Power vs. Weighted Avg Power

Power vs. Weighted Avg Power

Below is a screenshot from Strava of a club rider’s results:

Notice the two areas in yellow. One is titled “Weighted Avg Power” and the other is “Power.”

What’s the difference?

The three most popular bike computers (Garmin, Wahoo and Bryton) use the same methods of determining the power you put into each ride, and they offer the same options. If you have a power sensor on your bike,

Your computer records your power once each second, measured in watts. Weighted Avg Power and Power are both based upon a 30-second period derived from these one-second recordings. So twice a minute, records are made of your power output, each record having 30 items in it. If you don’t have a power meter connected to your computer, Strava estimates it.

*NOTE: If math is not your thing, just go to the last two paragraphs of this article.

Here’s how the Power metric works:

1. Let’s say you just rode a 1.5 hour route.

2. 1.5 hours = 90 minutes

3. 90 minutes = 180 unique 30-second recordings

4. Let’s say the average of those 180 unique 30-second recordings was 90 watts

5. 90 watts is your Power number, meaning your average power output during the entire ride was 90 watts. That includes coasting/stopping/pedaling.

At first glance, this seems to be the best way to determine the average power you put out on this ride, but you’d be right and wrong. It is the mathematical average of your coasting/stopping/pedaling power. Your computer adds up all the 30-second segments and then divides that by 180. It is the true average power.

However, for training purposes, it’s more important to know ***how much power*** you were putting out ***only while pedaling*** instead of adding in the coasting/stopping metrics, over which you may have no control (stop lights, traffic, your position in the group, etc.).

To provide a more meaningful number for the power you output on your ride, the cycling industry has agreed upon a method of emphasizing when you’re pedaling, and at how many watts, as opposed to giving equal importance to when you’re coasting/stopping and putting out zero watts. This is the Weighted Avg Power, sometimes called “Normalized Power.” It was originally developed by [Andrew Coggan Ph.D.](https://shhs.iupui.edu/connect/directory/coggan-andrew.html) , an associate professor in the Department of Kinesiology at the Indiana University School of Health & Human Sciences.

Here’s how the Weighted Avg Power works:

1. Let’s say you just rode a 1.5 hour route.

2. Your computer takes each 1-second segment and raises it to the 4th power (multiplies it by itself 3 times). This means when you’re coasting (0 watts), 0 x 0 x 0 x 0 = 0 watts. If when you’re pedaling you’re putting out 130 watts, that becomes 130 x 130 x 130 x 130 = 285,610,000 watts, computed to the 4th power. It then adds up each second’s computed number for 30 seconds and determines the mathematical average.

3. Let’s say you coasted for 15 seconds and pedaled at 130 watts for 15 seconds. That would compute to (15 x 0) + (15 x 285,610,000) = 0 + 4,284,150,000 = 4,284,150,000 watts, computed to the 4th power. Divide that by 30 seconds and you have an average of 142,805,000 watts, computed to the 4th power.

4. Your computer then takes that average and computes the 4th root of 142,805,000 watts, which equals 109.32 watts, becoming that 30-second segment’s Weighted Avg Power.

5. The mathematical average of those 180 unique 30-second recordings then becomes the Weighted Avg Power for your entire ride.

Notice that the Weighted Avg Power is greater than the Power number. This is because the formula emphasizes the watts you’re outputting while pedaling and minimizes the 0 watts while coasting/stopping.

In the screenshot above, you can see that the Weighted Avg Power was 118 watts, whereas when coasting/stopping info was combined into the true mathematical average, the average was only 98 watts. For training purposes, the 118-watt number is more meaningful because it indicates the average power while pedaling. Comparing the Power and Weighted Avg Power metrics is useful, but cycling trainers consider Weighted Avg Power as crucial for training because it better reflects the exertion and impact of the more intense portions of a ride that typically influence fitness gains and performance adaptations more significantly than steady or low power outputs.

Now you know the difference between, and the purposes of, Weighted Avg Power and Power on your Strava page.

Questions? Just ask!

Dick Brock, stats@bikeirvine.org

ETA-Estimated Time of Arrival

ETA - Estimated Time of Arrival

If you have your riding route uploaded into your bike computer, it will always be able to tell you your estimated time of arrival (ETA). This feature is not automatic, so you have to dive into your computer’s menu tree, find the “Time to Destination” option and add it to one of your screen displays.

More and more, BCI riders are choosing to use their phone for navigation, as it has spoken audio output that can warn you of upcoming turns, a Cue Sheet and display a map with metrics such as ETA and hands-free navigation! Here’s how to do that:

1. Open bikeirvine.org on your phone’s browser

2. Click the “Next Rides and Events” button

3. Click on the “Map/Profile/.tcx“ of the desired route

4. A screen will open, showing the route on a map. At the bottom-left of that screen will be a button named “Navigate.” Click on it.

5. You will automatically be brought to a navigation page with today’s route, and it will tell you where your next turn is, as well as how far away it is. This page will stay open until you close it by holding the Pause button down for 3+ seconds and selecting either SAVE or DELETE.

6. Your ETA will be in the lower right section of the display, along with the total distance left.

7. Also at the bottom of the page is a "CueSheet" button, which when pressed will show you every turn, with mileage, for the entire route. No more printed route sheets!

A HUGE shoutout to Bill Sellin for getting this system set up. It's a real game changer!

But alas, there are those who prefer route sheets to computers, and who must therefore do without all the easy info they offer. Still, those folks may want to know their ETA, and here's how to compute it:

You need two pieces of information:

1. Distance to the end of the ride

2. Your average speed

Utilizing these two metrics, here's the formula to figure out your ETA;

ETA (in hours) = Distance to the end of the ride / Your average speed

If you want the answer in minutes:

ETA (in minutes) = (Distance to the end of the ride / Your average speed) * 60

Below is a graph showing the ETA (minutes option) using a variety of "numbers of miles left" in the ride and "average speeds."

To use the graph:

1. Select the bar color of your "miles left" number, found at the top of the chart. For instance, if you have 15 miles left, you'd select the yellow bar.

2. Select the column that equates to your average speed (let's say, 14 MPH).

3. On the graph, "64.3" at the top of the yellow bar in the "14 MPH" column is your ETA in minutes.

4. For values that fall in between your average speed and/or miles left, just interpolate.

Let's hope for warm tail winds in April,

Dick, stats@bikeirvine.org

VeloViewer.com

“VeloViewer provides new insights, engaging visualisations, motivational goals and in-depth analysis to your Strava data. Simply connect to Strava to bring in a subset of your data for free and try out all of the features VeloViewer has to offer and use some of the same tools that have helped win 100’s of WorldTour races including all Tours de France since 2017. It is currently being used by all men’s and women’s WorldTour & Pro Tour teams along with numerous Continental teams, national federations and race organisers. Upgrade to PRO from just £10 per year to use VeloViewer on your entire Strava history.”

Yes, that's a mouthful with which to start off. This month's BCI Counts! is for those who can't get enough biofeedback. The beauty of VeloViewer is that you don't need to do anything but use it. All the information it shows you (in hundreds of different ways) is already captured in your Strava account. For those of you old enough to have a decent number of years with Strava, you can compare date ranges in all sorts of ways. Prepare yourself for insights you didn't expect. By default, all your info remains totally private.

When your non-riding friends or family members ask what exactly you do when riding your bike all the time, VeloViewer provides absolutely gorgeous infographics that highlight your accomplishments; not just in spreadsheet formats like your humble statistician does each month, but professional, drool-worthy graphic formats.

If you're goal-oriented and like all the watts, PRs, segments and stuff, VeloViewer has you covered. It's so good that all WorldTour teams along with many ProTour, Continental and national teams use VeloViewer.

So, click on this LINK and give it a free spin with a subset of your past rides. Try everything out. If you like it, it's only a few bucks per year.

Best,

Dick Brock, stats@bikeirvine.org

CALORIES, EXERCISE AND DIET

"Pretend you didn't exercise at all," she said. "You will most likely compensate anyway, so think of exercising just for health improvement but not for weight loss." Diana Thomas, a Montclair State University obesity researcher

In a recent discussion with a fellow member, I proferred the point that weight loss is not the prime benefit of exercise, but rather is the prime benefit of a proper diet. My friend rebutted me and said he felt exercise was at least an equal part of weight loss, along with a proper diet. I decided to investigate the issue to confirm the facts.

If you want to learn about (and finally understand) the connection between weight loss, exercise and diet, Click Here . It's an easy read, and there's also a short video that brings everything to a clear point.

What you’ll learn about:

1) An evolutionary clue to how our bodies burn calories

2) Exercise is excellent for health

3) Exercise alone is almost useless for weight loss

4) Exercise accounts for a small portion of daily calorie burn

5) It's hard to create a significant calorie deficit through exercise

6) Exercise can undermine weight loss in other, subtle ways

7) Exercise may cause physiological changes that help us conserve energy

8) Energy expenditure might have an upper limit

9) The government and the food industry are doling out unscientific advice

10) So what actually works for weight loss?

BCI Stats:

• Using Strava, BCI's range of calorie expenditure per mile of cycling is 20 to 70 calories, with the average being about 29 calories/mile. This shows three things:

1. How efficient our bodies can be.

2. The relatively small impact exercise can have on calorie consumption. One of our top-performing female members burns only 22 calories/mile. On a 2-hour ride, the average member burns about 800 calories. One typical slice of pizza ranges from 200 to 400 calories.

3. How different our bodies can be from one another, and why it’s important to learn yours well enough so you can adapt the best plan for weight loss/control.

The key takeaways from all this:

• Physical activity is excellent for health and weight control, but is not the primary driver of weight loss. Calorie deficit is the primary driver of weight loss.

• We only have control over about 30% of our caloric expenditures, and probably less. Of that 30%, at best only 50% of it, just 15% of the total, can be controlled by exercise.

• Exercise plays a crucial role in weight management, alongside a healthy diet, by impacting metabolism, appetite, and overall health (your vitals, like diabetes, hormonal balance and healthy joints). So, keep on riding!

• Using the services of science-based professionals can be useful in attaining your healthy weight loss/control goals. Here is one’s approach to the subject: Click Here

It’s anti-intuitive, but exercise without a substantial low-calorie diet adjustment is the least effective method of losing weight. Exercise for health and eat for weight control.

Until next month,

Dick Brock, BCI Statistician

statistician@bikeirvine.org

Hello, 2024!

Congratulations BCI Members… 2023 was quite a year!

Making 2024 Even Better!

Embrace the Joy of Cycling: Cycling isn't just about logging miles or scaling hills; it's a journey towards a healthier lifestyle. As we track our progress through our cycling computers and apps like Strava and Challenge Hound, let's remember that each pedal stroke is a step towards improved physical and mental health. In our club, whether you're in the 18-39 Age Group or the 80-150, every ride is a testament to your dedication and resilience.

Set Realistic Goals: With our club's detailed statistics, setting realistic goals becomes more manageable. Whether it's increasing the number of rides per month, adding a few more miles, or tackling a steeper climb, use the data to guide your objectives. Remember, improvement is personal, and every small achievement is worth celebrating. Soon there will be additional BCI statistics that allow you to identify those achievements as compared to the previous year and enjoy a little personal party… or not… it’s up to you!

Foster Community and Support: We are “The Friendliest Bike Club in Orange County!” This year, let's make a continued effort to support and motivate each other. Share your experiences, offer advice, invite new members or simply lend an ear. A strong community fosters a positive environment.

…and Now for Something Completely Different:

• We all know that losing muscle mass and flexibility as we age is a given. While cycling allows us to maintain our leg strength, it doesn’t do much for the rest of our structural and muscular systems. Stretching and weight lifting (even light weights) never stop!

• In CA, you do NOT need a doctor’s prescription to go to physical therapy (PT). PTs now offer nutritional support, so easy and healthy weight management goals can be met. Sports-oriented PTs perform physical exams and review your history before offering custom nutritional, weight and flexibility programs. Your insurance will probably pay for it, and once you learn your program and techniques, you can do everything at home!

• For example: Bob Forster is the official PT of the LA Marathon and has over 42 Olympic gold medals with athletes such as Jackie Joyner-Kersee and Alison Felix. He is a cyclist, having ridden La Ruta https://racelaruta.com/en/events/la-ruta-en/ twice. He keeps these athletes in top condition so they can respond to their coaches’ demands and perform at a level that lets them win. Yet, Bob’s bread-and-butter clients are regular folks just like us.

• Visit these links to see what a high-end sports PT does for elite athletes and can do for you as well: https://phase-iv.com  and https://www.youtube.com/watch?v=cWUb3Q3BAUM . There are many sports PTs in SoCal.

Conclusion:

• Set realistic goals.

• Foster a supportive community.

• Try new things.

• Focus on mental health.

By doing the above, we can make this year better than the last. Let's ride into 2024 with hope, determination, and the joy of cycling at our side.

Dick Brock, BCI Statistician

stats@bikeirvine.org

What is “BCI COUNTS!” ?

BCI Counts! is a monthly article by Dick Brock, the current statistician. Its purpose is to provide information and details regarding the general membership, such as enhanced statistics, survey results and musings derived from conversations at rides. You may also find the recognition and honoring of select members. Look for personal profiles, stories about adventures they’ve been on, and accomplishments.

If you have any questions or comments about BCI Counts!, or even an idea for an article, please e-mail Dick Brock at statistician@bikeirvine.org .