New photos and measurements are up on the progress page. Both pictures this week seem to show an increase in arch height. The arch index on the left went up from 1.02 to 1.06 and it also went up on the right from 1.16 to 1.26. This would seem to be a slight change in the wrong direction. What I’m aiming for is an index number below 1.0. I noted last week that the reliability of the measurements is probably not as good as it ought to be if this were a real clinical trial because the methods being employing are rather low-tech. I’m also trying to be as conservative as possible when taking measurements from the footprints. For example, here is a picture of what the left footprint looked like today:
If you look in the area of the medial arch you can see a small line separated from the rest of the sole imprint, almost like its own little isthmus. The imprint is taken with me walking over a sheet of paper and therefore I would expect the plantar pressure to vary from the time I step on the paper until the time I lift my foot off. The footprint is taken this way so I can get an idea of the dynamic arch height.
Judging from the picture, at some point, the medial border of my foot came in contact briefly with the floor, with enough pressure to create that line. If I took a standing imprint I’m guessing that line wouldn’t be there, in which case the arch index would be lower. I include every part of the footprint in the measurement to be as accurate and consistent as possible, although I suspect there is a lot of variability over the short term. For both the progress photos and measurements it will be more insightful to view the long-term trend in order to gauge real improvement.
Over the last week, I’ve been really optimistic about the progress because for the first time since starting this project there is real soreness in my arches, the good kind of soreness that you get from working out. I’ve suspected that weakness in the intrinsic foot muscles is one of the primary causes of flat feet, and I’m interpreting the soreness as a positive sign that those muscles are being engaged and strengthened. There is also soreness to a lesser degree on both sides of the ankle. This was most evident after I did some barefoot runs on pavement.
On the outside of the ankle are the peroneal muscles that work as foot evertors and plantar flexors. They are also important dynamic stabilizers of the foot and ankle. As the foot becomes more supinated (higher arch) these muscles stretch and work from a more lengthened position than they are accustomed to. On the inside of the ankle, there are three muscles: posterior tibialis, flexor digitorum longus, and flexor hallucis longus. These are foot invertors and that also function to elevate the arch. Posterior tibialis weakness is implicated in many cases of adult acquired flat foot deformity. Building strength in muscles takes time and now at five weeks into the project this should be close to the time when measurable strength improvements begin to appear.
In addition to increasing barefoot activity, I’ve been working on variations of the short foot exercise which directly targets the muscles of the arch. I’m still including exercises to address other issues indirectly related to foot posture and pronation, such as correcting anterior pelvic tilt, glute and hamstring strengthening etc. Because of the new muscle soreness I’ve started taking entire days off from some of the strengthening exercises to allow the muscles adequate time for recovery.