Tuesday, June 12, 2012

Update and Some New Studies - Toe Force and Ankle Flex

Update and Some New Studies

Quick update on the training and running. After doing St. Louis Peak, I did my "fast" loop to continue to work on form and foot placement. It went well, but it was harder to run continuously at a steady state on the fronts of the feet when tired. I kept finding myself wanting to open up my stride a bit (instead of the quicker turnover associated with frontal running), as it felt more relaxing in my slightly tired state. However, when I do that I notice instantly how I would slow down just a touch and begin to slightly strike the heel. The subtle difference between the two is really noticeable on flatter terrain over longer distances. On hills, I always land on the fronts and use a quicker cadence. Its the flats and downhills where I need to learn to make up time.

After a day off, I ran Bottle Peak again this morning. I really love this run, as it involves a nice opening trail and some fun climbing at the end. I felt pretty good, although I attribute eating out for lunch yesterday (sadly, a burger and fries) resulting in my slightly un-energized speed. It took me 2:16 today.

Speaking of running form, a new study published called The Potential of Human Toe Flexor Muscles to Produce Force is interesting, especially if you are into the barefoot running or even the more frontal running style (as opposed to the heel-toe style). The study looked at what point does the long and short toe flexor muscles produce force in relation to ankle flex. The long and short toe flexor muscles are the ones that help "push" off around the big toe and area. The researchers wanted to know at what point during a foot strike were these muscles producing the most force, i.e., when did they give you the biggest push/benefit. They found that the biggest push/benefit from your toes comes when your ankle is at 0-10 degrees dorsally flexed. What this means is that if you are running with more of a frontal strike pattern, then your toes will help contribute to your push off (and thus momentum) almost at the exact moment when you strike (when you ankle is flexed 0-10 degrees and your foot is on its upward journey), while if you are more of a heel-toe striker, you will not get quite as much benefit from your toes pushing off, primarily because your ankle will be already flexed beyond 0-10 degrees dorsally. This under utilization of your toe force will increase the wider your stride is because it will change the angle of your ankle flex. So, what this means in layman's terms is that you want to try and have a slightly smaller stride (and most likely higher cadence) so that when you push off you do so with a minimal bend at the ankle. If you land flat or slightly on your fronts, and immediately begin to push off, you will have the most force to propel you forward. If you open up your stride, that force will decrease (at least in the toes, it may increase in terms of other muscle force expenditures) because your ankle will be at a slightly greater angle.

This is something to think about, especially on longer trail runs or during ultras. To keep up a good pace, it seems you want to have a higher cadence with a more flat or frontal foot strike to help keep the forces you are generating in pushing you forward. If you have greater ankle flex, then you will not be using your maximum force, which over time could result in some serious time or distance variances. I'm not an advocate for the barefoot thing, but I think that working on one's form is essential in improving one's running. So, next time you are out, pay attention to how you are landing, at which point you "push" off, and if you can tweak that a bit. It might improve your time by just enough to make a difference.

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