Have you ever run a race & noticed that your watch didn’t match the mile markers or give you the same distance as someone else who ran the race?
Which is more reliable – the treadmill or your watch’s indoor running mode?
In episode 3 of The Art and Science of Running Podcast, Malc Kent & Jacob Puzey discuss GPS, indoor running metrics, treadmill training, race course certification & other running metrics and technologies.
Listen, subscribe, rate & review the show at Apple Podcasts, Spotify, Stitcher or wherever you listen to podcasts!
In episode 2, we discussed some of the work we’ve done as coaches as well as observing groups and other coaches such as Patrick Sang of the NN Running Team in Kenya.
Much of coaching we do now is done remotely via Runfisx and Peak Run Performance.
However, many of the athletes with whom we work train with others. Running is a social sport at it’s core.
In episode 2 we also discussed some of the work Malc has done with the development of wearable technologies / devices. These devices are used to measure a whole host of metrics.
Given that Malc is responsible for developing the algorithms and technologies behind many of these devices, Jacob asked Malc some of the most frequently asked questions he receives as a coach, race director, and athlete.
What is GPS and how does it work?
Malc explains that there are multiple satellites orbiting the planet. GPS devices regularly ping these satellites to get feedback about one’s location. There is a two way relationship between the satellite and device. GPS can be accurate as a remote means of telling where someone is. One can also be moving and get relatively accurate data as to where you are when moving.
Wearables are generally limited by batteries. The biggest problem with wearables is how to conserve battery. GPS hammers battery life. It becomes a question of how often do you sample the GPS location vs. how large do you want the device to be and how long can the battery last?
There is a tradeoff, as is always the case with wearables, between do you want an accurate location all the time or do you want a longer battery life?
Battery life has gotten better, but it is still a limiting factor.
Another issue with GPS is pace reading in real time. For example, you could have an individual runner running 4:00 per/km however, you’ll likely have a fluctuation in accuracy of pace coming off throughout the workout because you may or may not have multiple satellites to interact with at any given time – especially if running on trails or in an area obscured by shade or buildings. If you are looking for accurate pace feedback, use average pace at regular intervals rather than looking down at your watch as you run.
You can measure pace locally with an accelerometer with greater accuracy than GPS. These devices require less power / battery, however, such devices require better calibration. Accelerometers can give greater accuracy without the need of satellites.
What about if you are running inside on an indoor track or treadmill? How does that work?
Depending on the construction materials used in the building, you are likely going to have trouble picking up GPS signals if / when running indoors.
Why is there variability between advertised distance and what watch reads during and after a race?
Not everyone runs the tangents. For example, some may run long around the corners or at aid stations.
Newer watches should have firmware algorithms with automatic recalibration when stationary, however, hardware and firmware algorithms are not all equal. There will be natural differences between various brands and generation of brands
As a race director, Jacob has dealt with measuring and certifying di...
