Rehab & Recovery Zone!

Fascial Lines & Power of Propulsion

By Dr. Emily Splichal, DPM, MS, CES

Fascia. A term that just a few years ago had little meaning in the performance and fitness industry. The days of foam rollers collecting dust in the corner have been replaced with courses specializing in fascial dissection, trigger point release and rehab programming related to fascial slings.

As we enter this paradigm shift in the way we look at human movement, corrective exercise and performance I have seen an increase in the appreciation for the foot & the ankle. With almost every fascial line passing through the bottom of the foot, professionals worldwide and can experience how integrated the foot and the ankle really is with the rest of the body.

This article is dedicated to taking a closer look at how the fascial lines truly influence foot function. Much has already been described on how the fascial slings, namely the spiral line, influence the foot arch. But the importance of fasica and foot function doesn't stop here.

Let's take the importance of fascia and foot function one step further and look at propulsion!

Propulsive Phase of Gait

Whether we are walking, running or jumping – push-off or propulsion is characterized by dorsiflexion of our digits at the metatarsophalangeal joint (MPJ). The joint that takes a majority of the forces during push-off and is responsible for the release of elastic energy is the 1st MPJ.

As much as dorsiflexion of the 1st MPJ seem like a simple biomechanical movement, it is actually quite complex – requiring timed control and activation of our fascial slings.

Let's take a closer look at the 1st MPJ.

The First Metatarsophalangeal Joint

The 1st MPJ is formed by the base of the proximal phalynx and the head of the 1st metatarsal. Sitting directly under the head of the 1st metatarsal and lying within the tendons of the flexor hallucis brevis are the sesamoids. Inserting on the medial aspect of the proximal phalynx is the abductor hallucis which is opposed laterally by the adductor hallucis.

As we begin to transition onto the forefoot, what dictates the range of motion of the 1st MPJ is first metatarsal position in the sagittal plane. The image below illustrates how an elevation of the first metatarsal in the sagittal plane can block the dorsiflexion or gliding the proximal phalynx over the head of the first metatarsal.

So what dictates the position of the first metatarsal in the sagittal plane thereby playing a role in 1st MPJ dorsiflexion on propulsion?

If you guess the Spiral Line you are correct!

The Spiral Line – Expanded Version

In Thomas Myers' Anatomy Trains he describes the lower part of the Spiral Line as the tibialis anterior as it joins the peroneus longus at the level of the base of the 1st metatarsal.

Often referred by Myers at the "stirrup" of the foot, I want to expand upon this concept a little further and demonstrate how the Spiral Line plays a bigger role in propulsion than you may think!

The tibialis anterior muscle runs down the anterior aspect of the lower leg to insert on the medial aspect of the foot on the medial cuneiform (90%) and the base of the 1st metatarsal (10%). Joining plantarly is the peroneus longus tendon which runs along the lateral aspect of the lower leg, behind the fibular malleolus and under the cuboid to insert on the base of the 1st metatarsal (90%) and medial cuneiform (10%).

With 90% of it's insertion on the base of the 1st metatarsal, the peroneus longus plays an important role in plantarflexion of the 1st metatarsal allowing dorsiflexion of the 1st MPJ during propulsion.

So does this mean that for optimal propulsion all we need to do is ensure proper activation of the peroneus longus muscle or the Spiral Line? Unfortunately it isn't that easy. Proper activation of the Spiral Line is actually integrated with another fascial line, namely the Deep Frontal Line.

The Deep Front Line

For the Deep Front Line again we return to Myers Anatomy Trains. In the plantar foot the Deep Front Line consists of the deep posterior leg compartment including the posterior tibialis, flexor hallucis longus and flexor digitorum longus. For the purpose of this article we are going to focus on the posterior tibialis.

Running posterior to the medial malleolus and along the medial aspect of the foot, the posterior tibialis inserts onto the navicular. After attaching to the navicular the posterior tibialis fans out and has 9 osseous and fascial attachments which includes:

• every tarsal bone (except the talus)
• every metatarsal (except the 1st)
peroneus longus tendon
• flexor hallucis brevis muscle

This fascial attachment between the posterior tibialis and the peroneus longus joins the Deep Front Line to the Spiral Line allowing for more integrated foot biomechanics.

Because the posterior tibiailis activates prior to the peroneus longus this fascial integration actually prepares the foot for propulsion. With the posterior tibialis as a driver of subtalar joint supination or inversion just prior to heel lift, a reflexive activation of the Spiral Line and stabilization of the 1st metatarsal by the peroneus longus allows dorsiflexion of the 1st MPJ and propulsion.

Clients & Athletes Application

When assessing optimal propulsion in our clients and athletes remember the function of the Spiral Line and Deep Front Line on 1st MPJ dorsiflexion.   A limitation in 1st MPJ dorsiflexion or power at propulsion may be related to an impairment in posterior tibialis strength.

To optimize posterior tibialis strength in clients and athletes integrate barefoot exercises such as short foot which picks up the navicular bone and stimulates the Deep Front Line.   In addition single leg exercises can be used the strengthen the posterior tibialis and it's co-activation patterns with the gluteus medius and maximus.

To learn more about foot function, barefoot science and from the ground up training please visit www.ebfafitness.com.

References

McGlamry's Comprehensive Textbook of Foot and Ankle Surgery, Fourth Edition. Lippincott Williams & Wilkins

Thomas W. Myers (LMT.) (19 September 2001). Anatomy Trains: Myofascial Meridians for Manual and Movement Therapists. Elsevier Health Sciences. ISBN 978-0-443-06351-0



Dr Emily Splichal, Podiatrist and Human Movement Specialist, is the Founder of the Evidence Based Fitness Academy and Creator of the Barefoot Training Specialist®, Barefoot Rehab Specialist® and BARE® Workout Certifications for healh and wellness professionals. With over 12 years in the fitness industry, Dr Splichal has dedicated her medical career towards studying postural alignment and human movement as it relates to foot function and barefoot training.

(August 2014)