Thursday 8 November 2012

Western States 2012 Research Findings

I just got an email through about some research done at the 2012 Western States about stride length/rate and what type of foot strike individual runners had as well as the stats for the whole field.

Odd, considering I thought I was more of a mid-foot striker, but at 100-mile mountain speeds the whole running motion is shorter and slower, I suppose.

Here's the email:

Hi Ian,

As you may recall, we collected filming data at the 2012 Western States Endurance Run (WSER) to analyze foot strike pattern.  This email summarizes the overall as well as your individual results. 
Our interest in the study was four-fold.
1. We wanted to characterize foot strike patterns of ultramarathon runners during a 100 mile trail run.
2. We wanted to determine if foot strike pattern, stride rate, and stride length changed over the course of the run.
3. We wanted to determine if foot strike pattern was related to performance.
4. We wanted to determine if creatine kinase (CK, an indication of the extent of muscle damage) concentration was related to a runner's foot strike pattern.

There were 4 filming zones -  1 prior to the Lyon Ridge aid station (10.2 miles); 2 after the Michigan Bluff aid station - 1 on a level running surface (56.1 miles), 1 on a 9% downhill grade (56.4 miles); and 1 prior to the finish line (100.1 miles).
The overall results of the study are summarized as follows:
1. The rear-foot strike prevalence was approximately 80-90% at each of the 4 sites.  This is slightly less than previously observed in a marathon.  Rear-foot strike prevalence was approximately 80% at 10.2 miles.  It increased to 90% at 56.1 miles, then decreased to approximately 85% on the track near the finish line.
2. Stride length was longest at 10.2 miles, decreased at 56.1 miles, then increased at the finish, but was still shorter than the stride length observed at 10.2 miles. Stride rate was highest at 10.2 miles.  It decreased at 56.1 miles and remained similar at the finish.
3. Overall, a specific foot strike pattern was not related to better performance.
4. There was evidence of lower blood CK concentrations among those using a rear-foot strike pattern compared with runners using a mid-foot or fore-foot strike pattern.
Individually, your foot strike pattern, stride length, and stride rate at each site are included below. Foot strike patterns were classified as rear-foot strike (RFS), mid-foot strike (MFS), fore-foot strike (FFS), a combination of mid-foot and fore-foot strike (NON-RFS), a combination of rear-foot and non rear-foot strike (MIXED RFS/NON RFS), or undetermined (UNCLASSIFIED).  NOT DETERMINED will appear when stride length and stride rate could not be determined.  Averages for stride length and stride rate are included (in parentheses) at each site for your reference.
Site = 10.2 miles (Lyon Ridge)
Foot strike = RFS
Stride Length = 95.28 inches (79.12 inches)
Stride Rate = 1.75 strides/s (1.75 strides/s)

Site = 56.1 miles (Michigan Bluff - level)
Foot strike = RFS
Stride Length = 88.19 inches (74.45 inches)
Stride Rate = 1.46 strides/s (1.54 strides/s)

Site = 56.4 miles (Michigan Bluff - downhill)
Foot strike = RFS
Stride Length = 105.51 inches (82.88 inches)
Stride Rate = 1.54 strides/s (1.55 strides/s)

Site = 100.1 miles (Auburn)
Foot strike = RFS
Stride Length = 91.34 inches (78.94 inches)
Stride Rate = 1.58 strides/s (1.55 strides/s)

Thank you for your participation in the 2012 Western States Endurance Run and our research.  We will be presenting our findings at a national sports medicine conference and publishing the work in a sports medicine journal.  If you have any questions about the results please feel free to contact Dr. Marty Hoffman (
We look forward to seeing you on the Western States trails again.
Marty Hoffman, MD
Mark Kasmer, MD
Jeremy Wren, MD


  1. Probably I'm missing something but the stride rate numbers does not make any sense to me.

    According to the data, the average stride rate at mile 10 is 1.75 strides/sec. That means 105 strides per minute. Assuming this is for one foot, the total should be 210 per minute. I don't think anyone would have a stride rate of 210 let alone the average of all participants.

    Unless I'm missing something it doesn't sound right.

    1. Why would you assume that is for one foot?

    2. Well, because, 105 is not a running cadence. It's a typical cadence for slow walking. You can go 140-150 strides per minute with very fast walking, if not more. It's actually very hard, if not impossible, to run with a cadence below 130-140 or so. I can't imagine experienced ultrarunners averaging that cadence.

    3. Marty:

      Great job to you and your colleagues with this research. As others have noted in all previous research on this subject, rearfoot striking running is the preferred of footstrike for the majority of runners. I found it interesting also that CK concentrations were less in rearfoot strikers. Measuring CK levels may be a great subject for future research on how certain footstrike patterns are potentially more injurious to muscle than other footstrike patterns.

      Keep up the good work.



      Kevin A. Kirby, DPM
      Adjunct Associate Professor
      Department of Applied Biomechanics
      California School of Podiatric Medicine


      Private Practice:
      107 Scripps Drive, Suite 200
      Sacramento, CA 95825 USA

      Voice: (916) 925-8111 Fax: (916) 925-8136

  2. Mid foot, fore foot, stride rate, heart rate ... all interesting of course, but ... is the real letter to consider. Might be interesting to see what those stride rate, lengths multiply out to for a pace per mile and how that ties off to the average of 9:33 average.

  3. It's mainly for the sake of interest as I think whatever stride or type of strike a runner has is usually right for them. In a sprint race of 400m or less I'm on my toes; for a 5k my heels don't really touch the ground and in a 100 miler it depends on the incline and terrain. The main thing I know is that if I try to artificially change my gait it doesn't feel natural and isn't as much fun either. It also feels harder to go to any speed so is not as efficient.

  4. I am interested in the CK levels. Did they share those with you? I recently had Rhabdomyolysis and am curious what is "normal" for a hundred.

  5. I'd suggest that injury and recovery of athletes also needs to be taken into condideration. Interesting post but lacking substanance.


  6. @Paul, it's just a post copying an email from the researchers, not a full article for publication in a scientific journal. They were just measuring a couple of things as part of multiple studies that occur every year at Western States. They mentioned their full findings with their conclusions will be published soon.