How many caolories the Pro's Burn

[MotoManiac]

I am a personal trainer here in Dallas, TX . I have often defended motocross as both an anaerobic and aerobic exercise. It is often difficult to explain how Motocross is one of the most physical demanding sports (@ the professional level) today to people who have never raced. My question would be after an hour of racing motocross (accumulated heats or just flat out on hour) competitively around how many calories do the pro’s burn through. My buddy at the gym uses pre-core elliptical machines and those machines report that he burns around 850-900 calories for one hour. He insists that motocross is not aerobic at all. My basic argument was that an outdoor/supercross race is in fact an aerobic activity and it would burn significantly more calories than the pre-core machine. I know this question is out in left field, I figured I would try here 1st. Anyone have any scientific data or references I could check out. Thanks for any help!!!! Ryan

 

[Anssi]

It's not that far out there and is in fact very significant in determining how motocrossers should train.

I wore my recording heart rate monitor once for a moto and my HR shot through my anaerobic threshold in the first lap and stayed there. The pros stay a bit lower but your friend must not have a clue if he thinks MX is not an endurance sport. Taking him riding is the only way to prove it to him if he's that thick.

As you as a personal trainer must know, motocross is not the most physically demanding activity if only measuring calories burned (running must be pretty high up the list), but the demands come from the need to have excellent basic fitness to recover even during a moto (jumps, easy sections) and to have bursts of power available when needed (passing, places where you really have to hang on).

 

[zio]

Other than hooking a subject up to a spirometer, maybe something like a Caltrac Accelerometer? I don't there is any way to estimate the calories burned without actually measuring them during the activity with one of the above devices. Caltrac devices aren't that expensive, I think they can be had for about $70 and the manufacturer claims they're within 2-5% accuracy compared to a spirometer.

www.caloriesperhour.com has a calculator they've developed using actual test data on all the activities they list, but there's a footnote to motocross (as well as many other activities). I entered my data (male, age 29, 5'11, 175 lbs) for one hour of motocross, and it spit out only 305 calories. That's laughable. Also, once you take into consideration the type of activity involved (more of a HIIT or wind-sprint) versus a low-intensity "fat-burn" exercise, the lasting metabolic effects of motocross will continue to burn calories for several hours later as the body continues to recover.

 

[Anssi]

Originally posted by zio
Other than hooking a subject up to a spirometer, maybe something like a Caltrac Accelerometer?

Nope. The things work based on the very assumption that all of the movements it detects come from you using your muscles.

 

[Bill Hibbs]

I just got a Polar Heartrate Monitor that measures Calories. I'm sure it's not 100% accurate but probably pretty close. It's based off my heart rate, weight, height, Sex, and age. I don't really do MX very often but we're planning a ride this weekend. I'll wear it and let you know how many calories I burn throughout my ride. I'm sure we can make some uneducated assumptions after that. ;) The ride will be a moderate to fast paced ride with as few as stops as possible. I'll pause it during our typical lunch break. I'm interested as well to see what it comes out to. I'm sure the calories won't be as quite as high as a 100% race pace for 20 minutes. We'll see what happens.

 

[nephron]

Caloric expendature has little bearing on whether the process is aerobic or anaerobic. The latter only refers to the degree to which high energy phosphate bond is generated from the late reversal of glycolysis (Pyruvate oxidation to Lactate in the presence of inefficient quantities of NADH), as relates to the degree of ATP generation from O2/electron transport chain.

If you've got glycolytic muscle, the majority of your exercise, and thus ATP generation, will be done under anaerobic equivalents.

Sounds like you're talking to a guy with a big mouth and no idea. At least he could be somewhat humble. :silly:

There's a good paper out there somewhere I once or twice read, can't remember the exact title: "Fasting: A feast for the physiologist."???

 

[Bill Hibbs]

Well, I did a bike ride and got some calorie information but It doesn't sound correct to me. I rode for 2 hours 20 minutes with an average Heartrate of 146 (this was an easy recovery type ride) and it said I burnt over 1500 calories. That just doesn't sound right to me....

 

[nephron]

Bill, another simple way to think of it is this: Say you're out of shape (like me), and your resting HR is high, and then say you do 8 minutes on a max exercise stress test and your peak HR is 186. Another guy who's been running every day comes in with a HR 52, and peaks at 148 for the same exercise. Let's say they're the same body mass. They've done the same amount of work, but one more efficiently than the other. Yet both exercises were aerobic until the very last minute on the guy that was out of shape. Now you put an art line in, and CO2 sensor--you find out that the both guys had the same VO2MAX, which under aerobic conditions gives you an idea of how much expenditure there is. Same work, same VO2MAX. HR--not an issue, and only reflects the efficiency of the tissue at extracting O2 distally, and the performance of the heart for each stroke. Now put the guy that's in shape on a treadmill for 20 minutes. His VO2 max is higher, he's had more expenditure (caloric)--and the first guy isn't even capable of burning that many calories in one setting. Expenditure is therefore primarily a function of work and not HR, as the flaw with following HR is overestimation of work due to poor efficiency.

Now following METS (metabolic equivalents) on a treadmill for purposes of doing CARDIAC stress testing is different, since we're trying to get a look at cardiac work, not caloric expenditure.

 

[Bill Hibbs]

Just to make sure I'm on the same page here. The conditioned athlete will burn less calories doing the same amount of work (wattage) than an unconditioned athlete? If two people go up the same hill with different average heart rates (all other things the same) are you saying they're buring different amounts of calories or the same?

I need to give Polar a call and see what the deal is with their Calorie Counter. Check this out from their site

"The OwnCal™ feature will track your calories burned more accurately because it calculates consumption right from your body by using your heart rate. The almost all of the other calorie functions you see on watches or equipment are based on formulas. To see this, just step off your treadmill while it is still going and watch the calories continue to accumulate while you stand still."

 

[CRPilot]

Just latching on here. This is good reading material.

I wear a heart rate monitor when raceing sometimes and my BPM is highest during the first lap or two (165ish), then cools down into 155 range once my body (muscle) is up to optimum operating temps.

Also, take note that some heart rae monitors will not function properly when the bike is running. I'm guessing that the electrical impulse that the montitor picks up gets interfearance from the electrical system on the bike. I can watch the monitor with no signal and as soon as the I hit the kill switch the montors picks up the signal again.

 

[nephron]

Not really, Bill. Same work, same VO2 max. HR/the shape of the cardiovascular system, as I understand it (and could be wrong...I'll look it up for you) doesn't independently have an effect on caloric expenditure. It just allows you to work harder and expend more energy.

I can look it up to be sure, but I think those machines use a 'scalable' type equation where time, HR and body mass are all independent variables. HR in that case, is being 'scaled' to the average person---say two people are in exactly the same shape. You put them on treadmills side by side, one has a heart rate that's higher than the other. Why is that? The only explanation could be that his/her workload is greater. He's on the same speed (not measured with a wrist monitor), but at a greater load (eg, higher load setting or ramp degree).

 

[Bill Hibbs]

Here's what polar had to say:

Polar heart rate monitors with the OwnCal feature calculate the energy
expenditure based on the following factors:

weight
gender
heart rate
duration of exercise

The OwnCal feature has a +/- 15% error rate. The more the body weights the
higher the energy expenditure in a constant work. The higher the exercise
intensity, the higher the heart rate, and the faster the calorie accumulation.
However, at high exercise intensities the percentage of fat consumption of the
total energy expenditure is less than at lower intensities.

The intensity of exercise depends also on the amount of active muscle mass.
Cross-country skiing and rowing typically are more intensive than walking or
bicycling due to the upper body muscle mass activity needed. Brisk walk expends
more calories than slow walk when done for equally long time.