Mapping Aspect Ratios in the Age of High-Definition Television

Although high-definition television (HDTV) has led to more film and television content being presented in a widescreen aspect ratio, problems with formatting moving images in nontheatrical environments persist. Because of the different venues and delivery systems available for accessing televisual and cinematic content, the variety of high definition and standard definition television channels across cable and satellite providers, as well as the different aspect ratios filmmakers can choose to photograph their works, nontheatrical exhibition of the moving image continues to be a source of contention in the age of high definition. Drawing upon a number of comments from online home media forums, this study concludes that the variant quality of widescreen images for HDTV is not solely grounded on a subculture of home theatre enthusiasts, but rather how networks and studios negotiate new television technologies for the aesthetic preferences of both film and home theatre buffs and the general viewing audience.     

Biomechanical validation of a specific upper body training and testing drill in cross-country skiing

The aim of this study was to perform a biomechanical validation of a double poling imitation drill on a rollerboard. Six elite cross-country skiers performed three imitation drill trials at maximal speed at 13 degrees inclination and in double poling on roller skis on a paved road of 3 degrees. Pole and strap forces, elbow and hip angles and EMG activity of eight upper body muscles were measured. Force curves showed similar characteristics, except for impact force occurring only at pole plant in double poling on roller skis. Double poling on a rollerboard includes an eccentric roll-down phase not appearing in double polling on roller skis. Forces on the rollerboard were similar to those on roller skis. Courses of the elbow angles indicated similar shapes, except for the angle at the start of the propulsion phase and, consequently, during flexion (p < 0.01). Propulsion time and cycle duration were longer and frequency lower on the rollerboard (all p < 0.001). Muscle activities were not significantly different, except for stronger biceps brachii (p < 0.01) and weaker erector spinae activation (p < 0.05) on the rollerboard. Muscle coordination patterns showed similar onset and offset points of each muscle and comparable activations in both activities, except for biceps brachii. Two movement strategies on the rollerboard were found, which led to small differences in measured variables. The biomechanical validity of double poling on a rollerboard can be judged as moderately high, being aware of the differences in some variables that might be considered in training sessions on the rollerboard, particularly when using intervals with high number of repetitions.     

Education's “4th R”: Responsibility

The need for students to learn responsibility is considered. A current absence of such skills is described, followed by a straightforward approach for correcting the situation at the college level. The urgency for remediation in this area is discussed, emphasizing the importance of responsibility throughout life.     

Effects of wear on static and dynamic failure loads of aluminium-based alloy climbing karabiners

In rock climbing, karabiners are used to arrest falls and consequently must be able to withstand dynamic loads. The current international standard for rating karabiner strength prescribes a quasi-static tensile test, which poorly simulates the dynamic nature of an actual climbing fall. In this study, a new method was developed to measure the dynamic failure loads of climbing karabiners. Both new and heavily worn karabiners were tested open and closed, and results from static and dynamic tests were compared. We found that the dynamic failure loads of closed karabiners were up to 50% lower than the failure loads in static tests, while for open karabiners, the static and dynamic values were similar. The reason for this behaviour is unclear; it is most likely due to the combined effects of different stress concentrations and loading regimes of the two tests. Irrespective of test type, karabiner strength decreased with wear level. Based on our results, we advise frequent inspection of permanently placed karabiners for signs of excessive wear. In addition, testing of climbing karabiners in a dynamic test in addition to the standard static test might be considered when developing new karabiner models.     

Biomechanical comparison of the double-push technique and the conventional skate skiing technique in cross-country sprint skiing

The aims of the study were to: (1) adapt the "double-push" technique from inline skating to cross-country skiing; (2) compare this new skiing technique with the conventional skate skiing cross-country technique; and (3) test the hypothesis that the double-push technique improves skiing speed in a short sprint. 13 elite skiers performed maximum-speed sprints over 100 m using the double-push skate skiing technique and using the conventional "V2" skate skiing technique. Pole and plantar forces, knee angle, cycle characteristics, and electromyography of nine lower body muscles were analysed. We found that the double-push technique could be successfully transferred to cross-country skiing, and that this new technique is faster than the conventional skate skiing technique. The double-push technique was 2.9 +/- 2.2% faster (P < 0.001), which corresponds to a time advantage of 0.41 +/- 0.31 s over 100 m. The double-push technique had a longer cycle length and a lower cycle rate, and it was characterized by higher muscle activity, higher knee extension amplitudes and velocities, and higher peak foot forces, especially in the first phase of the push-off. Also, the foot was more loaded laterally in the double-push technique than in the conventional skate skiing technique.     

The international face of sports science through the window of the Journal of Sports Sciences--with a special reference to kinanthropometry

The history of the Journal of Sports Sciences is traced from the antecedents of its initiation to the current time. The developments of the sports sciences at large are reflected in the content of the journal. Its links with the international agenda are described, and related to landmark publications. Special attention is given to the relationships with international bodies, the International Society for Advancement of Kinanthropometry and the World Commission of Science and Sports. The expansion of sport and exercise sciences, both nationally and internationally, was reflected in the increased frequency of publication of the journal. Key areas in the kinanthropometric content are identified and placed in context. The review culminates in the highlighting of likely areas for future research.     

Effects of time of day and distance upon accuracy and consistency of throwing darts

We examined variations in dart-throwing performance during the daytime in 12 participants. Two distances from the dartboard were investigated - the normal distance (short throws) and another 50% further away than this (long throws). Intra-aural temperature and subjective fatigue were measured, and errors in performance were assessed as the radial distances of throws from the bulls-eye and the standard deviation of these distances. Long-distance throws improved significantly throughout the daytime and correlated positively with intra-aural temperature (r= -0.49, P=0.002 and r= -0.49, P=0.002 for errors and standard deviation of errors, respectively), but not with subjective fatigue (r= -0.10, P=0.56 and r= -0.05, P=0.74 for errors and standard deviation of errors, respectively). Short-distance throws were associated less with intra-aural temperature (r= -0.46, P= 0.005 and r= -0.17, P=0.31 for errors and standard deviation of errors, respectively), and worsened with fatigue (r=+0.34, P= 0.040 for errors). Compared with the short-distance throws, the long-distance throws were performed significantly less well than could be accounted for by the increased distance (mean errors were increased 1.67-2.78 times and standard deviation of errors of errors 1.58-3.68 times), supporting the concept of a trade-off between force of contraction and accuracy of performance. Throwing darts can be used as a model for investigating factors that influence motor performance, and our results indicate that the effects of time of day upon performance depend upon the relative importance of force and accuracy.     

Schooling for self-employment in Kenya: The acquisition of craft skills in and outside schools

Primary schooling will continue to be the terminal stage of education for most Kenyan children, and it will have to prepare them for employment that they will create for themselves. What this might imply for the teaching of craft skills is examined. Soapstone carving was selected as the subject of study because it is an important form of self-employment in western Kenya. The acquisition of craft skills in and outside schools was compared using observational and experimental methods. It is argued that school instruction provides little opportunity to develop competence in carrying out cognitive and psychomotor tasks important to expert performance in this and perhaps many other craft occupations.