Potentialities and Criticalities of Plantar Pressure Measurements in the Study of Foot Biomechanics: Devices, Methodologies and Applications
Literally speaking, Biomechanics is the discipline that applies the principles and laws of Mechanics to biological systems. As for the human body and, more specifically, the human foot, biomechanics focuses on the understanding of those laws of the Physics by which the human being moves within the Earth gravitational environment by adopting a bipedal posture and using a complex interfacing structure such as the foot and ankle system. Keeping the focus on the most common human displacement activity, i.e. gait, we may state that the main target of a functional gait is to push the body centre of gravity forward. To do that, gait has to deal with a set of forces the body exchanges with the environment especially with the ground and with a set of movements which represent both causes and effects of force transmission. A thorough description of the foot biomechanics should then mainly rely on the observation of both kinematic and kinetic variables, namely, i) forces and moments of force external to the body; ii) forces and moments of force internally generated by the musculo skeletal system; and iii) movements and timing of the movements in terms of linear and angular displacements, linear and angular velocities, linear and angular accelerations of the whole body or of specific body segments. On the other hand, the effects of loading under the sole of the foot in terms of plantar pressure have been reported since the late 1800's; and since the first attempts to measure it, its use has been ever increasing worldwide. In fact, plantar pressure assessment alone is not enough to thoroughly investigate biomechanics in terms of neither kinematics nor kinetics being pressure related to the only component of the force vector which is normal to the examined surface. Plantar pressure, however, has great potentialities in the field of Research but even more in Clinics and Podiatry. When compared with other assessment devices typically used in gait analysis, pressure measurement systems are easier to implement and use, less timeconsuming and cumbersome to the patient, less expensive than complex gait analysis equipment; measurements are more easily acquired, processed and interpreted, and last but not least they are meaningful and effective in the assessment or in the monitoring of any foot or ankle treatment. In the last ten years, a significant increase has been observed in peer reviewed publications dealing with studies focussed on plantar pressure