Here is Tom Scotto's first post in his official capacity as a Master Instructor here at ICI/PRO -
Indoor cycling instruction keeps progressing and improving and so do the bikes we ride. Today, many of our indoor bikes have more than the ability to add and remove resistance. Bikes are now providing us with cadence, heart rate, power, time and a host of other measurements to guide our rides and training. So I thought it would be good to talk about what these numbers actually mean and get some response from our knowledgeable community about experiences you”™ve had or ways you”™ve incorporated these tools into your classes and teaching.
OK, they are really not “Killer” calories but that is how is sounds much of the time when I hear people talk about it. We are referring to kcal. This is a scientific abbreviation for kilogram calories or kilocalories. It is generally used to indicate a “small calorie” or gram calorie. When written properly, it is presented with a lowercase “c” as in “cal”. However, like many things we try to understand these days, the inconsistency of how it is display and how it is calculated can create more confusion. So, by its original definition, kcal is 1000 “small” calories or simply a Calorie (note the uppercase “C”).
Without nose-diving into a verbose science lesson (which I”™m not qualified to give), kcal or Calories is simply a measurement of energy needed or required. In science terms a kcal represents the approximate "energy" needed to increase the temperature of 1 gram of water by 1 degree Celsius. So on the bike kcal is simply a measurement of how much "energy" we are generating.
So how does the bike know this? Enter the joule.
Since these bikes are also calculating power output (watts — we”™ll talk about that in another post), a joule is the measure of energy from the amount of force (mechanical work) required to move an object. Joules can be converted to calories (1 joule equates to 0.2389 calories or 0.0002388459 kilocalorie) - YIKES!!!!! Let”™s just say that with my math skills, I”™m glad computers can figure this stuff out.
Enough of that Brain Twisting — Is kcal Useful or Accurate?
In a “very” general sense 1 kcal = 1 calorie, but it is better to think of this as the energy that you produced during your ride rather than how many calories your body burned while riding. Here are some factors that affect the true conversion from 1 kcal to 1 Calorie:
(1) Muscle Mass
A person with a higher percentage or body fat will usually burn LESS calories than a person with more muscle mass. Since body fat percentage affects a person”™s metabolism, it will affect how much it will cost them (energy) to do a certain amount of work.
(2) Fitness Level
A person who has a greater fitness level will more likely burn LESS calories than someone who is not as fit for the same amount of work or activity. Hence the benefit of training and adaptation.
(3) Body Weight
A person that has more body weight may require LESS energy to push (move) a certain workload (force) than an smaller, lighter person.
(4) Mechanical Efficiency
A rider with good form, posture and technique will fight the mechanics of the bike LESS and may achieve the same output with LESS effort of energy expended.
Because of all the possible variations and factors, it is best to use kcal as a “personal” benchmark. If you generated 500 kcals during a certain ride or training focus, you can try to replicate this on a future ride or try to exceed it. Use it to measure your progress or gauge how hard you may be working during a given class. Just remember, that different pieces of fitness equipment may not calculate kcal the same. This may be due to the mechanics of the equipment (treadmill vs. bike) or because they may include additional measurements (like body weight) into the calculation. Consider each piece of equipment its own animal and use kcal an estimation of how much energy one workout required compared to another.
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Isn’t it the coolest thing to be able to SEE the work we do??
Some people think that Power/Watts is not necessary (or only for elite athletes) but they’re wrong!
Yesterday I rode long enough to use 545Kcals and ended up sweating off 4pounds of fluid…LOL…NEXT time I’d like to shave off some of that time and hopefully use the SAME Kcals or better AND nudge that average Watts a little higher than yesterday’s ride). The Cadence or RPM gauge is also wonderful – I no longer have to manually count using the 6sec or 15sec secondhand on my watch!! 😀
Power/Watts? – Yes!!!!
What’s really cool about this is riders get an idea of HOW LONG it takes to burn off each serving of A&W Root Beer (at 160kcals per serving) or a Vanilla Skinny Cow treat at 150kcals per cookie…(hmmm…how long does it take me to burn off that root beer and Vanilla Skinny Cow?? My personal favorites! 🙂
The other cool thing about WATTS? (Now I know how Hard to push on the pedals and for how Long in order to use up those very dense, (yummy) 310kcalories. Not bad for such a small gadget sitting on top of my handlebars! Oh BTW, 750 Watts equal 1 Horsepower / HP (I wonder how many Watts Lance can hold for 30minutes?? 😀 ) I’ll bet LOTS; more than I could ever do in a million years…did you know it takes 20million HP to send a rocket into space?) 😮
A great post and can’t wait to read more from you. Loved your sprint podcast, took my teaching and clients to the next level. Great “light bulb” moment!
I have to say that the calorie count is among my least favourite things about the computer. I suspect that weight management is one of our members’ main reasons for coming to class, but in the context of a rational (or nearly rational) training programme, it’s a bit of a second order phenomenon…..in that, yes it happens but if the primary focus is supposed to be on training effect etc sometimes being too concerned with calorie burn can be a bit counter-productive.
My “style” is a bit more about encouraging folk to leave weight issues at the door (they can pick ’em up on the way out if they want) and become Athletes in Training during class. The focus being on getting fitter, stronger, “faster”……and ultimately leaner.
After all, weight management is less about the calories you burn than the stuff you don’t overeat in the first place.
Then again, I’ve never been overweight…..so what do I know 😉
When I first read it, I think “Ok and … that is not really important” than my mind went back to a early past podcast on What do people want … and yes a part of our population would hear Caloties burn but not faster on the road and more effective.
It is how I coach talking to a lot using what they want to hear, each one can find what he/she research to help him/her reach his/her goals.
But calories data can be nonproductive … the higher you work the more you will use them … that is a way to go mostly for HIT classe … so we really have to take care using this data.
Power/Watts give us objective information about the work or ENERGY(KCALS) you are doing.
It is simply useful information as to how it works (beyond the mathematics value of a Joule; since 1 Joule of energy/sec equals 1 Watt).
So knowing this information will 1). prevent someone from over-eating (now that you know how many minutes and at what intensity it takes to utilize that energy taken in); and or 2). just knowing that when you increase the Power/Watts variable you know you are expending more energy (ultimately using more Kcals)
Welcome I have been following you for a while now on ICPro and really excited to learn from you.
I have a spinning studio with 9 bikes and just got star trek spinning monitors for all the Bikes. It has been great, because Now Everybody is feeling exactly what I have been telling them.
I have a Question most of them are wearing HR straps and on the People Who are wearing the HR Straps
There calorie burn is considerably higher than the ones not wearing a strap. Please explain .
Well, there’s one inconvenient problem with reading the power output, seeing, say 500 Cals (or 300…..or 700)for an hour’s work and assuming an automatic 500Cal deficit…….and that’s human physiology.
Even if a person were just laying down on the couch and watching television instead of working out, there’s going to be energy expenditure during that hour…..depending on weight/RMR/gender etc. this could easily be as much as 100Cals. Getting up and walking around adds to that so you already have a substantial margin of error built in if you have absolute faith in the numbers.
Add to that the fact that the power output necessary to burn 500 Cals in an hour on a stationary bike requires a pretty decent level of fitness. To be able to burn 500 Cals an hour and have it be of a moderate enough relative intensity that you haven’t a) created a big hunger-inducing glycogen deficit and b) produced enough fatigue that you have to lay about for the rest of the day …..or at the very least cut down on energy expended through NEAT (and “save” more Calories than you actually burned in the process)……requires an even greater level of fitness.
It’s been my experience that folk who glom on some arbitrary calorie burn, however accurate the calculation, as the main focus of their exercise session rarely reach this level of fitness. They just can’t let go of “the numbers” in order to train effectively. Heck, I’ve even had folk get fatter because they were just looking at the numbers as absolutes without factoring in the physiology and the psychology of weight loss.
I know that studies have shown that even people of the same weight, age, gender, and fitness levels utilize calories at vastly different levels. Obviously, a meter that is calculating calories using watts, and not just heart rate the way many of our bikes currently do is going to be better, but I still wonder if it’s just too big a ballpark estimate to be very useful.
Great to have you here, Tom.
The definition of Power Output is is the actual amount of effort or energy you put out in x amount of time and is measured as a Watt.
P = Force x Velocity
Measuring power is simply a product of how hard you push (F)on the pedals and how fast you are going (V). If you want to increase your work load (P) you simply push harder or pedal faster.
Heart rate monitors are a great tool- heart rate can be influenced by many other factors. Power/Watts is more objective.
Sharon….the simple explanation is that the read out’s wrong. Maybe both are “wrong” to a certain degree but the HR generated numbers are most likely to be off and will be the least consistent and reproducible.
HR monitors measure the cardiovascular response to the exercise you’re doing and aren’t an absolute measure of work done. I’ll give you a personal example that’ll put it in perspective. I started using an HR monitor nearly 10 years ago. I was just coming back after about 3 years of almost complete crippledom from plantar fasciitis and I’d lost a lot of fitness. I kept a training log from my very first time on the treadmill……when I started walking and a speed of about 3.8 mph had me at a heart rate of around 145-150 bpm. Within about 3 months, I was back on form and was running around an 8 minute mile pace…..at around 145-150 bpm. You’ll have to do the math yourself but I can tell you, an 8 minute mile pace is a lot faster than 3.8 mph and you’ll burn a lot more calories at that speed. However, a calorie readout based on my heart rate would’ve read about the same.
Polar even acknowledges that their “calorie” function isn’t a real measurement…..they claim it’s there for motivation. Yeah……real motivating to be working to inaccurate information and getting fatter!!
Great comments everyone (and thanks for the warm welcome)!
Just remember, my overall emphasis, specifically as it relates to kcal, is that we should NOT encourage our riders to consider this directly related to the exact amount of calories they are burning or use it as a weight loss tool. It is just a guideline of the amount of energy “generally” required to do a certain amount of work. All the other physiological and mechanical factors still play a major role making kcal insignificant except for mere casual observation.
that’s what I thought…….
Has anyone compared the Calorie count from the Keiser M3 display with the count from a Polar watch? I wonder if there is some reliable relationship between the two numbers (which I assume won’t be the same).