The development of a novel system to assess the effect of sudden foot and ankle inversion/supination on the musculoskeletal system

  • Ahmad Sami Dahrouj

    Student thesis: Doctoral ThesisDoctor of Philosophy


    Ankle sprains are one of the most common type of sports injury. They occur most frequently when the foot is in a supine or inverted position. Recovery from an ankle sprain can take from one and up to 26 weeks depending on the severity of the injury. During that period the individual will be unable to participate in any meaningful sports activity and as such it is important to be able to prevent the occurrence of such injuries. Prevention of ankle sprain injuries would require a better understanding of the risk factors of this injury. Several studies attempted to assess such risk actors by inducing foot inversion or supination however the platforms used in these studies were shown to be limited. Hence the main aim of this project is to develop a system that can be used to assess the effect of sudden foot and ankle inversion/supination on the musculoskeletal system of dynamic subjects (e.g. walking, running, jumping, etc...). For this purpose a three degrees of freedom (DOF) rotating platform has been designed, manufactured and installed in the Institute of Motion Analysis and Research (IMAR) Sports Laboratory. The platform rotates around 3 different axes allowing inversion or supination of the foot and ankle of dynamic subjects. The degree of rotation around each axis can easily be set by the researcher/operator. A strain gauge was used to detect foot strike to the platform. As a safety measure laser emitter/receivers check that the entire foot is on the footplate before the platform rotates. Optical encoders provide essential feedback of rotation angles, speed and acceleration. The necessary software and user interface for controlling the platform were also written and tested. The platform was synchronised with a bilateral four-channel EMG (electromyography) system and a 12 camera Vicon® MX-13 system thus allowing measurement of muscle activity and kinematic data during the supination of the foot. A set of software modules were written to allow automated management and processing of the data generated by the new system. The new system was then implemented in a study to validate it and to assess the role of shoes in ankle sprains. In this study, subjects would walk in three different foot conditions: barefoot, and with two different types of sports shoes, along the walkway of the Sports Laboratory where the platform was fitted. When a subject steps on the embedded platform, it rotates causing the subject's foot to supinate. At the same time, the EMG data from the peroneus longus, tibialis anterior, and lateral gastrocnemius muscles are recorded, along with the kinematics of the subject's whole body. The obtained results demonstrated the validity of the newly developed system. Data from the validation study also revealed increased muscle activity following induced foot supination in shod conditions compared to barefoot. Muscle activity of the rotating platform step was found to be significantly higher than the steps before and after. The platform rotation was also found to have an observable effect on body kinematics. The newly developed system is hoped to help provide a better understanding of the risk factors of ankle sprain injury and how to prevent this injury. The system can be used to help improve the design of current footwear and identify which footwear provides better protection against ankle sprain injury. The system can also be used to assess the effectiveness of different ankle injury rehabilitation schemes and different training programs that aim to reduce ankle sprain injuries. The new system can be utilised to identify individuals who are at risk of sustaining an ankle sprain injury. The system can also be utilised in studies outside the scope of ankle sprain injuries.
    Date of Award2011
    Original languageEnglish
    SupervisorRami Abboud (Supervisor) & Tim Drew (Supervisor)


    • Ankle sprain
    • Biomechanics
    • Ankle inversion
    • Ankle supination
    • Robotic platform
    • Footwear

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