Biomechanics

Lower Limb Biomechanics

The Role of the Foot:

The foot has a major impact on how the lower limb works. Efficient, injury-free functioning of the lower limb often depends on normal foot function (1). The human foot comprises a quarter of all bones in our body (26 bones), more than 30 joints, and 10 major extrinsic muscle tendons. These musculoskeletal structures work together with the neurovascular elements to provide support, balance, and locomotion during gait. The foot must be a loose adapter to accommodate uneven terrain, be able to absorb shock on impact, and form a rigid lever during push-off (2). However, when the foot fails to function correctly problems can arise anywhere along the ‘kinetic chain’ i.e. foot, ankle, shin, knee, pelvis and lower back -see Table 1.

Table 1.

Foot Types:

Both the low arched foot (exhibiting excess pronation) and high arched foot (supinated) have been reported as important factors in predisposing individuals to overuse injury (6,8) (Figs. 1 and 2). According to Vasyli (11) it is estimated that around 75% of the population suffer from ‘excess-pronation’. Appropriate foot orthotics can assist in controlling excessive foot pronation and form part of an effective treatment intervention (12,13).

Fig. 1 Fig. 2

Low arch foot High arch foot

(exhibits excess pronation) (exhibits excess supination)

References:

1. Cornwall, M. (2000). Common Pathomechanics of the Foot. Journal of Athletic Therapy Today. 5(1),10-16.

2. Padiar, N. (2001). Foot Orthotics: Their Role in Injury Management. Journal of Sportex Medicine. 8, 6-8.

3. Bolgla, L., Keskula, D. (2003). A Biomechanical Approach to Evaluating and Treating Lower Leg Dysfunction. Journal of Athletic Therapy Today, 8(5), 6-12.

4. Kulig, K., Burnfield, J. Reischl, S. et al. (2005). Effect of Foot Orthoses on Tibialis Posterior Activation in Persons with Pes Planus. Journal of Medicine & Science in Sports & Exercise, 37(1), 24-29.

5. O’Connor, K., Hamill, J. (2004). The Role of Selected Extrinsic Foot Muscles During Running. Journal of Clinical Biomechanics. 19 (1), 71-77.

6. Razeghi, M. Batt, M.E. (2000). Biomechanical Analysis of the Effect of Orthotic Shoe Inserts. Journal of Sports Medicine, 29, 425-438.

7. Reiley M. !995). Guidelines for Prescribing Foot Orthotics. SLACK Incorporated: USA.

8. Quinn, G. (2007). Foot Posture, Biomechanics & Orthotic Selection Workshop. Cheshire, July 2007.

9. Dananberg, J.H. (1993). Gait Style as an Etiology to Chronic Postural Pain. Part 1. Journal of American Podiatric Medical Association, 83(8), 433-441.

10. Dananberg, J.H., Guiliano, M. (1999). Chronic Low-Back Pain and its Response to Custom-Made Foot Orthotics. Journal of American Podiatric Medical association, 89(3), 109-117.

11. Vasyli, (2005). Lower Limb Biomechanics Workshops - Part 1, 2. Manchester Sept. & Nov. 2005.

12. Landorf, K.B., Keenan, A.M. (2000). Efficacy of Foot Orthoses. Journal of American Podiatric Medical Association. 90(3), 149-158

13. Ball, K., Afheldt, M. (2002). Evolution of Foot Orthotics - Part 1: Coherent Theory or Coherent Practice? Journal of Physical Therapy. 25, 116- 124.