The tropical climate is unique in that the seasons are dominated by the movement of the tropical rain belt, resulting in dry and wet seasons rather than the four-season pattern of changes in temperature and day length seen in other parts of the world. More than 33% of the world population lives in the humid tropics, which are characterized by consistently high monthly temperatures and rainfall that exceeds evapotranspiration for most days of the year. Both the 2014 Football World Cup (in Brazil) and the 2016 Olympic Games (in Rio de Janeiro) will take place in this climate. This review focuses on the effects of the tropical environment on human exercise performance, with a special emphasis on prolonged aerobic exercise, such as swimming, cycling, and running. Some of the data were collected in Guadeloupe, the French West Indies Island where all the French teams will be training for the 2016 Olympic Games. We will first fully define the tropical climate and its effects on performance in these sports. Then we will discuss the types of adaptation that help to enhance performance in this climate, as well as the issues concerning the prescription of adequate training loads. We will conclude with some perspectives for future research.
Daniel J. Daly, Laurie A. Malone, David J. Smith, Yves Vanlandewijck and Robert D. Steadward
A video race analysis was conducted at the Atlanta Paralympic Games swimming competition. The purpose was to describe the contribution of clean swimming speed, as well as start, turn, and finish speed, to the total race performance in the four strokes for the men’s 100 m events. Start, turn, and finish times, as well as clean swimming speed during four race sections, were measured on videotapes during the preliminary heats (329 swims). Information on 1996 Olympic Games finalists (N = 16) was also available. In Paralympic swimmers, next to clean swimming speed, both turning and finishing were highly correlated with the end race result. Paralympic swimmers do start, turn, and finish slower than Olympic swimmers but in direct relation to their slower clean swimming speed. The race pattern of these components is not different between Paralympic and Olympic swimmers.
Qiwei Huang and Ryan M. Brewer
This case examines dilemmas evolving in China’s premier soccer league, the Chinese Super League. A plan is suggested for confronting the league’s challenges, with recommendations that focus on creating a harmonious and competitive league. Challenges arise from the political and economic transformation currently taking place in China, affecting league operations. While the league stands at a precipice of change on the eve of the Beijing Olympic Games, its viability as a going concern is uncertain. Part of the uncertainty derives from an unregulated system of league policies that have been poorly communicated and unenforced, resulting in discord. Development of league regulations and communication protocols remains largely government driven and would be best if consistent with the local culture, but commercial issues of league operations are also important. Enhancing the effectiveness and consistency of culture-sensitive communication protocols—especially between the government, media, and league officials—will increase participation from league stakeholders.
Ruud W. de Boer and Kim L. Nilsen
The 1988 Winter Olympic Games provided a unique opportunity to study large numbers of optimally prepared speed skaters during ideal ice and weather conditions for all the competitors (indoor Olympic Oval in Calgary). In this study a kinematic analysis was conducted of the gliding and push-off technique during the Men’s and Ladies' 1,500-m and 5,000-m races. Statistical analysis showed that factors such as trunk position, preextension knee angle, and peak knee and hip angular velocities failed to correlate with mean lap speed. Within such a homogeneous group of elite athletes it was found that the higher work per stroke of the faster skaters was correlated to a longer gliding phase and a more horizontally directed push-off. All skaters showed plantar flexion at the end of the stroke, which is undesirable and indicates the complex nature of the gliding and push-off technique in speed skating.
Ruud W. de Boer and Kim L. Nilsen
The mechanics of speed skating the curves is described in a mathematical model, using the sideward push-off characteristics of the propulsion and the cyclic nature of the movement. Theoretical and experimental relations between mechanical work per stroke, stroke frequency, and speed were studied with Olympic speed skaters. High-speed film and video measurements collected at the 1988 Winter Olympic Games in Calgary provided the basic experimental data. Because of the ideal external conditions (indoor Olympic Oval) and the large numbers of optimally prepared specialists participating, unique scientific results on technical aspects of speed skating could be obtained. Statistical analysis and theoretical considerations showed that stroke frequency can be judged as the major regulator of speed. Unexpectedly, it was not possible to detect changes in speed within one lap.
Jos J. de Koning, Gert de Groot and Gerrit Jan van Ingen Schenau
Mechanical characteristics of the sprint start in speed skating were measured during the 1988 Winter Olympic Games. From three-dimensional film analysis of the first 4 seconds of the male and female 500-m races, biomechanical variables were determined. The first strokes during the start appeared to be performed by a running-like technique. At a forward velocity of approximately 4 m/sec, the skaters are forced to change this technique to the typical gliding technique as used during speed skating at steady speed. In explaining the time differences on the first 100 meters of the 500-m speed skating race, the effectiveness of the push-off appears to be more important than the observed high power output levels.
Michael M. Morlock and Vladimir M. Zatsiorsky
The performance in bobsledding is influenced by several factors. This study concentrated on influences of the environment and the bobsled crew on the final time of a bobsled run. The analysis was performed with data collected during the four-man competition at the 1988 Winter Olympic Games in Calgary. It was shown that the start order, the ice temperature, and the push time together explain about 50% of the variance in the performance (α=0.05). It is suggested that the existing rule concerning the start order in a heat be modified to guarantee a fair competition. Selected speed and turn time variables were shown to give an indication of the characteristics and the important sections of the bobsled track at Canada Olympic Park. It is speculated that the optimization of turn times is more important than the increase in speed in a turn.
Maurice R. Yeadon, Sung-Cheol Lee and David G. Kerwin
At the 1988 Seoul Olympic Games, eight full twisting somersault dismounts from the high bar were filmed using two cameras during the compulsory exercises of the Men’s High Bar competition. Angles describing body configuration and orientation were determined and were input into a computer simulation model of aerial movement. The deviations between simulation and film were less than 2.5° for tilt angles and less than 0.07 revolutions for twist angles. The twisting techniques employed were quantified using the tilt angle as a measure of twisting potential. Contributions to the maximum tilt angle were determined using simulations based on modifications of the film data. Each of the eight competitors obtained most of the tilt using aerial rather than contact techniques. In general, the majority of the aerial contributions arose from asymmetrical arm and hip movements.
David G. Kerwin, Maurice R. Yeadon and Sung-Cheol Lee
An 11-segment three-dimensional simulation model was used to modify the body configurations of eight gymnasts performing multiple somersault dismounts during the Men’s High Bar competition in the 1988 Seoul Olympic Games. Four layout double somersault performances were modified to change a characteristic backward arch to a straight body position. This modification reduced the somersault rotation by 0.03 to 0.10 somersaults. Four tucked triple somersault performances were modified so that the thigh abduction angle was reduced to zero. This modification resulted in underrotations ranging from 0.01 to 0.34 somersaults depending on the amount of thigh abduction in the original movement. The additional angular momentum needed for successful completion of the modified movements was small in general and in no case greater than 13%.
This study compared the techniques used by elite male gymnasts in performing blocking or pushoff against the horse and postflight in the handspring and salto forward tucked vault. Forty-one American gymnasts were compared with 51 Olympic gymnasts on the mechanical factors governing the blocking and body control for salto forward and kickout in postflight. A 16-mm high-speed camera recorded the performance of the gymnasts during the 1986 USA Gymnastics Championships and the 1988 Olympic Games. The results indicated that Olympic gymnasts assumed the tightest tuck position significantly nearer the peak of the parabolic path of CG and thus achieved significantly greater height of CG at the tightest tuck position during the somersault than did the U.S. gymnasts. The superiority of body control by the former after the tightest tuck to landing was evidenced by significantly longer time, larger horizontal and angular distances, greater average moment of inertia, and smaller angular velocity.