The distribution of I/D polymorphism in the ACE gene among Korean male elite athletes

AIM: The aim of this study was to examine the distribution of insertion/deletion (I/D) polymorphism in the ACE gene among Korean male elite athletes. METHODS: Participants of the study were 139 Korean male elite athletes (15 basketball, 41 soccer, 31 baseball, 12 gymnastics, 7 volleyball, 8 long-distance running, 8 judo, and 17 ice hockey players). The control group consisted of 163 non-athletes. Polymerase chain reaction method was used to investigate I/D polymorphism of the ACE gene. Collected data were analyzed by SPSS 11.0 program. RESULTS: The distribution of genotype and allele frequencies did not indicate the differences between the athletes and controls (P>0.05). However, the excess of II genotype and I allele was shown in long distance runners, although it was not statistically significant. CONCLUSION: It may be necessary to perform further studies using a homogeneous cohort of subjects from single sporting discipline, because the probable role of I allele in athletic performance has been hard to be detected by heterogeneous groups of diverse sporting disciplines.     

The C allele in NOS3 -786 T/C polymorphism is associated with elite soccer player's status

The NOS3-786 T/C polymorphism (rs2070744) is a candidate to explain individual variations in sports related phenotypes. We determined the genotype and allele frequency of NOS3-786 T/C in a group of 60 male professional elite soccer players. Their results were compared with those of 100 world-class endurance athletes, 53 elite power athletes, and 100 sedentary, healthy men (controls) of the same Caucasian (Spanish) origin. There were significant differences in genotype frequencies between soccer players, controls, endurance and power elite athletes (all P ≤ 0.02). These results were confirmed when we analysed allelic frequencies (all P<0.01). The likelihood of having the C allele was higher in soccer players compared with (i) controls [odds ratio (OR), 2.165, 95% confidence interval (CI): 1.362-3.441], (ii) endurance athletes (OR: 1.879, 95%CI: 1.184-2.984), and (iii) power athletes (OR: 4.032, 95%CI: 2.307-7.047). In conclusion, the -786C allele is associated with the status of being an elite soccer player, compared with non-athletic controls and also with elite endurance and power athletes. More research is needed in other groups of elite soccer players in order to replicate the results of the present study.     

上海地区汉族优秀游泳运动员ACE基因I/D多态性研究

目的:探讨上海地区汉族不同水平优秀游泳运动员ACE(血管紧张素转化酶)基因I/D多态性的分布特点。方法:采用PCR方法,对上海地区85名汉族优秀游泳运动员和90名汉族普通人的ACE基因I/D多态性进行检测。结果显示,上海地区汉族优秀游泳运动员的ACE基因的基因型和等位基因频率与上海和成都地区汉族普通人无明显差异(P>0.05);上海地区汉族游泳运动员和普通人以及成都地区汉族普通人的基因型和等位基因频率均与高加索人群存在高度显著性差异(P<0.0001),表现出明显的种族差异性。7名上海地区汉族国际健将ACE基因均为II型,运动水平越高的组别,II基因型和I等位基因频率越高,提示具有II基因型或I等位基因频率高的运动员经过多年运动训练,具有成为优秀运动员的可能,特别是II基因型的运动员可能性更大。     

ACE I/D polymorphism and cardiac adaptations in adolescent athletes

PURPOSE: The aim of this cross-sectional study was to determine whether there is a correlation between left ventricular hypertrophy (LVH) and angiotensin converting enzyme (ACE) insertion/deletion (I/D) polymorphism in adolescent athletes. METHODS: Seventy-five competitive soccer players (aged 15 +/- 1.2 yr) and 52 untrained control subjects (aged 15 +/- 1.6 yr) were examined with echocardiography (echo) and bioelectrical impedance analysis. The ACE genotype of all subjects was determined by PCR and correlated with left ventricular mass (LVM) indices. RESULTS: Allele frequencies were comparable between athletes and controls. Body surface area (BSA), fat-free mass (FFM), and all mean echo measurements were significantly greater in athletes than in controls. LVM and LVM indices for both BSA and FFM were all significantly greater in athletes than in controls (LVM 195.3 +/- 32 g vs 165.3 +/- 37.6 g; LVM/BSA 115.5 +/- 18.9 g x mq(-1) vs 95 +/- 18.2 g x mq(-1); LVM/FFM 3.5 +/- 0.5 vs 3 +/- 0.54, P < 0.001 for the three variables). Left ventricular hypertrophy was found in 17 (23%) athletes. There was no correlation between ACE I/D polymorphism and athletes with LVH as the II and DD genotype frequencies were identical (41%). However, in athletes with LVH, the presence of the D allele was associated with a greater LVM index than compared to homozygous II genotype (LVM = 145 +/- 7.6 g x mq(-1) in DD+ID group vs 135 +/- 2.9 g x mq(-1) in II group, P = 0.008). CONCLUSIONS: The results of the study show that significant changes occur in cardiac morphology and function in adolescent athletes. Interestingly, the ACE I/D polymorphism was associated with the degree of cardiac hypertrophy but not with the occurrence of LVH itself.     

The angiotensin converting enzyme I/D polymorphism in long distance runners

AIM: There is an assumption that ACE I/D polymorphism represents one of the possible genetic factors that might be associated with sports excellence. Recent studies have identified an increased frequency of I allele in elite endurance athletes, long distance runners, rowers and mountaineers. The aim of this study was to test the hypothesis that the ACE I/D polymorphism is associated with enhanced endurance performance. METHODS: We examined this hypothesis by determining ACE I/D allele frequency in 215 marathon runners, 222 half-marathon runners and 18 inline skaters classified by performance (marathon competition results). ACE genotype and allele frequencies were compared with 252 healthy controls. RESULTS: ACE genotype frequency in the whole cohort did not differ from that in the sedentary controls (P < 0.56). However, there was an increase of the I/I genotype incidence amongst successful marathon runners scoring on places from 1st to 150th (P < 0.01). These findings were confirmed in the group of inline skaters, similarly demonstrating an increase of the I/I genotype (P < 0.01). There was no association found between half marathon runners and the ACE genotype (P < 0.59). CONCLUSIONS: An excess of the I allele in long distance runners confirms the association between the ACE I/D polymorphism and endurance sports performance.     

The ACE gene and human performance: 12 years on

Some 12 years ago, a polymorphism of the angiotensin I-converting enzyme (ACE) gene became the first genetic element shown to impact substantially on human physical performance. The renin-angiotensin system (RAS) exists not just as an endocrine regulator, but also within local tissue and cells, where it serves a variety of functions. Functional genetic polymorphic variants have been identified for most components of RAS, of which the best known and studied is a polymorphism of the ACE gene. The ACE insertion/deletion (I/D) polymorphism has been associated with improvements in performance and exercise duration in a variety of populations. The I allele has been consistently demonstrated to be associated with endurance-orientated events, notably, in triathlons. Meanwhile, the D allele is associated with strength- and power-orientated performance, and has been found in significant excess among elite swimmers. Exceptions to these associations do exist, and are discussed. In theory, associations with ACE genotype may be due to functional variants in nearby loci, and/or related genetic polymorphism such as the angiotensin receptor, growth hormone and bradykinin genes. Studies of growth hormone gene variants have not shown significant associations with performance in studies involving both triathletes and military recruits. The angiotensin type-1 receptor has two functional polymorphisms that have not been shown to be associated with performance, although studies of hypoxic ascent have yielded conflicting results. ACE genotype influences bradykinin levels, and a common gene variant in the bradykinin 2 receptor exists. The high kinin activity haplotye has been associated with increased endurance performance at an Olympic level, and similar results of metabolic efficiency have been demonstrated in triathletes. Whilst the ACE genotype is associated with overall performance ability, at a single organ level, the ACE genotype and related polymorphism have significant associations. In cardiac muscle, ACE genotype has associations with left ventricular mass changes in response to stimulus, in both the health and diseased states. The D allele is associated with an exaggerated response to training, and the I allele with the lowest cardiac growth response. In light of the I-allele association with endurance performance, it seems likely that other regulatory mechanisms exist. Similarly in skeletal muscle, the D allele is associated with greater strength gains in response to training, in both healthy individuals and chronic disease states. As in overall performance, those genetic polymorphisms related to the ACE genotype, such as the bradykinin 2 gene, also influence skeletal muscle strength. Finally, the ACE genotype may influence metabolic efficiency, and elite mountaineers have demonstrated an excess of I alleles and I/I genotype frequency in comparison to controls. Interestingly, this was not seen in amateur climbers. Corroboratory evidence exists among high-altitude settlements in both South America and India, where the I allele exists in greater frequency in those who migrated from the lowlands. Unfortunately, if the ACE genotype does influence metabolic efficiency, associations with peak maximal oxygen consumption have yet to be rigorously demonstrated. The ACE genotype is an important but single factor in the determinant of sporting phenotype. Much of the mechanisms underlying this remain unexplored despite 12 years of research.     

The ACE gene and endurance performance during the South African Ironman Triathlons

PURPOSE: Several studies have suggested that the insertion (I) variant rather than the deletion (D) variant of the human angiotensin-converting enzyme (ACE) gene is associated with elite endurance performance. The aim of this study was to determine whether the ID polymorphism is associated with the performance of the fastest finishers of the South African Ironman Triathlons. METHODS: A total of 447 Caucasian male triathletes of a variety of nationalities and athletic ability who completed either the 2000 or 2001 South African Ironman Triathlons and 199 Caucasian male control subjects were genotyped for the ACE ID polymorphism. RESULTS: There was a significantly higher frequency of the I allele in the fastest 100 South African-born finishers (103 I, 51.5% and 97 D, 48.5%) compared with the 166 South African-born control subjects (140 I, 42.2% and 192 D, 57.8%) (P = 0.036). There was also a significant linear trend for the allele distribution among the fastest 100 finishers (I allele = 51.5%), slowest 100 finishers (I allele = 47.5%), and control (I allele = 42.2%) South African-born subjects (P = 0.033). There was, however, no significant difference in the ACE genotype or allele frequencies when athletes born outside South Africa were analyzed. CONCLUSION: To our knowledge this is the first study that has examined the effect of an athlete's ACE genotype on their actual performance during an ultra-endurance race. The I allele of the ACE gene was associated with the endurance performance of the fastest 100 South African-born finishers in these triathlons.     

ACTN3 genotype in professional soccer players

The authors studied the frequency distribution of alpha-actinin-3 (ACTN3) R577X genotypes in 60 top-level professional soccer players. The results were compared with those of 52 elite endurance athletes and 123 sedentary controls. The per cent distribution of RR and RX genotypes in soccer players (48.3% and 36.7%) was significantly higher and lower, respectively, than controls (28.5% and 53.7%) and endurance athletes (26.5% and 52%) (p = 0.041). Although there are notable exceptions, elite soccer players tend to have the sprint/power ACTN3 genotype.     

Sex-specific characteristics of cardiac function, geometry, and mass in young adult elite athletes

PURPOSE: To study young adult elite athletes with age- and sex-matched sedentary controls to assess sex-specific differences for left ventricular (LV) and right ventricular (RV) volumes and mass as well as for LV contraction and relaxation. MATERIALS AND METHODS: A total of 23 male athletes (mean age 25 +/- 4 years, training 22 +/- 7 hours/week in rowing, swimming, or triathlon) and 20 female athletes (mean age 24 +/- 4 years, training 19 +/- 5 hours/week in rowing, swimming, or triathlon) and age- and sex-matched sedentary controls (21 male/17 female) underwent cardiovascular magnetic resonance (CMR) imaging (1.5 Tesla). Cardiac phase contrast imaging using a black-blood k-space segmented gradient echo sequence was used for analysis of cardiac contraction and relaxation and steady-state free-precession cine images were acquired for determination of cardiac volumes and mass. RESULTS: Male and female athletes showed similar increases in LV and RV volume and mass indices when compared to controls (ranging between 15% and 42%). No sex-specific differences in training effect on LV and RV volumes, mass indices, and ejection fractions, as well as LV to RV ratios of these volume and mass indices (parameters of balanced LV and RV dilatation and hypertrophy) were observed (all P for interaction >0.05). Similarly, no sex-specific differences in training effect on cardiac contraction and relaxation were found (all P for interaction >0.05). CONCLUSION: Young adult elite athletes do not show sex-specific adaptive structural and functional changes to exercise training in accordance with the benign nature of the hypertrophy associated with athlete's heart.     

Neurochemical aftermath of amateur boxing

PURPOSE: To study young adult elite athletes with age- and sex-matched sedentary controls to assess sex-specific differences for left ventricular (LV) and right ventricular (RV) volumes and mass as well as for LV contraction and relaxation.
MATERIALS AND METHODS: A total of 23 male athletes (mean age 25±4 years, training 22±7 h/week in rowing, swimming, or triathlon) and 20 female athletes (mean age 24±4 years, training 19±5 h/week in rowing, swimming, or triathlon) and age- and sex-matched sedentary controls (21 males/17 females) underwent cardiovascular magnetic resonance (CMR) imaging (1.5 T). Cardiac phase contrast imaging using a black-blood k-space segmented gradient echo sequence was used for analysis of cardiac contraction and relaxation and steady-state free-precession cine images were acquired for determination of cardiac volumes and mass.
RESULTS: Male and female athletes showed similar increases in LV and RV volume and mass indices when compared with controls (ranging between 15% and 42%). No sex-specific differences in training effect on LV and RV volumes, mass indices, and ejection fractions, as well as LV to RV ratios of these volume and mass indices (parameters of balanced LV and RV dilatation and hypertrophy) were observed (all P for interaction >0.05). Similarly, no sex-specific differences in training effect on cardiac contraction and relaxation were found (all P for interaction >0.05).
CONCLUSION: Young adult elite athletes do not show sex-specific adaptive structural and functional changes to exercise training in accordance with the benign nature of the hypertrophy associated with athlete's heart.     

No association between variants in the ACE and angiotensin II receptor 1 genes and acute mountain sickness in Nepalese pilgrims to the Janai Purnima Festival at 4380 m

Koehle, Michael S., Pei Wang, Jordan A. Guenette, and Jim L. Rupert. No association between variants in the ACE and angiotensin II receptor 1 genes and acute mountain sickness in Nepalese pilgrims to the Janai Purnima Festival at 4380 m. High Alt. Med. Biol. 7:281-289, 2006.--Acute mountain sickness (AMS) causes significant morbidity among visitors to altitude. The primary contributors to developing AMS are altitude and rate of ascent; however, the substantial variation in susceptibility between individuals has led a number of investigators to propose that there may be genetic predilection to the disease. The ACE I/D polymorphism has been shown to predict performance among elite mountaineers. This study compares genotype and allele frequencies at the ACE I/D locus, two other loci in the ACE gene, and one locus in the angiotensin-2 receptor gene between individuals who did, or did not, express signs of AMS while attending a high altitude religious festival in Nepal (4380 m). Subjects (80 males, 23 females) were recruited and genotyped. All subjects were Nepalese. Forty-four of the subjects had been diagnosed with AMS by physicians at a high altitude health camp; the rest were free from altitude illness. All subjects were genotyped at polymorphic loci in the genes encoding angiotensin converting enzyme (ACE) and angiotensin II receptor type 1 gene (AGTR1). The polymorphisms examined were two single nucleotide polymorphisms (SNPs) in ACE (ACE(A-240T), dbSNP rs4291; and ACE(A2350G), dbSNP rs4343), the intronic Alu insertion in ACE (ACE I/D), and the SNP ATR(A1166C), (dbSNP rs17231380) in AGTR1d. All polymorphisms in ACE were found to be in linkage disequilibrium. No significant associations were found between AMS incidence and any of the alleles, suggesting that variants at these loci do not contribute to susceptibility to AMS in this population.     

Alterations in cardiac morphology and function in elite multi-disciplinary athletes.

Early echocardiographic studies of left ventricular (LV) morphology and function focused on single discipline athletes, primarily endurance and strength trained. To date there are few studies examining multi-disciplinary trained athletes. The present echocardiographic study examined LV morphology and function in 18 elite triathletes (swimming, cycling, and running) and 11 elite modern pentathletes (running, swimming, shooting, fencing, and show-jumping) compared with age- and sex-matched controls. Elite triathletes demonstrated significantly (p < 0.05) increased LV wall thickness and cavity dimensions together with LV mass, both in absolute terms and scaled for body surface area, compared with controls. Elite modern pentathletes demonstrated significantly (p < 0.05) increased LV wall thickness with a non-significant increase in LV internal diameter. Despite significant LV enlargement, the distribution of hypertrophy and diastolic filling indices were normal in both triathletes and modern pentathletes and significantly increased in the triathletes. It is concluded that multi-disciplinary training results in variations in LV morphology. The inciting stimulus resulting in LV enlargement in triathletes is associated with prolonged endurance activity, together with an isometric component accompanying cycling. In contrast, elite modern pentathletes experience a reduced endurance component combined with a high isometric component associated with fencing.     

ACTN3 genotype and swimming performance in Taiwan

Studies have shown that the 577R allele of α-actinin-3 (ACTN3) is more prevalent in sprint athletes than in the general population or in endurance athletes. We examined the distribution of ACTN3 R577X (rs 1815739) genotypes and alleles in the Taiwanese general population (603) and in elite sprint swimmers who had participated in international/national events (168). Additionally, 50 pre-adolescent (age 11-13 years) male students and 38 adult males who completed 12-weeks of swimming training, were included in the present study. We found that the frequencies of the R allele were significantly higher in female international sprint swimmers (67.6%) than in national sprint swimmers (50.0%) or in the general population (53.7%). The 25-m performance was significantly improved across the genotypes after swimming training among the pre-adolescent males but not among the adult males. In addition, pre-adolescents with the RR genotype had the best performance both before and after training although not statistically significant. In conclusion, the frequencies of ACTN3 577R allele were significantly higher in female international sprint swimmers than among national sprint swimmers or the general population. Furthermore, male pre-adolescents with either the ACTN3 RX or XX genotype showed a greater improvement in 25-meter swimming performance than those with the RR genotype.     

Is there an association between ACE and CKMM polymorphisms and cycling performance status during 3-week races?

In this paper, we examine the association between polymorphisms of the angiotensin-converting enzyme (ACE) and muscle-specific creatine kinase (CKMM) genes, and the actual performance status observed in professional cyclists capable of completing a classic tour stage race such as the Giro d'Italia, Tour de France, or Vuelta a Espa?a. To accomplish this, we compared the frequencies of the ACE and CKMM genotypes/alleles in 50 top-level Spanish professional cyclists that have completed at least one of these events to 119 sedentary controls, and 27 elite (Olympic-class) Spanish runners. The genetic polymorphism at the CK-MM locus was detected with the NcoI restriction endonuclease. The results of our study showed that the proportion of the DD genotype was higher in cyclists (50.0 %) than in the other two groups (p<0.05), the proportion of the ID genotype was higher in controls (46.2 %) than in the other two groups (p<0.05), and the proportion of the II genotype was higher in runners (40.7 %) than in the other two groups (p<0.05). The proportion of the D allele was higher in both cyclists (65.0 %) and controls (57.6 %) than in runners (46.3 %) (p<0.001), whereas the proportion of the I allele was higher in runners than in the other two groups (p<0.001). No statistical differences were found for CKK-MM- NcoI. We conclude that in top-level professional cyclists capable of completing a classic 3-wk tour race, the frequency distribution of the D allele and the DD genotype seems to be higher than in other endurance athletes such as elite runners (in whom the I allele is especially frequent).     

The ACTN3 R577X polymorphism in East and West African athletes

PURPOSE: To determine the frequency of the ACTN3 R577X polymorphism (functional R allele and nonfunctional X allele) in a variety of African populations and to examine its influence on the success of elite East African endurance runners and West African sprinters. METHODS: The R577X polymorphism was genotyped in 198 Ethiopian controls and 76 elite Ethiopian endurance athletes, 158 Kenyan controls and 284 elite Kenyan endurance runners, and 60 Nigerian controls and 62 elite Nigerian power athletes. Statistical analyses were performed by exact tests of population differentiation, using Arlequin, version 3. Analyses were carried out using 1 x 10(6) Markov chain steps, and 1 x 10(5) dememorization steps. RESULTS: The frequency of the X allele was extremely low among Kenyans and Nigerians (approximately 1% homozygosity) and higher in Ethiopians (approximately 11% homozygosity). The low baseline frequencies of the three populations tested mean that any associations with sprint performance would likely be obscured. In Ethiopians, where baseline levels of 577XX were about 11%, there was no increased frequency in the endurance athletes. CONCLUSION: Our data suggest that alpha-actinin-3 deficiency is not a major influence on performance in African athletes.     

中国优秀马拉松运动员ACE基因I/D多态性频率分布特征

通过分析中国马拉松运动员ACE基因I/D多态频率分布特征,探讨其作为杰出耐力基因标记的可行性。选择我国马拉松健将、国际健将级运动员26名作为马拉松运动员组,汉族学生216名作为对照组。对两组受试者进行ACE基因I/D多态性测定。结果显示:我国马拉松运动员组的等位基因频率和基因型频率与对照组比较无显著差异,其中15名国际健将中无一DD型纯合子,提示我国优秀马拉松运动员的纯合子DD型频率低下是其ACE基因多态频率分布的主要特征。     

RAS and MTHFR gene polymorphisms in a healthy exercise-trained population: association with the MTHFR (TT) genotype and a lower hemoglobin level

The aim of this study was to determine the frequencies of ACE (I/D), AGT (M235T), AT1R (A1166C) and MTHFR (C677T) polymorphisms in a well-defined (in regards to health and nutritional status and lifestyle) population of young, healthy, exercise-trained subjects (no. 100) from the Campania region of Southern Italy. We also investigated whether there was any correlation between these polymorphisms and biochemical, hematological and hemostatic parameters in this "low-risk" population. Gene polymorphisms were analyzed with the polymerase chain reaction and restriction enzyme analysis. Allele frequencies of the genotypes examined were in Hardy-Weinberg equilibrium and agree with those reported in the Italian population. No associations were found between ACE, AGT, AT1R gene polymorphisms and anthropometric, clinical and laboratory parameters. However, the MTHFR (C677T) polymorphism was significantly associated with lower hemoglobin plasma levels in TT vs. CC + CT females (p < 0.016). This report is the first to describe the frequencies of RAS and MTHFR gene polymorphisms in young, exercise-trained volunteers from Campania and to identify an association between the MTHFR gene polymorphisms and lower hemoglobin plasma levels in young healthy females.     

The Scandinavian athlete's heart; echocardiographic characteristics of male professional football players

This investigation explores the cardiac four‐chamber remodeling response to training in male players in Norwegian professional football league, and ethnicity as determinants in the development of athlete's heart. Standard 2D echocardiographic examination and analysis of all four cavities were performed in 504 football players of Caucasian origin, 49 of African origin, and 47 matched Caucasian controls (<3 h training /week). All results were indexed to body surface area (BSA). Most athletes exhibited BSA‐indexed values within normal ranges. Left ventricle (LV) mass was equally enlarged in both groups of athletes, but LV relative wall thickness and right ventricular (RV) relative wall thickness were increased in Africans compared with Caucasian athletes (0.37 ± 0.06 vs 0.33 ± 0.06 and 0.25 ± 0.06 vs 0.22 ± 0.04, respectively). Both LV and RV were smaller in Africans than in Caucasian athletes (67.8 ± 12.0 ml/m² vs 73.6 ± 13.2 ml/m² and 12.8 ± 2.1 vs 13.7 ± 2.4 cm²/m², respectively, both P < 0.05), while left and right atria increased similarly. This first large‐scale echocardiographic survey of elite football players in a Scandinavian league suggests use of BSA‐indexed upper normal limits for both LV and RV in athletes. African athletes had significantly more concentric remodeled LV and RV than the Caucasian athletes.     

Osteitis pubis and assessment of bone marrow edema at the pubic symphysis with MRI in an elite junior male soccer squad.

OBJECTIVES: To assess bone marrow edema at the pubic symphysis with magnetic resonance imaging (MRI), and its relation to training and osteitis pubis in an elite group of junior soccer players. SETTING: Soccer players on scholarship at the Australian Institute of Sport (AIS). PATIENTS: Nineteen players from an elite junior men's soccer squad. INTERVENTION/ASSESSMENT: Serial MRI examinations of the pubic symphysis over a 4-month training and playing period, training session questionnaire, and review of clinical diagnosis, investigations, and records on presentation of athletes with groin pain at the Department of Sports Medicine. MAIN OUTCOME MEASURES: Assessment of bone marrow edema (4-point scale) on MRI scans, review of athlete questionnaires, and review of clinical records. RESULTS: Initial MRI scans showed moderate to severe bone marrow edema at the pubic symphysis in 11 of the 18 asymptomatic players. There was a greatly decreased risk of developing groin pain (osteitis pubis) with more training prior to entry of the AIS soccer program (odds ratio per 4 sessions of training, 0.003). The correlation between initial bone marrow edema grading and pre-AIS training was small. The increase in bone marrow edema grading from baseline over the scans was 0.5 (90% CL, 0.4). CONCLUSIONS: Substantial amounts of bone marrow edema at the pubic symphysis can occur in asymptomatic elite junior soccer players, but it is only weakly related to the development of osteitis pubis. Progressing training loads more slowly in athletes presenting with low current training loads may be a useful strategy for the prevention of osteitis pubis in junior soccer players.     

Development of aerobic power in pubescent male soccer players related to hematocrit, hemoglobin and maturation. A longitudinal study

AIM: More than ever young athletes are training intensively and compete at high levels. As adolescent athletes are training in a period associated with many changes in growth and maturation longitudinal studies are important to elucidate the development in physical parameters. The aim of this study was to evaluate the development in aerobic power in elite as well as non-elite soccer players during the years of puberty and to relate it to maturation as well as hemoglobin and hematocrit. METHODS: Forty-nine young male soccer players at elite and non-elite levels (10.5-13 y) were recruited as subjects. All subjects were tested 4 times over a period of 3.5 years. Anthropometrical parameters including skinfold were measured. VO2max was assessed during treadmill run, testicular volume and testosterone levels were used to estimate maturation, and hemoglobin (Hb) as well as hematocrit (Htc) was measured from blood samples. RESULTS: A longitudinal development in VO2max (l/min) was found for all players together. The elite players have higher values and steeper increase compared to non elite-players. This difference was still present when VO2max was adjusted for body weight (ml/kg/min). CONCLUSIONS: The general development in VO2max was significantly correlated to the development in Hb and Htc as well as maturation, but the difference between elite and non-elite players could not be explained from differences in these variables. As elite players often are selected at a very young age it is possible that training effect is present but it cannot be excluded that genetic factors may play an important role.