What the experts say
Nigel Hetherington reviews the latest research material relating to coaching, exercise physiology and athletic development.
When your athlete tests positive for a banned substance and you know the athlete is not a cheat, what do you do? A report covers a challenge to the test result in this situation.
The substance in this instance was erythropoietin (EPO), the hormone released by the kidney to control the production of red blood cells. Injections of recombinant EPO (rEPO) produce major enhancements of endurance performance by increasing transport of oxygen to exercising muscles. Detection of trace amounts of injected rEPO in urine is the basis of the test.
In this case, to the coach the test was obviously wrong, so the first question was this: what is the false positive rate? It turned out that there is not one. The World Anti-Doping Authority (WADA) has not determined the false positive rate or factors that might increase it. Enquiries revealed one such factor: long hard exercise, which can result in an increase in the concentration of proteins in urine, including either EPO itself or other proteins that the EPO test erroneously identifies as rEPO. This athlete tested positive after an Ironman triathlon. He soon got her acquitted. Three other athletes have been exonerated recently under similar circumstances.
Testing an athlete for a drug is no different in principle from a doctor testing a patient for a disease. When the result comes back from the lab, the doctor considers not just the result of the test but all the other signs, symptoms, patient characteristics, and local factors that help reach a diagnosis. WADA could adopt a similar approach to testing for abuse of EPO and other drugs by taking other factors into account. For example, how much change has there been in the athlete's world ranking recently? Have there been any positives recently amongst the athlete's team-mates or compatriots? What is the attitude to cheating in the athlete's sport and in the athlete's home country? What other tests can be ordered on the spot, such as a blood test for haemoglobin concentration or other blood constituents that have unusual levels with EPO abuse? By itself, this extra information does not constitute a test for EPO abuse, but in conjunction with the main urine test, it may raise or lower the odds that the athlete is a true positive by a factor of 10 or even 100. The author concludes that research needs to be done to establish how useful this approach could be.
A study based on seven healthy males completing step tests examined the influence of metabolic alkalosis through sodium bicarbonate ingestion on pulmonary oxygen (pVO2) uptake, which has two characteristic mechanisms - 'fast' and 'slow'.
Subjects exercised at a work rate requiring 80% VO2 max on six separate occasions: three times after ingestion of 0.3 g/kg body mass sodium bicarbonate in 1 litre of fluid, and three times after ingestion of a placebo. Bicarbonate ingestion significantly increased blood pH both before and during exercise. The fast oxygen uptake response was unaffected, yet the slow component was delayed by bicarbonate ingestion, resulting in a significantly reduced end-exercise rate of oxygen uptake. Metabolic alkalosis had no effect on fast mechanisms but altered the slow component response, possibly because of the effects of bicarbonate ingestion on muscle pH.
This 'localised' benefit may support the specific benefit obtained by athletes in extending their anaerobic lactate tolerance through bicarbonate ingestion.
Conversely, slow component pulmonary oxygen uptake is not directly affected by pre-fatiguing muscle through multiple drops jumping prior to ergometer cycling ramp tests according to another paper.
A study examined the timing of supplement intake with respect to the muscle building (hypertrophic) outcomes by comparing consumption of a protein/creatine/glucose supplement (at the rate of 1g/kg body weight) either immediately before/after exercise versus in the morning/late evening of the day of exercise. A 10-week resistance-training programme was followed as part of the study. Consumption immediately before/after demonstrated a greater increase in lean body mass and 1RM strength in two of three assessments. The changes in body composition were supported by a greater increase in cross-sectional areas of the type II fibres and contractile protein content. This regime also resulted in higher muscle creatine and glycogen values after the training program. The authors concluded that supplement timing represents a simple but effective strategy that enhances the adaptations desired from resistance training.
Ephedra-containing supplements are consumed with a view to improving sports performance but may carry risks of cardiac and neurological adverse events. Little information is available of their use by young athletes. A survey, with a 68.2% response, aimed to determine the nature of ephedra use among high school athletes. 2.3% of respondents used dietary supplements containing ephedra.
Only one of these seven actual users knew that the supplements they used contained ephedra. Ephedra use was more common in boys (five) than girls (two). Ephedra use was only found in 17 and 18-year-olds. The most common sports among ephedra users were football, track and field athletics and weightlifting. This study suggests that ephedra use was infrequent among the young athletes in this population, users were likely to obtain supplements from their peers, and were uninformed of the content of their supplements.
Resistance training has been shown to increase muscular strength and muscular hypertrophy. A review paper continues that in general, resistance training causes a stimulation of protein synthesis as well as an increase in protein breakdown, resulting in a negative balance of protein. Providing nutrients, specifically amino acids, helps to stimulate protein synthesis and improve the overall net balance of protein. Strategies to increase the concentration and availability of amino acids after resistance exercise are of great interest and have been shown to effectively increase overall protein synthesis. After exercise, providing carbohydrate has been shown to mildly stimulate protein synthesis while the addition of free amino acids prior to and after exercise, specifically essential amino acids, causes a rapid pronounced increase in protein synthesis as well as protein balance
Evidence exists for a dose-response relationship of infused amino acids while no specific regimen exists for optimal dosing upon ingestion. Ingestion of whole or intact protein sources (e.g. protein powders, meal-replacements) has been shown to cause similar improvements in protein balance after resistance exercise when compared to free amino acid supplements. Future research should seek to determine optimal dosing of ingested intact amino acids.
A new test has been reported for the determination of peak oxygen uptake based on a three-minute all-out cycling test. Eleven subjects participated in the comparative test to the classical ramp test and results were found to correlate very closely.
A study investigated if six weeks of plyometric training could improve an athlete's agility. All subjects participated in two agility tests: T-test and Illinois Agility Test, and a force plate test for ground reaction times both pre and post-testing. Both agility tests showed statistically meaningful results for the plyometric training group in comparison to the control group. The plyometric training group had quicker post-test times compared to the control group for the agility tests. A significant group effect was found for the Force Plate test. The plyometric training group reduced time on the ground on the post-test compared to the control group. The results of this study show that plyometric training can be an effective training technique to improve an athlete's agility.
Proprioceptive neuromuscular facilitation (PNF) is a widely practiced form of developing an increased range of movement around a joint. Unexpectedly researchers discovered that there is a specific and measurable high strain placed on the cardiovascular system during such training indicated by a hemodynamic response (increased blood flow - heart rate/pressure) and elevated blood lactate concentrations (0.69 to 3.99 mmol/L). Coached should be aware of these responses.
The effects of resistance training on muscle buffer capacity, H+ regulation, and repeated-sprint ability (RSA) were reported recently. Sixteen females performed a graded exercise test to determine VO2 peak and the lactate threshold (LT), a repeated-sprint test (5 x 6 s, every 30 s) to determine RSA, and a 60-s high-intensity exercise test based on their pre-training RSA score (CIT60; continuous cycling at 160% VO2 peak). Muscle biopsies (vastus lateralis) were sampled before and immediately after CIT60. Subjects were then randomly assigned either to a high-repetition (three to five sets of 15-20 reps) short-rest (20 s) resistance-training group or to a control group. Training did not result in significant improvements in VO2 peak but did improve the LT, leg strength, and RSA. There were no significant improvements in muscle buffer capacity after training; however, there was a significant reduction in H+ in the muscle and blood after high-intensity exercise (CIT60). High-repetition, short-rest, resistance training does not improve muscle buffer capacity in active females, but it does reduce H+ accumulation during high-intensity exercise (~160% VO2 peak). It is likely that increases in strength, LT, and ion regulation contributed to the improved RSA.
Running shoes are designed to accommodate various arch types to reduce the risk of lower extremity injuries sustained during running. Yet little is known about the biomechanical changes of running in the recommended footwear that may allow for a reduction in injuries. A paper studied the effect of motion control and cushion trainer shoes on running mechanics in low- and high-arched runners.
Twenty high-arched and 20 low-arched recreational runners (>10 miles per week) were recruited for the study. Three-dimensional kinematics and kinetics were collected as subjects ran at 3.5 m/s along a 25-m runway. Specific 'motion control' and 'cushioning shoes' were evaluated. Statistical measures were used to determine if low- and high-arched runners responded differently to motion control and cushion trainer shoes.
Low-arched runners had a lower instantaneous loading rate in the motion control condition, and the high-arched runners had a lower instantaneous loading rate in the cushion trainer condition.
Overall, the results suggested that motion control shoes control rearfoot motion better than do cushion trainer shoes. In addition, cushion trainer shoes attenuate shock better than motion control shoes do. However, with the exception of instantaneous loading rate, these benefits do not differ between arch types.
Running footwear recommendations should be based on an individual's running mechanics. If a mechanical analysis is not available, footwear recommendations can be based empirically on the individual's arch type.
The second (2d) to fourth finger (4d) length ratio (2d:4d) is thought to be related to diverse traits including cognitive ability, disease susceptibility, and sexuality. A study examined the relationship between 2d:4d and sports ability in women.
The highest achieved level of participation in any sport was significantly negatively associated with 2d:4d as was the relationship between 2d:4d and running level. Ability in other sports also showed a negative relationship albeit non-significant.
These results suggest that a low 2d:4d ratio is related to increased female sports ability. It can be postulated that this ratio may predict potential sports ability. Understanding the mechanisms underpinning this relationship may give important insights into musculoskeletal fitness, health and disease.
A population-based study describes fitness profiles in aerobic capacity (12-min running test) during the years 1975-2004, muscle performance (sit-ups, push-ups, pull-ups, a back-muscle test, and standing long jump scored to produce a Muscle Fitness Index (MFI)) from 1982 to 2003, and body anthropometry from 1993 to 2004 among the Finnish conscripts at the age of 20 yr.
The mean body mass of the conscripts increased from 70.8 to 75.2 kg during the years 1993-2004. The mean distance of the conscript's 12-min running test increased by 4% from 1975 to 1979 but after that decreased by 12% (from 2760m to 2434m) compared with the year 2004. MFI increased during the first decade of the follow-up, but thereafter, the number of conscripts who achieved excellent and good MFI decreased from 66.8 to 41.2% during the years 1992-2004. The physical ability of the conscripts to meet military service declined during the last 15 yr.
Both the increase in body mass and the decrease in physical fitness may lead to serious health problems in the future - to say nothing of the effectiveness of the fighting force!
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About the Author
Nigel Hetherington was the Head Track & Field Coach at the internationally acclaimed Singapore Sports School. He is a former National Performance Development Manager for Scottish Athletics and National Sprints Coach for Wales. Qualified and highly active as a British Athletics level 4 performance coach in all events he has coached athletes to National and International honours in sprints, hurdles as well as a World Record holder in the Paralympic shot. He has 10 years' experience as senior coach educator and assessor trainer on behalf of British Athletics. Nigel is also an experienced athlete in sprint (World Masters Championship level) and endurance (3-hour marathon runner plus completed the 24 hour 'Bob Graham Round' ultra-endurance event up and down 42 mountain peaks in the English Lake District). He is a chartered chemist with 26 years' experience in scientific research and publishing.
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