Could middle- and long-distance running performance of well-trained athletes be best predicted by the same aerobic parameters?

Increased prevalence of the null allele of the p.Arg577Ter variant in the ACTN3 gene in Brazilian long-distance athletes: A retrospective study

INTRODUCTION

The phenotypic consequences of the p.Arg577Ter variant in the α-actinin-3 (ACTN3) gene are suggestive of a trade-off between performance traits for speed and endurance sports. Although there is a consistent association of the c.1729C allele (aka R allele) with strength/power traits, there is still a debate on whether the null allele (c.1729T allele; aka X allele) influences endurance performance. The present study aimed to test the association of the ACTN3 p.Arg577Ter variant with long-distance endurance athlete status, using previously published data with the Brazilian population.

METHODS

Genotypic data from 203 long-distance athletes and 1724 controls were analysed in a case-control approach.

RESULTS

The frequency of the X allele was significantly higher in long-distance athletes than in the control group (51.5% vs. 41.4%; p = 0.000095). The R/X and X/X genotypes were overrepresented in the athlete group. Individuals with the R/X genotype instead of the R/R genotype had a 1.6 increase in the odds of being a long-distance athlete (p = 0.012), whereas individuals with the X/X genotype instead of the R/R genotype had a 2.2 increase in the odds of being a long-distance athlete (p = 0.00017).

CONCLUSION

The X allele, mainly the X/X genotype, was associated with long-distance athlete status in Brazilians.

Is test specificity the issue in assessing aerobic fitness and performance of runners? A systematic review

INTRODUCTION

Various tests have been developed to evaluate aerobic fitness and performance of runners. However, a systematic understanding of which methods are more accurate is necessary to provide coaches and the sports sciences community with useful and confident outcomes. This study aims to summarize the evidence regarding the validity, reliability and sensitivity of tests for measuring aerobic fitness and performance in runners of several background of training.

EVIDENCE ACQUISITION

A systematic search was conducted of Web of Science, PubMed and Scopus up to 31st December 2022 according to PRISMA statement guidelines. Studies that reported findings about tests covering maximal aerobic speed, final velocity achieved during the test, average running speed or other method of evaluating the reference speed during the test were included. We evaluated the risk of bias in the included articles using the Risk of Bias Assessment Tool for Nonrandomized Studies (RoBANS). The tests were categorized into continuous incremental tests, intermittent tests and time-trial test.

EVIDENCE SYNTHESIS

A total of 23 studies met eligibility criteria. These studies contained three background of training: track and road runners (N.=15), trail runners (N.=7) and inexperienced runners (N.=1). Criterion validity was assessed in 73% of the studies, while only 41% of studies examined convergent validity. The majority of the reviewed studies (87%) ignored test-retest reliability. Test sensitivity was not reported in any study.

CONCLUSIONS

At least one aerobic fitness and performance test was identified for each types of background of training. However, some methodological aspects were not provided in the included articles. Most studies examined at least one aspect of validity (i.e., criterion or convergent-related validity), whilst few studies investigated test-retest reliability. Researchers and practitioners can use the information provided in this systematic review to select appropriate tests.

Personality of marathon runners: a narrative review of recent findings

Participation in marathons has dramatically increased over the last few years. Marathon running has many proven beneficial effects, especially on cardiovascular health and fitness. Most research has focused on physiologic and pathophysiologic adaptations in connection with endurance exercise. Nevertheless, marathon running also has a major impact on psychological aspects and positively influences mental health, which has only recently attracted research interest. The present narrative review aimed to review the personality traits of marathon runners with an emphasis on recent literature. Marathon runners show a distinct personality and highly characteristic personality traits needed to successfully finish such a demanding race, i.e., a strong sense of vigor, self-sufficiency, and intelligence as well as low scores in anger, fatigue, tension, and depression. Furthermore, personality differences are detectable between runners of different sexes, ages, and performance level groups. This has significant clinical implications for athletes, coaches and competition organizers, as these groups show different patterns of personality traits. Future studies should focus on changes in cognition and mood states pre-, during, and post-endurance events, as well as during training periods. Large-scale studies comparing personality differences by sex, age, and performance are also important for better clinical guidance. See also the graphical abstract(Fig. 1).

Contemporary blood doping-Performance, mechanism, and detection

Blood doping is prohibited for athletes but has been a well-described practice within endurance sports throughout the years. With improved direct and indirect detection methods, the practice has allegedly moved towards micro-dosing, that is, reducing the blood doping regime amplitude. This narrative review evaluates whether blood doping, specifically recombinant human erythropoietin (rhEpo) treatment and blood transfusions are performance-enhancing, the responsible mechanism as well as detection possibilities with a special emphasis on micro-dosing. In general, studies evaluating micro-doses of blood doping are limited. However, in randomized, double-blinded, placebo-controlled trials, three studies find that infusing as little as 130 ml red blood cells or injecting 9 IU × kg bw-1 rhEpo three times per week for 4 weeks improve endurance performance ~4%-6%. The responsible mechanism for a performance-enhancing effect following rhEpo or blood transfusions appear to be increased O2 -carrying capacity, which is accompanied by an increased muscular O2 extraction and likely increased blood flow to the working muscles, enabling the ability to sustain a higher exercise intensity for a given period. Blood doping in micro-doses challenges indirect detection by the Athlete Biological Passport, albeit it can identify ~20%-60% of the individuals depending on the sample timing. However, novel biomarkers are emerging, and some may provide additive value for detection of micro blood doping such as the immature reticulocytes or the iron regulatory hormones hepcidin and erythroferrone. Future studies should attempt to validate these biomarkers for implementation in real-world anti-doping efforts and continue the biomarker discovery.

Physiological characteristics and performance of a world-record breaking tower runner

This study reports the physiological and performance profiles of a world-class tower runner during a 6-week period surrounding a successful Guinness World Record (WR) attempt, and discusses the efficacy of a tower running specific field test. The world-ranked number 2 tower runner completed four exercise tests [laboratory treadmill assessment (3 weeks before the WR attempt), familiarisation to a specific incremental tower running field test (1 week before), tower running field test (1 week after), and tower running time trial (TT) (3 weeks after)] and the WR attempt within 6-week period. Peak oxygen consumption (VO₂peak) during the laboratory test, field test, and TT were 73.3, 75.5 and 78.3 mL·kg^-1·min^-1, respectively. The VO₂ corresponding to the second ventilatory threshold was 67.3 mL·kg^-1·min^-1 (89.1% of VO₂peak), identified at stage 4 (tempo; 100 b·min^-1), during the field test. The duration of the TT was 10 min 50 s, with an average VO₂ of 71.7 mL·kg^-1·min^-1 (91.6% of VO₂peak), HR of 171 b·min^-1 (92% of peak HR), vertical speed of 0.47 m·s^-1, and cadence was 117 steps·min^-1. A world-class tower runner possesses a well-developed aerobic capacity. A specific, field-based test revealed greater VO₂peak than a laboratory test, indicating a need for sport-specific testing procedures.