Julien S. Baker

Time course of changes in immuneoendocrine markers following an international rugby game.

Intense exercise is known to cause temporary impairments in immune function. Few studies, however, have investigated the effects of intense competitive exercise on immunoendocrine variables in elite team sport athletes. The aim of this study was to evaluate the time course of changes in selected immunoendocrine and inflammatory markers following an international rugby union game. Blood samples were taken from players (nxa0=xa010) on camp entry, the morning of the game (pre), immediately after (post) and 14 and 38xa0h into a passive recovery period. Players lost 1.4xa0±xa00.2xa0kg of body mass during the game (ambient conditions, 11°C, 45% RH). An acute phase inflammatory response was observed as reflected through immediate increases in serum cortisol and IL-6 (post) followed by delayed increases in serum creatine kinase (CK; 14xa0h) activity and C-reactive protein (CRP; 38xa0h); Pxa0<xa00.05. Decreases in the number of circulating T lympocytes, NK cells and bacteria-stimulated neutrophil degranulation were also observed post-exercise (Pxa0<xa00.05), indicative of decreased host immune protection. Following a large decrease in serum testosterone to cortisol (T/C) ratio immediately post and 14xa0h after exercise, T/C values then increased above those observed at camp entry 38xa0h into recovery (Pxa0<xa00.05). This rebound anabolic stimulus may represent a physiological requirement for recovery following intense tissue damage resulting from game collisions. The findings also suggest that a game of international rugby elicits disturbances in host immunity, which last up 38xa0h into the recovery period.

Anabolic steroid use: Patterns of use and detection of doping

Anabolic-androgenic steroids (AAS) were the first identified doping agents that have ergogenic effects and are being used to increase muscle mass and strength in adult males. Consequently, athletes are still using them to increase physical performance and bodybuilders are using them to improve size and cosmetic appearance. The prevalence of AAS use has risen dramatically over the last two decades and filtered into all aspects of society. Support for AAS users has increased, but not by the medical profession, who will not accept that AAS use dependency is a psychiatric condition. The adverse effects and potential dangers of AAS use have been well documented. AAS are used in sport by individuals who have acquired knowledge of the half-lives of specific drugs and the dosages and cycles required to avoid detection. Conversely, they are used by bodybuilders in extreme dosages with the intention of gaining muscle mass and size, with little or no regard for the consequences. Polypharmacy by self-prescription is prevalent in this sector. Most recently, AAS use has filtered through to ‘recreational street drug’ users and is the largest growth of drugs in this subdivision. They are taken to counteract the anorexic and cachectic effects of the illegal psychotropic street drugs. Screening procedures for AAS in World Anti-Doping Agency accredited laboratories are comprehensive and sensitive and are based mainly on gas chromatography-mass spectrometry, although liquid chromatography-mass spectrometry is becoming increasingly more valuable. The use of carbon isotope mass spectrometry is also of increasing importance in the detection of natural androgen administration, particularly to detect testosterone administration. There is a degree of contentiousness in the scenario of AAS drug use, both within and outside sport. AAS and associated doping agents are not illegal per se. Possession is not an offence, despite contravening sporting regulations and moral codes. Until AAS are classified in the same capacity as street drugs in the UK, where possession becomes a criminal offence, they will continue to attract those who want to win at any cost. The knowledge acquired by such work can only assist in the education of individuals who use such doping agents, with a view to minimizing health risks and hopefully once again create a level playing field in sport.

Established and recently identified coronary heart disease risk factors in young people. The influence of physical activity and physical fitness

Epidemiological studies have identified several risk factors for coronary heart disease (CHD), many of which are present in young people.1 One such risk factor is hypertension. In adults, exercise is thought to have a positive effect on blood pressure levels; however, findings are inconclusive for young people. Despite its association with CHD, obesity is on the increase in Western society’s young population; prevention and intervention during early years is needed. An active lifestyle is considered to have a beneficial effect on body fatness. Lipoprotein profiles are directly associated with CHD status. In adults, there is some evidence that physical activity and/or fitness have a favourable effect on lipoprotein levels. Although information regarding the younger population is more ambiguous, it tends to concur with these findings. High levels of lipoprotein(a), are considered an independent risk factor for CHD. Relatively little has been written on young people, although some studies have postulated a favourable relationship with physical activity.An inverse relationship between aerobic fitness and CHD has been confirmed in adults; an association is not as easily verified for young people. Physical activity is similarly deemed to have a beneficial effect on health status. A high-fat diet has been linked to CHD in adults, and evidence to date reports similar findings for young people. Smoking increases the risk of CHD and even moderate smoking during youth could have damaging long-term consequences. There is some evidence that smoking is related to physical activity and fitness levels in young people.In adults, high levels of homocyst(e)ine have been associated with CHD. As yet, little has been written on the relationship between physical activity or physical fitness and homocysteine status in young people. High levels of plasma fibrinogen have been linked to CHD. Several studies have explored the relationship between plasma fibrinogen and physical activity and/or fitness in adults, but findings are inconclusive; for young people, the ambiguity is even greater. C-reactive protein is a molecular marker for CHD but, to date, little attention has been given to this aspect, especially amongst young people. The link between high levels of plasminogen activator inhibitor-1 and CHD has been confirmed, although the essence of this relationship is not established. There is a paucity of data on the younger population and the relevance of collating such information is questionable.For the younger population, most research is limited to the established CHD risk factors and further investigations of recently identified CHD risk factors are needed.

Metabolic implications of resistive force selection for oxidative stress and markers of muscle damage during 30 s of high-intensity exercise

The purpose of this study was to compare power outputs, and blood concentrations of lipid hydroperoxides (LH), malondialdehyde (MDA), creatine kinase (CK), myoglobin (Mb) and lactate ([La−]B) following 30xa0s of maximal cycle ergometry when resistive forces were derived from total-body mass (TBM) or fat-free mass (FFM). Alpha-tocopherol (AT), retinol (R) and uric acid (UA) concentrations were also measured to qualify the activity of antioxidants. Cardiac troponin levels were determined to exclude myocardial damage and to verify that any CK was predominantly derived from skeletal muscle. Differences (P<0.05) in peak power output, pedal velocity and resistive forces were observed when the TBM and FFM protocols were compared [953 (114)xa0W vs 1,020 (134)xa0W; 134 (8)xa0rpm vs 141 (7)xa0rpm; 6 (1)xa0kg vs 5 (1)xa0kg respectively). LH and MDA concentrations increased immediately post-exercise during the TBM protocol only (P<0.05) and were greater when compared to FFM (P<0.05). LH and MDA values decreased 24xa0h post-exercise. Increases in CK concentrations were recorded immediately post-exercise for both the TBM and FFM protocols with greater concentrations recorded for TBM (P<0.05). Decreases were observed 24xa0h post-exercise. Mb concentrations were greater immediately post-exercise for the TBM protocol and were greater than those recorded for FFM (P<0.05). Values decreased 24xa0h later (P<0.05). AT and UA concentrations decreased immediately post-exercise for both protocols (P<0.05) and increased 24xa0h later (P<0.05). There were no changes observed in R concentrations at any of the blood sampling stages. [La−]B increased (P<0.05) immediately post-exercise for both protocols, and decreased 24xa0h later (P<0.05). The results of the study suggest that greater power outputs are obtainable with significantly less oxidative stress and muscle disruption when resistive forces reflect FFM mass as opposed to TBM.

Blood pressure and rate pressure product response in males using high-dose anabolic androgenic steroids (AAS).

The literature regarding the blood pressure response to AAS use is equivocal. In addition, there is currently little data available on the Rate Pressure Product (RPP) response to anabolic androgenic steroids (AAS) use. The experimental aim of this study was to investigate the effects of AAS administration in combination with resistance training on blood pressure and rate pressure product in male amateur bodybuilders and compare the results with a morphologically matched, resistance trained control group. Subjects were divided into two groups (n=16 AAS users; n=16 controls). Systolic and Diastolic Blood Pressure, RPP. Resting Heart Rate and Body Composition measurements were obtained before (Pre), during (During) and 6-8 weeks following (Post) the AAS cycle in the AAS users with similar time intervals for the control group. No significant cardiovascular or morphological changes in the control group were found throughout the study. Significant increases in both diastolic (P<0.01) and mean arterial blood pressures (P<0.05) were found from Pre to Post cycle in the AAS group. RPP also increased significantly (P<0.01) from pre to post AAS cycle. All cardiovascular parameters returned to normal baseline measurements between 6 and 8 weeks post cycle. No blood pressure measurements throughout the study were consistent with clinically defined hypertension. The findings indicate that the AAS group exhibited significant increases in standard cardiovascular measurements compared with the control bodybuilders, and provides a contraindication to AAS use especially in borderline hypertensives.

The repeatability and criterion related validity of the 20 m multistage fitness test as a predictor of maximal oxygen uptake in active young men

Objective: To investigate the repeatability and criterion related validity of the 20 m multistage fitness test (MFT) for predicting maximal oxygen uptake (Vo2max) in active young men. Methods: Data were gathered from two phases using 30 subjects (x̄±s; ageu200a=u200a21.8±3.6 years, massu200a=u200a76.9±10.7 kg, statureu200a=u200a1.76±0.05 m). MFT repeatability was investigated in phase 1 where 21 subjects performed the test twice. The MFT criterion validity to predict Vo2max was investigated in phase 2 where 30 subjects performed a continuous incremental laboratory test to volitional exhaustion to determine Vo2max and the MFT. Results: Phase 1 showed non-significant bias between the two applications of the MFT (x̄diff±sdiffu200a=u200a−0.4±1.4 ml kg−1 min−1; tu200a=u200a−1.37, pu200a=u200a0.190) with 95% limits of agreement (LoA) ±2.7 ml kg−1 min−1 and heteroscedasticity 0.223 (pu200a=u200a0.330). Log transformation of these data reduced heteroscedasticity to 0.056 (pu200a=u200a0.808) with bias −0.007±0.025 (tu200a=u200a−1.35, pu200a=u200a0.190) and LoA±0.049. Antilogs gave a mean bias on the ratio scale of 0.993 and random error (ratio limits) ×/÷1.050. Phase 2 showed that the MFT significantly underpredicted Vo2max (x̄diff±sdiffu200a=u200a1.8±3.2 ml kg−1 min−1; tu200a=u200a3.10, pu200a=u200a0.004). LoA were ±6.3 ml kg−1 min−1 and heteroscedasticity 0.084 (pu200a=u200a0.658). Log transformation reduced heteroscedasticity to −0.045 (pu200a=u200a0.814) with LoA±0.110. The significant systematic bias was not eliminated (x̄diff±sdiffu200a=u200a0.033±0.056; tu200a=u200a3.20, pu200a=u200a0.003). Antilogs gave a mean bias of 1.034 with random error×/÷1.116. Conclusions: These findings lend support to previous investigations of the MFT by identifying that in the population assessed it provides results that are repeatable but it routinely underestimates Vo2max when compared to laboratory determinations. Unlike previous findings, however, these results show that when applying an arguably more appropriate analysis method, the MFT does not provide valid predictions of Vo2max.

Fat and Carbohydrate Metabolism during Submaximal Exercise in Children

During exercise, the contribution of fat and carbohydrate to energy expenditure is largely modulated by the intensity of exercise. Age, a short- or long-term diet enriched in carbohydrate or fat substrate stores, training and gender are other factors that have also been found to affect this balance. These factors have been extensively studied in adults from the perspective of improving performance in athletes, or from a health perspective in people with diseases. During the last decade, lifestyle changes associated with high-energy diets rich in lipid and reduced physical activity have contributed to the increase in childhood obesity. This lifestyle change has emerged as a serious health problem favouring the early development of cardiovascular diseases, insulin resistance or type 2 diabetes mellitus. Increasing physical activity levels in young people is important to increase energy expenditure and promote muscle oxidative capacity. Therefore, it is surprising that the regulation of balance between carbohydrate and lipid use during exercise has received much less attention in children than in adults. In this review, we have focused on the factors that affect carbohydrate and lipid metabolism during exercise and have identified areas that may be relevant in explaining the higher contribution of lipid to energy expenditure in children when compared with adults. Low muscle glycogen content is possibly associated with a low activity of glycolytic enzymes and high oxidative capacity, while lower levels of sympathoadrenal hormones are likely to favour lipid metabolism in children. Changes in energetic metabolism occurring during adolescence are also dependent on pubertal events with an increase in testosterone in boys and estrogen and progesterone in girls. The profound effects of ovarian hormones on carbohydrate and fat metabolism along with their effects on oxidative enzymes could explain that differences in substrate metabolism have not always been observed between girls and women. Finally, although the regulatory mechanisms of fat and carbohydrate balance during exercise are quite well identified, there are a lack of data specific to children and most of the evidences reported in this review were drawn from studies in adults. Isotope tracer techniques and nuclear magnetic resonance will allow non-invasive investigation of the metabolism of the different substrate sources in skeletal muscle.

Physical effects of short-term recombinant human growth hormone administration in abstinent steroid dependency.

Background/Aims: Recombinant human growth hormone (rhGH) as opposed to cadaver pituitary GH is misused for physical improvement. Six days’ rhGH administration, in abstinent anabolic-androgenic steroid dependents, was compared with controls. Method: Male subjects (n = 48) were randomly divided into two groups: (1): control group (C), n = 24, mean ± SD, age 32 ± 11 years, height 1.8 ± 0.06 m; (2): rhGH-using group (0.058 IU·kg–1·day–1) (GH), n = 24, mean ± SD, age 32 ± 9 years, height 1.8 ± 0.07 m. Physiological measurements included anthropometry, strength, power and peak oxygen uptake (VO2 peak). Biochemical measurements included haemoglobin, packed cell volume, glucose, sodium, potassium, urea, creatinine, total protein, albumin, thyroid function, testosterone, prolactin, cortisol, GH and insulin-like growth factor-I (IGF-I). Results: Strength, peak power output and IGF-I significantly increased and total protein, albumin and free tetra-iodothyronine significantly decreased compared to controls (p < 0.05) and within the GH group (p < 0.017). Fat-free mass index and VO2 peak significantly increased, while body fat and thyroid-stimulating hormone significantly decreased within the GH group (p < 0.017). Conclusions: Short-term rhGH increased strength and power. Of therapeutic value is the possibility that muscle bulk and strength could be increased in patients with muscle-wasting conditions.

The relationship between total-body mass, fat-free mass and cycle ergometry power components during 20 seconds of maximal exercise

The purpose of this study was to compare the maximal exercise performance of 10 men during friction braked cycle ergometry of 20 s duration when resistive forces reflected total body mass (TBM) or fat free mass (FFM). Fat mass was calculated from the sum of skinfold thicknesses. Increases (P < 0.05) in peak power output (PPO) were found between TBM and FFM (1,015+/-165 W TBM vs 1,099+/-172 W FFM). Decreases (P < 0.05) were observed for the time taken to reach PPO (3.8+/-1.4 s TBM vs 2.9+/-1 s FFM). Pedal velocity increased (P < 0.05) during the FFM protocol (129.4+/-8.2 rpm TBM vs 136.3+/-8 rpm FFM). Rating of perceived exertion (RPE) was also (P < 0.05) greater for FFM (18.4+/-1.6 TBM vs 19.8+/-0.4 FFM). No changes were found for Mean Power Output (MPO), fatigue index (FI) or Work Done (WD) between trials. These findings suggest that high intensity resistive force loading protocols may need to be reconsidered. Results from this study indicate that the active tissue component of body composition needs consideration in resistive force selection when ascertaining maximal cycle ergometer power profiles.

Development of a healthy biscuit: an alternative approach to biscuit manufacture

ObjectiveObesity (BMI >30) and related health problems, including coronary heart disease (CHD), is without question a public health concern. The purpose of this study was to modify a traditional biscuit by the addition of vitamin B6, vitamin B12, Folic Acid, Vitamin C and Prebiotic fibre, while reducing salt and sugar.DesignDevelopment and commercial manufacture of the functional biscuit was carried out in collaboration with a well known and respected biscuit manufacturer of International reputation. The raw materials traditionally referred to as essential in biscuit manufacture, i.e. sugar and fat, were targeted for removal or reduction. In addition, salt was completely removed from the recipe.ParticipantsUniversity students of both sexes (n = 25) agreed to act as subjects for the study. Ethical approval for the study was granted by the University ethics committee. The test was conducted as a single blind crossover design, and the modified and traditional biscuits were presented to the subjects under the same experimental conditions in a random fashion.ResultsNo difference was observed between the original and the modified product for taste and consistency (P > 0.05). The modified biscuit was acceptable to the consumer in terms of eating quality, flavour and colour. Commercial acceptability was therefore established.ConclusionThis study has confirmed that traditional high-fat and high-sugar biscuits which are not associated with healthy diets by most consumers can be modified to produce a healthy alternative that can be manufactured under strict commercial conditions.