In Motion

Evaluating Runners with MotionMetrix

Posted by Oliver Watson

Jun 2, 2017 1:49:22 PM

 In this post, we will take a look at how MotionMetrix can be used actively in-session to evaluate running and to set a benchmark for improvement. 

We will be examining the running gait of the wife of one of the zFlo team members: Meredith. Meredith is 5'3" and weighs 115 pounds. She is an active athlete, taking part in regular exercise ranging from weight training to spinning, but does not describe herself as a regular runner.

In the nature of full disclosure: I (Oliver) am not a doctor, therapist, or running expert, and therefore I am not able to provide specific advice outside of what can be gathered by looking at the results and applying basic common sense. Any interpretations or suggestions provided in this blog post should not be considered medical advice or anything of the like.

Testing Process

Now that we have that out of the way - let's talk about the testing protocol we followed. We started out running a single test  at 12 Kph (roughly 7.5 Mph) after a short warmup. After this test, we took a look at the results and identified some specific areas of her gait that required improvement, and tested again. We repeated this for a total of three tests at 12 Kph, and added a fourth test at 14 Kph. From start to finish, we were able to get through all four tests in less than 30 minutes.  


After the first test, here are the results that were provided by the system:


Some key points from the Running Performance Summary page:

  • Running economy was nothing stellar at a grade of "C" - typically this is normal at low speeds, even the most elite runners don't exhibit exceptional running economy scores at lower speeds.
  • Meredith seems to gravitate more towards a glider stride type, as her vertical displacement was slightly lower than where we would like it to be
  • She seems to be slightly over-striding
  • Her running posture is too vertical - ideally we would like to see a slight forward lean



Key points from the Gait Characteristics page:

  • At first glance, it appears as though there is a slight left-right disparity for Displacement of the COM in the vertical plane, as well as for the hip and knee angle maxima and minima. Upon discussing this with Meredith, she mentioned that one of her legs is shorter than the other, so this could provide some clarity to her results.
  • Meredith exhibits a slight Varus alignment in her right knee and a more pronounced Valgus alignment in her left knee (both at mid-stance)



Key observations from the Joint Loading page:

  • Increased Frontal Knee Moment (.102 BWm) for the right leg - this correlates strongly to a Varus knee alignment at midstance, which we can look back and verify in the previous report page.
  • Right Hip Sagittal moment is elevated - which could be related to increased hip extension, as well as a decreased forward lean.

After taking Meredith through the results and glancing at basic changes she could make - such as aiming for more of a "Gazelle" or "Bouncer" Stride type, we ran a second test, and the results were as follows (note that test 1 is overlaid in these results):

Current test results are shown in light blue, overlay test results are shown in dark blue








After receiving the second trial results, I reviewed them with Meredith and together we observed:

  • Running economy improved slightly
  • Her speed capacity score was higher
  • She made improvements with regards to:
    • Forward lean
    • Footstrike Position
    • Stride Frequency
    • Vertical displacement
  • Her forces increased almost across the board, with a few more left-right disparities becoming clear, however this is to be expected as she switched her running style from that of a glider to a bouncer, and therefore should be experiencing higher loads on her hips and knees.

After going through the results, Meredith noted that she had a better idea of how she needed to adjust her stride, and we decided to run one more test:

Results from test 3 at 12 Kph with test 2 overlay






During the third trial, Meredith exhibited her best results yet.

  • Her running economy stayed the same, but her speed capacity score was shown in the elite marathoner range.

This lead us to wonder how she would perform at a higher speed, so we conducted one final test, but raised the test speed from 12 Kph to 14 Kph, and we our suspicions based on her high Speed Capacity score were confirmed:








Meredith's results at 14 Kph were excellent - she actually had the lowest Running Economy score (the lower the better) that we have tested in our lab. While these results are promising, there are a number of variables that could be cause for concern if she were consistently in training, such as her increased joint loading scores (in the red zone) as well as the disparities displayed in her hip and knee angle graphs.

To view all 4 video reports, check out our YouTube channel Here

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The zFlo blog is maintained by our team in hopes of providing some insight into the motion-analysis industry. We work with a large number of companies and have over 10 years of experience working with video and optical motion capture technology - this is where we do our best to explain some of the more important aspects of how this technology can be used.