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Discussion Starter · #1 · (Edited)
The Weight Loss Experiment... V 0.5

I'm going to test the effect of weight loss on cycling performance as I have recently lost 5+ lbs. Try the experiment and post results! I want to see what others report.

Attempt #0: Time 24:40 Weight 165 lbs.
Attempt #1:Time 23:44 Weight 160 lbs.
Attempt #2 Time 24.55 Weight 165 lbs.
Attempt #3 Time 25:09 Weight 165 lbs. (mountain bike)
Attempt #4 Time 23:45 Weight 160 lbs. should have been ~2% faster!! see the post
Attempt #5 Time 23:35 Weight 160 lbs.

End of trials See Conclusion post: http://forums.mtbr.com/9294515-post2.html
################ Better protocol

For each attempt starting with #2, I'll add a reply to the thread.

I've revised the test procedure using this post. http://forums.mtbr.com/9249778-post1.html This is much better science than my attempt. A big thank you to Nebulus911 for the help.

My stats:
gender: Male
age: 46
weight: 157
bike weight: 21 lbs.

The better test procedure:

The hill: Find a hill that's a very steady 8-10 minutes and not too steep. No big ring, no granny gear wobble. No tricky descent segments. The less technical the better. I don't think using a hill longer than 10 minutes improves the data. Strava and a gps device is great for collecting data. I use a blackberry and GPSLogger, so nothing fancy and does the job.

PREPARE
Step 1: Record bike weight. Just use the same equipment.
Step 2: Weigh yourself at the same time before a Personal Record attempt. Record weight.
Step 3: Choose the next available letter from this list of letters. I'm letter A.
a: 2, 4, 1, 3
b:1, 4, 2, 3
c: 3, 2, 1, 4
d: 2, 4, 1, 3
e: 2, 1, 4, 3
f: 2, 3, 1, 4
g: 4, 2, 1, 3
h: 2, 4, 3, 1
i: 3, 4, 1, 2
j: 2, 3, 1, 4
k: 4, 1, 2, 3
l: 4, 2, 3, 1
m: 3, 4, 2, 1
n: 4, 3, 1, 2
o: 2, 1, 3, 4
p: 2, 4, 1, 3
q: 2, 1, 3, 4
r: 2, 1, 3, 4
s: 1, 3, 4, 2
t: 4, 1, 3, 2

1 = control trial 1 (no added weight)
2 = control trial 2 (no added weight)
3 = weighted trial 1
4 = weighted trial 2

Step 4: PLAN to Perform trials in the order in which the numbers appear. Since I'm "A" my trial order is control trial 2, weighted trial 2, control trial 1, weighted trial 1 See how that corresponds to the letter A's 2, 4, 1, 3?

PERFORM
Adjust ride hour to compensate for warming weather.
The effort: Maximum intensity, personal record attempt.
The body: Ride the hill as close to fully recovered as possible. Be rested and ready.
The bike: just make sure everything is basically the same.
The "weighted trial:" I used a camelback and threw a combination of water and lead from a weight vest. Works for me. I think 5lbs. is a good number to add for a bunch of reasons. Just pick a value and stick with it.

I suggest doing a trial every other week at the same time. That's enough time to register slight improvements in performance due to training effect.

Post your body weight, bike weight, gender, age and results!
 

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Sweep the leg!
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Target weight: 170#
Weight at time of injury: 185#
Current weight: 228#

I already know if I lose the 40# I've put on in the last 8 months since breaking the leg that I'll be faster.
 

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I think a better way to run this test would be to climb a hill 4 times with 15-20 minutes recovery in between. First time, run up it like normal. 2nd and 3rd time, add 5 pounds in a backpack, water bottle, however. Then 4th time get rid of the weight again. It'd be interesting if you could climb it the 4th time faster than the 2nd or 3rd, provided proper recovery in between efforts. Over the time it takes to gain/lose 5 pounds, combined with varying trail, weather, and nutrition/preparation conditions, you're not likely to get very relevant data from what you're proposing.

Here a while back a link was posted to a masters thesis where the guy tested 15 bikers from Cat 5 to elite on a 2.5 mile climb. Each person climbed it twice, once with a water bottle that was empty, once with a bottle with 2 lbs of sand (randomized-some people had the sand for the first climb, some had an empty bottle). The average climb time was around 11 minutes IIRC, and adding the 2 lbs added an average of 21seconds per person.
 

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Unless you are using a power meter you are not going to get any meaningful data.

Even then you will need to perform a lot of trials to eliminate environment conditions, such as a wind.

The theoretical benifit of losing weight can be quite easily calculated using (Delta t) = ((delta m) gd) / P where delta m is change of mass of rider in bike in in kg, d is vertical distance in meters, g is 9.8N/kg, and P is average power output in watts.

For example a 5lb loss in weight a rider producing 250 watts should result in about an 18s quicker time on a hill with a 200m vertical change. Extrapolate that over a typical race 1000 vertical meters and you get 90s.

From the equation you can see the higher the wattage the smaller benifit the weight loss makes.

You can also go to Analytic Cycling, Interactive Methods for Estimating Cycling Performance Parameters. Tom Compton for a real good modeling program to the see the effect of weight loss on hill climbing speed.
 

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If you know the length and gradient of the climb then you can theoretically work out what the result would be using an online calculator, such as the analytic cycling ones.:)

http://www.analyticcycling.com/ForcesLessWeight_Page.html

(The hill gradient is expressed as a percentage. A 10% gradient would be 0.10 in the calculators)

An example would be a local road climb at close to sea level that I rode the other day.

Distance 1.3 miles (2092m),
9.1% average gradient (0.091)
Rolling Resistance 0.008 (knobbly offroad tyres so this might be a bit low still)
Average power of 260 watts from my Powertap.
I weigh 149lb approx and my bike weighs 27lb approx (total 176lb, 79.8kg).

According to the analytic cycling calculator I'd be 17 seconds quicker up the climb if I weighed 5lb (2.267kg) less and maintained the same 260 watt power output.:)

The other analytic cycling calculators to look at are Power Given Speed and Speed Given Power. If you put the above weight and power figures into the Speed Given Power calculator then it comes out with a slightly higher estimated average speed for the climb 7.3mph (3.29m/s) than the 7.0mph average speed that I actually managed on the day. That's possibly down to needing to change one of the calculator's parameters (higher drag or rolling resistance than I entered possibly) but it isn't that far out.

The calculators are something to check your actual results against when you've done the tests.:)

Pictured below: Analytic Cycling Calculator for losing 5lb body weight on a 1.3mile 9.1% gradient climb
 

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or, you can just look at the fastest cyclists in the world. all of the ones who race outside tend to range from skinny to really skinny. its not scientific, but i doubt its coincidence.
 

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I've had a good block of training since Attempt #1 so I know I am generating more power.
And there lies the problem of your experiment. If I read your post correctly, you are getting more fit and thus generating more power since attempt #1. So attempt #3 will not equal the same in fitness level. The differences will be due to fitness and not weight loss. By no means am I bashing you, just making the point.

However, WR304 covers this point by stating that if the power output equaled 260 watts of power output at both weight, then gives the differences.

WR304, from all of your posts on this forum, you are an encyclopedia of biking. Thanks for all of the info. Wait, I guess encyclopedias are no longer being made. Correction: wikipedia.
 

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Discussion Starter · #8 ·
Over the time it takes to gain/lose 5 pounds, combined with varying trail, weather, and nutrition/preparation conditions, you're not likely to get very relevant data from what you're proposing.
I want to see if there's meaningful data without controlling for too many things and using a longer trial distance, That's why I want others to contribute results.

I have an idea about what the data will say making a half-hearted effort at controlling external factors like weather and using a longer trial course. But I'd like to see more than just my results and see if it occurs elsewhere.
 

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it might just be placebo, but i can tell a pretty big difference on how fast i ride to class based on how many books i have in my backpack. when i ride my commuter without any weight on my back it feels a ton faster.

+1 for using weights instead of your own body weight.

and also, my body weight fluctuates by close to 5lbs throughout the day (about 2.5% of my body weight) based on how hydrated i am, how recently i have eaten, pooped, taken a wiz etc.

to get the most accurate results i would go with 10 lb weights, attached as close to your waist as possible. if you go just a standard backpack type of thing, the its going to affect your riding as well. if its on your hips it will basically just be dead weight.
 

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Discussion Starter · #10 ·
And there lies the problem of your experiment. If I read your post correctly, you are getting more fit and thus generating more power since attempt #1. So attempt #3 will not equal the same in fitness level. The differences will be due to fitness and not weight loss. By no means am I bashing you, just making the point.
This is exactly what I am trying to get at. How does 'fitness' and rider weight factor into a performance.

The second part of this is I chose around a 20 minute test for a reason. It returns very consistent performances for me where shorter efforts do not and longer ones definitely do not, both for different boring/intricate reasons though.

I hope that others would contribute their data and see if it is like mine.

I will definitely check the data against the suggested site and see what happens.
 

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Discussion Starter · #12 ·
to get the most accurate results i would go with 10 lb weights, attached as close to your waist as possible. if you go just a standard backpack type of thing, the its going to affect your riding as well. if its on your hips it will basically just be dead weight.
I'm going to vary the weight over different trials, so I'll definitely do this. I'm using lead weights in an empty camelback so I shouldn't have any extra discomfort.
 

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I'm going to test the effect of weight loss on cycling performance as I have recently lost 5+ lbs. Try the experiment and post results! I want to see what others report.

The hill: Find a hill that's 15-20 minutes start to finish with clear start/stop landmarks and no tricky descent segments. The less technical the better. Using a hill longer than 30 minutes definitely introduces some problems, so a longer effort is not better.

Attempt #0: Time 24:40 Weight 165 lbs.
Attempt #1:Time 23:44 Weight 160 lbs.
Attempt #2 Time ??:?? Weight 165 lbs.

This week I'm adding enough weight to myself to net out at 165 lbs. I've had a good block of training since Attempt #1 so I know I am generating more power.

The (long, boring) test procedure:
The weather: adjust ride hour to compensate for warming weather.
The effort: Maximum intensity, personal record attempt.
The body: Ride the hill as close to fully recovered as possible. Be rested and ready.
The bike: just make sure everything is basically the same.

Test step 1: Weigh yourself at the same time before a Personal Record attempt. Record weight.
Test step 2: Perform personal record attempt. Record time. Strava is good for this.
Test step 3: Consistently train for at least 2 weeks.
Test step 4: Alter your weight by at least 5 lbs. Wear a 10lb weight vest. Fill a big Camelback full of water. Lose weight! Do something to change your weight by at least 5 lbs.
Repeat step 1 and publish weight and time.
Train another at least 2 weeks then alter your weight again doing the opposite of what you did the second trial. If you rode with a 10lb weight vest on trial 2, do this one with no weight vest assuming your body weight hasn't changed.
Let us suppose that you collect the data accurately and are able to nullify the effects of temp humidity etc....

Basically all you will know is how external weight affects your riding...not body weight...

The body weight trade-off depends what ratio of fat to useful muscle you gain or lose....

And hence the power to weight ratio of your body.....

Better test perform training as per some schedule...then evaluate your power to weight raito...

Then adjust the training schedule....and re evaluate....

And so on.
 

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Discussion Starter · #14 ·
Basically all you will know is how external weight affects your riding...not body weight...

The body weight trade-off depends what ratio of fat to useful muscle you gain or lose....
I'm unclear on this. Are you claiming the ratio of fat to muscle has some relevance over and above the effects of gravity/frictions on performance?

What are useful muscles? What are the criteria for a useful muscle? Ones that work vs. ones that don't? I'm not trying to be obtuse. I'm not familiar with the term.
 

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I'm unclear on this. Are you claiming the ratio of fat to muscle has some relevance over and above the effects of gravity/frictions on performance? Well muslce to fat is what we have to control when you lose weight

What are useful muscles? What are the criteria for a useful muscle? Ones that work vs. ones that don't? I'm not trying to be obtuse. I'm not familiar with the term.Building up a lot of biceps is not going to help you go as fast as builing up the quads
When a person gains or loses weight it is generally good if it is done with exercise and diet....

If on the other hand one loses weight by just diet no exercise then the result is generally slower times...

That is fat to muscle ratio means....that is what one needs to focus on when training
 

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Discussion Starter · #16 ·
Unless you are using a power meter you are not going to get any meaningful data.
Sure I will. I'm testing for the effect of weight over a set distance. Yes, there will be some variability including fitness gains. But I think I've controlled for most of the relevant ones by using a 20-30 minute test.

Also, we don't have much weather to speak of in Southern California, so environment isn't really an issue.

Maybe I'm missing something though. How would knowing my output help? Can you calibrate the device for body weight changes?
 

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Adding weight that isnt body mass wont have an affect on power output. Therefore its obvious that carrying 5 extra pounds will slow you down.

A better experiment would be adding 5 pounds of muscle and measuring power/weight. But thats unrealistic to say the least.
 

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Too many variables to get usable data imo..

I am guessing that using a 5 lb weight and using a PM is the only way to get something close to accurate.

Perhaps ride with a camelbak on filled with water at 5 lbs.

Clearly limiting all variables among tests is essential too.

Like someone already mentioned, it is more than just losing body weight, it is the fitness acquired while doing so that matters also..
 

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Sure I will. I'm testing for the effect of weight over a set distance. Yes, there will be some variability including fitness gains. But I think I've controlled for most of the relevant ones by using a 20-30 minute test.

Also, we don't have much weather to speak of in Southern California, so environment isn't really an issue.

Maybe I'm missing something though. How would knowing my output help? Can you calibrate the device for body weight changes?
Because we aren't machines. We don't always test the same.

If you are talking about a 5lb weight loss that is only a 3% loss in weight for a 150lb cyclist with 30lb of gear. From day to day power output varies by at least 5%. What ever result you get can be explained quite easily by other factors.

Even in Southern Claifornia environmental has a huge roll. The smallest bit of wind changes things dramatically, or the texture of the soil changes due to different weather patters resulting in different coefficient of rolling resistance.

Here is a thread I did a couple years ago on tire testing. You can see some of the challenges that I faced:

http://forums.mtbr.com/xc-racing-training/some-testing-556418.html
 
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