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An intelligent sport shoe to prevent ankle inversion sprain injury


Ankle sprain injury is common in sports. This study presents an intelligent sport shoe to prevent it.

Materials and methods

(1) Sensing: Five subjects performed various sporting motions with data collected from a plantar pressure system to reconstruct the ankle supination torque determined from a motion capture system with a force plate. Validation test on another five subjects was conducted. (2) Identification: Six subjects performed simulated sub-injury and non-injury trials with the dorsal foot kinematics measured by 8 wearable motion sensors. Data was used to train a support vector machine to establish a mathematics algorithm for identification, which was validated on another 6 subjects, with an expected accuracy of 90%. An uni-axial gyrometer was placed at the position with the best accuracy for identifying ankle sprain hazard, with a threshold suggested from a database of ankle inversion velocity from real injury incidents, sub-injury trials and non-injury motions. (3) Correction: Myoelectric stimulations with different delay time (0, 5, 10 and 15ms) were delivered to the peroneal muscles of 10 subjects performing unanticipated sub-injury trials in a laboratory. The effect was quantified by the heel tilting angle and its velocity as determined by a motion analysis system.


(1) Sensing: a system with 3 pressure sensors was developed to monitor the ankle supination torque with overall root mean square error as 6.91Nm, which was 6% of the peak values recorded (Fong et al, 2008a). (2) Identification: A method with one gyrometer at the heel to identify hazardous motion with 91.3% accuracy was developed (Chu et al, 2010). (3) Correction: significant reduction of the heel tilting angle and velocity from 18 to 9-13 degrees and from 200-250 to 140-170 deg/s was achieved.


An intelligent anti-sprain sport shoe with a 3-step intelligent system is successfully invented, and is soon being ready for commercialization.


  1. Fong DTP, Chan YY, Hong Y, Yung PSH, Fung KY, Chan KM: A three-pressure-sensor (3PS) system for monitoring ankle supination torque during sport motions. Journal of Biomechanics. 2008, 41: 2562-2566. 10.1016/j.jbiomech.2008.05.035.

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  2. Chu VWS, Fong DTP, Chan YY, Yung PSH, Fung KY, Chan KM: Differentiation of ankle sprain motion and common sporting motion by ankle inversion velocity. Journal of Biomechanics. 2010, 43: 2035-2038. 10.1016/j.jbiomech.2010.03.029.

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Correspondence to Daniel TP Fong.

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This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Fong, D.T. An intelligent sport shoe to prevent ankle inversion sprain injury. J Foot Ankle Res 5 (Suppl 1), K6 (2012).

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