How we move - the Gait Cycle

Every step we take when we walk or run can be broken down into a several component movements or phases, together these form the Gait Cycle. A complete Gait Cycle begins when one foot hits with the ground, takes the weight of the body, propels the body forwards and ends when that same foot is lifted and brought forward ready to make contact with the ground again.

The foot is in Stance Phase for 60% of the time when it is in contact with the ground and Swing Phase for the remaining 40% when it is raised and airborne.

Stance Phase is critical as this is when the foot and leg bear your body weight and are most likely to sustain injury. This phase can in turn be divided into four stages:

1. Heel Strike where the foot makes initial contact with the ground normally at the outer edge of the heel with the toes and forefoot raised up towards the shin (dorsiflexed).

2. Flat Foot when the forefoot lowers and makes contact with the ground and accepts the weight of the body.The foot and ankle roll in (pronate) allowing maximum foot mobility so it can adapt to uneven terrain and absorb the ground reaction forces.

3. Midstance where the foot and leg bear all the body weight and provide a stable platform for the body weight to pass over as the foot and ankle start to roll out (supinate).

4. Heel Off the final phase during which the heel is raised and the bones of the midfoot are braced to produce a rigid lever arm. Heel off is completed as the ball of the foot and toes thrust down (plantarflex) momentarily against the ground propelling the body forward, known as "toe off".

The foot then begins the Swing Phase during which the foot initally sweeps back with the leg before being brought forward again as the leg strides forward and is dorsiflexed whilst it is airborne to position it for its next Stance Phase.

Effective forward movement whilst keeping the body upright and balanced requires the feet to work in sequence. So for example, Foot A enters stage 3. Midstance of its Stance Phase, taking the body's weight as Foot B toes off at the end of stage 4 and enters its Swing phase.

The Spring in your step!

In order to maintain the integrity of the foot's arch, its rigidity and to provide sufficient leverage and power for propulsion, the bones within the foot rely on various tendons and ligaments, primarily the Plantar Fascia. This ligament is connected to the heel bone (calcaneus) and runs horizontally along the underside of the foot connecting to the base of each toe, forming the base of a triangular shaped structure with the toes and ankle, when viewed through the saggital plane, which prevents the foot's structure collapsing during weight bearing.

At the beginning of the gait cycle when the toes are dorsiflexed, the Plantar Fascia is stretched, tightening around the ball of the foot. This movement flattens the arch of the foot and builds kinetic energy in the ligament.

As the toes are plantarflexed and the heel is lifted at stage 4 of the gait cycle, the Plantar Fascia contracts raising the arch. This releases the energy and provides the thrust which propels the body forwards. This is known as the Windlass Mechanism.

Get to know your feet ...

Overpronation - rear view

Overpronation - front view

Overpronation - side view

Wet footprint test
      

The human foot has evolved over millions of years to carry us in an upright position. It is really designed to perform best on soft uneven ground such as grassland or sand where the terrain compacts under the arch of the foot giving it additional support. However, most of our activity occurs on hard paved areas nowadays, so your choice of footwear, particularly for sporting activities is vitally important as it provides a micro-environment for your feet.

A normal gait pattern also requires the foot and ankle to be able to "rock" from side to side where they meet at the ankle - the Subtalar joint. This joint allows the foot to roll inwards "pronate" when the foot makes contact with the ground to absorb the shock and adapt the foot to whatever surface we walk on. The joint should also allow the foot to roll back outwards "supinate" so it becomes rigid enough to maximise propulsion during the last stage of the Stance Phase.

Ideally, the foot is slightly angled at 3 - 4 degrees at heel strike causing the foot to meet the ground on the outer edge of the heel allowing the maximum and strongest area of foot, ankle and lower leg to absorb the shock. This angle is referred to as the "Tibial Varum Angle".

Overpronation, where the foot rolls inwards for too long and too far consequently over-flattening the arch and impeding the Windlass mechanism is very common, affecting at least half the population. The effect is quite marked as can be seen in these images, the ankle bone is much more pronounced in an overpronated foot and the achilles tendon appears twisted.

It causes the lower leg to rotate inwards putting the knee and hip out of alignment. This rotation becomes more pronounced and exaggerated especially when running and without adequate support such as orthotics and correctly fitted footwear can cause injury and pain to the foot, ankle, lower leg and knee.

Oversupination, where the foot does not pronate enough thereby reducing its ability to absorb shock and mould to the ground is quite rare. It places additional stress on the muscles, tendons and ligaments of the lower limb and can lead to ankle sprains, plantar fasciitis and stress fractures without adequate footwear support.

There are many different types and builds of shoe available for all types of sports. Your foot shape, biomechanics and your weight are unique, so before investing, its vital to establish your foot type to ensure you select shoes which will give the best fit and right support.

You can easily determine the shape of your foot by doing a wet footprint test. Simply dampen the sole of your foot with water, then stand on a flat surface that will show an imprint such as a sheet of paper or even a dry concrete surface. Make sure there isn’t too much excess water on the feet. Your foot’s imprint should match one of the three generalized foot types:

Normal Feet: neutral arch – imprint is flared, with forefoot and heel connected by a wide band on the outside. A normal foot lands on the outside of the heel, then rolls inward (pronates) slightly to absorb shock.

Flat Feet: low arch leaves an imprint that looks like the whole sole of the foot. A flat foot strikes on the outside of the heel and rolls inward excessively which, over time, can lead to injury or disorders such as bunions and plantar fasciitis.

High-Arched Feet: imprint has a very narrow band connecting forefoot and heel. This type of foot tends to oversupinate making it less effective at absorbing shock.

The shape of your footprint roughly correlates with the amount of stability and cushioning you will need in your shoe. It is also very worthwhile to get a professional assessment of your running style particularly if your foot type is flat or you have a high arch.

Prevention is always better than the cure, so let us help get you started here at The Parkgate Podiatry Practice.

We provide a full gait analysis service including a biomechanical assessment of your feet and lower leg which will highlight any areas which may become problematic.

We can offer advice on footwear and also prescribe orthotics to help you manage any underlying problems.

We also treat ailments, disorders or injuries ... so you can keep going mile after mile after mile!

To book an appointment, simply contact us or telephone 01709 522334. Our opening hours are Monday - Thursday 9am - 5pm.