1st MTP Pain?

It may not be a trigger point. In this capsule summary, Dr Ivo discusses an interesting and perhaps revolutionary, theory on trigger point pain that refers to the 1st metatarsal phalangeal articulation. The anatomy of the joint and responsible muscles are also discussed

All about 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.

Born to Run?
Perhaps we really were born to run. This study looks at the forefoot, the phalanges and their potential role in the evolution of our feet. 

We know impact forces increase with running, so it makes sense that physical and metabolic demand to continue forward momentum would increase as well. Longer lever arms (such as longer toes) would require greater torque on the muscles as well as increased lift of the foot (to provide ground clearance), and most likely a different orientation of the rearfoot and trochlea that the flexor tendons would have to pass through. This would probably result in a more cavus, rigid foot as well.
The study did not state, but suggested muscular recruitment of the flexors is distinctly different in walking vs running, and that there is less “balance” between the flexors and extensors. We contend that with appropriate gait patterns (ie, using the glutes as a primary hip extensor), long flexor activity would be more balanced with long extensor activity and this disparity would not be seen.

The video has nothing to do with the study, we just thought it was pretty funny

Sorting out the details so you don’t have to; The Gait Guys

J Exp Biol. 2009 Mar;212(Pt 5):713-21. Walking, running and the evolution of short toes in humans. Rolian C, Lieberman DE, Hamill J, Scott JW, Werbel W. Source http://www.ncbi.nlm.nih.gov/pubmed/19218523

Department of Anthropology, Harvard University, Cambridge, MA 02138, USA. cprolian@ucalgary.ca

Abstract

The phalangeal portion of the forefoot is extremely short relative to body mass in humans. This derived pedal proportion is thought to have evolved in the context of committed bipedalism, but the benefits of shorter toes for walking and/or running have not been tested previously. Here, we propose a biomechanical model of toe function in bipedal locomotion that suggests that shorter pedal phalanges improve locomotor performance by decreasing digital flexor force production and mechanical work, which might ultimately reduce the metabolic cost of flexor force production during bipedal locomotion. We tested this model using kinematic, force and plantar pressure data collected from a human sample representing normal variation in toe length (N=25). The effect of toe length on peak digital flexor forces, impulses and work outputs was evaluated during barefoot walking and running using partial correlations and multiple regression analysis, controlling for the effects of body mass, whole-foot and phalangeal contact times and toe-out angle. Our results suggest that there is no significant increase in digital flexor output associated with longer toes in walking. In running, however, multiple regression analyses based on the sample suggest that increasing average relative toe length by as little as 20% doubles peak digital flexor impulses and mechanical work, probably also increasing the metabolic cost of generating these forces. The increased mechanical cost associated with long toes in running suggests that modern human forefoot proportions might have been selected for in the context of the evolution of endurance running.