22-2011, 01:31 PM
Power


watts 150

watts 200



Rider weight


lbs 140

lbs 140



Bicycle weight


lbs 28

lbs 28



Tires


Clinchers Tubulars MTB

Clinchers Tubulars MTB



Position


Hoods Bartops Bar ends Drops Aerobar

Hoods Bartops Bar ends Drops Aerobar



Grade


% 0

% 0



Head wind


mph 0

mph 0



Distance


miles 0

miles 0



Temperature


75 F

75F



Elevation


100 ft

100 ft



Trans. Efficiency


95%

95%



Predictions below:



Velocity


mph

mph



Time


58.14minutes

58.2minutes



Calories


500 KCal

667 KCal



Weight loss


.14 lbs

.19 lbs

Gears&Guts
09-22-2011, 02:06 PM
The values from the Table on my previous post did not post. I filled them in from memory. The calculator output was obtained from bikecalculator.com . I manipulated the distance until 500 Kcal appeared for the 150 Watt column . I also used an approximate 60 minute constraint for the length of the spin class.

The distance value was 14.9 miles for the 150 Watt column A and 18.6 miles for the 200 Watt column B. { 15.4 mph and 19.2 mph } .

One should keep in mind that extra calories are burned after the spin class has stopped . Metabolic rate is higher for many hours afterward .

I have found that I require fewer rest periods during the day, and my choice of activities during the day appear to utilize more energy also { stairs vs elevator} . Sometimes an extra hour of sleep is required if my distance gets above 50 miles per day { I discarded my car 6 months ago} .

I hope Tammy my Friday afternoon IC instructor forgives me for not matching her 130 cadence .{ 16 miles on a 29er into a 15 mph headwind on a sidewalk on a sunny summer South Florida afternoon { 95 F} leaves my legs a little flat for the hour spin} . of course the benefit is that I am down 60 lbs since March .

Vivienne
09-22-2011, 02:48 PM
The rough rule of thumb is 1 kilojoule of exercise equates to about 1 Calorie (capital C). (1 kilojoule = 0.239 kilocalories which just happens to be pretty close to most folks metabolic efficiency.)

Therefore, 1000 kilojoules (roughly equivalent to the magic 1000 Calories in an hour) requires an average of about 278 watts for an hour. 500 Calories in an hour would require the rider to average about 139 watts.

Not to nitpick (as if) but translated to "an hour's class"......i.e. if you're working within the w/u, c/d, stretch, bike housekeeping etc and out-the-door within 60 minutes that makes up the regular class ......you're looking at closer to 200 watts for 40-45 minutes of significant "work", right?? I never bothered to ever check the Keiser read-out because I'd be on and off the bike so frequently and for long enough to re-set the computer that it wasn't worth thinking about accumualted effort.

I'm not trying to talk myself out of my current fitness level but, if this would represent a tough enough workout for me that I'm wondering if I'd actually be able to train myself to the point where it'd be somethng I could do routinely or not need to have a bit of a sit-down afterwards, I think it's questionable whether my "average" class member could do it right now.....given the sporadic workout schedule of the folks I'm thinking of, that is.

What sort of effort rating do you think you'd personally put to the sort of thing I'm talking about if you were to show up in my class and do as you were told and drop the push-ups on the handlebars (or at least, what I think I'm talking about) I'm thinking you'd probably be in your "fat-burning zone", right? You can see where I'm going with this, right? Still trying to sell the "train to get fitter, stronger, "faster" etc." rather than chasing a presumed calorie burn.

Vivienne

Todd S
09-22-2011, 05:47 PM
Some others with more experience with typical power outputs of average people on indoor bikes may want to chime in here. (tking, Gene Nacy?) My experience is with athletes. I'm guessing the average Joe/Jane spinner would be somewhere around a 175 watt average over a typical class.

Funhog
09-22-2011, 08:22 PM
I hope Tammy my Friday afternoon IC instructor forgives me for not matching her 130 cadence .{ 16 miles on a 29er into a 15 mph headwind on a sidewalk on a sunny summer South Florida afternoon { 95 F} leaves my legs a little flat for the hour spin} . of course the benefit is that I am down 60 lbs since March .

Tammy needs to learn something about indoor cycling cadences - 130rpm is waaaaaay too high for most (99.9999%) indoor cycling students. It forces too many people to choose no resistance which means fewer watts (less power output) which means fewer calories burned (the discussion of this thread) so she is doing her students a disservice by asking for cadences that high. Don't do it...and don't apologize. Just do your 100-110rpm drills and smile, and know that you are getting a better workout than she is giving you.

130rpm is what very skilled cyclists (as in, elite) use with bikes with freewheels (not flywheels) to train their neuromuscular abilities.

liveon2wheels
09-23-2011, 02:11 AM
Some others with more experience with typical power outputs of average people on indoor bikes may want to chime in here. (tking, Gene Nacy?) My experience is with athletes. I'm guessing the average Joe/Jane spinner would be somewhere around a 175 watt average over a typical class. The real danger in all this is throwing around raw watt numbers and raw calorie numbers when both metabolism and power efficiency is so incredibly specific to the individual. That doesn't mean we can't guide them to a goal of what it might take for them to burn 500 calories in an hour or even 45 minutes - but I think we would serve our students much better by helping them come to an approach that allows them to find what it takes for THEM individually rather than guiding them to a set of numbers. I'd love to have a full blown discussion on the topic, but that would better served with verbal dialog among folks here - maybe a live podcast panel discussion or something. In any event, I'd like to leave two concepts on the table with regards to this specific topic of "wattage guidelines for losing weight" (my title for this discussion :)):

1. Burning calories is one thing... losing weight is another. Unless you can create a stress level that is considered "not the norm", your body will simply adjust to it, and you can burn those calories every day and not lose 1 net pound. I'm sure everyone has their share of students who have made the "I come every day and work my butt off and I'm not losing any weight - and I'm on a good diet, blah, blah, blah).

2. Even if we do take power to weight ratio into account, and two people are generating the same watts/lb in a given class - their fitness level, their efficiency and their God given VO2 capacity will translate that effort into a given level of metabolic burn and heart rate or heart zone. For example, Tom Scotto and I climbed at the same rate of speed up the same mountains in Spain, side by side - each generating the same watts/lb (hence, his raw wattage was more since he is taller & heavier), yet I can tell you that on average he was 1 to 2 heart zones (not beats - he's disgusting you know) below mine. So, you have him generating MORE raw watts than I am, but I can guarantee you that I was burning more calories. If you hooked us up to a New Leaf cart during the time, you would see the difference in calories burned per minute.

What's my point? It's simple. You're body's response to that power generation is what ultimately determines your rate of burn and thus your total calories expended. Use power to get stronger/faster. Use heart rate and a close eye on training load to shed pounds. They obviously will work together, but the distinctions are important.

There is so much more that can be said to clarify, qualify and explore this topic, but that should be enough to stir the pot :cool:

matteobma
09-23-2011, 03:44 AM
...
1. Burning calories is one thing... losing weight is another.

Burning calories is one thing... losing weight is another !!!

Gene, This should be written in Bold on the Gym building Wall !

Many times I try to explain this, to those people that ask me tip about weight management, or those ones that are "Numbers dependent".

They really need something to measure; sometimes micro details in a session, and the same people forget (or they can't see) what they "do" for the remain 23 hours a day.
Just for better explain: Someone say after IC session: "Now I can go home and eat everything I like without problem" or I see them take the lift to go upstairs (1 or 2 floors) when they exit the gym.
These people need time (not numbers !!!) in order to change and aquire knowledges about nutrition and about him/her self. This is a long (never ending) process.

Moreover, Do not forget that the main part of nutrition energy assumed are spend for Basal Metabolic Rate (around 60%) & Termogenic process, ie digestion (around 10%), and finally Exercise&Recovery (15% to 30%). :cool:The last one is is the "region" where Exercise Activity can do the (big) difference.

Ciao Matteo :)

Vivienne
09-23-2011, 06:04 AM
1. Burning calories is one thing... losing weight is another. Unless you can create a stress level that is considered "not the norm", your body will simply adjust to it, and you can burn those calories every day and not lose 1 net pound. I'm sure everyone has their share of students who have made the "I come every day and work my butt off and I'm not losing any weight - and I'm on a good diet, blah, blah, blah).



Ain't that the truth. I believe I've mentioned before (and will again) that I've had the experience of a couple of members actually getting fatter during the time they came to class.

Back on LI the Summer before I moved to MA, a couple of high school grads started coming to the gym. They were going away to college in the Fall and had a bit of extra poundage to lose. Perfectly doable over the 3+ months they had.......plus the opportunity to lay down a good fitness/dietary foundation for when they were out in the World. Lovely girls and it was a pleasure for all of us to share their excitement about college. Sadly, though, being teenagers they were still young enough to know it all.

They just couldn't get the idea of getting fit.....and then getting fitter WRT "Calorie burn" (to quote Len Kravitz) They'd beat themselves up every class like you see on some of the youtube videos....the result being that regardless of energy expenditure, which was likely never as great as they believed, they were working so far above their fitness level that a) they made greater use of glycogen stores for energy source (with the consequence that they were starving hungry for the remainder of the day.....or compensated by snacking) and b) were also wiped out......they mentioned quite proudly that they worked so hard that they had to sleep during the afternoon. Quite possible for these two girls, their total daily energy expenditure went down from compensatory behaviour while their energy intake increased.

Per matteo.....compensatory behaviour can ruin a perfectly good weight management strategy.

Vivienne

Vivienne
09-23-2011, 06:17 AM
2. Even if we do take power to weight ratio into account, and two people are generating the same watts/lb in a given class - their fitness level, their efficiency and their God given VO2 capacity will translate that effort into a given level of metabolic burn and heart rate or heart zone. For example, Tom Scotto and I climbed at the same rate of speed up the same mountains in Spain, side by side - each generating the same watts/lb (hence, his raw wattage was more since he is taller & heavier), yet I can tell you that on average he was 1 to 2 heart zones (not beats - he's disgusting you know) below mine. So, you have him generating MORE raw watts than I am, but I can guarantee you that I was burning more calories. If you hooked us up to a New Leaf cart during the time, you would see the difference in calories burned per minute.


Gene, I think what you'd see would be the reverse of what you're expecting.

Considering Tom's build alongside yours, if the two of you were sitting on the couch just reading, Tom would be using more calories. Even if everything else about your respective genetic make-up/physical potentials etc. put both you in the "outlyer" category, the minor variations wouldn't make much difference as compared to the difference in your relative muscle masses.

If the two of you were equally matched for speed going up them hills, I can't imagine that VO2Max/HR zone etc. or any other measurable parameters could compensate for the energy demands needed to haul all those extra muscles up the same hill at the same speed.

For anyone who doesn't know Tom Scotto, he could serve as the poster boy for Fast Twitch Man.....I think the BMR of just one of his legs is greater than my TDEE.

However, if the difference in HR zones was actually representative of the phenom I'm talking about (a relative "high end" effort causing greater glycogen depletion) then you'd be the one raiding the refridgerator afterwards, whereas Tom might make do with canapes (or would it be tapas) That's *if*, of course.

Vivienne

Vivienne
09-23-2011, 08:38 AM
130rpm is what very skilled cyclists (as in, elite) use with bikes with freewheels (not flywheels) to train their neuromuscular abilities.

Or what riders like me do if they want to practise how to fall over gracefully when their chains come off and they can't unclip quick enough.

I'm getting pretty slick

Vivienne

Todd S
09-23-2011, 10:12 AM
Gene, I think what you'd see would be the reverse of what you're expecting.


Agreed. Unless one of you is a gross outlier in terms of metabolic efficiency - energy is energy and you can't get something for nothing.

liveon2wheels
09-25-2011, 07:53 PM
Agreed. Unless one of you is a gross outlier in terms of metabolic efficiency - energy is energy and you can't get something for nothing. OK guys, I was trying to not fuss over a simple mistake, but with both of you trying to correct the concept, I can't let it go. The watts required to climb a given grade of hill at a set speed (recall that we maintained the same speed on the same hill) doesn't have anything to do with metabolic efficiency, and no the wattage numbers would NOT be the reverse of what I expected. The University of Wisconsin validated the equations used in my Speed and Power for Climbing chart (and this validation was presented this summer to the American College of Sports Medicine). This chart is available on our website, and an 8X10 version is included in my eBook. On that chart, you can do many simple examples.

To wit - if we were climbing a 7% grade at 13 mph, it would require 2 watts per pound of flesh and metal you are hauling up the hill. Given that Tom weighs about 25 lbs more than I do, for him to keep pace, he would be required to generate at least 2 X 25 more watts - in this example 50 more watts. SO... it's no big deal, it's just physics. You can pick up a copy of the abstract here: http://db.tt/2j3ZwtSd

Todd S
09-25-2011, 08:53 PM
OK guys, I was trying to not fuss over a simple mistake, but with both of you trying to correct the concept, I can't let it go. The watts required to climb a given grade of hill at a set speed (recall that we maintained the same speed on the same hill) doesn't have anything to do with metabolic efficiency, and no the wattage numbers would NOT be the reverse of what I expected. The University of Wisconsin validated the equations used in my Speed and Power for Climbing chart (and this validation was presented this summer to the American College of Sports Medicine). This chart is available on our website, and an 8X10 version is included in my eBook. On that chart, you can do many simple examples.

To wit - if we were climbing a 7% grade at 13 mph, it would require 2 watts per pound of flesh and metal you are hauling up the hill. Given that Tom weighs about 25 lbs more than I do, for him to keep pace, he would be required to generate at least 2 X 25 more watts - in this example 50 more watts. SO... it's no big deal, it's just physics. You can pick up a copy of the abstract here: http://db.tt/2j3ZwtSd

Agreed. However, what we were pointing out is that he would also be consuming a correspondingly greater amount of oxygen (in absolute terms) and burning a corresponding greater number of Calories over that time period than you. Just because he looks like he's not working hard or has a lower HR than you does not mean he's not burning more calories than you in your example.

We took issue with the following:

For example, Tom Scotto and I climbed at the same rate of speed up the same mountains in Spain, side by side - each generating the same watts/lb (hence, his raw wattage was more since he is taller & heavier), yet I can tell you that on average he was 1 to 2 heart zones (not beats - he's disgusting you know) below mine. So, you have him generating MORE raw watts than I am, but I can guarantee you that I was burning more calories. If you hooked us up to a New Leaf cart during the time, you would see the difference in calories burned per minute.

What's my point? It's simple. You're body's response to that power generation is what ultimately determines your rate of burn and thus your total calories expended.

Vivienne
09-26-2011, 06:33 AM
There's no real way to know for sure without objective testing, of course, but for two athletes matched for speed with one generating more power than the other, it'd defy the laws of physics for the lighter rider to be burning more calories (energy) just because of a higher heart rate.

It'd also defeat the purpose of using an HRM to track fitness gains......it'd mean a deconditioned individual on a treadmill at about 4 mph with a heart rate approached 160 bpm would be burning more calories than that same individual on the same treadmill a few months later, back to race shape and scampering along nice and easy at close to 7 mph. I use this example because I first started using an HRM over 10 years ago, before I even knew what a Spinning class was. I'd had about 3 years of virtual crippledom from plantar fasciitis and at the first sign of it easing up, the daughter bought me a month's gym membership, a Runner's World training log and a basic Polar HRM for Christmas.

I used it the way I still recommend for most new users as a way to monitor fitness gains.....after a decent warm up I eased into a treadmill speed that felt like something I could sustain for 30-40 minutes without pushing myself too much and checked my heart rate (discovered the phenom of cardiac drift within about 3 or 4 uses). 140-145bpm represented what I'd call a decent clip (for maybe 20 minuts or so, if I couldn't snag a treadmill underneath a fan) This was 3.8 mph on the treadmill when I first started my haul back to fitness.......and if I pushed the envelope to too much over 4 mph, I'd be sucking wind at around 160 or so. There's no way that the same relative intensity ..... a measured by heart rate.....on my runs today would be burning the same number of calories as those first stumbling efforts back then......unless the principles of homeopathy (less is more) are a reality.

Vivienne

liveon2wheels
09-26-2011, 11:04 AM
Agreed. However, what we were pointing out is that he would also be consuming a correspondingly greater amount of oxygen (in absolute terms) and burning a corresponding greater number of Calories over that time period than you. Just because he looks like he's not working hard or has a lower HR than you does not mean he's not burning more calories than you in your example: I'm wondering Todd, if you or Vivienne ever took a New Leaf test, and if so, if you've ever had an opportunity to compare caloric burn rates between individuals, or simply between heart zones. I suspect not, since that will put an end to all the anecdotal stuff and help us stick to the science. Unless of course the Med Graphics has produced a machine that is intentionally lying to the public when their reports post the burn rates with their metabolic graphs.

For an example, Tom and I were tested in the same month on a New Leaf cart, using the same protocol, on the same equipment, a few months prior to our departure. His burn rates in the 5 heart zones (calories per minute) were: 3.7, 6.6, 8.8, 13.4, and 16.6 My burn rates were 2.6, 8.5, 10.5, 13.2, 16.6

The first thing that jumps out is that the caloric expenditure when you are in the higher heart zones is substantially higher. This is one of the reasons a deconditioned individual can not burn a lot of calories, they FEEL like they are dying when they are only in zone 3 - anecdotally, my daughter when she was 18 was tested in a completely deconditioned state, and she could not get her heart rate above 140 - after training a few months later, she was easily clocking 180. The other thing to note is that our burn rates are simply different - I could pull numerous individuals whose burn rates are WIDELY different than these. Tom and mine are actually a lot closer than many I see.

Now, for the coup de gras - As I stated, he was typically 1 to 2 heart zones below me when we were in the thick of it. So let's just say 1 heart zone, and we are on a 10 minute climb. I'm in zone 4 and he is in zone 3 - for the 10 minutes I burn 132 calories, and he burns 88 calories. So, there you have it - I burned more calories while producing LESS watts.

It's nothing personal, it's just math. :)

Todd S
09-26-2011, 01:31 PM
Three comments:

1) You're implying variation in metabolic efficiencies of what? 33% In reality, the literature shows we all fall within a very narrow range of around 20 to 25 percent.

2) All metabolic carts typically used in health club settings (including New Leaf) are notoriously inaccurate. If the cart isn't calibrated against standardized gases you probably shouldn't trust it. Ask a reputable physiologist at your local university if you don't believe me. There's a reason the New Leaf units are affordable and there's a reason you won't find them in a physiology lab.

2) The comments section on the attached gives a sample of some of the shortcomings of indirect calorimetry.

http://www.sciencedirect.com/science/article/pii/0026049588901102

(open the .pdf)

Vivienne
09-26-2011, 02:15 PM
2) All metabolic carts typically used in health club settings (including New Leaf) are notoriously inaccurate. If the cart isn't calibrated against standardized gases you probably shouldn't trust it. Ask a reputable physiologist at your local university if you don't believe me. There's a reason the New Leaf units are affordable and there's a reason you won't find them in a physiology lab.


Even if this weren't the case, there's a fundamental error in assigning a calorie burn to a heart rate number.

The calorie burn for the training zones that these metabolic carts spit out are based on oxygen utilisation at given intensities/heart rate ranges under the conditions of the test. It's faulty reasoning to infer that this calorie burn/O2 utilisation is always going to be the same at any given heart rate since heart rate response to exercise is influenced by any one of a number of confounders in addition to absolute work done. I

This is one of the frustrations I have with the heart rate monitors that include a calorie burn feature. I happen to have had 2 VO2Max tests done (Korr's CardioCoach both times) and have a vague idea of my calorie burn for my "zones". When I say a vague idea, it's because calorie burn is a second order phenomenon for me as I'm not personally interested in exercise/training for weight management. Regardless, since I've got a pretty good clue about the anomolies that can occur when assuming that heart rate is an automatic proxy for "work done", I could manage to give myself all sorts of outrageously incorrect calorie readings for the same effort just by doing some of the stunts class members do when they fall into the trap of thinking "bigger is better" WRT heart rate.

It's the kjoules, not the heart rate.

Vivienne

Todd S
09-26-2011, 02:45 PM
Even if this weren't the case, there's a fundamental error in assigning a calorie burn to a heart rate number.

The calorie burn for the training zones that these metabolic carts spit out are based on oxygen utilisation at given intensities/heart rate ranges under the conditions of the test. It's faulty reasoning to infer that this calorie burn/O2 utilisation is always going to be the same at any given heart rate since heart rate response to exercise is influenced by any one of a number of confounders in addition to absolute work done. I

This is one of the frustrations I have with the heart rate monitors that include a calorie burn feature. I happen to have had 2 VO2Max tests done (Korr's CardioCoach both times) and have a vague idea of my calorie burn for my "zones". When I say a vague idea, it's because calorie burn is a second order phenomenon for me as I'm not personally interested in exercise/training for weight management. Regardless, since I've got a pretty good clue about the anomolies that can occur when assuming that heart rate is an automatic proxy for "work done", I could manage to give myself all sorts of outrageously incorrect calorie readings for the same effort just by doing some of the stunts class members do when they fall into the trap of thinking "bigger is better" WRT heart rate.

It's the kjoules, not the heart rate.

Vivienne

+1 Well said.

bbkies
10-28-2011, 08:40 PM
Anyone want to try to give a simplied summary to this? Heart rate response to exercise changes on any given day due to a number of factors, rest & recovery etc. Calorie burn/O2 utilisation is not constant for a given HR. How does a person's metabolic efficiency affect the calorie burn?

Todd S
10-29-2011, 12:13 AM
Anyone want to try to give a simplied summary to this? Heart rate response to exercise changes on any given day due to a number of factors, rest & recovery etc. Calorie burn/O2 utilisation is not constant for a given HR. How does a person's metabolic efficiency affect the calorie burn?

HR varies from day to day because it is one of many responses to exercise. It varies primarily because plasma volume varies from day to day and that in turn affects stroke volume. Metabolic efficiency is by definition the relationship between the amount of work one can do vs the number of Calories they have to burn to do that work. Metabolic efficiency is primarily determined by biochemical factors, not biomechanical factors (in other words, there's no magical way to pedal that will improve it). Therefore, it's not that different from individual to individual and the only way you can improve it is to make your muscle fibers more oxidative in nature - make the type IIa fibers more like the type I fibers. That happens when you raise your lactate threshold (the pedaling power you can sustain for long periods of time).

That is a whole physiology text book summarized in a paragraph.

Vivienne
10-29-2011, 05:02 AM
Anyone want to try to give a simplied summary to this?

That'd be nice!

Vivienne

Vivienne
10-29-2011, 06:02 AM
HR varies from day to day because it is one of many responses to exercise. It varies primarily because plasma volume varies from day to day and that in turn affects stroke volume. Metabolic efficiency is by definition the relationship between the amount of work one can do vs the number of Calories they have to burn to do that work. Metabolic efficiency is primarily determined by biochemical factors, not biomechanical factors (in other words, there's no magical way to pedal that will improve it). Therefore, it's not that different from individual to individual and the only way you can improve it is to make your muscle fibers more oxidative in nature - make the type IIa fibers more like the type I fibers. That happens when you raise your lactate threshold (the pedaling power you can sustain for long periods of time).

That is a whole physiology text book summarized in a paragraph.

That'd be nice!

For bbkies.....

Although it's true that HR varies from day to day.....and also time of day....plasma volume plays a fairly minor role in these fluctuations. There's a constant fluid exchange between the vascular bed and the interstitial spaces, even during sleep, but the volume change in absolute terms (absent pathology) is barely enough to make a tremendous difference to heart rate.

The primary control is neuro-endocrine.....a combo of autonomic nervous sytem and circulating catecholeamines/thyroid hormones etc. Absent this control, the SA node (the heart's intrinsic pacemaker) is capable of generating an impulse up to about 300 times a minute. This wouldn't be a tremendously efficient way to operate....you'd run out of your heart beats too soon......so Nature has gifted us with an exquisitely sensitive and sophisticated system to save them beats for later. Long story way too short, the autonomic nervous system has two "parts".....the symapthetic system which prepares you for a flight or fight and, among other things, raises your heart rate and the parasympathetic system which lowers the rate and force of contraction...... among other things. Endurance training, along with producing a significant increase in blood volume also increases parasympathetic drive. So does meditation, minus the fluctuations in blood volume.

Most folk who use HR monitors a lot will probably have noticed that you can get a pretty darn good workout (per the "numbers") just from, say, taking a drive in an unexpected snowstorm due to an increase in sympathetic firing and an increase in circulating adrenaline etc. ( fancy I used up more heart beats on the white knuckle drive I had back from my CycleOps training in Vermont than I did trying to compete with 360 Watt Phil sitting next to me, thanks to this phenom) OTOH, I'd compensated for that a year or two earlier when I was waiting for my colonoscopy, hooked up to all the gizmos and entertaining onlookers by "thinking" my heart rate down to about 50 bpm.

Heart rate response can vary a fair bit depending on time of day also. It's generally pretty well recognised that HR response can be a bit more sluggish in the morning than later in the day......even with that am jolt of Java. One of the features of circulating thyroid and thyroid-stimulating hormones is that they sensitize the heart to circulating adrenaline and noradrenaline. Levels are generally a bit lower in the morning, hence a slightly blunted response to "exercise". Back when I was in dental school, we were advised to try to schedule uber-nervous patients very early in the day to capitalise on this circadian rhythm so that the vaso-constrictor in the local anaesthetic didn't add to the cardiac burden of already high levels of adrenaline.

Not much to do with metabolic efficiency, for sure......much like calorie burn.......but an explanation as to how easy it is to influence HR without any exercise and calorie expenditure at all

A very short and sketchy precis of about 2 pages from a cardiovascular physiology textbook......I haven't even started on the pharmacology

Vivienne

Todd S
10-29-2011, 07:31 PM
Your explanation provides a plausable explanation for why HR would vary, but for performance capabilities (and therefore cardiac output) to remain relatively constant while HR can vary substantially from day to day, I would think you would need to find a mechanism that would explain why stroke volume would vary in pretty much inverse proportion to HR variation. Make sense?

How does an increase in parasympathetic drive increase stroke volume? I can take a beta blocker to lower my HR in the same way, but I will also have a corresponding decrease in cardiac output. An increase in parasympathetic drive will do nothing to increase stroke volume.

Vivienne
10-30-2011, 04:54 AM
Your explanation provides a plausable explanation for why HR would vary, but for performance capabilities (and therefore cardiac output) to remain relatively constant while HR can vary substantially from day to day, I would think you would need to find a mechanism that would explain why stroke volume would vary in pretty much inverse proportion to HR variation. Make sense?

How does an increase in parasympathetic drive increase stroke volume? I can take a beta blocker to lower my HR in the same way, but I will also have a corresponding decrease in cardiac output. An increase in parasympathetic drive will do nothing to increase stroke volume.


Well, the caveat here is....plausible or no....... this isn't actually my explanation. More a mish-mash of what, over the years, Drs Samson-Wright, Guyton & Hall, McArdle & Katch, Costill & Wilmore, Ward & Linden (not Big Names but authors of one of a nifty new series I've discovered to prep for my battle with The People's Democratic Republic of Massachusetts and their professional licensing division!) all the nameless lecturers whose talks I often dozed through have reckoned......not to mention Dr Baby, the cardiology resident. A long winded way of saying it's not my dog barking here.

First off......cardiac output doesn't remain constant for performance purposes.....it increases with exercise demand. That's the assumption made using HR to monitor exercise.....heart rate increases with increase in exercise demand. A proportionatly greater parasympathetic drive doesn't place an arbitrary limit on HR rise per beta blockers (where a sabre-toothed tiger could leap out at you and not provoke more than a few extra beats depending on when you took your meds) it modifies the HR response (cardiac glycosides do the opposite). Manifestly not in a way that limits performance because it's a physiological process, not a pharmacologic intervention.

Remember, I (as the messenger) stated that the neuro-endocrine control was a combination of autonomic nervous system and hormonal control.....not one or the other. The greater influence of the parasympathetic nervous system doesn't prevent the "flight or fight" response by overiding it......it augements it to make it more efficient. For instance, one feature of endurance conditioning is a drop in heart rate at sub max levels. With a the greater blood volume and consequent hypervolemic pre-loading, more blood returning to the heart potentially allows for greater stroke volume......if there's sufficient time between contractions to allow for maximum filling. A proportionately greater vagal input just increases the efficiency over and above a lesser input and allows for a bit more stretch in the cardiac fibers (Drs Frank and Starling have a say about this) You don't get the same increase in stroke volume accompanying the increase in blood volume with congestive heart failure, for instance so it'd be a mistake to assume it's just a feature of increased blood volume. Without input from the parasympathetic system (and remember pretty much every organ in the body is influenced, not just the heart) I suspect that there might well be a tendancy for stoke volume to vary inversely the way it would with a simple mechanical pump set-up.

Second caveat......even if this synopsis included everything know to Man about cardiovascular phsyiology as of right now (as if) it'd be out of date within a very short time as a result of the increase in knowledge that comes with the current pace of progress. My brand new textbooks are going to look like fossils pretty soon.

Apologies for the long-winded response. Where physiology is concerned, there aren't enough hours in the day to construct a short one.

Vivienne

Todd S
10-30-2011, 01:05 PM
With a the greater blood volume and consequent hypervolemic pre-loading, more blood returning to the heart potentially allows for greater stroke volume......if there's sufficient time between contractions to allow for maximum filling. A proportionately greater vagal input just increases the efficiency over and above a lesser input and allows for a bit more stretch in the cardiac fibers (Drs Frank and Starling have a say about this) You don't get the same increase in stroke volume accompanying the increase in blood volume with congestive heart failure, for instance so it'd be a mistake to assume it's just a feature of increased blood volume. Without input from the parasympathetic system (and remember pretty much every organ in the body is influenced, not just the heart) I suspect that there might well be a tendancy for stoke volume to vary inversely the way it would with a simple mechanical pump set-up.


You're making my argument for me....

http://www.ncbi.nlm.nih.gov/pubmed/2451658

http://www.ncbi.nlm.nih.gov/pubmed/1692570

http://www.ncbi.nlm.nih.gov/pubmed/3944049

Haven't we been through this before?

Vivienne
10-30-2011, 02:44 PM
You're making my argument for me....

http://www.ncbi.nlm.nih.gov/pubmed/2451658

http://www.ncbi.nlm.nih.gov/pubmed/1692570

http://www.ncbi.nlm.nih.gov/pubmed/3944049

Haven't we been through this before?

You mean the word according to Andy.....well, we've gone the link dumping route, if that's what you mean (multiple near-identical studies from one research group over 20 years ago doesn't make a "concensus")

Thing is, when looking at a topic from just one angle....say a PubMed trawl and glomming onto something that resonates (either from author's name recognition, multiple papers that all seem to concur.....even if they are by the same author, from the same lab)....it's very easy to get a distorted impression of the *whole* A bit like the parable of the blind men and the elephant http://en.wikipedia.org/wiki/Blind_men_and_an_elephant a sort of proxy for knowing what you know and being confident about it when you don't know what you don't know.

It's something of an inevitable difference between self directed study in a given area and a compoulsory didactic core curriculum. Not that one's necessarily "better" than the other.....I tend to retain stuff that I've hunted down from choice or general interest......but there's something to be said for being made to study what "someone else" has determined to be important when it comes to seeing the big picture as opposed to a handful of random puzzle pieces. It must be the same for most every field when specific knowledge is involved....designing cathedrals, composing violin concertos etc. etc......you get "specialists" (in my case usually PhDs in various of the biomedical sciences) lecturing on their very specific, very narrow and very limited fields.....complete with all the insecurities and ego that's tied up with all that..... and "generalists" putting the whole lot together to make a working model. You're ignoring all the other elephant parts by selecting a few very specific supporting abstracts.....which are always there on PubMed, whichever topic you want to find support for.

So I'll see your Andy links and raise you

http://www.amazon.com/Wrights-Physiology-Thirteenth-Medicine-Publications/dp/0192632108

http://www.amazon.com/Guyton-Hall-Textbook-Medical-Physiology/dp/1416045740/ref=sr_1_2?ie=UTF8&qid=1320002967&sr=8-2

http://www.amazon.com/Exercise-Physiology-Nutrition-Performance-Lippincott/dp/0781797810/ref=ntt_at_ep_dpt_1

with my latest

http://www.amazon.com/dp/1405177233/?tag=googhydr-20&hvadid=7343813139&ref=pd_sl_2ft4bex1ir_e

So no, I wasn't actually "making your argument"....or making any argument come to that.....but observing that volume pre-load isn't the major determinant of heart rate variation and/or cardiac output in the short term (per Dr's Ward and Linden in their chapter on control of cardiac output and contractility of heart muscle......I've got it open right here in front of me)

It's not my fault.....I'm only the messenger not the designer.

Vivienne

bbkies
11-02-2011, 05:25 PM
lol link dropping

Todd S
11-02-2011, 05:44 PM
Beats title/cert dropping. :)

Vivienne
11-03-2011, 06:36 AM
lol link dropping

No, link dumping. It's not something I do that frequently because it just takes too much time to find something that explains what it is that I want to say.

Here's an exception...

http://www.biosbcc.net/doohan/sample/htm/COandMAPhtm.htm

I was looking around for something to give a brief overview of cardiovascular function that'd be pertenant to the question of why heart rate isn't a totally reproducible proxy for work done. My new physiology crammer is great because it has a lot of diagrams but you have to buy it first....

The above online course is very nice and succinct.....in fact, all the topics in that "lesson 4" are pretty useful for anyone who's interested.

Time was, you could find courses like this (stuff that's supposed to accompany a didactic college lecture series) all the time but places have started to realise that they shouldn't be giving stuff away for free if enrolled students have to pay for it. Guess these dudes are a bit slow.

Vivienne

Todd S
11-03-2011, 10:31 AM
No, link dumping. It's not something I do that frequently because it just takes too much time to find something that explains what it is that I want to say.

Here's an exception...

http://www.biosbcc.net/doohan/sample/htm/COandMAPhtm.htm

I was looking around for something to give a brief overview of cardiovascular function that'd be pertenant to the question of why heart rate isn't a totally reproducible proxy for work done. My new physiology crammer is great because it has a lot of diagrams but you have to buy it first....

The above online course is very nice and succinct.....in fact, all the topics in that "lesson 4" are pretty useful for anyone who's interested.

Time was, you could find courses like this (stuff that's supposed to accompany a didactic college lecture series) all the time but places have started to realise that they shouldn't be giving stuff away for free if enrolled students have to pay for it. Guess these dudes are a bit slow.

Vivienne

From your link:

"If the blood volume is increased, then venous return of blood to the heart will increase. An increase in venous return will, by Starling's Law, cause stroke volume to increase."

I agree with your point that there are many factors that affect HR, the point I was trying to make was in reference to what those who have trained with a power meter commonly observe - HR at a given power level can vary greatly from day to day while at the same time performance capabilities vary to a much lesser extent. HR varies for all of the reasons you outlined. What matters is a mechanism (or mechanisms) that allow cardiac output to remain relatively constant at significantly different exercise HRs.

Make sense?

Vivienne
11-03-2011, 12:06 PM
From your link:

"If the blood volume is increased, then venous return of blood to the heart will increase. An increase in venous return will, by Starling's Law, cause stroke volume to increase."

I agree with your point that there are many factors that affect HR, the point I was trying to make was in reference to what those who have trained with a power meter commonly observe - HR at a given power level can vary greatly from day to day while at the same time performance capabilities vary to a much lesser extent. HR varies for all of the reasons you outlined. What matters is a mechanism (or mechanisms) that allow cardiac output to remain relatively constant at significantly different exercise HRs.

Make sense?

Well, I still doubt that an increase in blood volume plays that significant a role since, from your links, you need to give an infusion of over 1/2 liter of fluid to untrained exercisers to produce an increase in stroke volume or, per the link you've just quoted from, folk with kidneys that are on the fritz and retaining water and/or sodium. I think it's a mistake to extrapolate from experimentally induced or pathological conditions to what you're describing. On a day to day basis, the circulatory system and blood volume functions as pretty much a closed sytem.

Vivienne

yumipon
11-04-2011, 06:24 PM
We know that the total calorie generated (not burn really) in the display is reference to what you have just done. While it is not really significant as far as burned calories are concerned, you still can compare from one class to the other. I have this guy in my class who always check the total calorie shown. I taught the same profile with same music with same intensity, his display showed under 800 calorie on one, and over 800 calorie on the other class. So, it is obvious that you can not get caught up with calorie burned or generated shown in that display unit. He seemed happier when it showed over 800 for the second time, but I still emphasize on learning different heart rate training zones. But, some people like to go "all out" effort each and every single ride. I hope he knows that he cannot go home and take 800 calorie of extra food thinking he can afford it because his body may swallow the entire calorie and want to keep it in. Are we talking about Keiser M3 still? I just jumped in.

Vivienne
11-05-2011, 06:07 AM
We know that the total calorie generated (not burn really) in the display is reference to what you have just done. While it is not really significant as far as burned calories are concerned, you still can compare from one class to the other. I have this guy in my class who always check the total calorie shown. I taught the same profile with same music with same intensity, his display showed under 800 calorie on one, and over 800 calorie on the other class. So, it is obvious that you can not get caught up with calorie burned or generated shown in that display unit. He seemed happier when it showed over 800 for the second time, but I still emphasize on learning different heart rate training zones. But, some people like to go "all out" effort each and every single ride. I hope he knows that he cannot go home and take 800 calorie of extra food thinking he can afford it because his body may swallow the entire calorie and want to keep it in. Are we talking about Keiser M3 still? I just jumped in.

Yes you can!! That's the message I had a hard time getting across when I taught on the Keisers........to treat it as a proxy for accumulated work done rather than "x" number of chocolate chip cookies you now have to play with.

Sort of morphed into a discussion of HR......but it's just as relevant as far as I'm concerned. At least on the Keisers, if you want to increase your calorie burn read-out, you can only do it by increasing power......i.e. working harder.

The calorie burn readout on an HRM isn't such a consistent tool. It depends ultimately only on heart rate and it's possible to ramp that heart rate up just by riding inefficiently.....so you get a higher apparent calorie burn for less work, or appear to burn fewer calories the fitter you get (but at least the % coming from fat is "higher" ;) )

That's the problem with "numbers" in a way and I fancy we're all susceptible to it to some degree. Bigger is better......unless it's interest rate on your credit card statement, blood pressure readout or total cholesterol. etc. etc.......even if the number itself isn't tremendously relevant in the grand scheme of things.


Vivienne

hally
11-05-2011, 11:07 AM
I attended another instructors class this week he is fairly new and he attends my classes on a regular basis. He taught a good solid class just the right amount of cues, good cadence and no crazy moves. Half way thru class he told everyone to look at their calories on our KM3 bikes and try to double the number by the end of class. He asked everyone at the end of class how they did regarding calories burned. I imagine he does this for every class which would give the students a baseline. I never thought of it as my class are very structured and more focused on the goal of the profile and not really about calories burned. I did note my calories as 710 for a 45 minute class which means nothing to me as I NEVER look at calories on my power meter. My students often ask me how many calories I "burn" in class and I tell them to focus on the watt number and heart rate and not the kcal number and you will become fitter and will shed the weight. All this calorie counting is the most challenging part of teaching for since God give me the gift of a great metabolism, I am one of those tall, slender people who eat non stop :).

I have so some lovely women with curve figures who want to look like Adriana Lima and stress to them it more important to be fit and work with body type we have.

yumipon
11-08-2011, 06:09 PM
It's so true. After giving a class designed for specific training, their concern is how high their gears were and how much calories they had generated. Like Hally said, my students also ask me how much calories I had generated. But, I don't look at the calories on the display either. People are still excited about the highest gear they use, and how much calories shown in the display. They want the music to pound from the beginning to the end running up and down with the heaviest gear they can handle shifting body weight side to side or as much as they can shift. Believe or not, those classes are very popular and lined up for 5:45 a.m. class.

So, what can I say.... if that pleases them.

yumipon
12-13-2011, 05:47 PM
So, is it good idea to mark calories burned? If students are trying hard to burn 600 calories, do we say "Go for it", or "Don't get caught up with calories"? I'm not quite sure if it is a good thing to pay attention to, or just another number students can follow. It is obviously better than focusing on "higher the number of gear is the better" kind of effort everybody still goes for. If someone is eating the same type of food, he or she got 600 calories instead of 500 they have been seeing on the display, should they be happy if burning calories are their goal?

Vivienne
12-14-2011, 01:46 AM
So, is it good idea to mark calories burned? If students are trying hard to burn 600 calories, do we say "Go for it", or "Don't get caught up with calories"? I'm not quite sure if it is a good thing to pay attention to, or just another number students can follow. It is obviously better than focusing on "higher the number of gear is the better" kind of effort everybody still goes for. If someone is eating the same type of food, he or she got 600 calories instead of 500 they have been seeing on the display, should they be happy if burning calories are their goal?

Not necessarily.

It's a good idea in theory......burn an extra 100 Cals to automatically create a 100 Cal larger daily energy deficit and lose even more weight, right? Well, if that's what actually happens, then it'll "work". However, what invariably seems to happen is that the extra work needed to chase the bigger number in class pushes the envelope on what they can sustain and then go about their business as normal the rest of the day. They're often a bit more tired......so cut down on activity (either consciously or not) and a bit hungrier and end up eating a bit more (or being miserable) with the net result that the extra Calories that they worked so hard to burn have disappeared in compensatory behaviour. A similar thing happens when folk try to diet with too big a calorie deficit......they just move less. I noticed it over the Summer when I was subbing a lot of extra classes and was out of the habit of budgeting my energy as I'd done in the past. I was positively sleepy some days.

No one will believe you if you explain this, mind...... even if the strategy is obviously not working for them.....because they're different. They're commited.......not like all those subjects who've been observed closely by either ex. physiologists or obesity researchers in the numerous studies that've tracked this phenomenon.

This is why folk are so surprised when they train properly for any big endurance event and don't lose weight they way they expected.

Conversely, I have friends who've had quite a bit of success with using the SPINNING weight loss programme and "endurance" rides and the concept of the "fat burning zone". As faulty as the idea is from a physiological standpoint, the exercise intensity was just enough for the folk taking part to create a consistently sustainable energy deficit (quite possibly nowhere near a 500 Cal workout) for the long haul.


Vivienne

Vivienne
12-14-2011, 05:25 AM
BTW, yumi, if you scroll back to the beginning of the thread, this is pretty much the reason I asked the initial question.......to get an idea of just how hard folk have to be working in order to generate the calorie burn that's generlly believed for an IDC class. Indirectly asking just how fit do they need to be in order for that output to be effective in their weightloss strategies.

I know I've read discussions before about using the power output of the bike to generate a 500 kcal a day/3500kcal a week deficit and gua-RON-tee a weight loss of one pound as if we were glorified bomb calorimeters or something (that's where the 3500kcal=1 pound of fat comes from, BTW.......the physics not the physiology lab).

To create a 3500kcalor whatever a week deficit by exercise alone requires some serious work. Nothing wrong with that, mind, but you do first have to train yourself into the sort of shape to be able to do it day after day without it affecting you too much for the remaining 15 or so hours you're wake. That's the part the average class member doesn't appreciate and I think sometimes imagines that you're supposed to be able to do it by your second or third class just for a bit of huffing and puffing and high heart rate.....especially on the bike without the power output.

Weight management is as simple as calories in vs. calories out. What makes it interesting is that neither the calories in nor the calories out bits are particularly easy to understand or control and adding "calorie burn" features to all these feedback devices we want to use just makes it even harder, if you ask me.

With the Keisers, you could use the feature as a proxy for accumulated work done......but we know that's not what goes on in the class members' minds, right?


Vivienne

Vivienne
12-14-2011, 05:43 AM
A bit off-topic WRT to calorie burn during class, but a while back and in the context of diet/weight management someone mentioned getting their clients to document sitting time as well as what they eat. Reading that post was an "A-ha!" moment for me (and I thank the particular poster!!!) as I fancy this sedentary, compensatory behaviour can end up increasing in the class members who push a bit too hard for their fitness level (yes, it's the way to get fitter but not necessarily increase the TDEE in the short term)

That got me thinking a bit and I have a strong suspicion that what we consider "reasonably active" by today's standards (i.e. you toddle along to an IDC class 3 times a week......or you pretend you do ;) ) would actually have been considered "sedentary" as little as 2 or 3 decades ago. Not so much from the stuff we decide to do but the little things like getting up to answer the one telephone in the house as opposed to having a cell-phone glued to our person, no internet forums to sit on to correct everyone in cyberspace who's wrong etc. etc

It makes you think.


Vivienne

yumipon
12-15-2011, 06:40 PM
Thank you for the full explanation. My thoughts were going different directions though I was telling my students not to focus so much on total calories. As I was telling them, they are looking at me with "why" look though they were nodding their heads. I knew sooner or later, I had to tell them the exact reason why. As I was reading your comments, I remembered that one of the articles talked about exercising too much can give you negative results. It went on by saying that when you work out way above your fitness level, your body reacts like being on a diet and they would hang on to every calorie in take.

It is also true that when you push yourself too far, you end up not doing much for the rest of the day. Or, I myself noticed that I eat a lots of sweets after certain work out. They all make sense.....

Vivienne
12-16-2011, 05:30 AM
... As I was reading your comments, I remembered that one of the articles talked about exercising too much can give you negative results. It went on by saying that when you work out way above your fitness level, your body reacts like being on a diet and they would hang on to every calorie in take.

It is also true that when you push yourself too far, you end up not doing much for the rest of the day. Or, I myself noticed that I eat a lots of sweets after certain work out. They all make sense.....

Although it's true about the "exercising too hard" thing, I seriously doubt that many of our class members are doing that, in reality......even the ones chasing the calorie burn.

To experience gen-U-ine negative results, I think you'd need to be hammering every workout with a training load of about 12-15 hours week (outliers excepted, of course) What usually happens boils down to stuff that's counterproductive......as in, the person who's doing it is not getting the effect from their effort that they believe they are. To use one of my regular analogies......a slow moving elevator car doesn't get to the 5th floor any quicker if you stab that 10th floor button until you ruin your manicure!! There's a limit to what you can do to get folk to let go of what's counterintuitive to them........even when what they're doing manifestly isn't *working*

To folk who've never experienced teaching on a bike with power/cadence readout etc., it might be a surprise that what yumi and I are discussing aren't somewhat self correcting. WRONG!! If folk are bound and determined to grind away at a cadence of, say 40 rpm, they're not going to listen to any rational explanation of a better way.........likewise the whipping along at 120 rpm.........or ignoring cues for "recovery" in an interval ride. I assume it's because they think they *know* better. Truth be told, I don't have a problem with folk ignoring my *words of wisdom* as long as they're aware that they're choosing a different route from mine.....and that they're satisfied with whatever outcome they manage to achieve and only ever report back with positive results. I don't remember ever getting any feedback to that effect......

It's good to *know* and understand this stuff for yourself, mind, but you'll drive yourself crazy if you think knowledge and education is going to automatically effect behaviour change in others......even if they do voluntarily step into something called a *class*!.


Vivienne

yumipon
12-16-2011, 05:12 PM
In addition to what we have been discussing, about the people who are focused on higher calories in the display, what they have to know is how they had achieved that calorie. If your rides consists of a lots of standing hills and runs, the display will show higher power output and more calorie. If the same person sitting on the saddle mostly and created the same power output and the calories, wouldn't he or she burned more of their own body energy? The reason is because there was no body weight used for leverage.

Viking
12-18-2011, 06:29 PM
Vivienne makes a huge number of great points! i've been in a 45 minute class as a particpate to hear people claiming they have burned 700 calories or more! i look at my HR monitor, i'm not at 700. another piece to the weight loss puzzle, is what are you eating. carbs are fast and easy to grab and eat, we eat way too many - needless calories for many. how many people do you see drinking a smoothie after their workout - if this is lunch or supper - ok, if it is in addition, maybe too many calories.

take a look at bob seebohar's website http://www.fuel4mance.com/