Kinematic foot models for instrumented gait analysis

Abstract

In many clinical and biomechanical contexts of human motion analysis the model assumption of the foot as a single rigid segment is no longer acceptable. This has given rise to a large number of proposals for multi-segment foot models. The relevant experimental and analytical techniques differ for many aspects: the number of foot segments; the bony landmarks involved; the type of marker clusters; the definition of the anatomical frames; and the convention for the calculation of joint rotations. Different definitions of neutral reference posture have also been adopted, along with their utilization to offset kinematic data. Following previous partial review papers, the present chapter aims at introducing the current methodological studies for in vivo analysis of multi-segment foot kinematics. The survey has found more than 30 different techniques; however, only a limited number of these have reported convincing validation activities and have been exploited in a clinical context. A number of papers have also compared the experimental performance of different multi-segment foot models and highlighted the main advantages and disadvantages of each of them. Important biomechanical applications of musculoskeletal models for reliable estimation of biomechanical parameters are also discussed. In addition, we report on the feasibility and limitations of kinetic analysis applied to multi-segment foot models from ground reaction force data. The chapter ends with recommendations both for the selection of a most suitable technique from those already available, as well as for the design of an original one suitable to address the needs of the specific application.