Thomas Stief

A new insole measurement system to detect bending and torsional moments at the human foot during footwear condition: a technical report

BackgroundStress occurring at the feet while wearing footwear is often determined using pressure measurement systems. However, other forms of stress, such as bending, torsional and shear loadings, cannot be detected in shoes during day-to-day activities. Nevertheless, the detection of these types of stresses would be helpful for understanding the mechanical aspects of various kinds of hard and soft tissue injuries. Therefore, we describe the development of a new measuring device that allows the reliable determination of bending and torsional load at the foot in shoes.MethodsThe system consists of a measuring insole and an analogue device with Bluetooth interface. The specific shape of the insole base layer, the positions of the strain gauges, and the interconnections between them have all been selected in such a way so as to isolate bending and torsional moment detections in the medial and lateral metatarsal region. The system was calibrated using a classical two-point test procedure. A single case study was executed to evaluate the new device for practical use. This application consisted of one subject wearing neutral shoes walking on a treadmill.ResultsThe calibration results (coefficients of determination R2u2009>u20090.999) show that bending and torsional load can be reliably detected using the measurement system presented. In the single case study, alternating bending and torsional load can be detected during walking, and the shape of the detected bending moments can be confirmed by the measurements of Arndt et al. (J Biomech 35:621–8, 2002).ConclusionsDespite some limitations, the presented device allows for the reliable determination of bending and torsional stresses at the foot in shoes.

Bending and torsional stress detection at the human foot during footwear conditions

Stress detection at the feet during footwear conditions is of great interest in the prevention of overstressing in orthopaedics, surgery and sports (Lieberman et al., 2010; Long et al., 2007). Until now, loads acting at the lower limb and the feet were determined with measurement systems using single pressure sensors, strips or insoles with pressure sensors. Other mechanical variables except pressure, such as bending, torsional moments and shear forces, cannot yet be detected in daily practice (Chen et al., 2010). But these loads in various forms could play an important role in the cause of disease and trauma at the lower limb and feet (Arndt, Ekenman, & Lundberg, 2002).

The influence of rocker soles on bending loads acting on the forefoot during walking and slow jogging

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COMPARISON OF DIFFERENT HEEL PADS VARYING IN SHORE HARDNESS

Heel pads are commonly used for the treatment of plantar heel pain, plantar fasciitis and knee arthrosis, which might lead to discomfort during walking and running. Force plates as well as foot pressure measurement systems are well accepted for clinical examination of gait analysis. In this study the effect of three different heel pads (variation in Shore hardness) was evaluated with respect to the validation of using both measurement systems in combination.

INFLUENCES OF SPECIAL FOOTORTHOSES ON EMG AND PLANTAR PRESSURE IN PATIENTS WITH LOW BACK PAIN

Bourdiol developed an insole concept with so called Neuromuscular Operating Elements (NME). By influencing the plantar foot sensibility with NME, reflexes should activate so called muscle chain reactions and as a result of that, malposition of the whole locomotors system should be treated. New footorthoses(FO)-concepts use the NME. But they are controversially discussed, cause of the missing scientific background. In contrast to these FO, classical ones like Custom Moulded FO (CMFO) focus on lower limb problems [Collins et al]. Their effects are quiet validated [Murley et al]. So the aim of this study was to test the influences of CMFO with NME (Figure 1; total left) on muscle activation and plantar pressure distribution.