Effects of isometric elbow flexion on electromyographic spike analysis

The main objective of this research was to examine the relationship between surface electromyographic (SEMG) spike activity and force. The secondary objective was to determine to what extent subcutaneous tissue impacts the high frequency component of the signal, as well as, examining the relationship between measures of SEMG spike shape and their traditional time and frequency analogues. A total of96 participants (46 males and 50 females) ranging in age (18-35 years), generated three 5-second isometric step contractions at each force level of 40, 60, 80, and 100 percent of maximal voluntary contraction (MVC). The presentation of the contractions was balanced across subjects. The right arm of the subject was positioned in the sagittal plane, with the shoulder and elbow flexed to 90 degrees. The elbow rested on a support in a neutral position (mid pronation/mid supination) and placed within a wrist cuff, fastened below the styloid process. The wrist cuff was attached to a load cell (JR3 Inc., Woodland, CA) recording the force produced. Biceps brachii activity was monitored with a pair of Ag/AgCI recording electrodes (Grass F-E9, Astro-Med Inc., West Warwick, RI) placed in a bipolar configuration, with an interelectrode distance (lED) of 2cm distal to the motor point. Data analysis was performed on a I second window of data in the middle of the 5-second contraction. The results indicated that all spike shape measures exhibited significant (p < 0.01) differences as force increase~ from 40 to 100% MVC. The spike shape measures suggest that increased motor unit (MU) recruitment was responsible for increasing force up to 80% MVC. The results suggested that further increases in force relied on MU III synchronization. The results also revealed that the subcutaneous tissue (skin fold thickness) had no relationship (r = 0.02; P > 0.05) with the mean number of peaks per spike (MNPPS), which was the high frequency component of the signal. Mean spike amplitude (MSA) and mean spike frequency (MSF) were highly correlated with their traditional measures root mean square (RMS) and mean power frequency (MPF), respectively (r = 0.99; r = 0.97; P < 0.01).

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 .

Psychographic characteristics of weekend wine tourists : a multiple case study of four wineries in the Niagara Region

The purpose of this study is to examine the psychographic (product attributes, motivation opinions, interest, lifestyle, values) characteristics of wine tourists along the Niagara wine r,~ute, located in Ontario, Canada, using a multiple case study method. Four wineries were selected, two wineries each on the East, and West sides of the wine route during the shoulder-season (January, February, 2004). Using a computer generated survey technique, tourists were approached to fill out a questionnaire on one of the available laptop computers, where a sample ofN=321 was obtained. The study findings revealed that there are three distinct wine tourist segments in the Niagara region. The segments were determined using an exploratory factor analysis (EFA) and a K-means cluster analysis: Wine Lovers, Wine Interested, and Wine Curious wine tourists. These three segments displayed significant differences in their, motivation for visiting a winery, lifestyles, values, and wine purchasing behaviour. This study also examined differences between winery locations, on the East and West sides of the Niagara wine route, with respect to the aforementioned variables. The results indicated that there were significant differences between the regions with respect to these variables. The findings suggest that these differences present opportunities for more effective marketing strategies based on the uniqueness of each region. The results of this study provide insight for academia into a method of psychographic market segmentation of wine tourists and consumer behaviour. This study also contributes to the literature on wine tourism, and the identification of psychographic characteristics of wine tourists, an area where little research has taken place.

Compensatory Arm Reactions in Individuals with Parkinson’s Disease

This study examined how perturbation-evoked compensatory arm reactions in individuals with Parkinson’s disease (PD) are influenced by explicit verbal instruction. Ten individuals with PD and 15 older adults without PD responded to surface translations with or without specific instruction to reach for and grasp the handrail. Electromyographic (EMG) and kinematic recordings were taken from the reaching arm. Results showed that individuals with and without PD benefitted similarly from explicit instruction. Explicit instruction resulted in earlier (p=0.005) and larger (p<0.001) medial deltoid EMG responses in comparison to no specific instructions. Compensatory arm reactions also occurred with a higher peak medio-lateral wrist velocity (p<0.001) and higher peak shoulder abduction angular velocity (p<0.001) with explicit instruction. Explicit instruction positively influenced compensatory arm reactions in individuals with and without PD. Future research is needed to determine whether the benefits of instruction persist over time and translate to a loss of balance in real life.

Photograph - Arthur A. Schmon receives Honourary Doctorate, 1952

A photograph of Arthur A. Schmon receiving an Honourary Doctorate of Science Degree from Laval University. The reverse of the photo describes the event: "Laval University - Quebec City - September 22, 1952. Arthur A. Schmon receiving Doctorate of Science Degree (honourary). The Right Honourable Louis St. Laurent, K.C., Prime Minister of Canada His Excellency Msgr. Maurice Roy, Archbishop of Quebec, Chancellor of Laval Arthur A. Schmon Behind Archbishop Roy is Cardinal McGuigan of Toronto Msgr. Garant is immediately behind Arthur A. Schmon and about to pin the epitage on his left shoulder. Young Priest immediately behind the Archbishop's chair is Father Garneau, Secretary to Msgr. Parent, Vice-Rector of the University."

Photograph - Hamilton Killaly Woodruff and Julia

A photograph of Hamilton K. Woodruff and Julia holding a baby. Julia is standing with her back to the camera as the baby looks over her shoulder. They are outdoors with a couple of trees surrounding them. The reverse of the photo has a handwritten note that reads, "A good picture of a Tweed Skirt!", referring to Julia's skirt (since her face cannot be seen).

Maid of the Mist, Niagara, U.S.A.

The description of the image is "(6) Majestically Grand - the Falls from the 'Maid of the Mist,' Niagara, U.S.A.". The reverse of the image reads "You are on the deck of the small but sturdy little steamer that runs along near the foot of the falls. At this moment you are pretty nearly mid-stream, looking south. The American shore are up over your left shoulder. That tall, dark cliff at the extreme left of what you see is Goat Island. The people up there outlined against the sky look like dolls and no wonder; they are more than 160 feet above your head. Some of them are looking off over the unspeakable grandeurs of the Horseshoe Fall there at the right; some are without doubt looking down at the very boat and remarking that the passengers look like dolls. It is an awesome experience to go so near that never-ceasing downpour of waters from the sky. The air is full of the roar and iridescent spray, and it seems as if the boat must be drawn in under the overwhelming floods never to rise again. Yet, curiously enough, the river right around the boat is not so madly excited as you might expect. It seems more like some great creature, dazed, bewildered, stunned by some incredible experience and not yet quite aware of what has happened. (When it gets down into the Whirlpool Rapids, two miles below here, it is dramatically alive to its situation!) The gigantic curve of the cliffs, reaching in up-stream straight ahead, makes a contour line of over 3000 feet before it comes up against the Canadian banks on the west (right). Geologists say that the Falls ages ago must have been at least seven miles farther down the river (behind you) and have gradually won their way back. Even now the curve of the Horseshoe is worn away from two to four feet in a year. No wonder; 12, 000, 000 cubic feet of water (about 375, 000 tons) sweep over the rocks in one minute, and the same the next minute and the next and the next. See Niagara through the Stereoscope, with special maps locating all the landmarks about the Falls.