Athletic Footwear and Orthoses in Sports Medicine by Matthew B. Werd E. Leslie Knight & Paul R. Langer

Author:Matthew B. Werd, E. Leslie Knight & Paul R. Langer
Language: eng
Format: epub
Publisher: Springer International Publishing, Cham

Biomechanic Role of the Foot

Root et al. proposed a Subtalar Joint Neutral Theory to classify the foot, basing this theory on subtalar joint (STJ) neutral position and a fully pronated midtarsal joint. This system, although dated, classified structure, function, and functional relationships of the foot and the lower extremity; it remains the most comprehensive and widely applied system with which to classify the foot and its biomechanics. This theoretical and conceptual model of foot function has undergone relatively little change since its first introduction; however, it has spawned several alternative theories which also strive to explain the function of the foot and more importantly the influence of foot orthoses upon the symptomatic lower extremity. These theories include the “Tissue Stress Theory,” “Sagittal Plane Facilitation of Motion Theory,” and “Preferred Movement Pathway Theory”.

Root et al. described the ideal or normal foot, its function, and based upon the STJ Neutral Theory a system of classification how the symptomatic foot should be supported with foot orthoses. Central to the STJ Neutral Theory is foot function which is most efficient around a neutral STJ with the midtarsal joints “locked” in a maximally pronated position. By accomplishing this, the foot orthoses would (1) limit extraneous motion, control the foot around the STJ neutral position during gait, (2) minimize potentially harmful compensation(s) by the foot for lower extremit abnormalities, and (3) induce a strong “locking” action of the midfoot across the midtarsal joints.

Unfortunately, this STJ Neutral Theory of function has not been adequately tested and limited evidence exists to support the concept that to remain injury free the foot must function around the STJ neutral position. (John Weed, 1985–1992, Personal communications). Yet, convincing clinical evidence exists to suggest that patients treated with foot orthoses constructed upon a model of the foot in the STJ neutral position tolerate the orthoses well and symptoms improve. The lack of clinical and research evidence validating the STJ Neutral Theory has stimulated research to explain functional and mechanical action of the foot.

Alternative theories have been proposed in an effort to better explain foot function and the impact of foot orthoses. Each of these theories recognizes that a unique STJ axis of rotation exists and that foot orthoses directly or indirectly influences the motion at this joint. The Tissue Stress Theory proposed by McPoil and Hunt strives to associate treatment of injuries with orthoses as a process of assessment leading to orthoses management directed at the compromised anatomical unit or tissue. McPoil and Hunt suggest that by utilizing the Tissue Stress Theory the clinician will have a better system from which to develop a system of examination and management of individual foot disorders. The Tissue Stress Theory should allow clinicians the opportunity to more accurately develop a prescription for a foot orthoses which meets the anatomical/structural needs of an injured tissue rather than developing an orthoses prescription based upon unreliable measurements.

The Sagittal Plane Facilitation of Motion Theory described by Payne and Dannenberg hypothesizes that functional limitations of hallux dorsiflexion during the propulsive phase of gait may be responsible for abnormal foot function and complaints of pain.

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