International SportMed Journal - Volume 8, Issue 1, 2007
Volume 8, Issue 1, 2007
Source: International SportMed Journal 8, pp 2 –10 (2007)More Less
Dietary supplements are used by at least 40% of athletes, and depending on the sport, up to 100%. Often multiple supplements are taken in higher than normal doses. Both competitive and recreational athletes take supplements, though sometimes for different reasons. Some take them to support a poor quality diet; others take supplements because they simply feel that an ordinary diet, even a good one, is unable to provide the necessary nutrients in adequate quantity. Female endurance athletes frequently supplement their diet with extra iron, with natural losses exacerbated by hard training, menses and often a low intake of iron-rich red meat. Nutritionists and dieticians usually recommend whole food solutions to these and other problems first, but some are now starting to accept the use of low dose vitamin and mineral supplements as a way to prevent deficiencies.
Dietary supplements can be categorised according to several classifications like type, accessibility, utility or scientific merit. Even if a well-monitored daily diet should allow athletes to meet their nutritional needs, in some cases, the use of supplements can be beneficial to support a high level of physical activity. However, athletes and their medical staff should be aware of potential adverse analytical findings following supplement contamination.
In conclusion, to avoid problems associated with the consumption of dietary supplements, athletes should balance the risks and benefits of these products and consult a nutritionist or dietician for expert advice on the appropriate use of supplements.
Source: International SportMed Journal 8, pp 11 –23 (2007)More Less
Objective: To perform a literature review of the current available data on protein and amino acid supplementation in sports, their efficacy and safety.
Data sources: The search was limited to English language citations published in the years 1980-2007. MEDLINE and PubMed searches were performed in March 2007 on all studies using the Mesh terms: proteins, amino acids, supplement, the desired supplement name and sports / exercise.
Study section: Initially, only randomised controlled clinical trials were included in the analysis. In addition, several recent reviews and relevant meta-analyses were used.
Data extraction: A title scan was performed to exclude references that did not include protein supplementation, exercise, or the population's health status was abnormal. Relevant literature was identified, sourced, and reviewed and the selected manuscripts are cited.
Data synthesis: Although protein supplementation has been widely discussed in the literature for many years, it was surprising to find the relatively low number of randomised controlled trials that met the inclusion criteria for this review. When the general terms "protein / amino acids" were used, 43 citations met the criteria; "creatine" yielded 53 citations; "glutamine" 2 citations, and "β-hydroxy-β-methylbutyric acid (HMB)" 9 citations. The bulk of the data suggests that protein requirements are usually met by an iso-caloric, balanced diet, for both endurance and resistance training. Supplementing the athlete's diet with protein or amino acids has not proven beneficial and may even sometimes be harmful. Creatine is currently the only product that has clear scientific support to enhance sporting performance. The timing of protein supplementation may be an important factor in trying to achieve anabolic effects.
Conclusions: The use of protein supplements for the healthy, non-competitive adult engaged in recreational sports is usually not warranted. There are only limited data to support protein supplementation in competitive sports. There is some evidence supporting the use of creatine and possibly HMB as ergogenic aids in specific situations. Further research is needed before definitive recommendations can be made on the type, timing and effectiveness of protein supplements.
Author Andrew N. BoschSource: International SportMed Journal 8, pp 24 –30 (2007)More Less
The effects of carbohydrate ingestion on prolonged exercise performance have been extensively studied. Particularly, many studies have paid specific attention to the effect of carbohydrate ingestion on time to fatigue, the effect on the respiratory exchange ratio (RER), the effect that the time at which the carbohydrate is ingested may have on performance, and the optimal amount of carbohydrate to be ingested. In addition, the effect of different types of carbohydrate and the influence of exercise intensity has been studied, including the influence on hepatic glycogenolysis and on ratings of perceived exertion (RPE)
The most important findings have been that there is a beneficial effect from ingestion of carbohydrate during prolonged exercise due to prevention of hypoglycaemia, the provision of blood glucose for oxidation late in exercise, and that there is a hepatic glycogen sparing effect as a result ingesting carbohydrate. Importantly, the majority of carbohydrate types are oxidised at similar rates when ingested singularly. However, a mixture of specific carbohydrates ingested together are oxidised at a much higher rate.
Despite the volume of research in this area, some questions remain unclear, specifically information pertaining to feedforward control mechanisms in the brain that integrate exercise performance on the basis of feedback from different body organs, and the role that carbohydrate ingestion may have on this control, including the effect of body carbohydrate reserves.
Using ratings of perceived exertion to regulate exercise intensity following different perceptual anchoring : original research articleAuthor Randall F. Gearhart Jr.Source: International SportMed Journal 8, pp 31 –37 (2007)More Less
Ratings of perceived exertion (RPE) have been used to regulate exercise intensity in previous investigations. Comparisons of relative, self-selected exercise intensities have not been done when different types of anchoring have been employed. This investigation compared percent VO2 max at an RPE of 13 on the Borg 15-category scale during perceptually regulated treadmill exercise following memory (M) or combined exercise and memory (EM) anchoring. Thirty-two participants volunteered. Eight males and eight females were assigned to each group. The M received a verbal description of the low (i.e. 7) and high (i.e. 19) perceptual anchors immediately prior to the experimental trial. For EM, the anchors were established during a maximal, graded treadmill exercise test. The low perceptual anchor was established during light walking and the high perceptual anchor was established following volitional termination. The EM group was read the anchoring instructions again prior to the experimental trial. VO2 max was determined during the orientation trial for EM, and in a separate session following the experimental trial for M. Expired gases were analyzed following three minutes of exercise at an RPE of 13. Percent VO2 max for the M and EM was compared using an independent t-test. VO2 max did not differ between M (49.29 + 11.09 mlÂ·kg-1Â·min- 1) and EM (51.07 + 11.79 mlÂ·kg-1Â·min-1). Percent VO2 max at an RPE of 13 also did not differ between M (83.18 + 6.86 %) and EM (85.02 + 4.47 %). The current results indicate that regulating exercise intensity using RPE is not affected when different anchoring procedures are employed.
Source: International SportMed Journal 8, pp 38 –41 (2007)More Less
Spinning exercise cycle machines are becoming increasingly popular. They provide the health benefits of cycling without the injury risks of road usage. This is the report of a unique case of cervical spine fracture sustained whilst exercising in a gym on a stationary SpinningÂ® bike.