Friday, April 7, 2017

How to contribute Cadence Data

I study cadence-versus-speed data to determine how a runner's performance varies with their height, weight, age, gender and distance-run-per-week.  The project needs runners of any skill level who have access to a treadmill and a running watch (or a video camera) to record their cadence.


So far the data indicates how a runner’s cadence relates to their maximum speed, and how height affects cadence.  As you can see below, taller runners have a higher maximum speed and a lower cadence.  Even at moderate speeds, taller runners have a lower cadence compared to shorter runners.  Of course, faster runners exhibit higher estimates of their VO2max (2) than slower runners.  These runners represent a spectrum of heights, weights and ages.  By looking at all the runners at a one speed, (along a vertical line), you can see how taller runners have a lower cadence than shorter runners.


If you would like to see how your cadence and speed compare with others of the same height, weight and/or age consider adding your data by following the procedure below.  All data is submitted anonymously through email.  (Do not include any personal information, such as, your name or address.)

If you are interested in seeing how your cadence curve compares with other runners, follow the procedure below and I will email a new curve to you.

The test takes about 10 minutes and requires an initial warm-up.  After the warm-up you are asked to run through a series of increasing 1-minute speed-steps up to your maximum safe speed on the treadmill.  The test is similar to that of a VO2max measurement, except that it requires that you maintain a running or jogging gait throughout the test, starting at the very lowest speed.

Your cadences at the very lowest speeds provide valuable information on your leg-stiffness or springiness.  This information can be used in a physics-based model (2) to help understand how a runner's power output changes with speed.

By participating in this effort you will be able to compare your performance with others, obtain two estimates for your VO2 consumption (1) and see how your cadence and step-length affect your speed.  If you have a treadmill and a running watch or a video camera, consider contributing your data to this research.

Overview:

The test takes about 10 minutes.

After a warm-up the test begins with of a series of increasing 1-minute speed-steps starting from the slowest speed of 1 and increasing up to your maximum safe speed on the treadmill. 

Procedure:

1. Begin with a warm-up run on or off the treadmill.  You can perform the test after a regular run or a short run on the treadmill.

2. Turn on your running watch.

3. Set the treadmill to 0% grade.

4 Set the treadmill to a first speed step of 1 mph or kph and run at this speed for 1 minute.  (Remember to use a running or jogging gait.  Do not walk.)

5. Increase the speed by 1 mph or kph and run at that speed for 1 minute.

6. Repeat step 5 increasing the speed by 1 mph or kph up to the highest speed that is just below your maximum safe running speed.

6. Finally, set the treadmill to your maximum safe running speed and run at that speed for 1 minute.

When you are done, capture your cadence by one of two methods. 

If you have a watch that recorded your cadence, transfer your run to your computer software.  Write down your speed and cadence at each speed-step.

If you made a video recording of your test, follow the guidance below (3) for computing your cadence.  Write down your speed and cadence at each speed-step.

Email your cadence to me at Ted.Andresen@gmail.com


As shown below, begin your information with any two-letter identification code of your choice.  Add a "1", "2", "3",  … in case you decide to repeat the test after a few months of training.  On the following lines enter your height, weight, age, gender, average distance-run-per-week along with your speed-steps and cadence (steps/min) as shown below.  Indicate if your speed is measured in Metric or American units.  Depending on the system of measurement; your column of data should look similar to one of the columns shown below. Email your data and any comments to Ted.Andresen@gmail.com


Description
Metric
American
2-Letter
code +
number
AB1
CD1
Height
1.63 m
66 in
Weight
67 kg
145 lbs
Age
45
66
Gender
M
F
Distance
per
week
35 km
21 miles
speed
and
cadence
1 kph,155
1 mph, 167

2 kph, 157
2 mph, 166

3 kph, 160
3 mph, 170

4 kph, 165
4 mph, 174

5 kph, 165
5 mph, 176

6 kph, 172
6 mph, 180
Max Speed
6.7 kph, 180
6.5 mph, 182


I will add your data to the system and email a graph to you, so you can view the estimates for your VO2 consumption and see how your cadence compares with others of the same height and weight.

As the database grows I will continue to update the graph above, so you will be able to see how your performance compares with that of similar runners.

What you may find:

If you are concerned with your speed, you may find that as your highest cadence increases your speed remains the same.  Then, you might consider increasing your step-length by increasing your hip-rotation or your range-of-motion.  Or, you may find that you are performing the same as other runners who have similar physical measurements and run the same distance-per-week.

Thank you for your help.

(1)  There are two equations for estimating VO2 consumption.  Both depend only on your speed.  One estimate is based on an equation from the American College of Sports Medicine (ACSM).  The other is based on Dr. H. Cooper’s 12-minute run test.

(2)  This is the Spring Mass model.  It was introduced in 1989.  You can find many good examples of it on the internet.  Basically, it represents the runner as a central mass bounding along on a set of spring-like legs.  By running at slow speeds it is possible to estimate the legs-spring’s stiffness and hence the energy due to leg-compression and expansion with each step


(3) To measure your cadence from a video, focus on one foot so you can count the strides not your steps.  Begin the stopwatch and the count with the number “0”, not “1”.  Measure the time in seconds required to make 30 strides.  Use a calculator to divide 3600 by the time on the stopwatch.  That is your cadence in steps per minute.  Repeat this process for each speed-step.