Pre-Season Stride Analysis for Maximum Efficiency and Injury Prevention

Could a sub-2 hour American marathon record really be possible? This youtube video is pretty convincing that there are some surmountable barriers that could lead to super-duper-improved marathon finish times, even among the most elite American runners. If there is room for them to improve, then certainly there is room for me. As a matter of fact, only 10% of Ironman participants finish the marathon portion in under 4 hours . This is a MONSTROUS opportunity where I can improve my time because I'm actually a damn fast white man... on a soccer field, anyway.

Not Michael Jordan.

I've decided to take an analytical look at my stride to see if I can access some of these speed/efficiency gains, BUT I want to balance these adjustments with the success of my newly-adopted injury-prevention running form. The video had me wondering, "does speed necessarily come at the expense of a sustainably safe form?" After analyzing my form, I am hopeful that, yes, they can coexist.

RUNNING INJURY HISTORY
After the 2009 Ironman, I would suffer sharp knee pain any time my runs exceeded 10 miles or so. My brother-in-law is a physical therapist and discovered that I had wimpy hip stability and weak gluteus medius. I also read Born to Run and Chi Running and became convinced of a more natural way to run than my body has adapted to over years spent playing soccer and running in whatever running shoes were on sale/in style when I needed them. Thus, my recovery strategy became 4-fold:
1) butt/hip/IT strength exercises
2) Pilates 2-3x/week
3) minimalist running shoe that mimics barefoot running
4) technique overhaul

MY CURRENT TECHNIQUE
What I took from Born To Run and Chi Running as far as practical application to my stride were the following:
1) quick, light steps
2) land on mid-foot
3) excellent posture, leaning forward at the ankles (not the waste) to go faster (rather than spinning legs faster)
4) upper body should remain quiet, starting at T12 vertebra and up.
5) speed? I simply haven't been tested yet. (I ran the Flying Pig Marathon in excruciating knee pain last spring, and I just didn't get the preparation I needed while we spent our evenings and weekends planning and constructing Studio S.)

ANALYSIS SUMMARY
If you watched the "2 hr marathon" youtube video, then you saw the breakdown of some of the important body metrics. Here are mine:
1) Bounce Height- 2.2"-2.9"
2) Stride Angle/Stride Length- 64 degrees
3) Over-stride Angle- 0-1 degrees
4) Toe Lift Angle - 0 degrees
5) Cross-over Angle- 6 degrees

I set the treadmill to 12 mph, which is the speed the top Americans run when they compete, so, I felt this a fair way to compare my metrics to their metrics. (I realize that at lower speeds, my metrics might be way different. Also, this whole exercise may be as irrelevant as measuring my butterfly stroke. This type of 12mph running just doesn't happen after cycling 112 miles. But, if nothing else, it was kind of fun using a protractor for the first time since 8th grade.)

Maximum stride angle - 64 degrees. Note the height of my nose.

At minimum, nose height is 2.2-2.8 inches lower than at max height.

Right foot crossover angle ~ 6 degrees.

Left foot crossover angle ~ 6 degrees

At first glance, it almost appears that I am way over-striding, but my foot has a long way to go before landing on the treadmill.

Here's a snapshot of the first frame of my video where I can tell that my foot touches the treadmill. I land my foot almost completely parallel with the ground and with my ankle directly beneath the knee. That would be an over-stride angle of 0-2 degrees and a toe lift angle of 0 degrees. (I really need a better image to draw reliable conclusions. )

ANALYSIS (LENGTHIER)
BOUNCE HEIGHT-- the wasteful vertical height traveled each stride. Multiplied by ~1000 strides per mile x 26+ miles = extra miles traveled upward, requiring more energy, and downward falling of several miles' worth of impact (yuck). If you watched the video, then you realize how big of a deal this for someone like Ryan Hall. His bounce height is supposedly 4", adding up to over 3 miles of extra climb and 3 miles downward impact. My bounce height is about 2.2"-2.9". The Kenyans? More like 1"-1.5"


STRIDE ANGLE- the angle formed between the two legs as the leading knee comes up. The greater the stride angle, the greater the stride length, and the fewer the steps taken over the course of the race. One degree of increase in stride angle turns into ~2% increase in stride length. My stride angle is about 64 degrees. I am going to work to increase this.


OVERSTRIDE ANGLE- Most runners compensate for a small stride angle by reaching their planting heal ahead of their knee. Heal bone stores no elastic energy compared to an achilles heal. So, it's like throwing on the breaks. Mine is tough to measure due to the image quality, but appears close to 0 degrees, maybe slightly over-striding by a degree or two.



TOE LIFT ANGLE- Occurs when shins are flexing the toes upward when impact occurs. Very risky for stress fractures and is exhausting! This is the metric that I have had no problem working on since using the minimalist shoes and doing more and more barefoot running. I am pretty sure I land on the imaginary line that crosses my foot at the bony knob on the outside (5th metatarsel) rather than the heel. However, after cycling 112 miles, the calves are kinda sore, so running "on the toes" hurts. This may be more of a cycling fitness issue than a running technique problem.


CROSSOVER ANGLE- by twisting our shoulders and trying to over-stride we tend to allow our forward leg to cross our bodies' mid-line-- the sagittal plane. The Kenyans plant their right foot on the right side of the sagittal plane and their left foot on the left side. My disappointing crossover angle of ~6 degrees is possibly contributing to my lingering knee/IT pain. It may also be due to an improper application of the Chi Running T12 pivot point or it might be residual baggage from years of running however the heck I felt like it. Then again...how natural is it to run on pavement? And how natural is it to NOT run however the heck we feel like it?