This study investigated body segment contributions to javelin throwing during the last thrust phases. A 3-D analysis was performed on male and female javelin throwers during the finals of the 1992 Olympic Games in Barcelona. The subjects were videotaped from the right sight of the throwing area by two NAC high-speed cameras operating at 100 frames per second. Both men’s and women’s grip of javelin and body center of mass displayed a curved pathway to the right from the left (bracing) foot during the final foot contact. The position of the body center of mass decreased at the beginning of the final foot contact, but after the decrease period it began to increase. Simultaneously with the increase, the peak joint center speeds occurred in a proper sequence from proximal to distal segments and finally to the javelin at release. Release speed correlated significantly with throwing distance in both male and females.
Mero Antti, Paavo V. Komi, Tapio Korjus, Enrique Navarro and Robert J. Gregor
Maurice R. Yeadon
At the 1992 Olympic Games six full twisting double somersault dismounts were recorded with two video cameras during the rings individual apparatus finals in the men's Artistic Gymnastics competition. Angles describing body configuration were determined from video data and were input, together with initial orientation angle values and angular momentum components, into a computer simulation model of aerial movement. Mean absolute deviations between simulation and video after the completion of one half twist were 0.01 rev for somersault, 2.8° for tilt, and 0.08 rev for twist. When the estimate of the initial tilt angle was adjusted by up to 1° these deviations fell to 1.6° for tilt and 0.02 rev for twist. All 6 competitors produced the majority of the tilt using aerial techniques that were predominantly asymmetrical movements of the arms. Contributions to the subsequent removal of tilt were determined using reverse simulations, and again arm movements were the main contributors.
Rosa M. Angulo-Kinzler, Stephen B. Kinzler, Xavier Balius, Carles Turro, Josep M. Caubet, Josep Escoda and J. Antoni Prat
This study explains the general aspects of the biomechanics of the pole vault and presents a 3D analysis of the best official performances of the top 8 pole vaulters at the 1992 summer Olympic Games in Barcelona. Two time code synchronized S-VHS video cameras operating at 50 Hz were used. All vaulters showed a reduced last stride and a low CM during the penultimate foot support. Great horizontal velocity at takeoff, high grip, and well timed angular momentum serve as good indicators of a jumper's performance. An early positioning of the hips parallel to the bar can be very beneficial, as can a close placement of the CM to the bar at the time of pole release. Finally, an advantageous bar clearance technique used by the winning Unified Team vaulters is noted.
Gert-Peter Brüggemann, Phillip J. Cheetham, Yilmaz Alp and Diamantis Arampatzis
At the 1992 Barcelona Olympic Games, 70 dismounts and release-regrasp movements on the high bar were selected from films gathered with three synchronized cameras during the compulsory and the optional men's high bar competition. The skills were classified into 10 groups depending on the direction of rotation, body configuration, and flight projection. Kinematic variables were used to profile the movement groups. Statistically significant differences between the groups were identified by ANOVA. Three groups with significant differences in terms of the maximum values and the locations of the maxima could be differentiated. These were (a) backward rotating swings with an increase of rotation (e.g., overgrip giant swing—triple backward tuck somersault dismount), (b) backward rotating swings with a change of the direction of rotation (e.g., overgrip giant—Tkatchov straddle), and (c) forward rotating swings with an increase or a decrease of rotation (e.g., undergrip giant swing—Jaeger somersault).
Glenn M. Street and Robert W. Gregory
While the scientific literature has confirmed the importance of high maximal aerobic power to successful cross-country skiing performance, the same cannot be said of skiing technique or gliding characteristics of skis. The purpose of this study was to determine whether glide speed was related to Olympic race performance. Male competitors in the 50-km freestyle event were videotaped during the 1992 Winter Olympic Games. Glide speeds of the entire field were measured through a 20-m flat section at the bottom of a 150-m, 12° downhill. A significant correlation (r = -.73) was found between finish time and glide speed, showing that the more successful competitors tended to have faster glide speeds through this section of the course. A predictive model of glide speed suggested that the faster glide speeds were due primarily to differences in friction. There was little evidence to suggest that differences in air drag, body mass, or initial speed accounted for the major differences in glide speeds.
Gert-Peter Brüggemann, Michael Morlock and Vladimir M. Zatsiorsky
Performance in bobsled and luge events is influenced by several environmental, material/equipment, and team-related factors. This study concentrated on the influences of equipment and athlete on overall performance and compared the luge, 2-man bobsled, and 4-man bobsled competitions at the 1994 Lillehammer Winter Olympic Games. Start time and overall acceleration in the analyzed straight section showed significant correlations with the final time. It was concluded that for the top teams in bobsled and luge, fast start time and high speed at the end of the start section were prerequisites for an excellent overall performance. Driving capacities in the most difficult sections of the track were more statistically important among the top 15 competitors, especially in the luge. The influence of the runners could not be identified in either bobsled or luge competitions.
Anna-Liisa Ojala and Holly Thorpe
Action sports (e.g., snowboarding, skateboarding, windsurfing, BMX) have traditionally celebrated antiauthoritarian, do-it-yourself and anticompetition cultural values. With the institutionalization and commercialization of action sports over the past two decades, and the introduction of mega-sports events such as the X Games, and the inclusion of some action sports into the Olympic Games (i.e., snowboarding, freestyle skiing, BMX), action sport athletes are increasingly working with coaches, psychologists, agents, managers and personal trainers to improve their performances. In this Insights paper we consider coaching in action sports via the case of Finnish professional snowboarders’ attitudes to coaches. Drawing upon conversations with elite freestyle snowboarders we briefly present insights into their perceptions of the various positions of coaches in professional snowboarding before we offer suggestions built upon a Problem-based learning approach for coaches interested in working with action sport athletes.
Maurice R. Yeadon and David G. Kerwin
At the 1996 Atlanta Olympic Games, 18 single somersaults with one twist in the women’s compulsory floor exercises were recorded using two video cameras. An 11 segment computer simulation model was used to analyze the twisting techniques used. It was found mat counter-rotation techniques accounted for less than one third of the twist for all gymnasts, indicating that the production of twist was mainly a consequence of the angular momentum and a non-zero tilt angle. Contributions to the tilt angle reached at the mid-twist position were used as measures of the twisting potential of various techniques. Contact techniques accounted for 30% of the tilt produced, the remainder being produced using aerial techniques, which primarily comprised a symmetrical lowering of the arms together with minor contributions from asymmetrical arm and hip movements. There was no evidence of a difference in technique between the highest and lowest scoring competitors.
Richard C. Nelson, Ted S. Gross and Glenn M. Street
The purpose of this report was to provide a model analysis of biomechanical films taken during the women's gymnastic vaulting events of the 1984 Los Angeles Olympic Games. Although a majority of the optional vaults were filmed, only the 16 vaults performed by the competitors in the individual championships were examined. The analysis included calculations of temporal, spatial, and velocity parameters as the gymnast's center of mass moved through four phases of the vault. The phases were identified as Reuther board contact, prehorse flight, horse contact, and posthorse flight. A representative profile of a female gymnast competing in the Games was compiled based on these parameters. This profile indicated that the gymnasts were much smaller than the average population, efficient in the use of the Reuther board and the horse to reach and maintain CM velocities necessary to complete the vault, and agile enough to perform complex airborne rotations during an average posthorse flight duration of .80s.
Robert W. Gregory, Sean E. Humphreys and Glenn M. Street
The women's 30-km freestyle cross-country race at the 1992 Winter Olympic Games was selected to determine the kinematic differences between more and less successful skiers. Three-dimensional filming techniques were used to capture the movement patterns on level terrain of 8 skiers who placed in the top 50% (Group 1) and 8 skiers who placed in the bottom 50% (Group 2) of the field. The mean cycle velocity for Group 1 was significantly faster (p < .005) than the velocity for Group 2. Significant correlations (p < .05) were found between race velocity and cycle velocity (r = .89) and between cycle length and cycle rate (r = -.82). Group 1 had significantly greater (p < .03) weak-side elbow flexion at pole plant, as well as less (p < .01) weak-side elbow extension and more (p < .05) trunk flexion during poling. The mean cycle velocity differences between Groups 1 and 2 may have been the result of smaller resistive and/or larger propulsive forces.