For most consumers, the idea of monitoring movement through wearable technology is new. However, coaches, trainers, and athletes have been using lightweight sensing devices for more than a decade. While the consumer markets have focused on activity tracking and coaching, the power and accuracy available in today’s wearables are bringing lab-grade technology into the field for specialized use cases. This includes everything from tracking your golf swing to concussion sensing.
At Scribe Labs, we developed a wearable sensor for running, called RunScribe. Over the past year, we’ve amassed what we believe is one of the largest databases of “real world” run data comprised of advanced metrics, including: symmetry, flight ratio, pronation, pronation velocity, footstrike type, shock, impact Gs, and braking Gs. At last count, we’ve captured more than 45,000 runs, 200,000 miles and 245 million steps. From those runs, we’ve calculated more than three billion run metrics. So yeah, we’ve got a lot of data. With that data, we have a unique perspective on what works—and what doesn’t—when sports professionals bring wearable tech into their programs.
We’ve captured more than 45,000 runs, 200,000 miles and 245 million steps.
The Wearable Tech Opportunity
First, let’s start with the opportunity. Wearable tech offers substantial benefits. These include the following.
Real World Data
By capturing metrics “in the wild,” wearable data reflects an athlete’s natural movement. It doesn’t provide a complete or accurate picture when you’re restricted to lab environments or video analysis that can only evaluate narrow aspects of an athlete’s performance — like one or two steps of a marathon. Running on a treadmill is different than running on a trail [1,2]. With wearables capable of capturing every footstrike of a race or training program, we can get a much more accurate and nuanced view of performance, form, and risk.
Small and Unobtrusive
The last thing you want is to impede an athlete with technology. Today’s wearables can weigh just a few ounces and transmit information wirelessly. This means that athletes can focus on performance without distraction.Today’s sport tech wearables are small & unobtrusive, so athletes can focus on their performance. Click To Tweet
Low Cost = Democratization of Data
With the cost of advanced sensor tech dropping, many of these systems are priced below $200. This finally makes them accessible for everyone from high school track teams to the pros.
A Better Yardstick
When advanced metrics are accessible on a consistent basis, coaches and therapists can quickly quantify progress in performance and injury recovery, and identify areas of weakness. A couple of examples of this are:
- A coach can watch an interval session and see the entire team successfully completing intervals at pace, but some individual athletes report struggling. Looking at the data, that coach can then determine what changed in the running mechanics over the last few intervals and get a better picture of how fatigue affects those athletes. In turn, coaches can add specific drills that address those kinematic changes.
- A therapist who suspects that over pronation or high pronation velocity is contributing to a patient’s knee pain can try multiple orthotics or shoe inserts in one session. They can then collect objective data quickly and inexpensively, to see which insert may have the best result before sending the athlete out on a longer run.
Variability is a natural part of running, and understanding it is the Holy Grail. Mechanics change with pace, shoes, terrain, and fatigue. It is not unusual to see a 30% difference in a particular metric when an athlete changes terrain. Wearable technology gives an opportunity to understand variability in ways that haven’t been possible before.
For instance, while you may have previously just assumed that a forefoot striker is always a forefoot striker, this is not necessarily the case. You may shift your footstrike pattern based on the shoes you’re wearing or the terrain you’re on, or as you get fatigued over the course of your run. The understanding of variability is a huge missing piece in the way that runners are assessed and helps to make decisions on training programs and shoe wear.
Many runners don’t understand the importance of training specificity. In order to race successfully at a given pace, an athlete needs to spend significant time training at or near that pace. Many of us that don’t train with a coach or a group will often do the same thing in training almost every session and then whine about not getting faster. Movement patterns and footstrike characteristics can be very different at race pace, as compared to an athlete’s standard training pace. If you run the same pace every day in training then, by default, that becomes your race pace. Real-world wearable data illustrates these differences and can help athletes and coaches to develop pace-specific programs.
Wearable Sports Tech Risks
Wearable technology can provide more meaningful running metrics that capture real-world performance. However, as with any technology, there are risks and reasons to be cautious.
Accuracy and Consistency
Sensor technology has become increasingly accurate with incredible processing speeds, but the devil is in the details of what you do with that raw sensor data. We’ve all heard that the accuracy of step counters and activity trackers can be off by as much as an astounding 20% [3,4]. Validating metrics through third-party research is critical to becoming a trusted tool.
Scribe Labs is one of the few wearable tech companies to publish our research and validation studies on Running Unraveled. In the rush to take advantage of wearable technology opportunities, we’ve seen a substantial range in accuracy and consistency. If coaches and athletes make training decisions based on new metrics, it’s important to research the validity of the data. Companies are always working to improve accuracy and handle outliers, but it’s important to have transparency in data accuracy and validation.
So Much Data
Did we mention that we had three billion calculated footstep metrics? That’s a lot of data, and it can be overwhelming. New metrics are less understood and there can be a learning curve to grasping their implications. Wearable technology is shortening the time frame between academic study and practical application. This is exciting, but it can also be daunting. New communities are popping up where athletes, coaches, and trainers share how they use wearable technology in their programs. Scribe Labs publishes its research and use cases on Running Unraveled.
There is a deep human desire to narrow down complex information to its simplest form. In a sport like running, this can cause more harm than good. In analyzing the RunScribe community data (all three billion footsteps!), there is very little that we can generalize about running. At first glance, what seems like common sense gets twisted.
For example, to the naked eye, many world-class runners appear to be very light on their feet, so you might assume they have low impact Gs and shock. And yet, looking at data from an Olympic runner with sky-high shock values, we could see they’ve learned that higher impact values and a shorter ground contact phase help utilize elastic energy to propel them forward. However, many average runners wouldn’t be able to withstand that level of pounding for long.
There are also a number of generic “metric targets” around stride rate (180 target) or contact time (200ms) that don’t hold true for everyone, or even show consistent correlation to hitting goals. In a study done at the 2015 New York City Marathon, we compared stride rate to finish times and found almost no correlation. But we did find that flight ratio is much more likely to correlate to finish times.
Many running wearables provide real-time feedback and coaching through a mobile app. This makes a lot of sense. “You’ve given me all this data—so tell me what to do with it!” The problem is that most of these coaching applications fall victim to the risks we’ve outlined.
The oversimplification of advice can range from being slightly useful to dangerous. Providing guidance without accounting for variability or context is a huge risk because we know there is no “one size fits all” advice for runners. For example, the Golden Rule of a 180-step rate was derived from legendary coach Jack Daniels, when he was observing middle and long distance runners at the ’84 Olympics. The key to this “rule” that is nearly always missed is that these athletes were running at race pace. We see some apps and coaches assuming that a 180-step rate should be a target at every pace. It shouldn’t.
Integrating Wearable Tech Into Your Practice: Coaches
So how are coaches and trainers using wearable technology in their practices? We’re seeing the RunScribe system used in very different ways, based on the type of user. For coaches, RunScribe data quantifies performance and progress, but also helps solve very specific issues. Here are some examples.
Establishing a Baseline
If you’ve got a healthy runner, get their data snapshot. This allows you to do an in-depth assessment, identify areas of potential concern (rapid and extreme pronation, large asymmetries, high shock values, and big differences in metrics in different shoes), and track progress. Additionally, if a runner does get injured, having a baseline assessment of their metrics can help coaches determine when they are fully recovered.
Tracking Progress Holistically
For running, it all comes down to pace. But we know that the way athletes get to pace can be very different. Traditionally, there have been limited metrics to guide a runner’s training, like cadence, pace, and heart rate. While useful, these metrics don’t provide a holistic view of performance. By tracking change against an athlete’s baseline, a coach can see if progress is being made with efficiency metrics like flight ratio and contact time, but with an eye toward maintaining consistent motion and shock metrics. Slow and steady improvements can win the race and keep a runner healthy.
Coach and author, Steve Magness, wrote a case study on how he uses RunScribe data to help his athletes run a better race. By breaking down interval sessions, he can see when his athletes are hitting their rhythm, and can help train them to find their rhythm faster without exerting needless energy.
The implications of pace on mechanics are relatively straightforward: As running speed increases, impact Gs, pronation, pronation velocity, and flight time usually increase; whereas contact time drops because our feet spend less time on the ground. When fatigue is introduced, the dynamics change: Impact Gs can rise as pace decreases; contact time can increase even though a runner maintains pace. Understanding how a distance runner’s mechanics change to compensate for fatigue can open up opportunities for training to target areas of weakness and combat the impact of fatigue .
Integrating Wearable Tech Into Your Practice: Clinicians
For sports doctors and therapists helping athletes recover from injury, or adjusting mechanics, wearable technology is supplementing and—in some cases—replacing, lab-based systems like high speed motion capture and force platforms. In the case of RunScribe, data collection and analysis tends to have a faster turnaround time than traditional lab-based equipment and can be extremely helpful in gait retraining scenarios. Therapists can send their clients out into the real world and find out if changes seen in the lab are maintained outside.
Here are some examples of applications of wearable technology being used in clinics today.
Wearable technology allows sports pros to capture client run data in the wild, establishing a baseline for a runner’s mechanics in their preferred environment—on a treadmill, track, trail, or road. Understanding the impact of variables on a runner’s stride creates deeper and more meaningful insights during the assessment process.Wearable tech captures data ‘in the wild,’ creating a baseline for a runner’s mechanics. Click To Tweet
Advanced metrics can provide deeper insight into a runner’s symptoms. Pronation excursion and velocity, symmetry, footstrike, impact Gs, and braking Gs frequently provide a clearer picture of a runner’s issues.
Accurate wearables eliminate the need for manual calculation of metrics from video footage. Physios and PTs can use advanced metrics to reinforce and quantify what they see in video footage. When tracking progress for injury recovery or the impact of orthotics on stride, wearables rapidly illustrate the changes in a runner’s mechanics.
Symmetry imbalances are a natural part of runner’s stride, but identifying substantial asymmetries—particularly in footstrike patterns, pronation excursions, and pronation velocities—help to assess the severity of issues and the effects of treatment over the course of multiple sessions.
Objective Feedback Loop Creation
The success or failure of a treatment plan is frequently based on a client’s ability to stick to the plan. Overdoing it or overexerting is common. By using wearable technology between appointment periods, clinicians can monitor the effects of the plan and also evaluate objective data to ensure the runner is sticking to the program.
Wearable Sports Tech Is Not a Threat
No wearable device is ever likely to replace the value a coach or clinician can bring to a runner. That wealth of knowledge and the ability to analyze the many components of a runner’s history and form is invaluable. By providing reliable and accurate measurement tools in the field, wearables like RunScribe put more meaningful data in the hands of sports professionals, which allows them to perform in-depth real-world assessments, track change, and quantify progress. As this data becomes more accessible and more broadly understood, we can learn to train smarter and improve treatment programs as a community.
John Litschert is the biomechanist and co-founder of Scribe Labs. Prior to co-founding Scribe Labs, John worked at the U.S. Olympic Training Center and at Colorado State University where his focus was on gait analysis.
Tim Clark is CEO and co-founder of Scribe Labs. Tim’s background in engineering has spanned consumer electronics to sports technology. Previously, Tim worked at Red Octane (Activision), MetriGear (Garmin), and the U.S. Olympic Training Center.
- Nigg, Benno M., Ruud W. De Boer, and Veronica Fisher. “A kinematic comparison of overground and treadmill running.” Medicine and Science in Sports and Exercise 27.1 (1995): 98-105.
- Wank, V., U. Frick, and D. Schmidtbleicher. “Kinematics and electromyography of lower limb muscles in overground and treadmill running.” International journal of sports medicine 19.07 (1998): 455-461.
- Sasaki, Jeffer Eidi, et al. “Validation of the Fitbit wireless activity tracker for prediction of energy expenditure.” J Phys Act Health 12.2 (2015): 149-154.
- Dannecker, Kathryn L., et al. “Accuracy of fitbit activity monitor to predict energy expenditure with and without classification of activities.” Medicine & Science in Sports & Exercise 43.5 (2011): 62.
- “The Unescapable Fatigue Effect.” Running Unraveled, 1 August 2016, www.runningunraveled.com/2016/08/01/the-fatigue-effect.