GENES IN SPORT AND DOPING

Genes control biological processes such as muscle production of energy, mitochondria biogenesis, bone formation, erythropoiesis, angiogenesis, vasodilation, neurogenesis, etc. DNA profiling for athletes reveals genetic variations that may be associated with endurance ability, muscle performance and power exercise, tendon susceptibility to injuries and psychological aptitude. Already, over 200 genes relating to physical performance have been identified by several research groups. Athletes’ genotyping is developing as a tool for the formulation of personalized training and nutritional programmes to optimize sport training as well as for the prediction of exercise-related injuries. On the other hand, development of molecular technology and gene therapy creates a risk of non-therapeutic use of cells, genes and genetic elements to improve athletic performance. Therefore, the World Anti-Doping Agency decided to include prohibition of gene doping within their World Anti-Doping Code in 2003. In this review article, we will provide a current overview of genes for use in athletes’ genotyping and gene doping possibilities, including their development and detection techniques.     

Functional and Structural Correlates of Motor Speed in the Cerebellar Anterior Lobe

In athletics, motor performance is determined by different abilities such as technique, endurance, strength and speed. Based on animal studies, motor speed is thought to be encoded in the basal ganglia, sensorimotor cortex and the cerebellum. The question arises whether there is a unique structural feature in the human brain, which allows “power athletes” to perform a simple foot movement significantly faster than “endurance athletes”. We acquired structural and functional brain imaging data from 32 track-and-field athletes. The study comprised of 16 “power athletes” requiring high speed foot movements (sprinters, jumpers, throwers) and 16 endurance athletes (distance runners) which in contrast do not require as high speed foot movements. Functional magnetic resonance imaging (fMRI) was used to identify speed specific regions of interest in the brain during fast and slow foot movements. Anatomical MRI scans were performed to assess structural grey matter volume differences between athletes groups (voxel based morphometry). We tested maximum movement velocity of plantarflexion (PF-V_max) and acquired electromyographical activity of the lateral and medial gastrocnemius muscle. Behaviourally, a significant difference between the two groups of athletes was noted in PF-V_max and fMRI indicates that fast plantarflexions are accompanied by increased activity in the cerebellar anterior lobe. The same region indicates increased grey matter volume for the power athletes compared to the endurance counterparts. Our results suggest that speed-specific neuro-functional and -structural differences exist between power and endurance athletes in the peripheral and central nervous system.     

Echocardiographic characteristics in adolescent junior male athletes of different sport events

The purpose of this study was to examine the effects of different sport activities on cardiac adaptation. Echocardiographic data of 137 athletes and 21 non-athletes were measured and compared in two age groups 15-16 and 17-18 years of age. Athletes belonged into three groups according to their sports activity (endurance events, power athletes, ball game players). The observed variables were related to body size by indices in which the exponents of the numerator and the denominator were matched. Left ventricular hypertrophy was manifest in all athletic groups. Power athletes had the largest mean left ventricular wall thickness (LVWTd) in both age groups. In the older age group differences between the athletic groups were smaller, but the endurance and power athletes had significantly higher wall thickness. Left ventricular internal diameter (LVIDd) was the largest in the endurance athletes, while mean relative muscle mass (LVMM) was the largest in the power athletes. LVMM of the older endurance athletes was significantly larger. Muscular quotient (MQ) was the highest in the endurance athletes; in the 17-18-year group there was no inter-event difference. Bradycardia was most manifest in the endurance athletes and ball game players, power athletes had higher resting heart rates than non-athletic subjects. It can be inferred that endurance training induces firstly an enlargement of the left ventricle what is then followed by an increase of muscle mass. In the studied functional and regulatory parameters no difference was found between the athletic and non-athletic groups.     

Elite athletes’ genetic predisposition for altered risk of complex metabolic traits

Background

Genetic variants may predispose humans to elevated risk of common metabolic morbidities such as obesity and Type 2 Diabetes (T2D). Some of these variants have also been shown to influence elite athletic performance and the response to exercise training. We compared the genotype distribution of five genetic Single Nucleotide Polymorphisms (SNPs) known to be associated with obesity and obesity co-morbidities (IGF2BP2 rs4402960, LPL rs320, LPL rs328, KCJN rs5219, and MTHFR rs1801133) between athletes (all male, n = 461; endurance athletes n = 254, sprint/power athletes n = 207), and controls (all male, n = 544) in Polish and Russian samples. We also examined the association between these SNPs and the athletes’ competition level (‘elite’ and ‘national’ level). Genotypes were analysed by Single-Base Extension and Real-Time PCR. Multinomial logistic regression analyses were conducted to assess the association between genotypes and athletic status/competition level.

Results

IGF2BP2 rs4402960 and LPL rs320 were significantly associated with athletic status; sprint/power athletes were twice more likely to have the IGF2BP2 rs4402960 risk (T) allele compared to endurance athletes (OR = 2.11, 95% CI = 1.03-4.30, P <0.041), and non-athletic controls were significantly less likely to have the T allele compared to sprint/power athletes (OR = 0.62, 95% CI =0.43-0.89, P <0.0009). The control group was significantly more likely to have the LPL rs320 risk (G) allele compared to endurance athletes (OR = 1.26, 95% CI = 1.05-1.52, P <0.013). Hence, endurance athletes were the “protected” group being significantly (p < 0.05) less likely to have the risk allele compared to sprint/power athletes (IGF2BP2 rs4402960) and significantly (p < 0.05) less likely to have the risk allele compared to controls (LPL rs320). The other 3 SNPs did not show significant differences between the study groups.

Conclusions

Male endurance athletes are less likely to have the metabolic risk alleles of IGF2BP2 rs4402960 and LPL rs320, compared to sprint/power athletes and controls, respectively. These results suggest that some SNPs across the human genome have a dual effect and may predispose endurance athletes to reduced risk of developing metabolic morbidities, whereas sprint/power athletes might be predisposed to elevated risk.     

EPAS1 gene variants are associated with sprint/power athletic performance in two cohorts of European athletes

Background

The endothelial PAS domain protein 1 (EPAS1) activates genes that are involved in erythropoiesis and angiogenesis, thus favoring a better delivery of oxygen to the tissues and is a plausible candidate to influence athletic performance. Using innovative statistical methods we compared genotype distributions and interactions of EPAS1 SNPs rs1867785, rs11689011, rs895436, rs4035887 and rs1867782 between sprint/power athletes (n = 338), endurance athletes (n = 254), and controls (603) in Polish and Russian samples. We also examined the association between these SNPs and the athletes’ competition level (‘elite’ and ‘sub-elite’ level). Genotyping was performed by either Real-Time PCR or by Single-Base Extension (SBE) method.

Results

In the pooled cohort of Polish and Russian athletes, 1) rs1867785 was associated with sprint/power athletic status; the AA genotype in rs1867785 was underrepresented in the sprint/power athletes, 2) rs11689011 was also associated with sprint/power athletic status; the TT genotype in rs11689011 was underrepresented sprint/power athletes, and 3) the interaction between rs1867785, rs11689011, and rs4035887 was associated with sprint/power athletic performance; the combinations of the AA genotype in rs4035887 with either the AG or GG genotypes in rs1867785, or with the CT or CC genotypes in rs11689011, were underrepresented in two cohorts of sprint/power athletes.

Conclusions

Based on the unique statistical model rs1867785/rs11689011 are strong predictors of sprint/power athletic status, and the interaction between rs1867785, rs11689011, and rs4035887 might contribute to success in sprint/power athletic performance.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-382) contains supplementary material, which is available to authorized users.     

Telomere Length and Long-Term Endurance Exercise: Does Exercise Training Affect Biological Age? A Pilot Study

Background

Telomeres are potential markers of mitotic cellular age and are associated with physical ageing process. Long-term endurance training and higher aerobic exercise capacity (VO_2max) are associated with improved survival, and dynamic effects of exercise are evident with ageing. However, the association of telomere length with exercise training and VO_2max has so far been inconsistent. Our aim was to assess whether muscle telomere length is associated with endurance exercise training and VO_2max in younger and older people.

Methods

Twenty men; 10 young (22–27 years) and 10 old (66–77 years), were studied in this cross-sectional study. Five out of 10 young adults and 5 out of 10 older were endurance athletes, while other halves were exercising at a medium level of activity. Mean telomere length was measured as telomere/single copy gene-ratio (T/S-ratio) using quantitative real time polymerase chain reaction. VO_2max was measured directly running on a treadmill.

Results

Older endurance trained athletes had longer telomere length compared with older people with medium activity levels (T/S ratio 1.12±0.1 vs. 0.92±0.2, p = 0.04). Telomere length of young endurance trained athletes was not different than young non-athletes (1.47±0.2 vs. 1.33±0.1, p = 0.12). Overall, there was a positive association between T/S ratio and VO_2max (r = 0.70, p = 0.001). Among endurance trained athletes, we found a strong correlation between VO_2max and T/S ratio (r = 0.78, p = 0.02). However, corresponding association among non-athlete participants was relatively weak (r = 0.58, p = 0.09).

Conclusion

Our data suggest that VO_2max is positively associated with telomere length, and we found that long-term endurance exercise training may provide a protective effect on muscle telomere length in older people.     

Concurrent training enhances athletes' cardiovascular and cardiorespiratory measures

We evaluated the effects of concurrent strength and aerobic endurance training on cardiovascular and cardiorespiratory adaptations in college athletes and compared two concurrent exercise (CE) protocols. Separate experiments were performed on 30 women (mean age 19.6 years) and 20 men (20.4 years). In both experiments, subjects were divided into two groups (serial CE and integrated CE) matched for initial physical condition and trained in a vigorous 3-day per week CE program of 9 (men) to 11 (women) weeks. The two CE training protocols were equilibrated for exercise mode, intensity, and volume, differing only in the timing and sequence of exercises. During training, serial CE discernibly (p < 0.05) increased cardiovascular adaptation in women, indicated by reduction (-5.7%) in active heart rate (HR) (HR/aerobic exercise intensity), whereas integrated CE discernibly reduced active HR in women (-10.7%) and men (-9.1%). Before and after comparisons in the larger sample of women showed that serial CE discernibly reduced systolic and diastolic blood pressure (BP) (-8.7% and -14.0%, respectively), increased estimated [latin capital V with dot above]o2max (18.9%), and produced a trend (0.10 > p > 0.05) toward reduced resting HR (-4.9%). Integrated CE in women discernibly reduced systolic and diastolic BP (-13.2% and -12.6%, respectively), increased estimated [latin capital V with dot above]o2max (22.9%), and produced a trend toward reduced resting HR (-2.4%). Integrated CE produced discernibly larger gains than serial CE or a trend for four of six training adaptations. Effect sizes were generally large (60.0% of discernible differences). We conclude that, for cardiovascular and cardiorespiratory adaptations in athletes, strength and endurance training are compatible and that exercise timing and sequence significantly influence training adaptations, complimenting our previous similar conclusions for strength, muscle endurance, body composition, and flexibility.     

Effectiveness of a Video-Feedback and Questioning Programme to Develop Cognitive Expertise in Sport

The importance within sport expertise of cognitive factors has been emphasised in many research studies. Adaptations that take place in athletes’ long-term memories are going to condition their decision-making and performance, and training programmes must be developed that improve these adaptations. In our study, we provide a tactical-cognitive training programme based on video-feedback and questioning in order to improve tactical knowledge in tennis players and verify its effect when transferred to athletes’ decision-making. 11 intermediate tennis players participated in this study (12.9±0.7 years old), distributed into two groups (experimental, n = 5; control, n = 6). Tactical knowledge was measured by problem representation and strategy planning with a verbal protocol. Decision-making was measured by a systematic observation instrument. Results confirm the effectiveness of a combination of video-feedback and questioning on cognitive expertise, developing adaptations in long-term memory that produce an improvement in the quality of tactical knowledge (content, sophistication and structure). This, in turn, is transferred to the athletes’ decision-making capacity, leading to a higher percentage of successful decisions made during game play. Finally, we emphasise the need to develop effective programmes to develop cognitive expertise and improve athletes'' performance, and include it in athletes’ formative stages.     

Comparison of blood and saliva lactate level after maximum intensity exercise

Several studies have described high correlation of salivary and blood lactate level during exercise. Measuring the effectiveness and intensity of training, lactate concentration in blood, and lately in saliva are used.The aim of our study was to evaluate the correlation between the concentration and timing of salivary and blood lactate level in endurance athletes and non-athletes after a maximal treadmill test, and to identify physiological and biochemical factors affecting these lactate levels.Sixteen volunteers (8 athletes and 8 non-athletes) performed maximal intensity (Astrand) treadmill test. Anthropometric characteristics, body composition and physiological parameters (heart rate, RR-variability) were measured in both studied groups. Blood and whole saliva samples were collected before and 1, 4, 8, 12, 15, 20 min after the exercise test. Lactate level changes were monitored in the two groups and two lactate peaks were registered at different timeperiods in athletes. We found significant correlation between several measured parameters (salivary lactate - total body water, salivary lactate - RR-variability, maximal salivary lactate - maximal heart rate during exercise, salivary- and blood lactate -1 min after exercise test). Stronger correlation was noted between salivary lactate and blood lactate in athletes, than in controls.     

The MCT1 gene Glu490Asp polymorphism (rs1049434) is associated with endurance athlete status,lower blood lactate accumulation and higher maximum oxygen uptake

The purpose of this study was to explore the association of the MCT1 gene Glu490Asp polymorphism (rs1049434) with athletic status and performance of endurance athletes. A total of 1,208 Brazilians (318 endurance athletes and 890 non-athletes) and 867 Europeans (315 endurance athletes and 552 non-athletes) were evaluated in a case–control approach. Brazilian participants were classified based on self-declared ethnicity to test whether the polymorphism was different between Caucasians and Afro-descendants. Moreover, 66 Hungarian athletes underwent an incremental test until exhaustion to assess blood lactate levels, while 46 Russian athletes had their maximum oxygen uptake (V⋅O2max ) compared between genotypes. In the Brazilian cohort, the major T-allele was more frequent in Caucasian top-level competitors compared to their counterparts of lower competitive level (P = 0.039), and in Afro-descendant athletes compared to non-athletes (P = 0.015). Similarly, the T-allele was more frequent in European athletes (P = 0.029). Meta-analysis of the Brazilian and European cohorts confirmed that the T-allele is over-represented in endurance athletes (OR: 1.48, P = 0.03), especially when Afro-descendant athletes were included in the meta-analysis (OR: 1.58, P = 0.005). Furthermore, carriers of the T/T genotype accumulated less blood lactate in response to intense effort (P < 0.01) and exhibited higher V⋅O2max (P = 0.04)_. In conclusion, the Glu490Asp polymorphism was associated with endurance athletic status and performance. Our findings suggest that, although ethnic differences may exist, the presence of the major T-allele (i.e., the Glu-490 allele) favours endurance performance more than the mutant A-allele (i.e., the 490-Asp allele).     

Prediction of muscle fiber composition using multiple repetition testing

Direct determination of muscle fiber composition is invasive and expensive, with indirect methods also requiring specialist resources and expertise. Performing resistance exercises at 80% 1RM is suggested as a means of indirectly estimating muscle fiber composition, though this hypothesis has never been validated against a direct method. The aim of the study was to investigate the relationship between the number of completed repetitions at 80% 1RM of back squat exercise and muscle fiber composition. Thirty recreationally active participants’ (10 females, 20 males) 1RM back squat load was determined, before the number of consecutive repetitions at 80% 1RM was recorded. The relationship between the number of repetitions and the percentage of fast-twitch fibers from vastus lateralis was investigated. The number of completed repetitions ranged from 5 to 15 and was independent of sex, age, 1RM, training frequency, training type, training experience, BMI or muscle fiber cross-sectional area. The percentage of fast-twitch muscle fibers was inversely correlated with the number of repetitions completed (r = –0.38, P = 0.039). Participants achieving 5 to 8 repetitions (n = 10) had significantly more fast-twitch muscle fibers (57.5 ± 9.5 vs 44.4 ± 11.9%, P = 0.013) than those achieving 11–15 repetitions (n = 11). The remaining participants achieved 9 or 10 repetitions (n = 9) and on average had equal proportion of fast- and slow-twitch muscle fibers. In conclusion, the number of completed repetitions at 80% of 1RM is moderately correlated with muscle fiber composition.     

Sports genetics: the PPARA gene and athletes’ high ability in endurance sports. A systematic review and meta-analysis

A meta-analysis was performed with the aim of re-evaluating the role of the peroxisome proliferator activated receptor alpha (PPARA) gene intron 7 G/C polymorphism (rs4253778) in athletes’ high ability in endurance sports. Design: A meta-analysis of case control studies assessing the association between the G/C polymorphisms of the PPARA gene and endurance sports was conducted. The Cochrane Review Manager software was used to compare the genotype and allele frequencies between endurance athletes and controls to determine whether a genetic variant is more common in athletes than in the general population. Five studies, encompassing 760 endurance athletes and 1792 controls, fulfilled our inclusion criteria. The pooled odds ratio (and confidence intervals, CIs) for the G allele compared to the C allele was 1.65 (95% CI 1.39-1.96). The pooled OR for the GG genotype compared to the GC genotype was 1.79 (95% CI 1.44-2.22), and for the GG genotype compared to the CC genotype 2.37 (95% CI 1.40-3.99). There was no evidence of heterogeneity (I² =0%) or of publication bias. Athletes with high ability in endurance sports had a higher frequency of the GG genotype and G allele.     

Dynamics of cardiac performance in athletes during isometric exercise

The main structural-functional indices of cardiac performance during isometric exercise were recorded in athletes and non-athletes. The physiological shifts in response to exercise were less obvious in the athletes than in the non-athletes. This was mainly determined by the structural features of the “athlete’s heart.” The dependence of a series of physiological indices on the heart rate was revealed: as cardiac rhythm increased in response to a submaximal isometric exercise, the systolic and, to a lesser degree, diastolic arterial pressure grew and the stroke volume of blood decreased.     

Determining the Optimum Power Load in Jump Squat Using the Mean Propulsive Velocity

The jump squat is one of the exercises most frequently used to improve lower body power production, which influences sports performance. However, the traditional determination of the specific workload at which power production is maximized (i.e., optimum power load) is time-consuming and requires one-repetition maximum tests. Therefore, the aim of this study was to verify whether elite athletes from different sports would produce maximum mean propulsive power values at a narrow range of mean propulsive velocities, resulting in similar jump heights. One hundred and nine elite athletes from several individual/team sport disciplines underwent repetitions at maximal velocity with progressive loads, starting at 40% of their body mass with increments of 10% to determine the individual optimum power zone. Results indicated that regardless of sport discipline, the athletes’ optimum mean propulsive power was achieved at a mean propulsive velocity close to 1.0 m.s⁻¹ (1.01 ± 0.07 m.s⁻¹) and at a jump height close to 20 cm (20.47 ± 1.42 cm). Data were narrowly scattered around these values. Therefore, jump squat optimum power load can be determined simply by means of mean propulsive velocity or jump height determination in training/testing settings, allowing it to be implemented quickly in strength/power training.     

Effect of Chronic Athletic Activity on Brown Fat in Young Women

BackgroundThe effect of chronic exercise activity on brown adipose tissue (BAT) is not clear, with some studies showing positive and others showing negative associations. Chronic exercise is associated with increased resting energy expenditure (REE) secondary to increased lean mass and a probable increase in BAT. Many athletes are in a state of relative energy deficit suggested by lower fat mass and hypothalamic amenorrhea. States of severe energy deficit such as anorexia nervosa are associated with reduced BAT. There are no data regarding the impact of chronic exercise activity on BAT volume or activity in young women and it is unclear whether relative energy deficiency modifies the effects of exercise on BAT.PurposeWe assessed cold induced BAT volume and activity in young female athletes compared with non-athletes, and further evaluated associations of BAT with measures of REE, body composition and menstrual status.MethodsThe protocol was approved by our Institutional Review Board. Written informed consent was obtained from all participants prior to study initiation. This was a cross-sectional study of 24 women (16 athletes and8 non-athletes) between 18–25 years of age. Athletes were either oligo-amenorrheic (n = 8) or eumenorrheic (n = 8).We used PET/CT scans to determine cold induced BAT activity, VMAX Encore 29 metabolic cart to obtain measures of REE, and DXA for body composition.ResultsAthletes and non-athletes did not differ for age or BMI. Compared with non-athletes, athletes had lower percent body fat (p = 0.002), higher percent lean mass (p = 0.01) and trended higher in REE (p = 0.09). BAT volume and activity in athletes trended lower than in non-athletes (p = 0.06; p = 0.07, respectively). We found negative associations of BAT activity with duration of amenorrhea (r = -0.46, p = 0.02).BAT volume correlated inversely with lean mass (r = -0.46, p = 0.02), and positively with percent body fat, irisin and thyroid hormones.ConclusionsOur study shows a trend for lower BAT in young female athletes compared with non-athletes, and shows associations of brown fat with menstrual status and body composition. Brown fat may undergo adaptive reductions with increasing energy deficit.     

The effects of athletic training and muscle contractile character on the pressor response to isometric exercise of the human triceps surae

In this study, the influence of athletic training status and the contractile character of the active muscle on the magnitude of the pressor response (PR) to voluntary and electrically evoked isometric plantar flexion was investigated. Subjects were 10 sprint-trained athletes (sprint) (100-m, 200-m and 400-m) [mean (SD) age, 21 (2) years], 14 endurance trained athletes (distance) [22 (2) years] and 8 untrained men (control) [23 (3) years]. Twitch time to peak tension (TPT) in the sprint group [108 (7) ms] was significantly less (P<0.001) than that of the distance group [124 (10) ms]. During voluntary contraction, the mean change in systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (fc) was not significantly different between groups. During electrically evoked contractions, mean changes in SBP, DBP and fc were not significantly different between the sprint, distance and control groups. However, division of the sprint group into 400-m (sprint I) and 100/200-m athletes (sprint II) showed that an increase in DBP of 1.6 kPa (12 mm Hg) in sprint I was significantly less (P<0.05) than the 2.5 kPa (19 mm Hg) increase observed for both the distance and control groups. Prediction of the DBP response from our previously published relationship between TPT and DBP showed close agreement in all subject groups except sprint I; in these subjects the observed DBP response was only 55% of that predicted. Attenuation of the PR in the involuntary experiment suggests that some aspect of sprint training, but not endurance training, modifies the muscle afferent input to the PR in man.     

Left-Handedness in Professional and Amateur Tennis

Negative frequency-dependent effects rather than innate predispositions may provide left-handers with an advantage in one-on-one fighting situations. Support mainly comes from cross-sectional studies which found significantly enhanced left-hander frequencies among elite athletes exclusively in interactive sports such as baseball, cricket, fencing and tennis. Since professional athletes’ training regimes continuously improve, however, an important unsolved question is whether the left-handers’ advantage in individual sports like tennis persists over time. To this end, we longitudinally tracked left-hander frequencies in year-end world rankings (men: 1973–2011, ladies: 1975–2011) and at Grand Slam tournaments (1968–2011) in male and female tennis professionals. Here we show that the positive impact of left-handed performance on high achievement in elite tennis was moderate and decreased in male professionals over time and was almost absent in female professionals. For both sexes, left-hander frequencies among year-end top 10 players linearly decreased over the period considered. Moreover, left-handedness was, however, no longer seems associated with higher probability of attaining high year-end world ranking position in male professionals. In contrast, cross-sectional data on left-hander frequencies in male and female amateur players suggest that a left-handers’ advantage may still occur on lower performance levels. Collectively, our data is in accordance with the frequency-dependent hypothesis since reduced experience with left-handers in tennis is likely to be compensated by players’ professionalism.     

Effects of Long Term Supplementation of Anabolic Androgen Steroids on Human Skeletal Muscle

The effects of long-term (over several years) anabolic androgen steroids (AAS) administration on human skeletal muscle are still unclear. In this study, seventeen strength training athletes were recruited and individually interviewed regarding self-administration of banned substances. Ten subjects admitted having taken AAS or AAS derivatives for the past 5 to 15 years (Doped) and the dosage and type of banned substances were recorded. The remaining seven subjects testified to having never used any banned substances (Clean). For all subjects, maximal muscle strength and body composition were tested, and biopsies from the vastus lateralis muscle were obtained. Using histochemistry and immunohistochemistry (IHC), muscle biopsies were evaluated for morphology including fiber type composition, fiber size, capillary variables and myonuclei. Compared with the Clean athletes, the Doped athletes had significantly higher lean leg mass, capillary per fibre and myonuclei per fiber. In contrast, the Doped athletes had significantly lower absolute value in maximal squat force and relative values in maximal squat force (relative to lean body mass, to lean leg mass and to muscle fiber area). Using multivariate statistics, an orthogonal projection of latent structure discriminant analysis (OPLS-DA) model was established, in which the maximal squat force relative to muscle mass and the maximal squat force relative to fiber area, together with capillary density and nuclei density were the most important variables for separating Doped from the Clean athletes (regression  =  0.93 and prediction  =  0.92, p<0.0001). In Doped athletes, AAS dose-dependent increases were observed in lean body mass, muscle fiber area, capillary density and myonuclei density. In conclusion, long term AAS supplementation led to increases in lean leg mass, muscle fiber size and a parallel improvement in muscle strength, and all were dose-dependent. Administration of AAS may induce sustained morphological changes in human skeletal muscle, leading to physical performance enhancement.     

Effects of conjugated linoleic acid and endurance training on peripheral blood and bone marrow of trained mice

Fat supplements, especially conjugated linoleic acid (CLA), are increasingly popular ergogenic aids among endurance athletes. To evaluate the importance of fat supplementation in the practice of endurance sports, we investigated the effects of CLA supplementation on body weight, muscle hypertrophy, peripheral blood composition, and bone marrow composition in healthy, young, endurance-trained mice. Young, healthy mice were subdivided into control, trained, and treated groups, according to their running attitudes. Training was performed over a period of 6 weeks on a treadmill, at a gradually increasing duration and speed. CLA-treated groups were gavaged with 0.425 mg x d(-1) CLA supplement for the entire training period. The exercise protocol induced a significant decrease in body weight (p < 0.003) and a consistent muscle hypertrophy (p < 0.003). A morphological evaluation of bone marrow from trained mice revealed an accelerated turnover of the erythroid lineage, i.e., a relative increase in proerythroblasts. Conjugated linoleic acid supplementation did not induce a further decrease in total body weights in either untrained or trained mice (p = 0.747), but induced a further increase in muscle hypertrophy in trained mice (p = 0.009). Furthermore, CLA feeding induced an important lymphopenia in peripheral blood of CLA-fed trained mice (p < or = 0.05). These findings suggest that CLA may improve the performance of endurance athletes by increasing muscle hypertrophy, and, at the same time, that it may cause oxidative stress damage, leading to a peripheral blood lymphopenia and a consequent neutrophilia as a defensive response. Despite the positive increase in muscle hypertrophy claimed by the pharmaceutics companies, we suggest that endurance athletes and those looking to improve their own skeletal muscle mass refrain from CLA supplementation, because it seems to intensify the oxidative stress caused by exhaustive exercise.     

Effects of Heavy Strength Training on Running Performance and Determinants of Running Performance in Female Endurance Athletes

Purpose

The purpose of the current study was to investigate the effects of adding strength training to normal endurance training on running performance and running economy in well-trained female athletes. We hypothesized that the added strength training would improve performance and running economy through altered stiffness of the muscle-tendon complex of leg extensors.

Methods

Nineteen female endurance athletes [maximal oxygen consumption (VO_2max): 53±3 ml∙kg^-1∙min^-1, 5.8 h weekly endurance training] were randomly assigned to either normal endurance training (E, n = 8) or normal endurance training combined with strength training (E+S, n = 11). The strength training consisted of four leg exercises [3 x 4–10 repetition maximum (RM)], twice a week for 11 weeks. Muscle strength, 40 min all-out running distance, running performance determinants and patellar tendon stiffness were measured before and after the intervention.

Results

E+S increased 1RM in leg exercises (40 ± 15%) and maximal jumping height in counter movement jump (6 ± 6%) and squat jump (9 ± 7%, p < 0.05). This was accompanied by increased muscle fiber cross sectional area of both fiber type I (13 ± 7%) and fiber type II (31 ± 20%) in m. vastus lateralis (p < 0.05), with no change in capillary density in m. vastus lateralis or the stiffness of the patellar tendon. Neither E+S nor E changed running economy, fractional utilization of VO_2max or VO_2max. There were also no change in running distance during a 40 min all-out running test in neither of the groups.

Conclusion

Adding heavy strength training to endurance training did not affect 40 min all-out running performance or running economy compared to endurance training only.