Athletes' knowledge and views on OTC medication

A questionnaire was administered to elite athletes from Australia, Canada, the UK, and the USA representing 10 Olympic sports in order to explore knowledge and understanding of over-the-counter (OTC) medication since the removal of many of these substances from the World Anti-Doping Agency (WADA) Prohibited List, in 2004. Athletes demonstrated limited knowledge and understanding. Around half (50.5 %) knew the penalty incurred following a doping violation involving a banned OTC stimulant. The terms Monitoring Program and Specified Substance List were understood by 43.3 % and 67.5 % of respondents, respectively. Overall, the status of substances in relation to the Prohibited List was correctly identified in just 35.1 % of cases. As a whole, athletes were of the opinion that OTC stimulants posed a risk to health, were performance enhancing and that their use was against the spirit of sport. They were undecided as to whether these drugs should be returned to the Prohibited List. Elite athletes require targeted education programmes that will enable them to make informed decisions on the potential of OTC medications for therapeutic or performance enhancing purposes.

Effects of Repeated Bouts of Soccer-Specific Intermittent Exercise on Salivary IgA

Failure to recover fully between sessions has been suggested to cause immunodepression. Therefore, the cumulative effects of soccer-specific intermittent exercise undertaken on different days 48 h apart on salivary IgA, cortisol and total protein concentration were investigated. Nine male subjects completed two trials of soccer-specific intermittent exercise 48 h apart on a motorised treadmill. Timed unstimulated saliva samples were collected immediately before and after exercise, and 24 and 48 h post-exercise. Salivary IgA concentration (EX (1): 215 +/- 160 to 335 +/- 246 and EX (2): 144 +/- 93 to 271 +/- 185 mg . l (-1), p = 0.007), osmolality (p = 0.001) and total protein (p = 0.001) increased immediately following exercise in both trials and decreased 24 h afterwards, whereas saliva flow rate decreased significantly (p = 0.015) before returning to pre-exercise values 24 h postexercise. The IgA secretion rate, IgA to osmolality ratio, IgA to total protein, solute secretion rate, total protein secretion rate, and cortisol did not differ between the time-points. The results suggest that performing two bouts of moderate intensity soccer-specific intermittent exercise 48 h apart does not suppress resting salivary IgA concentration significantly although a small progressive reduction in salivary IgA was observed. These findings may not extend to successive competitive soccer games when vulnerable players might experience clinically relevant reductions in s-IgA.

The role of a short post-lunch nap in improving cognitive, motor, and sprint performance in participants with partial sleep deprivation

The aim of this study was to determine the effects of a post-lunch nap on subjective alertness and performance following partial sleep loss. Ten healthy males (mean age 23.3 years, s = 3.4) either napped or sat quietly from 13:00 to 13:30 h after a night of shortened sleep (sleep 23:00-03:00 h only). Thirty minutes after the afternoon nap or control (no-nap) condition, alertness, short-term memory, intra-aural temperature, heart rate, choice reaction time, grip strength, and times for 2-m and 20-m sprints were recorded. The afternoon nap lowered heart rate and intra-aural temperature. Alertness, sleepiness, short-term memory, and accuracy at the 8-choice reaction time test were improved by napping (P < 0.05), but mean reaction times and grip strength were not affected (P > 0.05). Sprint times were improved. Mean time for the 2-m sprints fell from 1.060 s (s(x) = 0.018) to 1.019 s (s(x) = 0.019) (P = 0.031 paired t-test); mean time for the 20-m sprints fell from 3.971 s (s(x) = 0.054) to 3.878 s (s(x) = 0.047) (P = 0.013). These results indicate that a post-lunch nap improves alertness and aspects of mental and physical performance following partial sleep loss, and have implications for athletes with restricted sleep during training or before competition.

Variable versus constant power strategies during cycling time-trials: prediction of time savings using an up-to-date mathematical model

Swain (1997) employed the mathematical model of Di Prampero et al. (1979) to predict that, for cycling time-trials, the optimal pacing strategy is to vary power in parallel with the changes experienced in gradient and wind speed. We used a more up-to-date mathematical model with validated coefficients (Martin et al., 1998) to quantify the time savings that would result from such optimization of pacing strategy. A hypothetical cyclist (mass = 70 kg) and bicycle (mass = 10 kg) were studied under varying hypothetical wind velocities (-10 to 10 m x s(-1)), gradients (-10 to 10%), and pacing strategies. Mean rider power outputs of 164, 289, and 394 W were chosen to mirror baseline performances studied previously. The three race scenarios were: (i) a 10-km time-trial with alternating 1-km sections of 10% and -10% gradient; (ii) a 40-km time-trial with alternating 5-km sections of 4.4 and -4.4 m x s(-1) wind (Swain, 1997); and (iii) the 40-km time-trial delimited by Jeukendrup and Martin (2001). Varying a mean power of 289 W by +/- 10% during Swain's (1997) hilly and windy courses resulted in time savings of 126 and 51 s, respectively. Time savings for most race scenarios were greater than those suggested by Swain (1997). For a mean power of 289 W over the "standard" 40-km time-trial, a time saving of 26 s was observed with a power variability of 10%. The largest time savings were found for the hypothetical riders with the lowest mean power output who could vary power to the greatest extent. Our findings confirm that time savings are possible in cycling time-trials if the rider varies power in parallel with hill gradient and wind direction. With a more recent mathematical model, we found slightly greater time savings than those reported by Swain (1997). These time savings compared favourably with the predicted benefits of interventions such as altitude training or ingestion of carbohydrate-electrolyte drinks. Nevertheless, the extent to which such power output variations can be tolerated by a cyclist during a time-trial is still unclear.

Acceptability of Power Variation during a Simulated Hilly Time Trial

We investigated the acceptability of power variation during a cycling time trial (TT) with simulated uphill and downhill sections. Seven cyclists first completed an 800-kJ self-paced TT on a simulated flat course. An 800-kJ TT course with four sections of uphill/downhill was then modeled. Each section involved 100 kJ of cycling up a simulated gradient of 5 % followed by 100 kJ of riding down a simulated gradient of - 5 %. Participants were required to complete this simulated course using two pacing strategies; (i) at a constant power equivalent to the mean power achieved during the initial TT, and (ii) increasing power by 5 % of mean power when traveling uphill (mean duration of each climb = 714 s) and decreasing power in the downhill sections (mean duration of each descent = 190 s), so that overall mean power was equivalent to that in (i). All participants maintained this variable power strategy during the first half of the TT, but two riders could not adhere to the power variations during the final 400 kJ. Nevertheless, mean +/- SD finish time for the variable power trial (3670 +/- 589 s) was significantly faster than that for the constant power TT (3758 +/- 645 s), the 95 % confidence interval for the percentage improvement being 0.4 to 4.3 %. Heart rate and lactate responses were highest in the initial self-paced TT and did not differ between the subsequent constant and variable power trials. Ratings of perceived exertion were also similar between trials. In our externally-valid TT, we found that some cyclists cannot fully adhere to a pacing strategy involving an approximate +/- 5 % variation in mean power in parallel with gradient variation. Nevertheless, an important time saving can still result even if a variable pacing strategy is only partially adopted during a hilly time trial, so that no additional physiological strain is incurred.

The ecological validity of laboratory cycling: Does body size explain the difference between laboratory- and field-based cycling performance?

Previous researchers have identified significant differences between laboratory and road cycling performances. To establish the ecological validity of laboratory time-trial cycling performances, the causes of such differences should be understood. Hence, the purpose of the present study was to quantify differences between laboratory- and road-based time-trial cycling and to establish to what extent body size [mass (m) and height (h)] may help to explain such differences. Twenty-three male competitive, but non-elite, cyclists completed two 25 mile time-trials, one in the laboratory using an air-braked ergometer (Kingcycle) and the other outdoors on a local road course over relatively flat terrain. Although laboratory speed was a reasonably strong predictor of road speed (R2 = 69.3%), a significant 4% difference (P < 0.001) in cycling speed was identified (laboratory vs. road speed: 40.4 +/- 3.02 vs. 38.7 +/- 3.55 km x h(-1); mean +/- s). When linear regression was used to predict these differences (Diff) in cycling speeds, the following equation was obtained: Diff (km x h(-1)) = 24.9 - 0.0969 x m - 10.7 x h, R2 = 52.1% and the standard deviation of residuals about the fitted regression line = 1.428 (km . h-1). The difference between road and laboratory cycling speeds (km x h(-1)) was found to be minimal for small individuals (mass = 65 kg and height = 1.738 m) but larger riders would appear to benefit from the fixed resistance in the laboratory compared with the progressively increasing drag due to increased body size that would be experienced in the field. This difference was found to be proportional to the cyclists' body surface area that we speculate might be associated with the cyclists' frontal surface area.

Dietetic guidelines on food and nutrition in the secondary prevention of cardiovascular disease ? evidence from systematic reviews of randomized controlled trials (second update, January 2006)

AIM

To update dietetic guidelines based on systematic review evidence on dietary advice to prevent further events in people with existing cardiovascular disease (CVD) (secondary prevention).

METHODS

The Cochrane Library, MEDLINE and EMBASE were comprehensively searched to January 2005 for systematic reviews on aspects of diet and heart health. Reviews were included if they searched systematically for randomized controlled trials relating to diet and secondary prevention of CVD. Each review was critically appraised by at least two members of the UK Heart Health and Thoracic Dietitians Group. The quality and results of each review were discussed and summarized at a group meeting.

RESULTS

Evidence-based strategies that reduce cardiovascular events in those with CVD include reduction in saturated fat and substitution with unsaturated fats. Individuals who have suffered a myocardial infarction may also benefit from adopting a Mediterranean type diet and increasing intake of omega 3 fats, but it is not clear whether they are beneficial for all patients with CVD. There is no systematic review evidence to support the use of antioxidant vitamins supplements, low glycaemic index diets, or homocysteine lowering therapies in this group.

CONCLUSION

There remains good evidence that reducing saturated fat reduces morbidity in patients with CVD. This advice is consistent for most manifestations of CVD, with the addition of Mediterranean dietary advice and increased omega 3 fats for those who have had a myocardial infarction.

Planning for an adaptive design: a case study in COPD

We discuss the practical and clinical considerations encountered when planning a Phase IIa trial in chronic obstructive pulmonary disease (COPD). Various adaptive strategies for reducing the cost of the trial and the statistical implications of these are explored. Use of the EAST software to evaluate the properties of the study designs with one or more interim analyses for futility, efficacy or either is described. We emphasize the rationale for choosing between alternative designs and the relationship between the clinical and statistical considerations.

Liver transplant in a four-month-old child with biliary atresia, unilateral pulmonary agenesis, and diaphragmatic hernia: first case report

Bilateral pulmonary agenesis (PA) is a rare embryological defect incompatible with life. Unilateral PA has a wide range of clinical presentations: its prognosis depends on the presence and severity of other associated anomalies. Fetal biliary atresia has been associated with a number of congenital anomalies, but the etiology is still not understood. An unusual case of a child with right PA, right diaphragmatic hernia, and delayed diagnosed biliary atresia leading to liver failure is presented herein. At the age of 4 months the patient was referred to the Transplant Department at Children Healthcare of Atlanta at Egleston with cholestasis and failure to thrive. With a rapidly progressive liver insufficiency, this child was evaluated for liver transplantation. In the absence of any respiratory symptom, the patient received a deceased donor size-matched left lateral segment liver transplant, which covered the diaphragmatic defect, with no further repair required. Twenty-seven months post-transplant, the patient has good graft function, a normal Z-score and is thriving. In spite of the increased physiological and surgical challenges (absence of right lung tissue, hemi-diaphragm, and ectopic position of the liver in the right chest), liver transplantation was performed with positive outcome in this high-risk child. Whether PA, may have developmentally contributed to expression of biliary atresia will need further investigation.

Some chronobiological considerations related to physical exercise

Variables associated with physical activity show circadian rhythms in resting subjects; these rhythms have both exogenous (due to the individual's lifestyle and environment) and endogenous (due to the "body clock") components. During exercise, many of the rhythms persist, even though some show decreasing amplitude with increasing severity of exercise. Whilst the value of physical fitness is not disputed (for elite athletes, for individuals who just want to be physically fit, or for patients undertaking physical rehabilitation regimens), there are certain times of the day when special care is needed. These times are soon after waking--when there is the possibility of an increased risk of cardiovascular morbidity and damage to the spine--and late in the day--when there is an increased risk of respiratory difficulties. Since physical exercise is inextricably linked with thermoregulation, there are special considerations to bear in mind when exercise takes place in cold or hot environments. Further, due to the effects of the body clock, exercise and activity during night work and after time-zone transitions presents problems peculiar to these circumstances. In addition, the menstrual cycle affects physical performance, and these circatrigintan rhythms interact with the circadian ones. Bearing in mind these factors, advice that is based upon knowledge of circadian and circatrigintan rhythms can be given to all those contemplating physical activity. Chronobiologically, there is advantage in undertaking physical activity programmes towards the middle of the waking day and not at times when a sleep or nap has just been taken.

Epidemiology of injuries and illnesses in America's Cup yacht racing

OBJECTIVES

To determine the incidence and severity of injuries and illnesses incurred by a professional America's Cup yacht racing crew during the preparation for and participation in the challenge for the 2003 America's Cup.

METHODS

A prospective study design was used over 74 weeks of sailing and training. All injuries and illnesses sustained by the 35 professional male crew members requiring medical treatment were recorded, including the diagnosis, nature, location, and mechanism of injury. The volume of sailing and training were recorded, and the severity of incidents were determined by the number of days absent from both sailing and training.

RESULTS

In total, 220 injuries and 119 illnesses were recorded, with an overall incidence of 8.8 incidents/1000 sailing and training hours (injuries, 5.7; illnesses, 3.1). The upper limb was the most commonly injured body segment (40%), followed by the spine and neck (30%). The most common injuries were joint/ligament sprains (27%) and tendinopathies (20%). The incidence of injury was significantly higher in training (8.6) than sailing (2.2). The most common activity or mechanism of injury was non-specific overuse (24%), followed by impact with boat hardware (15%) and weight training (13%). "Grinders" had the highest overall injury incidence (7.7), and "bowmen" had the highest incidence of sailing injuries (3.2). Most of the illnesses were upper respiratory tract infections (40%).

CONCLUSIONS

The data from this study suggest that America's Cup crew members are at a similar risk of injury to athletes in other non-collision team sports. Prudent allocation of preventive and therapeutic resources, such as comprehensive health and medical care, well designed conditioning and nutritional programmes, and appropriate management of recovery should be adopted by America's Cup teams in order to reduce the risk of injury and illness.

Can Cycling Performance in an Early Morning, Laboratory-Based Cycle Time-Trial be Improved by Morning Exercise the Day Before?

The normal circadian rhythm in exercise performance may be altered by the habitual timing of training. We have investigated if morning time trial performance is affected by the time at which moderate exercise is performed on the previous day. Eight male cyclists undertook two separate exercise sessions of sub-maximal cycle ergometry (60% V.O2peak for 30 min) at 07:00 h and 12:00 h the day before a 16.1-km time trial at 07:00 h. Heart rate, power output, ratings of perceived exertion, and rectal temperature were measured at rest and every 5 min in the pre-time trial exercises, and every 1.61 km during the time trial. Blood samples were taken at rest and immediately after the time trial for the measurement of lactate concentration. The time trial performed the day after the 07:00 h sub-maximal exercise was completed in 1672+/-135 s, compared to 1706+/-159 s for the time trial performed the day after the noon pre-time trial exercise (p=0.027). The time trial after exercise the previous morning was associated with higher work-rates (p=0.031), a higher net lactate accumulation after the time trial (p=0.018), and a trend for higher heart rates (p=0.093) compared to the time trial after exercise the previous noon. These findings suggest that cycling performance in an early morning time trial is improved if an athlete participates in early-morning rather than noontime moderate exercise the day before. This finding cannot be attributed to the physiological responses to the exercise on the pre-time trial day or to environmental factors. It is suggested that it might partly reflect an advantage gained by performing exercise in the day(s) immediately beforehand at the same time as the competition.

Effects of daytime ingestion of melatonin on short-term athletic performance

The immediate effects of ingesting melatonin in the daytime include decreased alertness and body temperature. To date, no researcher has examined whether daytime ingestion of melatonin leads to impairments in variables relevant to short-term (<10 min) athletic performance. Twelve physically active participants (mean +/- s age = 25.2 +/- 5.0 years, body mass = 81.4 +/- 12.1 kg and chronotype = 33.8 +/- 6.3 units) ingested 5 mg of melatonin or placebo at 11:45 hours in a double-blind experiment. At 13:00 and 17:00 hours, subjective alertness was measured, together with intra-aural temperature, reaction time (two-, four- and eight-choice), short-term memory recall and grip strength. Performance, ratings of perceived exertion (RPE) and heart rate were also recorded during a 4-km cycling time trial. At 13:00 hours, the mean +/- s intra-aural temperature was 0.49 +/- 0.79 degrees C lower after ingestion of melatonin than after placebo (p = 0.015), but this difference was not apparent at 17:00 hours. At both 13:00 and 17:00 hours, melatonin reduced (p < 0.05) alertness, short-term memory and exercise heart rate by 1.5 +/- 1.8 units, 1 +/- 1 digits and 6 +/- 9 beats.min(-1), respectively (mean +/- s). Eight-choice reaction time was also slower at both times of day after ingesting melatonin. Melatonin did not influence time trial performance or RPE (p > 0.05). The effects of 5 mg of melatonin seem more pronounced for mental rather than physical components of short-term athletic performance, although the cardiovascular responses to exercise are affected. Some effects of melatonin were apparent 5 h after ingestion when the hypothermic effects of melatonin had dissipated.

Low incidence of hepatic artery thrombosis after pediatric liver transplantation without the use of intraoperative microscope or parenteral anticoagulation

The risk of hepatic artery thrombosis (HAT) after pediatric liver transplantation (PLT) has been reported to range from 0 to 25%. We report our experience focusing on the interrelationships between risk factors, surgical technique and the incidence of HAT after liver transplantation in the pediatric age group. From February 18, 1997 to December 31, 2003, 150 consecutive liver transplants were performed in 132 pediatric patients. There were similar numbers of whole grafts when compared with partial grafts, 80 (53.3%) vs. 70 (46.7%), p = 0.30. Four grafts (2.7%) developed HAT. Of the grafts with HAT, three were successfully revascularized within the first 24 h. Only one graft (0.66%) was lost to HAT. A single surgeon utilizing 3.5-6.0 magnification loupes performed all but one hepatic arterial anastomoses. All patients were followed postoperatively by a daily ultrasound protocol and with anticoagulation of aspirin and alprostadil only. Living and deceased donor left lateral segment grafts had an increased rate of HAT when compared with whole liver grafts. HAT with subsequent graft loss may be minimized in PLT with the use of surgical loupes only, anticoagulation utilizing aspirin, alprostadil, and daily ultrasounds.

Circadian rhythms in sports performance--an update

We discuss current knowledge on the description, impact, and underlying causes of circadian rhythmicity in sports performance. We argue that there is a wealth of information from both applied and experimental work, which, when considered together, suggests that sports performance is affected by time of day in normal entrained conditions and that the variation has at least some input from endogenous mechanisms. Nevertheless, precise information on the relative importance of endogenous and exogenous factors is lacking. No single study can answer both the applied and basic research questions that are relevant to this topic, but an appropriate mixture of real-world research on rhythm disturbances and tightly controlled experiments involving forced desynchronization protocols is needed. Important issues, which should be considered by any chronobiologist interested in sports and exercise, include how representative the study sample and the selected performance tests are, test-retest reliability, as well as overall design of the experiment.

Performance Characteristics of Gas Analysis Systems: What We Know and What We Need to Know

It is important that sources of variation in gas analysis measurements are identified and described in an accurate and informative manner. In this paper, we discussed the potential sources of error, which should be considered in any measurement study on gas analysis systems. We then covered how errors in various terms associated with gas laws propagate to outcome measurements of gas exchange to help quantify the relative importance of sources of error. Finally, we performed a literature survey to explore the statistical methods researchers have employed to arrive at conclusions on the performance characteristics of gas analysis methods. We found examples of excellent practice in the literature, but there were also gaps in the knowledge of error in gas analysis systems. Consequently, we supplied guidelines for future method comparison studies. These guidelines included (i) a sample size of at least 40 participants and the citation of confidence intervals, (ii) a description of the relationships between systematic and random errors and the size of measured value, (iii) the parallel examination of test-retest error within a method comparison study, and (iv) an a priori-made judgement on how much systematic and random error between methods is acceptable for practical applications. We stressed that this judgement should be based on expert-agreed position statements about acceptable error, which unfortunately have yet to be formulated for gas analysis systems.