P&G on a bycicle?

[HyperMileQC]

Since I got aware of P&G, I was always wondering if Pulse and Glide would be a good technique when riding a bike too.

So I begun thinking about how to test it. My bycicle computer records calories even if I am coasting. My theory about it's recording, is it adds or remove calories if I go faster or slower than my average speed.

So I was thinking, I could do a sort of A-B-A-B Test. A will be riding at an average speed of 20 Km/h without P&G, and B will be riding in Pulse and Glide from 10 Km/h to 30 Km/h.

I will use my Commute Bike. It will be the same 3.2 kilometers (EDIT : 2.5 Kilometers) route for the 4 tests (A-B-A-B). Each run will be bi-directional. My tires will be inflated at 100 Psi, and I will try to be positioned the more aerodynamicly possible. In both test situations, I will use DWB and DWL.
The only difference between testing method A and B will be :

A : Computer always recording calories.

B : Computer recording calories only when pulsing.

After testing, I will compilate the data :

Step 1 : Number of calories burned with the average of the 2 A tests divided by 31000 (number of calories in 1 gallon (US) ).

Step 2 : Use the number of miles of the test route divided by the gallons used.

Step 3 : Number of calories burned with the average of the 2 B tests divided by 31000.

Step 4 : Same as Step 2 for the B runs.

Waiting for a good day this week to test this.
And finally I will share my results.

[HyperMileQC]

Good weather in general, sunny, little wind, 11-13°C.

I did an B-A-B-A test with the same 2.5 kilometers route. Two run per tests, bi-directionaly.

A = Steady Speed (AVG 19.7 Km/h)

B = Pulse & Glide (10 Km/h to 30 Km/h)

B1 Run #1 : AVG Speed : 20.3 Km/h / MAX Speed : 31.7 Km/h / 12.7 Cal
B1 Run #2 : AVG Speed : 19.1 Km/h / MAX Speed : 32.5 Km/h / 12.5 Cal

A1 Run #1 : AVG Speed : 19.9 Km/h / MAX Speed : 24.2 Km/h / 29.2 Cal
A1 Run #2 : AVG Speed : 19.9 Km/h / MAX Speed : 24.1 Km/h / 29.4 Cal

B2 Run #1 : AVG Speed : 19.6 Km/h / MAX Speed : 33.5 Km/h / 13.7 Cal
B2 Run #2 : AVG Speed : 19.1 Km/h / MAX Speed : 33.1 Km/h / 11.2 Cal

A1 Run #1 : AVG Speed : 19.6 Km/h / MAX Speed : 23.6 Km/h / 28.8 Cal
A1 Run #2 : AVG Speed : 19.5 Km/h / MAX Speed : 23.9 Km/h / 28.7 Cal

AVG B1 : AVG Speed : 19.7 Km/h / MAX Speed : 32.1 Km/h / 12.6 Cal
AVG B2 : AVG Speed : 19.3 Km/h / MAX Speed : 33.5 Km/h / 12.4 Cal

AVG A1 : AVG Speed : 19.9 Km/h / MAX Speed : 24.1 Km/h / 29.3 Cal
AVG A2 : AVG Speed : 19.5 Km/h / MAX Speed : 23.7 Km/h / 28.7 Cal

AVG B : AVG Speed : 19.5 Km/h / MAX Speed : 32.8 Km/h / 12.5 Cal

AVG A : AVG Speed : 19.7 Km/h / MAX Speed : 23.9 Km/h / 29.0 Cal

A : 2.5 Kilometers (1.55 Miles) divided by 29.0 Calories (0.000935 Gallons (US) ) = 1657 MPG (US)

B : 2.5 Kilometers (1.55 Miles) divided by 12.5 Calories (0.000403 Gallons (US) ) = 3846 MPG (US)

According to the results. P&G is better than going at a steady speed. But remember that my computer records calories even if I am coasting, and that when I did my P&G (B) tests, I removed my computer when coasting. When doing the steady speed (A) tests, I tried to not coast, and maintain a 19.7 AVG Speed. So READER SKEPTISISM IS AVDICED.

Those tests we're made for fun and I am not trying to prove anything. I was only trying to see with my computer if It'll be better or not. From what I could feel between the tests, I had more sweat after a steady speed test than a P&G test, probably because of the loooooog coasts provided by the boat-tail!

[bikin' Ed]

I've often wondered the same thing and decided that there is no inexpensive way to accurately test this.

Rider position is about 80% of aero drag, so keeping you body exactly the same for all of those rides is going to be tough.

It will take some time to complete the entire battery of tests and counting on the wind and weather as well as traffic to be the same is a concern.

Will you start your course at speed? How fast you accelerate will have a bearing on calorie burn.

My thought was that you would need a watt meter, heart rate monitor, and perhaps a velodrome to get a fairly accurate test--then you still need to deal with body position.

Please don't think I'm trying to dis courage you (I'd love to know the answer) just mentioning things to be aware of.

[HyperMileQC]

yes, I understand your POV, this will be tough to get accurate numbers, but even if I fail to get good accurate data, It will have been a nice try!

Starting from 0 km/h and finishing at 0 km/h. I will try to accelerate from 10 to 30 km/h in 5-7 secs, and then coast until my speed drops to 10 km/h, etc...

Also, updated the bike to help data hehe... :

BOAT TAIL!





I have tested it on 5 miles for now and I can feel a diffence in longer coast.

[Piwoslaw]

I haven't seen BSFC maps for biker legs, but I have noticed that

• Brisk acceleration makes me tire quicker than slow acceleration,
• Coasting allows my legs to rest.

Both of these are specific for the way that living organisms work, not mechanical engines. The reason that P&G works in a car is it allows you to use the engine only in its most efficient rpm/load range, while turning it off for the rest of the distance. The engine is killed not because it needs to rest, but because it is not needed at the moment. The most efficient setup would be to downsize the engine so that your whole trip is one long pulse, ie the engine is at optimal rpm and load for the whole duration. But this isn't possible in the real world, so P&G is the next best option.

Originally Posted by HyperMileQC

My bycicle computer records calories even if I am coasting. My theory about it's recording, is it adds or remove calories if I go faster or slower than my average speed.

So according to your computer, you are burning the same amount of calories whether you are coasting downhill or sweating your pants trying to keep up speed going uphill. If so, then you computer is just plain wrong

Originally Posted by bikin' Ed

Rider position is about 80% of aero drag, so keeping you body exactly the same for all of those rides is going to be tough.

If the bike comp only inputs speed, then aero position won't effect its calorie display.

Without complicated equipment (monitoring heart and breathing rate, how much oxygen is used in each breath, how much power you need, etc.), it will be hard to get any kind of accurate data. The best simple test that I can think of at the moment is to see how far you can ride your bike. Do this every 2 days (allowing a day of rest between tests), and you will have to alternate between P&G for the whole distance, or steady speed. Do this for 2-3 months to take account for your physical condition improving, and for weather variations. Then you will see if you tire quicker when P&Ging or steadly pedalling.

Originally Posted by HyperMileQC

A will be riding at an average speed of 20 Km/h without P&G, and B will be riding in Pulse and Glide from 10 Km/h to 30 Km/h.

If you P&G between 10 and 30 km/h, then your average will be less than 20 km/h. So, first P&G, then set your steady speed to the average you had while P&Ging.

[HyperMileQC]

Thanks for your input, nice tips and clarifications. I will do then B-A-B-A tests

And for how long I can bike, I think I could do 35 Kilometers without trying really hard, so that's not gonna be the test i'll do.

Originally Posted by Piwoslaw

So according to your computer, you are burning the same amount of calories whether you are coasting downhill or sweating your pants trying to keep up speed going uphill. If so, then you computer is just plain wrong

This is why I am trying to make a "computer calorie kill switch" for when I coast.

[bdesj]

Not meaning to carry this too far OT, but how does your computer figure calories? If it connects to or includes a watt meter, it won`t count anything while you`re coasting. If it doesn`t make use of a Powertap or some other type of meter, I can`t imagine how it estimates your power useage.

[bikin' Ed]

After a night of thought and reading others thoughts here's what I got.

Do you want to measure P&G by heart rate? You could get a monitor with current and average BPM.

It would probably be best to do these tests in the most upright, comfortable riding position you can. That way you are less likely to skew the results with better or worse body position. The numbers won't be the same but the measurable effect will be the same.

There are also physiological reasons to keep your legs moving while on the bike--like transport of nutrients and wastes to and from the muscles, and keeping the muscles warm.

I'd love to know the answer but there are sure a lot of variables to deal with.

[ecomodded]

Pulse n glide on a bicycle does work.
After a particularly fast stretch of road i can exhaust myself to nearly requiring a rest stop, but when i pulse and glide (coast and pedal) i can reduce my heart rate and breathing back to a rate i can cruise with. I think most of us pulse n glide on our bikes without realizing it. I coast quite a lot when resting on the fly.

[HyperMileQC]

Originally Posted by bdesj

Not meaning to carry this too far OT, but how does your computer figure calories? If it connects to or includes a watt meter, it won`t count anything while you`re coasting. If it doesn`t make use of a Powertap or some other type of meter, I can`t imagine how it estimates your power useage.

It is a magnet that is attached to the front wheel, the magnets detect the other each turn the wheel make. I entered into my computer that each turn of a wheel is XX inch. And the computer do the rest.

Originally Posted by bikin' Ed

After a night of thought and reading others thoughts here's what I got.

Do you want to measure P&G by heart rate? You could get a monitor with current and average BPM.

It would probably be best to do these tests in the most upright, comfortable riding position you can. That way you are less likely to skew the results with better or worse body position. The numbers won't be the same but the measurable effect will be the same.

There are also physiological reasons to keep your legs moving while on the bike--like transport of nutrients and wastes to and from the muscles, and keeping the muscles warm.

I'd love to know the answer but there are sure a lot of variables to deal with.

No I will not measure P&G by heart rate, because I don't have any monitor that shows my BPM, and I don't think I'll buy one too. For the position, I'll try to be positioned the more aerodynamicly possible to coast the longest distance possible, it is not inconfortable at all.

Originally Posted by ecomodded

Pulse n glide on a bicycle does work.
After a particularly fast stretch of road i can exhaust myself to nearly requiring a rest stop, but when i pulse and glide (coast and pedal) i can reduce my heart rate and breathing back to a rate i can cruise with. I think most of us pulse n glide on our bikes without realizing it. I coast quite a lot when resting on the fly.

After going fast, I tend to coast the longer possible to reduce my heart rate. I coast alot when going downhill.