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Pressure measurement
Published in Paul Grimshaw, Michael Cole, Adrian Burden, Neil Fowler, Instant Notes in Sport and Exercise Biomechanics, 2019
Thus far, only static pressure or steady-state measurements have been considered, but such techniques are useful only in applications where very slow changing conditions or equilibrium are experienced. If one were interested in the rate or pattern of change in pressure over short periods of time, dynamic pressure measurements that rely on electromechanical pressure sensors (e.g. strain gauges, variable capacitance, piezoelectric transducers) must be used. Electromechanical pressure sensors, or pressure transducers, convert motion generated by a pressure-sensitive device into an electrical signal that is proportional to the size of the applied pressure. A common application of dynamic pressure measurement in human movement is in the analysis of the pressure distribution beneath the foot during standing, walking or running. Such assessments often use thin pressure-sensitive insoles that comprise a large number of pressure sensors. These sensors allow detection of high- and low-pressure areas beneath the feet at any time point throughout the movement. This information is usually presented as a series of colours or shades that represent the different pressures (Figure G4.4a) or as a 3D graph that is characterised by bars of different heights (Figure G4.4b), each indicating the magnitude of pressure at each point. Foot pressure analysis has been widely used to investigate the effect of different types of footwear on pressure patterns and injury risk and research tends to suggest that higher pressures are indicative of a greater risk of injury.
Parametric modeling and performance analysis of a personalized insole based on 3D scanning and selective laser sintering
Published in International Journal of Computer Integrated Manufacturing, 2020
Junchao Li, Wenhao Shu, Yanan Yang, Ran Yan
A Footscan system for foot pressure measurement provides static testing and dynamic testing during which one is required to walk through the pressure plate (Low and Dixon 2010; Su et al. 2017). In this study, dynamic tests were conducted when the same person as in FE analysis was wearing the flat insole and the personalized insole respectively. Figure 7 compares the stress historical curves and the stress distributions under the two conditions. It turns out that the forefoot and the heel areas for a personalized insole have a much lighter color than that for a flat insole, indicating that the personalized insole is helpful for reducing plantar pressure. It is also shown that the stress concentration mainly occurs in Meta 2, Meta 3, Medial heel, and Lateral heel for the flat insole. However, a much more uniform stress distribution can be seen for the personalized insole. The measured stress distributions are similar to the simulation results verifying the effectiveness of the FE model.
Arch-support foot-orthoses normalize dynamic in-shoe foot pressure distribution in medial tibial stress syndrome
Published in European Journal of Sport Science, 2019
Aynollah Naderi, Hans Degens, Ainollah Sakinepoor
During the use of arch-support foot-orthoses, the center of pressure during the FFPOP shifted medially and became similar to that seen in healthy control participants. One factor that is thought to contribute to this medial shift is the increase in aponeurotic tension that would tether the plantar plate of the first metatarsophalangeal joint and thereby stabilize this joint (Aquino & Payne, 2001). Thus, the push off occurs through the first metatarsophalangeal joint and the final point of contact is the hallux similar to the healthy control participants. The use of arch-support foot-orthoses in the MTSS participants also resulted in a reduced peak pressure and impulse rate underneath the midfoot to values in the normal range seen in the healthy control group. In addition, the abnormal distribution of foot pressure during the FFCP, and at the HO and FFF instants became similar to that of the control participants. Such a result was also observed in runners with lower extremity overuse injuries (Scranton, Pedegana, & Whitesel, 1982). In addition, previous studies have reported that applying arch-support foot-orthoses resulted in a decreased force, impulse and time-to-peak ground-reaction force in the midfoot during the stance phase of gait in people with excessive foot pronation (Farahpour, Jafarnezhad, Damavandi, Bakhtiari, & Allard, 2016). It thus appears that the reduction of foot pronation with foot orthoses (Hsu et al., 2014) may well be an effective means to restore and optimize lower limb biomechanics, and a normal dynamic foot-pressure distribution.
Modelling error distribution in the ground reaction force during an induced-acceleration analysis of running in rear-foot strikers
Published in Journal of Sports Sciences, 2019
Sekiya Koike, Seigo Nakaya, Hiroto Mori, Tatsuya Ishikawa, Alexander P. Willmott
Although the ground reaction force is distributed over the contact surface of the foot segment, where the support-leg foot segment touches its environment (i.e. the ground surface), the model used in this paper assumes that the ground reaction force acts at the COP of the foot and that the foot segment connects to the surface via a virtual joint situated between the ground surface and the COP of the foot segment. Despite the fact that the contact points distributed over the surface of the foot do not move in the foot segment coordinate system, except in the case of foot segment deformation, the COP defined as a representative joint centre point moves largely along the longitudinal axis of the foot during the support phase of rear-foot strikers. This motion causes the overestimation of segment length fluctuations due to the rapid movement of the COP that occurs when using the COP as the virtual joint between the foot and ground. Smoothing with a polynomial function during the induced acceleration analysis would be an effective way to avoid overestimating the contribution of the fluctuation of the COP. When using foot pressure sensing devices (Putti, Arnold, Cochrane, & Abboud, 2007; Woodburn & Helliwell, 1996), or instrumented shoe soles equipped with a number of force sensors (Moriyasu, Nishiwaki, Yamaguchi, & Hokkirigawa, 2010), the actual contact points can be defined from the sensor positions fixed to the foot segment rather than being estimated from the position of the COP. Additionally, the use of three points fixed to the support-leg foot segment, with forces exerted at those points that are calculated so as to satisfy the equilibrium conditions with respect to force and moment at COP, would be an effective way in the future to reduce the error arising from the COP’s fluctuation because the points of the virtual joint between the foot and ground would be fixed to the foot segment.