Yehuda Weizman

Assessment of grip difficulty of a smart climbing hold with increasing slope and decreasing depth

In order to assess the grip difficulty of a curved climbing hold, an experimental hold was designed and instrumented with two force transducers. The holds surface was restricted to steeper gradients by adding wooden panels to the wall. The more the centre of pressure on a curved hold surface moves off the wall, the steeper the surface gradient becomes and the more difficult it is to grip the hold. As the surface gradient steepens, the coefficient of friction increases, whereas contact time and forces decrease. At flatter gradients, the hand exerts a pulling force to the hold whereas at steeper gradients, the hand pushes against the hold. The latter action is only possible if the body moves dynamically in horizontal direction, by accelerating backwards. The transition from pulling to pushing occurs in the more experienced climber at a centre of pressure position of approximately 0.045 mm off the wall (34° slope), and in the less experienced climber earlier at approximately 30 mm off the wall (22° slope).

Accuracy of Centre of Pressure Gait Measurements from Two Pressure-Sensitive Insoles

Footwear-based wearable applications are relevant to numerous fields and have great commercial and clinical potential. However, scientifically validated, reliable data on these devices is largely missing. Centre of pressure (COP) is an important and common factor for measuring balance and gait and hence the validity of such devices is essential for reading accurate data. This study aims to investigate COP accuracy of an existing system, Pedar (PE), and a newly designed Smart Insole (SI) using a force plate (FP). This was done by means of COP data noise (R2), and gradient of the fit function (k). For the SI, the maximum COPx and COPy data achieved R2 values of 0.7837 and 0.9368 and k values of 0.8867 and 0.8538 respectively when compared with the FP. Conversely, the Pedar achieved R2 values of 0.8409 and 0.9401 and k values of 1.0492 and 1.08 when compared with the FP respectively.

Discovery of a Sweet Spot on the Foot with a Smart Wearable Soccer Boot Sensor That Maximizes the Chances of Scoring a Curved Kick in Soccer

This paper provides the evidence of a sweet spot on the boot/foot as well as the method for detecting it with a wearable pressure sensitive device. This study confirmed the hypothesized existence of sweet and dead spots on a soccer boot or foot when kicking a ball. For a stationary curved kick, kicking the ball at the sweet spot maximized the probability of scoring a goal (58–86%), whereas having the impact point at the dead zone minimized the probability (11–22%). The sweet spot was found based on hypothesized favorable parameter ranges (center of pressure in x/y-directions and/or peak impact force) and the dead zone based on hypothesized unfavorable parameter ranges. The sweet spot was rather concentrated, independent of which parameter combination was used (two- or three-parameter combination), whereas the dead zone, located 21 mm from the sweet spot, was more widespread.