Diarmaid Fitzgerald

Development of a wearable motion capture suit and virtual reality biofeedback system for the instruction and analysis of sports rehabilitation exercises

This paper describes the design and development of a computer game for instructing an athlete through a series of prescribed rehabilitation exercises. In an attempt to prevent or treat musculoskeletal type injuries along with trying to improve physical performance, athletes are prescribed exercise programmes by appropriately trained specialists. Typically athletes are shown how to perform each exercise in the clinic following examination but they often have no way of knowing if their technique is correct while they are performing their home exercise programme. We describe a system that allows an automatic audit of this activity. Our system utilises ten inertial motion tracking sensors incorporated in a wearable body suit which allows a Bluetooth connection from a root hub to a laptop/computer. Using our specifically designed software programme, the athlete can be instructed and analysed as he/she performs the individually tailored exercise programme and a log is recorded of the time and performance level of each exercise completed. We describe a case study that illustrates how a clinician can at a later date review the athletes progress and subsequently alter the exercise programme as they see fit.

Development and user evaluation of a virtual rehabilitation system for wobble board balance training

We have developed a prototype virtual reality-based balance training system using a single inertial orientation sensor attached to the upper surface of a wobble board. This input device has been interfaced with Neverball, an open source computer game to create the balance training platform. Users can exercise with the system by standing on the wobble board and tilting it in different directions to control an on-screen environment. We have also developed a customized instruction manual to use when setting up the system. To evaluate the usability our prototype system we undertook a user evaluation study with twelve healthy novice participants. Participants were required to assemble the system using an instruction manual and then perform balance exercises with the system. Following this period of exercise VRUSE, a usability evaluation questionnaire, was completed by participants. Results indicated a high level of usability in all categories evaluated.

Usability evaluation of e-motion: A virtual rehabilitation system designed to demonstrate, instruct and monitor a therapeutic exercise programme

The importance of systematic usability evaluation of virtual rehabilitation systems cannot be underestimated. We have developed a virtual rehabilitation system with the functionality to guide a user through a therapeutic exercise programme. Progression is determined by userspsila ability to replicate movements as demonstrated by an on-screen character. Visual and auditory corrective feedback is provided during exercise in order to improve the userpsilas postural control and biomechanical alignment. The objective of this study was to evaluate the usability of our system and subsequently implement modifications aimed at improving fidelity and ease of use. The first stage of our evaluation involved conducting an expert walkthrough with six experts currently researching in areas related to the system design. Following system refinement and modification we conducted a user evaluation study with twelve novice users using VRUSE, a computerised questionnaire-based usability evaluation tool for assessment of virtual environments. Results have provided a systematic evaluation of the system, provided information for guidance on system alterations and will allow comparison of usability levels with similar virtual rehabilitation systems tested with the same protocol.

Therapeutic Exergaming

Exercise therapy is prescribed by physiotherapists and rehabilitation practitioners as part of the treatment programme for many movement impairment disorders. Poor adherence and inadequate exercise technique often result in poor outcomes for these patients and delays their return to full physical function. Therapeutic exergaming, which is the use of computer games and body-worn motion tracking sensors to teach therapeutic exercise programmes to patients, may offer solutions to these problems. In this paper we describe one such system, known as FlyFit, which offers a sensor-driven flight game environment that allows physiotherapists to intuitively design game levels that will induce patients to correctly carry out their exercises programme. A 4-week pilot study to investigate the training effect of the system compared to a conventional exercise training approach is described. Results suggest these exergaming systems may induce improvements in balance and strength similar to the conventional programme along with increased levels of intrinsic motivation but further research is warranted.

A Prototype Sourceless Kinematic-Feedback Based Video Game for Movement Based Exercise.

This paper presents a prototype kinematic and audio feedback based video game, availing of a scalable motion capture acquisition system, based around a number of orientation sensors. The orientation sensors used are USB based tri-axis magnetic and gravitational field transducers. The novel video-game is capable of incorporating the real time data from these sensors to control an on screen avatar, which in turn can be programmed to give appropriate instructions to the user i.e. play a sound file, once the user obtains a certain posture. The video game is designed to promote physical exercise and movement based relaxation, in particular; yoga. In addition, design considerations; implementation and performance of the system are analyzed, discussed and the accuracy qualitatively analyzed by comparing movement data obtained from it to that of a validated motion analysis technique, the CODA motion analysis system

Lower body reaction testing using ultrasonic motion capture

This paper presents a lower body reaction test that utilizes a new portable ultra-sound based motion capture system (MobiFit) combined with a synchronized visual stimulus. This novel system was tested first for criterion validity and agreement against a gold standard laboratory based optical motion capture system (CODA). It was subsequently tested in the field during Gaelic football (GAA) team gym sessions with 35 subjects to demonstrate its utility and versatility. The lower body reaction test itself is novel in that it can be applied to a gross motor task. During testing, participants had sensors attached to their lower limbs and trunk. The speed of movement for each sensor was monitored at 500Hz using the Mobifit motion capture system, and reaction time was measured as the elapsed time from the appearance of a green indicator on the screen to a sensor reaching a set threshold velocity as the participant raised the corresponding leg. Pearsons correlation coefficient tested criterion validity against the CODA system and Intra class correlation coefficients and Bland-Altman plots assessed agreement of velocity measures obtained from the MobiFit and CODA systems. Results indicate that the MobiFit system is an accurate device to assess lower body reaction time and has advantage over standard laboratory measures in terms of portability and ease of set-up.

A virtual rehabilitation system for wobble board balance training with children

Virtual reality-based computer games may be a useful way to develop motor skills and increase activity levels in children. We have developed an interactive computer platform where users must tilt a wobble board to complete on-screen computer game tasks. We have conducted a pilot study with 81 school children who played the game and used a questionnaire to gather information on childrens enjoyment levels and perceptions of the system. Findings showed a high level of enjoyment with the game and provided useful information for future research and development.