Monday, October 22, 2012

Update, Foot Strike, Low Back Posture, Comfort, And Fatigue And Vertical Ground Reaction Force

Update, Foot Strike, Low Back Posture, and Comfort, and Fatigue and Vertical Ground Reaction Force


Friday: Off - 6 hours standing and walking.

Saturday: Off - 6 hours standing and walking.

Sunday: 11 miles, 1,400' gain, 1:21. A solid effort on the Creekside-Leland-Zoom-Chainsaw loop. There was still a little snow, but most of the sketchy ice has melted.

Monday: 9 miles, 1,700' gain, 1:21. Deadhorse climb. Funny how I did the exact same time both yesterday and today, but the mileage was different.

Planning on having a mellow week before this weekends race. Hopefully I can make it, as right now I don't have any way of getting to the race.

Two more studies have been published. The first, entitled "Effects of Foot Strike on Low Back Posture, Shock Attenuation, and Comfort in Running" looked at the differences between rearfoot and forefoot strike and biomechanical changes, specifically within terms of barefoot running. The authors wanted to know if the change from a rearfoot to a forefoot strike pattern as a result of switching to barefoot running also had an impact on lumbar spine range of motion. Surprisingly, the authors found that there was a decrease in the range of motion of the lumbar spine when runners switched to a forefoot strike pattern. However, this decrease in the range of motion did not make a difference in the flexion or the extension in which the lumbar spine is positioned, and that the rearfoot strike pattern was perceived to be a more comfortable running pattern. Of course, the study was limited to a single experiment, and over time barefoot running may be perceived as being similarly comfortable once a runner has become accustomed to it. As noted previously, the science on barefoot running is still out, but a rearfoot strike pattern does result in higher ground reaction forces, despite being perceived as being more comfortable. 

Interestingly, the second study conducted a meta-analysis of these ground reaction forces and muscle fatigue in the legs. Entitled "The effects of lower extremity muscle fatigue on the vertical ground reaction force: a meta-analysis" the authors found that over the course of running, the ground reaction force impact peak did not change as muscles became fatigued. Basically, the impact of the foot striking the ground during running did not change - it is the same whether you are tired or not. So, even when you are tired and your feet are dragging during the last stages of a long run or ultra, remember, the impact force is the same, it just feels like it is more. Here again then is a study showing that for the long runs and races, the mind plays almost a more important role then the body. Hopefully I can remember that next time I get tired and want to just walk - everything is really the same as when I started the run, I just think it is harder.

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