Detection of testosterone administration based on the carbon isotope ratio profiling of endogenous steroids: international reference populations of professional soccer players.

BACKGROUND AND OBJECTIVES: The determination of the carbon isotope ratio in androgen metabolites has been previously shown to be a reliable, direct method to detect testosterone misuse in the context of antidoping testing. Here, the variability in the 13C/12C ratios in urinary steroids in a widely heterogeneous cohort of professional soccer players residing in different countries (Argentina, Italy, Japan, South Africa, Switzerland and Uganda) is examined. METHODS: Carbon isotope ratios of selected androgens in urine specimens were determined using gas chromatography/combustion/isotope ratio mass spectrometry (GC-C-IRMS). RESULTS: Urinary steroids in Italian and Swiss populations were found to be enriched in 13C relative to other groups, reflecting higher consumption of C3 plants in these two countries. Importantly, detection criteria based on the difference in the carbon isotope ratio of androsterone and pregnanediol for each population were found to be well below the established threshold value for positive cases. CONCLUSIONS: The results obtained with the tested diet groups highlight the importance of adapting the criteria if one wishes to increase the sensitivity of exogenous testosterone detection. In addition, confirmatory tests might be rendered more efficient by combining isotope ratio mass spectrometry with refined interpretation criteria for positivity and subject-based profiling of steroids.

Steroid profiles of professional soccer players: an international comparative study.

BACKGROUND AND OBJECTIVES: Urinary steroid profiling is used in doping controls to detect testosterone abuse. A testosterone over epitestosterone (T/E) ratio exceeding 4.0 is considered as suspicious of testosterone administration, irrespectively of individual heterogeneous factors such as the athlete's ethnicity. A deletion polymorphism in the UGT2B17 gene was demonstrated to account for a significant part of the interindividual variability in the T/E between Caucasians and Asians. Here, the variability of urinary steroid profiles was examined in a widely heterogeneous cohort of professional soccer players. Method: The steroid profile of 57 Africans, 32 Asians, 50 Caucasians and 32 Hispanics was determined by gas chromatography-mass spectrometry. RESULTS: Significant differences have been observed between all ethnic groups. After estimation of the prevalence of the UGT2B17 deletion/deletion genotype (African: 22%; Asian: 81%; Caucasian: 10%; Hispanic: 7%), ethnic-specific thresholds were developed for a specificity of 99% for the T/E (African: 5.6; Asian: 3.8; Caucasian: 5.7; Hispanic: 5.8). Finally, another polymorphism could be hypothesised in Asians based on specific concentration ratio of 5alpha-/5beta-androstane-3alpha,17beta-diol in urine. CONCLUSION: These results demonstrate that a unique and non-specific threshold to evidence testosterone misuse is not fit for purpose. An athlete's endocrinological passport consisting of a longitudinal follow-up together with the ethnicity and/or the genotype would strongly enhance the detection of testosterone abuse. Finally, additional genotyping studies should be undertaken to determine whether the remaining unexplained disparities have an environmental or a genetic origin.

Repeated sprinting on natural grass impairs vertical stiffness but does not alter plantar loading in soccer players.

This study aimed to determine changes in spring-mass model (SMM) characteristics, plantar pressures, and muscle activity induced by the repetition of sprints in soccer-specific conditions; i.e., on natural grass with soccer shoes. Thirteen soccer players performed 6 × 20 m sprints interspersed with 20 s of passive recovery. Plantar pressure distribution was recorded via an insole pressure recorder device divided into nine areas for analysis. Stride temporal parameters allowed to estimate SMM characteristics. Surface electromyographic activity was monitored for vastus lateralis, rectus femoris, and biceps femoris muscles. Sprint time, contact time, and total stride duration lengthened from the first to the last repetition (+6.7, +12.9, and +9.3%; all P < 0.05), while flight time, swing time, and stride length remained constant. Stride frequency decrease across repetitions approached significance (-6.8%; P = 0.07). No main effect of the sprint number or any significant interaction between sprint number and foot region was found for maximal force, mean force, peak pressure and mean pressure (all P > 0.05). Center of mass vertical displacement increased (P < 0.01) with time, together with unchanged (both P > 0.05) peak vertical force and leg compression. Vertical stiffness decreased (-15.9%; P < 0.05) across trials, whereas leg stiffness changes were not significant (-5.9%; P > 0.05). Changes in root mean square activity of the three tested muscles over sprint repetitions were not significant. Although repeated sprinting on natural grass with players wearing soccer boots impairs their leg-spring behavior (vertical stiffness), there is no substantial concomitant alterations in muscle activation levels or plantar pressure patterns.

Relationships between anthropometric measures and athletic performance, with special reference to repeated-sprint ability, in the Qatar national soccer team.

The aim of this study was to determine potential relationships between anthropometric parameters and athletic performance with special consideration to repeated-sprint ability (RSA). Sixteen players of the senior male Qatar national soccer team performed a series of anthropometric and physical tests including countermovement jumps without (CMJ) and with free arms (CMJwA), straight-line 20 m sprint, RSA (6 × 35 m with 10 s recovery) and incremental field test. Significant (P < 0.05) relationships occurred between muscle-to-bone ratio and both CMJs height (r ranging from 0.56 to 0.69) as well as with all RSA-related variables (r < -0.53 for sprinting times and r = 0.54 for maximal sprinting speed) with the exception of the sprint decrement score (Sdec). The sum of six skinfolds and adipose mass index were largely correlated with Sdec (r = 0.68, P < 0.01 and r = 0.55, P < 0.05, respectively) but not with total time (TT, r = 0.44 and 0.33, P > 0.05, respectively) or any standard athletic tests. Multiple regression analyses indicated that muscular cross-sectional area for mid-thigh, adipose index, straight-line 20 m time, maximal sprinting speed and CMJwA are the strongest predictors of Sdec (r(2) = 0.89) and TT (r(2) = 0.95) during our RSA test. In the Qatar national soccer team, players' power-related qualities and RSA are associated with a high muscular profile and a low adiposity. This supports the relevance of explosive power for the soccer players and the larger importance of neuromuscular qualities determining the RSA.

The Effect of Two Speed Endurance Training Regimes on Performance of Soccer Players.

In order to better understand the specificity of training adaptations, we compared the effects of two different anaerobic training regimes on various types of soccer-related exercise performances. During the last 3 weeks of the competitive season, thirteen young male professional soccer players (age 18.5±1 yr, height 179.5±6.5 cm, body mass 74.3±6.5 kg) reduced the training volume by ~20% and replaced their habitual fitness conditioning work with either speed endurance production (SEP; n = 6) or speed endurance maintenance (SEM; n = 7) training, three times per wk. SEP training consisted of 6-8 reps of 20-s all-out running bouts followed by 2 min of passive recovery, whereas SEM training was characterized by 6-8 x 20-s all-out efforts interspersed with 40 s of passive recovery. SEP training reduced (p<0.01) the total time in a repeated sprint ability test (RSAt) by 2.5%. SEM training improved the 200-m sprint performance (from 26.59±0.70 to 26.02±0.62 s, p<0.01) and had a likely beneficial impact on the percentage decrement score of the RSA test (from 4.07±1.28 to 3.55±1.01%) but induced a very likely impairment in RSAt (from 83.81±2.37 to 84.65±2.27 s). The distance covered in the Yo-Yo Intermittent Recovery test level 2 was 10.1% (p<0.001) and 3.8% (p<0.05) higher after SEP and SEM training, respectively, with possibly greater improvements following SEP compared to SEM. No differences were observed in the 20- and 40-m sprint performances. In conclusion, these two training strategies target different determinants of soccer-related physical performance. SEP improved repeated sprint and high-intensity intermittent exercise performance, whereas SEM increased muscles' ability to maximize fatigue tolerance and maintain speed development during both repeated all-out and continuous short-duration maximal exercises. These results provide new insight into the precise nature of a stimulus necessary to improve specific types of athletic performance in trained young soccer players.

Moral Disengagement in the Legitimation and Realization of Aggressive Behaviors in Soccer and Ice Hockey

The aim of the present study was to test the effect of moral disengagement on the tolerance and realization of aggressive acts in male soccer and ice hockey players in Switzerland. One hundred and four soccer and 98 ice hockey players evaluated the legitimacy of four videotaped aggressive behaviors and completed a questionnaire that included a moral disengagement scale and self-reported aggression. The level of moral disengagement, which mediates the effects of perceived coach and ego attitudes toward transgressions, largely explains the tolerance of hostile aggression within teams, as well as the level of high aggressive acts reported by the participants.

A comparison of injuries among children and adult football (soccer) players

Football is a universal and an affordable game but we need to minimize the incidence of accidents among the increasing number of young football players. Our 11 year retrospective epidemiological study (1990-2000) of football injuries in children (N= 1000) was compared with those of adult players in the 2006 European Championship. This comparative study confirmed that the anatomical, biomechanical and biological conditions differ between adults and children and that they warrant particular attention to protect the latter vulnerable group against bone avulsions, overuse pathologies and fatigue-fractures. Injuries were shown to increase significantly with age up to 16 years (P=0.005). Children suffer mainly from contusions, fractures and sprain injuries. Head injuries were more common in boys (P=0.070), while girls were more prone to sprains. The types of injuries differ between adults and children (sprain versus fractures), the anatomical location of injuries is different (lower limbs in adults, lower and upper limbs in children), the circumstances of the injuries are different (contact in adults versus non-contact in children), and teenage girls have different types of injuries than teenage boys. An increased incidence of injuries is due to changes in the position of the center of gravity and in the morphotype during rapid growth. For these reasons it is mandatory to adapt the training to the age and sex of the players. It is unsafe to train children the same way as adults. The height, the weight and the speed of growth must be taken into account by the multidisciplinary team when organising the training programmes. -- Le football fait partie des sports les plus pratiqués au monde en raison de sa popularité et de son accessibilité économ ique. L'incidence des blessures liées à cette pratique doit être diminuée surtout chez les jeunes joueurs en raison de la croissance exponentielle du nombre de joueurs féminins et masculins. Une étude épidémiologique rétrospective sur 11 ans (1990-2000) a été réalisée chez les enfants victimes de blessures liées au football (N==1000), puis a été comparée aux données recueillies de l'UEFA lors d'un Championnat Européen en 2006 sur les lésions des joueurs adultes. Cette étude comparative confirme que les structures anatomiques, biologiques et les tensions biomécaniques chez l'enfant diffèrent de celles de l'adulte. Les enfants ont un risque plus élevé de souffrir d'avulsion osseuse et de fractures de fatigue que les adultes. Les blessures augmentent significativement avec l'âge jusqu'à 16 ans (P==0,005). Les traumatismes crâniens sont plus fréquents chez les garçons tandis que les entorses sont plus à risque chez les filles. Les adultes font plus souvent des entorses tandis que les enfants font plus de fractures. La localisation anatomique diffère également entre ces deux groupes (les membres inférieurs chez l'adulte et les membres inférieurs et supérieurs chez l'enfant). La circonstance des blessures diffère également (choc avec un autre joueur chez l'adulte et des blessures sans contact chez l'enfant). Chez les adolescents, les blessures des filles diffèrent de celles des garçons. L'augmentation chez les enfants de cette incidence est liée au déplacement lors de la croissance du centre de gravité, avec une maladresse accrue lors des phases de croissance. Pour toutes ces raisons, il est justifié d'adapter les entraînements de football en fonction de l'âge, du sexe et du morphotype. L'entrainement des enfants doit être différent de celui des adultes. Le poids, la taille et la vitesse de croissance doit être prise en compte dans des structures multidisciplinaires afin de permettre une meilleure longévité sportive des jeunes joueurs de football.

Anti-doping testing at the 2008 European football championship.

Big sports events like the 2008 European Football Championship are a challenge for anti-doping activities, particularly when the sports event is hosted by two different countries and there are two laboratories accredited by the World Anti-Doping Agency. This challenges the logistics of sample collection as well as the chemical analyses, which must be carried out timeously. The following paper discusses the handling of whereabouts information for each athlete and the therapeutic use exemption system, experiences in sample collection and transportation of blood and urine samples, and the results of the chemical analysis in two different accredited laboratories. An overview of the analytical results of blood profiling and growth hormone testing in comparison with the distribution of the normal population is also presented.

Detection of nandrolone metabolites in urine after a football game in professional and amateur players: a Bayesian comparison.

Nandrolone (19-nortestosterone) is a widely used anabolic steroid in sports where strength plays an essential role. Once nandrolone has been metabolised, two major metabolites are excreted in urine, 19-norandrosterone (NA) and 19-noretiocholanolone (NE). In 1997, in France, quite a few sportsmen had concentrations of 19-norandrosterone very close to the IOC cut off limit (2ng/ml). At that time, a debate took place about the capability of the human male body to produce by itself these metabolites without any intake of nandrolone or related compounds. The International Football Federation (FIFA) was very concerned with this problematic, especially because the World Cup was about to start in France. In this respect, a statistical study was held with all football players from the first and second divisions of the Swiss Football National League. All players gave a urine sample after effort and around 6% of them showed traces of 19-norandrosterone. These results were compared with amateur football players (control group) and around 6% of them had very small amounts of 19-norandrosterone and/or 19-noretiocholanolone in urine after effort, whereas none of them had detectable traces of one or the other metabolite before effort. The origin of these compounds in urine after a strenuous physical activity is still unknown, but three hypotheses can be put forward. First, an endogenous production of nandrolone metabolites takes place. Second, nandrolone metabolites are released from the fatty tissues after an intake of nandrolone, some related compounds or some contaminated nutritive supplements. Finally, the sportsmen may have taken something during or just before the football game.

The relationship between muscle strength and physiological age: a cross-sectional study in boys aged from 11 to 15.

OBJECTIVE: To investigate the relationships between isokinetic knee flexor and extensor muscle strength and physiological and chronological age in young soccer players. MATERIAL AND METHODS: Seventy-nine young, healthy, male soccer players (mean+/-standard deviation age: 12.78+/-2.88, range: 11 to 15) underwent a clinical examination (age, weight, height, body mass index and Tanner puberty stage) and an evaluation of bilateral knee flexor and extensor muscle strength on an isokinetic dynamometer. Participation in the study was voluntary. RESULTS: The peak torque increased progressively (by 50%) between the ages of 11 and 15 and most significantly between 12 to 14. The knee flexor/extensor ratios only decreased significantly between 14 and 15 years of age. Puberty stage was the most important determinant of the peak torque level (ahead of chronological age, weight and height) for all angular velocities (p<0.0001). Muscle strength increased significantly between Tanner stages 1 and 5, with the greatest increase between stages 2 and 4. CONCLUSION: The present study showed that isokinetic muscle strength increases most between 12 and 13 years of age and between Tanner stages 2 and 3. There was strong correlation between muscle strength and physiological age.