5K Running Math - Cadence and Stride Length
This article discusses cadence and stride length for 5k races. I show how I improved my 5k time from 24:53 to 20:47 over 6 months in 2018 (18.0% improvement, 4:06 minutes faster).
To read about steps and stride length for sprinters, see also my article on Sprinting Math - Steps and Step Length.
1. Basic Running Math
At it’s core, running a 5K race is simple. The goal is to run 5,000 meters as fast as you can. Put one leg in front of the other, pump your arms and legs, run straight ahead, and follow the course until the finish line.
There are two ways to run faster: 1. Take longer steps, and 2. Take faster steps.
Two key terms for every runner are (1) Stride length and (2) Cadence. Stride length (or step length, see footnote ) is the length of each step, and cadence is the number of steps per minute. In the formulas below, Stride Length and Cadence are averages throughout a race.
Finishing Time = Race Distance / ( Stride Length * Cadence )
Example #1. If stride length is 1.000 meters and cadence is 170 steps/min, finishing time will be 5,000 / ( 1.000 *170 ) = 29:25. In this example, you need to take 5,000 steps (5,000 / 1.000) to complete a 5k race.
Example #2. If you increase stride length to 1.100 meters (10%) and keep cadence at 170, finishing time improves to 5,000 / ( 1.100 *170 ) = 26:44 (10%). Here, you only need 4,545 steps (10% fewer) to complete the race.
2. How to Improve Your Time
The below chart shows the relationship between 5k finishing time as a function of cadence and stride length. As you move up and to the right, you get faster!
The curved colored lines show (stride length, cadence) combinations that yield the finishing times shown in the legend. For example, anywhere along the green line will get you a 5k finishing time of 22:00.
From January 14, 2018 to July 4, 2018 (171 days), I improved my 5k time from 24:53 to 20:47 (18.0% improvement, 4:06 minutes faster).
I did this by improving:
Stride length from 1.24 to 1.36 = 9.7% improvement
Cadence from 162 to 180 = 11.1% improvement
In addition to sticking to my workout plan from Hal Higdon's 5K training guide, I focused on specific drills to improve my cadence: Turnovers and a Walk/Run Progression. For more tips for increasing cadence and running mechanics, here’s a great article from Active.com with Simple Drills to Improve Running Economy.
3. Measuring Stride Length and Cadence with Garmin
When I train, I am able to see my cadence in real-time on my Garmin watch, so I know when I need to keep my legs moving faster. This has helped a lot!
I use the Garmin Fenix 5 watch ($550) and the Garmin Running Dynamics Pod ($70) to measure my stride length and cadence. Below is a picture of the Garmin Running Dynamics pod. You clip this little gizmo on the back of your belt, and it measures stride length, as well as vertical oscillation and ground contact time!
Below are screenshots from the Garmin app. This will give you a taste of the data Garmin collects.
It’s a lot of data, so keep focused on the average improvements: mile pace (8:02 to 7:10), stride length (1.24 to 1.29), and cadence (162 to 174).