What 500,000 Miles of Running Can Tell About Your Form

An “unprecedented” understanding of how runners perform and what shoes they wear

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Milestone Sports, a sports technology company, has collected data from more than 8,000 people who ran over 500,000 miles, wearing Milestone Pod’s a shoe-worn running wearable. The result is a detailed and “unprecedented” understanding of how runners perform and what shoes they wear.

The device was synched to the runners’ smartphones through an app. That’s how the company knows exactly how well each runner was doing – how often they ran, how long, how fast, foot strike, cadence, leg swing, and the rate of impact.

All type of runners, including elites, marathoners, speedsters, advanced and beginners participated in the assessment. “Our data can be looked at as a broad stroke across what “real-life” running looks like,” Jason Kaplan, CEO of Milestone Sports, says. “The Milestone Pod collects data throughout a runners’ session. We are able to see their rate of impact for every minute of a run and track how it increases or decreases during a run,” he adds.

Pace generally slows at the halfway mark in runs 30 minutes or longer, but rate of impact (ROI), a measure of how well you are able to absorb the maximum force of impact during foots trike, and cadence does not deteriorate at the same rate. This may show that form does not automatically break down when a runner begins to tire.

The ROI measure provides information about a runner’s form when taken in conjunction with the other data. “So, for example, using the Milestone Pod app you can compare ROI and cadence or ROI and foot strike to see if changes in cadence or foot strike are correlated with increased or decreased ROI,” Kaplan says. “Just today we had a consumer say ‘the numbers I pay attention to the most are my cadence, stance time, stride length, and obviously pace. I've also noticed that when those numbers improve, my rate of impact also improves.’” He dropped from an 8 min mile to a 7 in 2 months using the Pod data.

Overall, in all runs of 30 minutes or longer, the average cadence increases during the first 10 percent of the run, then plateaus, until dramatically dropping during the last 10 percent of the run. This shows smart warm ups and cool downs.

“For a handful of people in our database we have observed that during interval training (alternating very hard running and resting running), ROI has increased during the rest periods,” Kaplan says. “Imagine that you do an 800-meter hard sprint then rest for 400 meters. Most people are highly focused on form during the hard run, but during the recovery run they are just trying to catch their breath. During the recover run it appears runners lose complete focus on form and actually increase ROI, so while they are ‘recovering,’ they may actually be increasing the wear and tear on their bodies.”

A cadence of 180 steps per minute or higher has been described as ideal by many physiologists. The average cadence for runners in the database is 164. “We do see cadence highly correlated to speed,” Kaplan adds. “For example, the average cadence for a woman running 6:30-7:00 pace is 177 whereas the average cadence for a woman running 9:30-10:00 pace is 167.”

Another finding is that 81 percent of runners are heel strike, 11 percent are mid-foot strike, and 8 percent are toe strike. Experts generally agree that runners who are heel-striking are most likely, but not always, over striding. This is not supported by the data. “We think the heel striking/over striding relationship is the other way,” Kaplan says. “That is, most over striders are heel striking, but it is not necessarily true that most heel strikers over stride. Our research clearly shows that it is possible to heel strike and still land with your foot under your knee, and that it is possible to heel strike and have a consistently low ROI.”

As is the case with cadence, there is a pattern in the data that faster runners tend to heel strike less. “For example, the average percentage of heel striking during a run for a man running a 6:30 –7:0 pace is 56 percent whereas the average percentage of heel strikes for a man running a 9:30-10:00 pace is 77 percent.

Other trends include:

A runner’s rate of impact begins to increase when their shoes reach 65 percent of its suggested life span; a runner’s rate of impact increases dramatically when their shoes reach 110 percent of its suggested life span

Across all brands, a runner’s rate of impact increases dramatically when their shoes reach the 425-mile mark

At the end of a shoe’s life (at the 105 percent mark of suggested life span and beyond), runners intuitively seem to know how to deal with increased rate of impact from shoe breakdown: by staying on the ground for less time. They accomplish this through increased cadence, higher leg swing and decreased stance time

The top three shoe models for women are Brooks Glycerin 12, Brooks Ghost 7 and Asics Gel-Kayano 20

 The top three shoe models for men are Adidas Boost, Asics Gel Kayano 21 and Brooks Glycerin 12

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