Canadian journal of applied sport sciences. Journal canadien des sciences appliquees au sport最新文献

This paper describes a specific system analytic approach to the coaching and teaching of team sports. Computer technology is used to acquire the sequential history of critical events that occur during competition. A system is described that allows the analyst to enter data directly on a microcomputer and then compute relevant statistics for immediate use by the coach or teacher. The implications for the microcomputer system's use in high performance sports is also discussed.

As a follow-up to De Garay et al. (1976) and Chagnon et al. (1984) studies, we are reporting on the genetic variation of four red blood cell enzymes in 49 athletes with isoelectric-focusing and electrophoresis techniques. The athletes were Caucasians participating in the 1976 Montreal Olympic Games. They were performing in 5 different sports and the sample included 18 women and 31 men. No uncommon allele was found and all known alleles were detected for each enzyme. Phenotypes and gene frequencies were computed and compared with appropriate populations of reference. No significant differences were observed for any of the enzymes. Moreover, no association was found between variation in these proteins and participation in rowing (N = 25) or track (N = 13) event.

Physiological profiles of elite athletes are becoming increasingly important both for the sport scientist and coach, primarily to effectively develop training programs and to use as a motivational tool in the pursuit of excellence. Descriptive profiles were developed on 16 aspirants of the Canadian Olympic Soccer team during their training program at U.B.C. Selected strength measures were obtained from a Cybex II isokinetic dynamometer at 30 degrees sec-1. Metabolic variables were derived utilizing a Beckman metabolic cart interfaced with a Hewlitt Packard 3052A data acquisition system. Protocols involved were the following: VO2max (initial velocity 8.05 km X h-1, greater than 0.805 km X min-1); Anaerobic speed test (AST) (20% grade, 12.8 km X h-1). the nonlinear increase in excess CO2 was utilized to determine the anaerobic threshold (AT). (Table: see text). Recommendations emphasized maintenance of low body fat, increasing maximal aerobic power by approximately 10% and creating a hams/quads ratio of 60%. Also, a nutritional survey and periodic evaluation of iron status is necessary for the athletes.

This study investigated the relationship of individual anaerobic thresholds to oxygen debt. Anaerobic threshold speed (VTAM) was determined for 21 male university students using a continuous ramp treadmill protocol. The onset of anaerobiosis was determined by visual inspection of excess CO2 elimination. The following week, all subjects ran at the treadmill speed 3.3 m.sec-1 for 10 minutes (this speed split the group into two halves). Recovery oxygen consumption was monitored after this run. Application of double exponential equations by computer and subsequent integration was used to calculate total, alactic, and lactic oxygen debts. Subjects who ran above their VTAM (group L-VTAM) had significantly (p less than .05) higher total, lactic and alactic debts compared to subjects who ran below their VTAM (group H-VTAM). The total debt demonstrated a significant (p less than .05) negative correlation (r = .77) to VTAM in group L-VTAM. This appears to be due to increasing lactic debt, that was also significantly (p less than .05) negatively correlated (r = -.73) to VTAM. Group H-VTAM did not exhibit this characteristic. This study demonstrates that VTAM, as determined by excess CO2 elimination, is a critical factor in determining oxygen debt and therefore, work above this point (which results in the onset of metabolic acidosis) may limit the optimal running speed for a given distance.

The purpose of this research was to examine how temperature and velocity affect coefficient of restitution and how temperature affects the force-deformation properties of balls used in the international game of squash. The balls used were the international yellow dot and a newly developed double yellow dot. Coefficient of restitution increased with temperature and decreased with increases in projection velocity. The effect of temperature was most marked at low projection velocities. Coefficient of restitution was smallest for the double yellow dot ball but differences between balls decreased with increases in both temperature and projection velocity. Static tests showed increasing ball stiffness with increases in both force applied and temperature, and the yellow dot ball showed the greatest stiffness. Static tests indicated that standards published by the Canadian Squash Racquets Association are inappropriate. These results are discussed in the contexts of play and testing and design criteria for the balls.

The influence of mental imagery perspective on figure skating performance was investigated. Fifty-nine skaters, who were in attendance at the Canadian Figure Skating Association's National Singles Seminar, participated in the study. Subjects performed a modified senior level figure as a pre-test measure, and then were randomly assigned to one of four treatment groups: an internal kinesthetic imagery group, an internal visual imagery group, an external visual imagery group, and a control training group. All treatment groups underwent four training sessions. Post-test performance revealed no significant differences between the three types of imagery training, and imagery training subjects failed to perform significantly better than control subjects. However, senior skaters showed both greater performance improvements and were superior kinesthetic imagers than novice skaters.

Anecdotal and research evidence suggest that imagery rehearsal can improve performance in a variety of sports activities at least some of the time. However, the reasons for the effects (or lack of them) are unclear. This paper proposes a conceptual framework that could be used to evaluate the available research literature and guide further research on the use of imagery techniques to modify performance. The framework is based on evidence that imagery mediates behaviour through either cognitive or motivational mechanisms, which affect specific or general response systems. Special emphasis is given to task analysis and the functions of memory and verbal mechanisms in imagery rehearsal.

This paper provides a critical review of research on mental practice, with special emphasis on works investigating the role of visual imagery in this type of learning technique. Relevant properties of images and conditions required for their effectiveness in mental practice of motor skills are analyzed in the light of empirical evidence. The paper examines the specific question of individual imagery differences in mental practice research. Finally, implications for future research are discussed as regards the impact of certain kinds of physical training on mental imagery.

We have designed, constructed and tested a restraining apparatus to permit safe uninhibited hand propulsion of a wheelchair on a motor driven treadmill. The special design features of the tracking assembly minimize any potential hazard or apprehension associated with possible lateral or rearward displacement of a chair from the belt surface. Special linear bearings minimize any increase in rolling resistance (less than 1.23 X 10(-3) N force displacement) at speeds ranging from 4 to 282 m. min.-1. The supporting frame is adjustable for variations in treadmill belt widths and different model wheelchairs. Easy removal of the chair enables convenient conversion of the treadmill for walking/running activity.