3D movement and muscle activity patterns in a violin bowing task

Objective: Overuse injuries in violinists are a problem that has been primarily analyzed through the use of questionnaires. Simultaneous 3D motion analysis and EMG to measure muscle activity has been suggested as a quantitative technique to explore this problem by identifying movement patterns and muscular demands which may predispose violinists to overuse injuries. This multi-disciplinary analysis technique has, so far, had limited use in the music world. The purpose of this study was to use it to characterize the demands of a violin bowing task. Subjects: Twelve injury-free violinists volunteered for the study. The subjects were assigned to a novice or expert group based on playing experience, as determined by questionnaire. Design and Settings: Muscle activity and movement patterns were assessed while violinists played five bowing cycles (one bowing cycle = one down-bow + one up-bow) on each string (G, D, A, E), at a pulse of 4 beats per bow and 100 beats per minute. Measurements: An upper extremity model created using coordinate data from markers placed on the right acromion process, lateral epicondyle of the humerus and ulnar styloid was used to determine minimum and maximum joint angles, ranges of motion (ROM) and angular velocities at the shoulder and elbow of the bowing arm. Muscle activity in right anterior deltoid, biceps brachii and triceps brachii was assessed during maximal voluntary contractions (MVC) and during the playing task. Data were analysed for significant differences across the strings and between experience groups. Results: Elbow flexion/extension ROM was similar across strings for both groups. Shoulder flexion/extension ROM increaslarger for the experts. Angular velocity changes mirrored changes in ROM. Deltoid was the most active of the muscles assessed (20% MVC) and displayed a pattern of constant activation to maintain shoulder abduction. Biceps and triceps were less active (4 - 12% MVC) and showed a more periodic 'on and off pattern. Novices' muscle activity was higher in all cases. Experts' muscle activity showed a consistent pattern across strings, whereas the novices were more irregular. The agonist-antagonist roles of biceps and triceps during the bowing motion were clearly defined in the expert group, but not as apparent in the novice group. Conclusions: Bowing movement appears to be controlled by the shoulder rather than the elbow as shoulder ROM changed across strings while elbow ROM remained the same. Shoulder injuries are probably due to repetition as the muscle activity required for the movement is small. Experts require a smaller amount of muscle activity to perform the movement, possibly due to more efficient muscle activation patterns as a result of practice. This quantitative multidisciplinary approach to analysing violinists' movements can contribute to fuller understanding of both playing demands and injury mechanisms .

Economic security & reconstruction: utility, history and practice in post-conflict environments

Please consult the paper edition of this thesis to read. It is available on the 5th Floor of the Library at Call Number: Z 9999 P65 D53 2007

Sir Isaac Brock Facial Reconstruction Project, n.d.

Christian Cardell Corbet, a descendant of Guernsey, Channel Islands, was born in 1966 at Pickering Beach on Lake Ontario. He developed his talents as a landscape artist and at the young age of 14 he began his informal education in commercial signage from his paternal grandfather. He studied at the University of Guelph and McMaster University Anatomy Laboratory. Corbet traveled to England where he began to experiment more in abstraction and non-objective work. In 1995, he presented a portrait of HM Queen Elizabeth the Queen Mother at Clarence House. This brought his career to an international level. He also creates two-dimensional works and has received acclaim for his bronze art medallions. He has gained international recognition as a Forensic Artist working as Artist in Residence for the University of Western Ontario. He does facial reconstructions for special assignments. These original drawings relate to a sculpted medallion of Brock which was authorized by Sir Geoffrey Rowland, Bailiff, Guernsey, Channel Islands and Minister of Education of the States of Guernsey. This is the first time in known recorded history that a forensic analysis and sculpture has been created to accurately depict the facial likeness of Sir Isaac Brock. This project has been established to mark the 2012 anniversary of the death of Brock.