Journal of biomechanics
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Journal of biomechanics · Nov 2012
A non-invasive technique for estimating carpal tunnel pressure by measuring shear wave speed in tendon: a feasibility study.
Although a close relationship between carpal tunnel pressure and median nerve dysfunction has been found, the current methods for pressure measurements are invasive, using a catheter in the carpal canal to monitor the pressure. A noninvasive method for quantifying carpal tunnel pressure would be useful as an alternative to the catheter method. ⋯ This indicates that the tendon could serve as a strain gauge to evaluate the tunnel pressure by detecting the changes of wave propagation speed. However, further validations in human cadavers and clinical subjects are necessary.
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Journal of biomechanics · Nov 2012
Gait strategy changes with acceleration to accommodate the biomechanical constraint on push-off propulsion.
To maintain steady and level walking, push-off propulsion during the double support phase compensates for the energy loss through heel strike collisions in an energetically optimal manner. However, a large portion of daily gait activities also contains transient gait responses, such as acceleration or deceleration, during which the observed dominance of the push-off work or the energy optimality may not hold. In this study, we examined whether the push-off propulsion during the double support phase served as a major energy source for gait acceleration, and we also studied the energetic optimality of accelerated gait using a simple bipedal walking model. ⋯ We measured the ground reaction force (GRF) of three consecutive steps and the corresponding leg configuration using force platforms and an optical marker system, respectively, and we compared the mechanical work performed by the GRF during each single and double support phase. In contrast to the model prediction of an increase in the push-off propulsion that is proportional to the acceleration and minimizes the mechanical energy cost, the push-off propulsion was slightly increased, and a significant increase in the mechanical work during the single support phase was observed. The results suggest that gait acceleration occurs while accommodating a feasible push-off propulsion constraint.