Here's on one of our favorite subjects: toe break:
No, this is not a post about fractures phalanges, but rather where your shoe bends, or should bend.
Toe break is where the shoe bends anteriorly. Ideally, we believe this to be at the 1st metatarsal phalangeal joint and metartarsal phalangeal articulations. This allows for the best “high gear” push off as described by Bojsen-Moller (1) High gear push off means that the pressure goes to the base of the great toe (1st MTP joint) for push off. (for an interesting post on this, see here .
If we think about rockers of the foot during the gait cycle (need a review? click here), it seems best that we accommodate each of them to the best of our abilities. Since most of us wear shoes, it would make sense that it flex in the right places. With regards to the forefoot, it should (theoretically) be under the 1st metatarsal phalangeal joint. This should provide both optimal biomechanical function (distribution of force to the 1st metatarsal phalangeal joint for push off/ terminal stance) and maximal perceived comfort (2).
If the shoe bends in the wrong place, or DOES NOT bend (ie, the last is too rigid, like a rockered hiking shoe, Dansko clog, etc), the mechanics change. This has biomechanical consequences and may result in discomfort or injury.
If the axis of motion for the 1st metatarsal phalangeal joint is moved posteriorly, to behind (rather than under) the joint, the plantar pressures increase at MTP’s 4-5 and decrease at the medial mid foot. If moved even further posteriorly, the plantar pressures, and contact time in the mid foot and hind foot (3). A rocker bottom shoe would also reduce the plantar pressures in the medial and central forefoot as well (4). It would stand to reason that this would alter gait mechanics, and decrease mechanical efficiency. That can be a good thing or a bad thing, depending on what you are trying to accomplish.
Take home messages:
Where a shoe flexes will, in part, determine plantar pressures
Changes in shoe flex points can alter gait mechanics
More efficient “toe off” will come from a shoe flexing at the 1st metatarsal phalangeal joint and across the lesser metatarsal phalangeal joints
examine the “toe break” in your clients shoes, especially of they have a foot problem
1. F Bojsen-Møller Calcaneocuboid joint and stability of the longitudinal arch of the foot at high and low gear push off. J Anat. 1979 Aug; 129(Pt 1): 165–176.
2. Jordan C1, Payton C, Bartlett R Perceived comfort and pressure distribution in casual footwear. Clin Biomech (Bristol, Avon). 1997 Apr;12(3):S5.
3. van der Zwaard BC1, Vanwanseele B, Holtkamp F, van der Horst HE, Elders PJ, Menz HB Variation in the location of the shoe sole flexion point influences plantar loading patterns during gait. J Foot Ankle Res. 2014 Mar 19;7(1):20.
4. Schaff P, Cavanagh P Shoes for the Insensitive Foot: The Effect of a “Rocker Bottom” Shoe Modification on Plantar Pressure Distribution Foot & Ankle International December 1990 vol. 11 no. 3 129-140
plantar pressure image above from : Dawber D., Bristow I. and Mooney J. (1996) “The foot: problems in podiatry and dermatology”, London Martin Dunitz Medical Pocket Books.