Genetic research and testing in sport and exercise science: A review of the issues

Abstract

This review is based on the BASES position stand on “Genetic Research and Testing in Sport and Exercise Science”. Our aims are first to introduce the reader to research in sport and exercise genetics and then to highlight ethical problems arising from such research and its applications. Sport and exercise genetics research in the form of transgenic animal and human association studies has contributed significantly to our understanding of exercise physiology and there is potential for major new discoveries. Researchers starting out in this field will have to ensure an appropriate study design to avoid, for example, statistically underpowered studies. Ethical concerns arise more from the applications of genetic research than from the research itself, which is assessed by ethical committees. Possible applications of genetic research are genetic performance tests or genetic tests to screen, for example, for increased risk of sudden death during sport. The concerns are that genetic performance testing could be performed on embryos and could be used to select embryos for transplantation or abortion. Screening for risk of sudden death may reduce deaths during sporting events but those that receive a positive diagnosis may suffer severe psychological consequences. Equally, it will be almost impossible to keep a positive diagnosis confidential if the individual tested is an elite athlete.     

The effect of induced alkalosis and submaximal cycling on neuromuscular response during sustained isometric contraction

Abstract

The aim of this study was to determine if inducing metabolic alkalosis would alter neuromuscular control after 50 min of standardized submaximal cycling. Eight trained male cyclists (mean age 32 years, s = 7; [Vdot]O_2max 62 ml · kg^?1 · min^?1, s = 8) ingested capsules containing either CaCO₃ (placebo) or NaHCO₃ (0.3 g · kg^?1 body mass) in eight doses over 2 h on two separate occasions, commencing 3 h before exercise. Participants performed three maximal isometric voluntary contractions (MVC) of the knee extensors while determining the central activation ratio by superimposing electrical stimulation both pre-ingestion and post-exercise, followed by a 50-s sustained maximal contraction in which force, EMG amplitude, and muscle fibre conduction velocity were assessed. Plasma pH, blood base excess, and plasma HCO₃ were higher (P < 0.01) during the NaHCO₃ trial. After cycling, muscle fibre conduction velocity was higher (P < 0.05) during the 50-s sustained maximal contraction with NaHCO₃ than with placebo (5.1 m · s^?1, s = 0.4 vs. 4.2 m · s^?1, s = 0.4) while the EMG amplitude remained the same. Force decline rate was less (P < 0.05) during alkalosis-sustained maximal contraction and no differences were shown in central activation ratio. These data indicate that induced metabolic alkalosis can increase muscle fibre conduction velocity following prolonged submaximal cycling.     

Home advantage in southern hemisphere rugby union: Nationaland international

Abstract

This study evaluates home advantages both for national (Super 12) and international (Tri-nations) rugby union teams from South Africa, Australia and New Zealand, over the five-year period 2000 – 2004 using linear modelling. These home advantages are examined for statistical and practical significance, for variability between teams, for stability over time and for inter-correlation. These data reveal that the overall home advantage in elite rugby union has a mean of +6.7 points, and that this changes little from year to year. Closer scrutiny nevertheless reveals a high degree of variability. Different teams can and do have different home advantages, which ranges from a low of ?0.7 to a high of +28.3 points in any one year. Furthermore, some team home advantages change up or down from one year to the next, by as much as ?36.5 to +31.4 points at the extremes. There is no evidence that the stronger teams have the higher home advantages, or that a high home advantage leads to a superior finishing position in the competition.     

Sand training: a review of current research and practical applications

Abstract

Sand surfaces can offer a higher energy cost (EC) and lower impact training stimulus compared with firmer and more traditional team sport training venues such as grass. This review aims to summarise the existing research on sand training, with a specific focus on its application as a team sports training venue. Compared with grass, significant physiological and biomechanical differences are associated with sand exercise. However, evidence also exists to suggest that training adaptations unique to sand can positively influence firm-ground performance. Furthermore, the lower impact forces experienced on sand can limit muscle damage, muscle soreness, and decrements in performance capacity relative to exercise intensity. Therefore, using a sand training surface in team sports may allow greater training adaptations to be achieved, while reducing performance decrements and injuries that may arise from heavy training. Nevertheless, further research should investigate the effect of sand surfaces over a greater range of training types and performance outcomes, to increase the application of sand training for team sports.     

Personal and Situational Factors Affecting Exercise Involvement: The Importance of Enjoyment

Abstract

Interviews were conducted with continuing participants (n=51) and dropouts (n=60) from a male employee fitness program in order to investigate programmatic, personal, and social factors affecting involvement. It was found that a combination of items pertaining to reactions to the program, goals for initially joining the program, and social support for involvement in the program could effectively discriminate between the participant and dropout groups. Continuing participants scored higher than dropouts on the goals to develop recreational skills, to go out with friends, to satisfy curiosity, to release competitive drive and to develop social relationships. They also reported a greater increase in positive reactions to the program over their period of involvement in it than did the dropouts. Continuing participants rated the level of friendship within the exercise class higher and reported receiving more encouragement for involvement from their friends and work supervisor than did dropouts. Participants reported greater liking for the program activities than did the dropouts, while dropouts reported a greater dislike for the inconvenient program schedule. Implications of the results for program organization and conduct are discussed.     

Laboratory Assessment of Choice between Exercise or Sedentary Behaviors

The purpose of this study was to compare cardiovascular fitness between obese and nonobese children. Based on body mass index, 118 were classified as obese (boys [OB] = 62, girls [OG] = 56), while 421 were nonobese (boys [NOB] = 196, girls [NOG] = 225). Cardiovascular fitness was determined by a 1-mile [1.6 km] run/walk (MRW) and estimated peak oxygen uptake (VO₂peak) and analyzed using two-way analyses of variance (Gender x Obese/Nonobese). MRW times were significantly faster (p < .05) for the NOB (10 min 34 s) compared to the OB (13 min 8 s) and the NOG (13 min 15 s.) compared to the OG (14 min 44 s.). Predicted VO₂peak values (mL·kg^-1·min^-1) were significantly higher (p < .05) for the NOB (48.29) compared to the OB (41.56) and the NOG (45.99) compared to the OG (42.13). MRW was compared between obese and nonobese participants on the President's Challenge (2005), the National Children and Youth Fitness Study, and FITNESSGRAM® HFZ standards. The nonobese boys and girls scored higher on all three, exhibiting better cardiovascular fitness as compared to obese counterparts.     

Effects of Various Training Programs on Speed of Swimming

Abstract

Six groups of subjects were tested to determine if various training programs affected performance in speed in swimming 30 yards. No evidence of improvement was found after one group of subjects had been exposed to absolutely no exercise for six weeks and, also, after a group of subjects had participated in various exercises with weights three times weekly for six weeks. Two groups of swimmers who participated in practicing starts, kicking, arm stroking, and sprinting 30 and 60 yards significantly improved their performances in speed in swimming; one group of subjects followed the preceding program three times weekly and another group used the same routine six times a week. Two other groups, one of which was exposed to weight training and swimming, and one of which was exposed only to 30-yard sprints and practicing starts, both showed statistically significant differences in performance.