Podiatry Biomechanics

By Wayne Edwards D.Pod.M M.Ch.S., Senior Podiatrist

Historically, the use of podiatric techniques and foot orthoses have been used to successfully treat a wide variety of foot and foot related conditions, with varying success.

The treatment of these conditions when combined with the application of core stability training provides a potent preventative and successful rehabilitative approach to the injuries experienced by the modern runner at any level.

The success of the core stability approach:

  • Prevention of injury through sound assessment and application of multi-disciplinary treatment.
  • A Podiatric assessment is considered an essential part of an overall assessment to understand injury and identify the factors contributing to injury in the lower limb and in chronic low back pain.
  • Core Stability training is used as a foundation for movement control and postural stability.
  • The use of orthotic devices is recommended only when necessary to complete the rehabilitation process, and enable prevention of an injury in the future.
  • All treatment is based on the application of research based approaches in musculoskeletal healthcare.

What is Podiatric Biomechanics?

Podiatric biomechanics is the area of human biomechanics that deals essentially with the structure and function of the segments of the feet and as they relate to each other and to the legs, hips and spine.

Podiatric biomechanics relates to human motion, gait, pedal (foot) stability, propulsion and muscle action, and gives us the basis for determining the neutrality, normality and abnormality of body structure (bio) and motion / forces acting on these body structures (mechanics) (Langer 1980).

Running Injuries and Podiatric Biomechanics

"The head cannot say to the feet "I have no need for thee".
God has so adjusted the body that there be no discord.
If one member suffers, all suffer together.
If one member is honoured, all rejoice together."

I Corinthians

This quote taken from the preface of a text on functional foot orthoses (Anthony 1991), is a reminder of the importance of foot function to the runner of every level, from elite to recreational, in the unfortunate occurrence of injury.

Many running injuries are linked to foot compensation as a direct result of foot structure or leg and hip alignment. Foot compensation may cause pronation of the foot (rolling in of the foot and lowering of the arch), but it must be remembered that many injuries can be associated with the inability of a foot to pronate normally, the highly arched or supinated foot type (Valmassey 1998). Foot compensation can occur for many reasons and these are identified using physical and gait analysis during podiatric consultation.

Over-use injuries

Running and jogging are excellent forms of exercise but they subject the body to considerable stress. Each time a runner's foot hits the ground it generates forces equivalent to at least three and a half times body weight (Whiting 1998). This force is absorbed by the foot and skeleton and transmitted to enable forward movement.

The commonest types of injury to the runner are those arising from "over-use". The term over-use injury is applied to injury resulting from the repeated loading (stress and strain) of body tissues such as tendon and muscle. Micro damage (damage invisible to the naked eye) to the structure of the tissue accumulates at a level that is undetected until an injury or failure of the tissue occurs. Pain and inflammation are the result of the damage and may give rise to weakness in the tissue and prevent it from managing its proper function (Hess et al 1989). This repeated stress and strain is often due to poor alignment that can be present throughout the posture, arising with, or as a direct result of foot compensation (Herrington 1999).

An example of poor alignment is highlighted in the runner with weak gluteal (buttock) muscles and foot pronation. The upper leg can drift in towards the opposite leg when taking bodyweight in single stance (on one leg) with a drop in height of the opposite hip. During running this muscle weakness, associated with the foot pronation, can cause a detrimental mis-alignment in the lower leg.

Q angleThe Q Angle

It results in an angle forming between the foot and hip that causes stress on the knee and the patella (kneecap) sliding across the knee joint resulting in pain and swelling (see diagram right).

The increase in angle Q can result in poor tracking of the patella Identification of poor alignment is a key examination undertaken as part of podiatric consultation.

Common running injuries

The commonest injuries to runners that are associated with faulty foot function and poor alignment include:

  • Low back injuries (eg Sacro-iliac joint pain)
  • Hip injuries (eg Ilio-tibial band irritation)
  • Knee injuries (eg Patellofemoral pain)
  • Leg injuries (eg Medial shin pain and irritation)
  • Foot injuries (eg Heel-pain syndrome and achilles tendon problems) (Valmassey 1998).

Running shoes and technique

It is important then, to consider technique and equipment used in running. Running shoes are very important and evaluation of this piece of kit forms part of a good podiatric consultation.

In recent years the manufacturers of shoes have highlighted many foot types and related them to specific shoes on offer, (motion control, stability and neutral shoes for example).

It is useful to remember that a change in footwear can often precede a running injury and that research suggests that a foot will pronate more in a shoe than when running barefoot! (Nigg et al 1988). The correct selection of shoe can make a significant difference in the treatment of running injuries.

Technique is related to muscle balance (flexibility and strength) and dynamic ability (balance and postural control).

A good podiatric consultation can identify problems with technique and also improve existing movement patterns with the use of video analysis and force platform analysis.

Orthotic Devices

Orthoses are orthopaedic devices designed to treat or adjust various biomechanical foot disorders. They are usually manufactured from an impression of the foot called a cast. The cast duplicates any misalignments in the foot allowing specialist trained technicians in a laboratory to correct the misalignments with compensation and stabilisation techniques. Finished orthoses are worn in the shoe to help keep the foot in proper alignment.

Who should use foot orthoses?

Perfect feet are rare, almost everyone can benefit from orthoses. An analogy can be made between orthoses and prescription spectacles. Both adjust bodily imperfections that can inhibit people from functioning at their maximal physical potential.

Your feet should not hurt. Pain is the body’s way of warning that something is wrong. If you ignore pain the condition causing it could become worse.

Orthoses are functional orthoses incorporating a specialised prescription to correct and control defects in the foot that may cause poor shock absorption or lower limb malalignment, predisposing the runner to various related injuries.


  • Anthony RJ (1991) The Manufacture and Use of Functional Foot Orthoses.
  • Karger Herrington L (1999) Diagnosis and Management of Anterioir Knee Pain. Sportex 12 p 26 32
  • Hunter G (1994) Specific Soft Tissue Mobilisations in the Treatment of Soft Tissue Lesions.Physiotherapy. Vol 80 No 1. p15-21
  • Nigg BM, Denoth J (1984) Load Sports Shoes and Playing Surfaces.Frederick EC .Sports Shoes and Playing Surfaces. Human Kinetics. Champaigne, Illinois
  • Valmassey R (1998) Clinical Biomechanics of the Lower Extremity. Chapter 5. Mosby .St Louis. Whing W, Zernicke R (1998). Biomechanics of Musculoskeletal Injury. Chapter 2. Human Kinetics.