Acute effects of overspeed stimuli with towing system on athletic sprint performance: A systematic review with meta-analysis.

Overspeed-based training is widely used to improve athletes' maximum running speed and towing systems are one of the most frequently employed methods for this purpose. However, the effectiveness of this modality has not been thoroughly determined. This review analyzes the acute effects of overspeed conditions with towing systems in sprinters. The articles were searched, analysed and selected following the PRISMA methodology in the PubMed, SPORTDiscus and Google Scholar databases. Sixteen studies were included, with a total sample of 240 men and 56 women (14 to 31y; 1.73 to 1.82 m; 66.2 to 77.0 kg). The main acute responses found were: 1) an increase in maximum running speed (ES = 1.54, large), stride length (ES = 0.92, moderate), flight time (ES = 0.28, small) and stride rate (ES = 0.12, trivial); and, 2) a decrease in contact time (ES = 0.57, small). However, analysis of the reported ground reaction forces and electromyography data did not provide enough consistent evidence to conclusively determine whether the changes are due to a greater muscular response of the athlete or the effect of the towing system. Future research should focus on studying the mechanisms responsible for the observed acute effects.

The GALNTL6 Gene rs558129 Polymorphism Is Associated With Power Performance.

Díaz, J, Álvarez Herms, J, Castañeda, A, Larruskain, J, Ramírez de la Piscina, X, Borisov, OV, Semenova, EA, Kostryukova, ES, Kulemin, NA, Andryushchenko, ON, Larin, AK, Andryushchenko, LB, Generozov, EV, Ahmetov, II, and Odriozola, A. The GALNTL6 gene rs558129 polymorphism is associated with power performance. J Strength Cond Res 34(11): 3031-3036, 2020-The largest genome-wide association study to date in sports genomics showed that endurance athletes were 1.23 times more likely to possess the C allele of the single nucleotide polymorphism rs558129 of N-acetylgalactosaminyltransferase-like 6 gene (GALNTL6), compared with controls. Nevertheless, no further study has investigated GALNTL6 gene in relation to physical performance. Considering that previous research has shown that the same polymorphism can be associated with both endurance and power phenotypes (ACTN3, ACE, and PPARA), we investigated the association between GALNTL6 rs558129 polymorphism and power performance. According to this objective we conducted 2 global studies regarding 2 different communities of athletes in Spain and Russia. The first study involved 85 Caucasian physically active men from the north of Spain to perform a Wingate anaerobic test (WAnT). In the second study we compared allelic frequencies between 173 Russian power athletes (49 strength and 124 speed-strength athletes), 169 endurance athletes, and 201 controls. We found that physically active men with the T allele of GALNTL6 rs558129 had 5.03-6.97% higher power values compared with those with the CC genotype (p < 0.05). Consistent with these findings, we have shown that the T allele was over-represented in power athletes (37.0%) compared with endurance athletes (29.3%; OR = 1.4, p = 0.032) and controls (28.6%; OR = 1.5, p = 0.015). Furthermore, the highest frequency of the T allele was observed in strength athletes (43.9%; odds ratio [OR] = 1.9, p = 0.0067 compared with endurance athletes; OR = 2.0, p = 0.0036 compared with controls). In conclusion, our data suggest that the GALNTL6 rs558129 T allele can be favorable for anaerobic performance and strength athletes. In addition, we propose a new possible functional role of GALNTL6 rs558129, gut microbiome regarding short-chain fatty acid regulation and their anti-inflammatory and resynthesis functions. Nevertheless, further studies are required to understand the mechanisms involved.

Techniques, procedures, and applications in microbiome analysis.

Microbiota is a complex community of microorganisms living in a defined environment. Until the 20th century, knowledge of microbiota was partial, as the techniques available for their characterization were primarily based on bacteriological culture. In the last twenty years, the development of DNA sequencing technologies, multi-omics, and bioinformatics has expanded our understanding of microorganisms. We have moved from mainly considering them isolated disease-causing agents to recognizing the microbiota as an essential component of host biology. These techniques have shown that the microbiome plays essential roles in various host phenotypes, influencing development, physiology, reproduction, and evolution. This chapter provides researchers with a summary of the primary concepts, sample collection, experimental techniques, and bioinformatics analysis commonly used in microbiome research. The main features, applications in microbiome studies, and their advantages and limitations are included in each section.

Microbiome and physical activity.

Regular physical activity promotes health benefits and contributes to develop the individual biological potential. Chronical physical activity performed at moderate and high-intensity is the intensity more favorable to produce health development in athletes and improve the gut microbiota balance. The athletic microbiome is characterized by increased microbial diversity and abundance as well as greater phenotypic versatility. In addition, physical activity and microbiota composition have bidirectional effects, with regular physical activity improving microbial composition and microbial composition enhancing physical performance. The improvement of physical performance by a healthy microbiota is related to different phenotypes: i) efficient metabolic development, ii) improved regulation of intestinal permeability, iii) favourable modulation of local and systemic inflammatory and efficient immune responses, iv) efective regulation of systemic pH and, v) protection against acute stressful events such as environmental exposure to altitude or heat. The type of sport, both intensity or volume characteristics promote microbiota specialisation. Individual assessment of the state of the gut microbiota can be an effective biomarker for monitoring health in the medium to long term. The relationship between the microbiota and the rest of the body is bidirectional and symbiotic, with a full connection between the systemic functions of the nervous, musculoskeletal, endocrine, metabolic, acid-base and immune systems. In addition, circadian rhythms, including regular physical activity, directly influence the adaptive response of the microbiota. In conclusion, regular stimuli of moderate- and high-intensity physical activity promote greater diversity, abundance, resilience and versatility of the gut microbiota. This effect is highly beneficial for human health when healthy lifestyle habits including nutrition, hydration, rest, chronoregulation and physical activity.

Impact of evolution on lifestyle in microbiome.

This chapter analyses the interaction between microbiota and humans from an evolutionary point of view. Long-term interactions between gut microbiota and host have been generated as a result of dietary choices through coevolutionary processes, where mutuality of advantage is essential. Likewise, the characteristics of the intestinal environment have made it possible to describe different intrahost evolutionary mechanisms affecting microbiota. For its part, the intestinal microbiota has been of great importance in the evolution of mammals, allowing the diversification of dietary niches, phenotypic plasticity and the selection of host phenotypes. Although the origin of the human intestinal microbial community is still not known with certainty, mother-offspring transmission plays a key role, and it seems that transmissibility between individuals in adulthood also has important implications. Finally, it should be noted that certain aspects inherent to modern lifestyle, including refined diets, antibiotic intake, exposure to air pollutants, microplastics, and stress, could negatively affect the diversity and composition of our gut microbiota. This chapter aims to combine current knowledge to provide a comprehensive view of the interaction between microbiota and humans throughout evolution.

Circadian rhythm and host genetics.

This chapter aims to explore the usefulness of the latest advances in genetic studies in the field of the circadian system in the future development of individualised strategies for health improvement based on lifestyle intervention. Due to the multifactorial and complex nature of the circadian system, we focus on the highly prevalent phenotypes in the population that are key to understanding its biology from an evolutionary perspective and that can be modulated by lifestyle. Therefore, we leave in the background those phenotypes that constitute infrequent pathologies or in which the current level of scientific evidence does not favour the implementation of practical approaches of this type. Therefore, from an evolutionary paradigm, this chapter addresses phenotypes such as morning chronotypes, evening chronotypes, extreme chronotypes, and other key concepts such as circadian rhythm amplitude, resilience to changes in circadian rhythm, and their relationships with pathologies associated with circadian rhythm imbalances.

Sleep regulation and host genetics.

Due to the multifactorial and complex nature of rest, we focus on phenotypes related to sleep. Sleep regulation is a multifactorial process. In this chapter, we focus on those phenotypes inherent to sleep that are highly prevalent in the population, and that can be modulated by lifestyle, such as sleep quality and duration, insomnia, restless leg syndrome and daytime sleepiness. We, therefore, leave in the background those phenotypes that constitute infrequent pathologies or for which the current level of scientific evidence does not favour the implementation of practical approaches of this type. Similarly, the regulation of sleep quality is intimately linked to the regulation of the circadian rhythm. Although this relationship is discussed in the sections that require it, the in-depth study of circadian rhythm regulation at the molecular level deserves a separate chapter, and this is how it is dealt with in this volume.

Host genetics and nutrition.

Optimal nutrition is essential for health and physiological performance. Nutrition-related diseases such as obesity and diabetes are major causes of death and reduced quality of life in modern Western societies. Thanks to combining nutrigenetics and nutrigenomics, genomic nutrition allows the study of the interaction between nutrition, genetics and physiology. Currently, interrelated multi-genetic and multifactorial phenotypes are studied from a multiethnic and multi-omics approach, step by step identifying the important role of pathways, in addition to those directly related to metabolism. It allows the progressive identification of genetic profiles associated with specific susceptibilities to diet-related phenotypes, which may facilitate individualised dietary recommendations to improve health and quality of life.

Techniques, procedures, and applications in host genetic analysis.

This chapter overviews genetic techniques' fundamentals and methodological features, including different approaches, analyses, and applications that have contributed to advancing health and disease. The aim is to describe laboratory methodologies and analyses employed to understand the genetic landscape of different biological contexts, from conventional techniques to cutting-edge technologies. Besides describing detailed aspects of the polymerase chain reaction (PCR) and derived types as one of the principles for many novel techniques, we also discuss microarray analysis, next-generation sequencing, and genome editing technologies such as transcription activator-like effector nucleases (TALENs) and the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) systems. These techniques study several phenotypes, ranging from autoimmune disorders to viral diseases. The significance of integrating diverse genetic methodologies and tools to understand host genetics comprehensively and addressing the ethical, legal, and social implications (ELSI) associated with using genetic information is highlighted. Overall, the methods, procedures, and applications in host genetic analysis provided in this chapter furnish researchers and practitioners with a roadmap for navigating the dynamic landscape of host-genome interactions.

Microbiome-based precision nutrition: Prebiotics, probiotics and postbiotics.

Microorganisms have been used in nutrition and medicine for thousands of years worldwide, long before humanity knew of their existence. It is now known that the gut microbiota plays a key role in regulating inflammatory, metabolic, immune and neurobiological processes. This text discusses the importance of microbiota-based precision nutrition in gut permeability, as well as the main advances and current limitations of traditional probiotics, new-generation probiotics, psychobiotic probiotics with an effect on emotional health, probiotic foods, prebiotics, and postbiotics such as short-chain fatty acids, neurotransmitters and vitamins. The aim is to provide a theoretical context built on current scientific evidence for the practical application of microbiota-based precision nutrition in specific health fields and in improving health, quality of life and physiological performance.

Conjugated linoleic acid metabolite impact in colorectal cancer: a potential microbiome-based precision nutrition approach.

Colorectal cancer (CRC) is the second most deadly and the third most diagnosed cancer in both sexes worldwide. CRC pathogenesis is associated with risk factors such as genetics, alcohol, smoking, sedentariness, obesity, unbalanced diets, and gut microbiota dysbiosis. The gut microbiota is the microbial community living in symbiosis in the intestine, in a dynamic balance vital for health. Increasing evidence underscores the influence of specific gut microbiota bacterial species on CRC incidence and pathogenesis. In this regard, conjugated linoleic acid (CLA) metabolites produced by certain gut microbiota have demonstrated an anticarcinogenic effect in CRC, influencing pathways for inflammation, proliferation, and apoptosis. CLA production occurs naturally in the rumen, and human bioavailability is through the consumption of food derived from ruminants. In recent years, biotechnological attempts to increase CLA bioavailability in humans have been unfruitful. Therefore, the conversion of essential dietary linoleic acid to CLA metabolite by specific intestinal bacteria has become a promising process. This article reviews the evidence regarding CLA and CLA-producing bacteria as therapeutic agents against CRC and investigates the best strategy for increasing the yield and bioavailability of CLA. Given the potential and limitations of the present strategies, a new microbiome-based precision nutrition approach based on endogenous CLA production by human gut bacteria is proposed. A literature search in the PubMed and PubMed Central databases identified 794 papers on human gut bacteria associated with CLA production. Of these, 51 studies exploring association consistency were selected. After excluding 19 papers, due to health concerns or discrepancies between studies, 32 papers were selected for analysis, encompassing data for 38 CLA-producing bacteria, such as Bifidobacterium and Lactobacillus species. The information was analyzed by a bioinformatics food recommendation system patented by our research group, Phymofood (EP22382095). This paper presents a new microbiome-based precision nutrition approach targeting CLA-producing gut bacterial species to maximize the anticarcinogenic effect of CLA in CRC.

Development and validation of a multiplex reaction analyzing eight miniSTRs of the X chromosome for identity and kinship testing with degraded DNA.

We report the development of an effective system for analyzing X chromosome-linked mini short tandem repeat loci with reduced-size amplicons (less than 220 bp), useful for analyzing highly degraded DNA samples. To generate smaller amplicons, we redesigned primers for eight X-linked microsatellites (DXS7132, DXS10079, DXS10074, DXS10075, DXS6801, DXS6809, DXS6789, and DXS6799) and established efficient conditions for a multiplex PCR system (miniX). The validation tests confirmed that it has good sensitivity, requiring as little as 20 pg of DNA, and performs well with DNA from paraffin-embedded tissues, thus showing potential for improved analysis and identification of highly degraded and/or very limited DNA samples. Consequently, this system may help to solve complex forensic cases, particularly when autosomal markers convey insufficient information.

miRNA analysis in vitreous humor to determine the time of death: a proof-of-concept pilot study.

We hypothesized that miRNAs present in vitreous humor could be a sort of "biological black box," storing information about physiological and environmental circumstances at death. As a proof of concept, we analyzed the vitreous humor miRNA signature to explore its forensic potential applications, such as determining the time of the day at death. The miRNAs present in vitreous humor from individuals who died at daytime or at nighttime were analyzed by quantitative real-time polymerase chain reaction (qPCR) array. Target miRNAs showing significant differences between groups were studied in a larger sample by individual qPCR assays. After array analysis of miRNAs in seven samples, significant expression differences were detected between individuals who died at daytime and at nighttime regarding mir-34c, mir-541, mir-888, mir-484, and mir-142-5p. miR-222 appeared as the best reference gene. The results were replicated in 34 vitreous humor samples, and the day-night differences were confirmed for miR-142-5p and miR-541, suggesting that miRNA levels may be related to either the ambient light or the circadian clock at the time of death. There was no correlation between miRNA levels and the time elapsed after death, suggesting that they were stable at least for 24 h. In conclusion, this report supports the potential forensic utility of the analysis of miRNAs in the vitreous humor in applications such as determining the time of death.

Possible relationship between the gut leaky syndrome and musculoskeletal injuries: the important role of gut microbiota as indirect modulator.

This article aims to examine the evidence on the relationship between gut microbiota (GM), leaky gut syndrome and musculoskeletal injuries. Musculoskeletal injuries can significantly impair athletic performance, overall health, and quality of life. Emerging evidence suggests that the state of the gut microbiota and the functional intestinal permeability may contribute to injury recovery. Since 2007, a growing field of research has supported the idea that GM exerts an essential role maintaining intestinal homeostasis and organic and systemic health. Leaky gut syndrome is an acquired condition where the intestinal permeability is impaired, and different bacteria and/or toxins enter in the bloodstream, thereby promoting systemic endotoxemia and chronic low-grade inflammation. This systemic condition could indirectly contribute to increased local musculoskeletal inflammation and chronificate injuries and pain, thereby reducing recovery-time and limiting sport performance. Different strategies, including a healthy diet and the intake of pre/probiotics, may contribute to improving and/or restoring gut health, thereby modulating both systemically as local inflammation and pain. Here, we sought to identify critical factors and potential strategies that could positively improve gut microbiota and intestinal health, and reduce the risk of musculoskeletal injuries and its recovery-time and pain. In conclusion, recent evidences indicate that improving gut health has indirect consequences on the musculoskeletal tissue homeostasis and recovery through the direct modulation of systemic inflammation, the immune response and the nociceptive pain.

Development and validation for identity testing of I-DNADuo, a combination of I-DNA1 and a new multiplex system, I-DNA2.

The I-DNADuo multiplex system combination is composed of previously validated I-DNA1 and a new short tandem repeat (STR) multiplex named I-DNA2 that analyses 11 STR loci plus amelogenin. I-DNADuo, with amplicon sizes ranging from 57 to 298 bp, is specifically designed to analyse amelogenin and 15 STR loci (ten of them plus amelogenin in duplicate), including all the STR loci of the CODIS, ISSL and ECL databases, and seven of the eight in GCL. The validation of I-DNADuo shows that it is a highly sensitive, robust multiplex system for obtaining individual genetic profiles and for detecting and preventing allelic dropouts.

Y-STR variation in the Basque diaspora in the Western USA: evolutionary and forensic perspectives.

Individuals of Basque origin migrated in large numbers to the Western USA in the second half of the nineteenth century, and the flow continued with less intensity during the last century. The European source population, that of the Basque Country, has long been a cultural and geographical isolate. Previous studies have demonstrated that Y-STR frequencies of Basques are different from those of other Spanish and European populations [1]. The Basque diaspora in the Western USA is a recent migration, but the founder effect and the incorporation of new American Y chromosomes into the paternal genetic pool of the Basque diaspora could have influenced its genetic structure and could thus have practical implications for forensic genetics. To check for genetic substructure among the European source and Basque diaspora populations and determine the most suitable population database for the Basque diaspora in the Western USA, we have analysed the haplotype distribution of 17 Y-STRs in both populations. We have found that the Basque diaspora in the Western USA largely conserve the Y chromosome lineage characteristic of the autochthonous European Basque population with no statistically significant differences. This implies that a common 17 Y-STR Basque population database could be used to calculate identification or kinship parameters regardless of whether the Basque individuals are from the European Basque Country or from the Basque diaspora in the Western USA.

Acute Effects of Different Overspeed Loads with Motorized Towing System in Young Athletes: A Pilot Study.

Overspeed is a training method used to improve running speed, although its effects are not supported by consensual scientific evidence. The overspeed stimulus can be boosted by several methods, including motorized towing devices. Our objectives were to analyze the acute effects of three overspeed loads in young athletes and to select optimal loads for training periods. Eight young athletes (16.73 ± 1.69 years) performed one unassisted sprint and three assisted sprints, and kinematic and biomechanical data were compared. Significant increases (p < 0.05) in step velocity and step length were found with 2, 4, and 5.25 kg in maximum running speed, flight time and horizontal distance from the first contact to the vertical projection of the center of mass with 4 and 5.25 kg. Significant time decreases were found in 5 m flying sprint and contact time with 4 and 5.25 kg, and no significant changes were observed in step rate. The individually recommended loads would be between 3.47 ± 0.68% and 6.94 ± 1.35% body weight. Even having limitations, we can understand this work and its results as a pilot study to replicate the methodology and the use of new devices to more broadly investigate the effects of overspeed.

The maternal legacy of Basques in northern navarre: New insights into the mitochondrial DNA diversity of the Franco-Cantabrian area.

Autochthonous Basques are thought to be a trace from the human population contraction that occurred during the Last Glacial Maximum, based mainly on the salient frequencies and coalescence ages registered for haplogroups V, H1, and H3 of mitochondrial DNA in current Basque populations. However, variability of the maternal lineages still remains relatively unexplored in an important fraction of the Iberian Basque community. In this study, mitochondrial DNA diversity in Navarre (North Spain) was addressed for the first time. To that end, HVS-I and HVS-II sequences from 110 individuals were examined to identify the most relevant lineages, including analysis of coding region SNPs for the refinement of haplogroup assignment. We found a prominent frequency of subhaplogroup J1c (11.8%) in Navarre, coinciding with previous studies on Basques. Subhaplogroup H2a5, a putative autochthonous Basque lineage, was also observed in Navarre, pointing to a common origin of current Basque geographical groups. In contrast to other Basque subpopulations, comparative analyses at Iberian and European scales revealed a relevant frequency of subhaplogroup H3 (10.9%) and a frequency peak for U5b (15.5%) in Navarre. Furthermore, we observed low frequencies for maternal lineages HV0 and H1 in Navarre relative to other northern Iberian populations. All these findings might be indicative of intense genetic drift episodes generated by population fragmentation in the area of the Franco-Cantabrian refuge until recent times, which could have promoted genetic microdifferentiation between the different Basque subpopulations.

Genetic Variants and Hamstring Injury in Soccer: An Association and Validation Study.

PURPOSE: This study aimed to investigate the association of candidate single nucleotide polymorphisms (SNP) with noncontact hamstring muscle injuries in elite soccer players and to create and validate a model to assess the risk of hamstring injury. METHODS: A total of 107 elite male outfield players were prospectively followed for six seasons. Players were genotyped for 37 SNP previously investigated in relation to musculoskeletal injuries. The association of SNP, previous injury, age, level of play, position, and anthropometric data with 129 hamstring injuries (413 observations) was investigated in the discovery phase (2010-2015), and a multivariable Cox frailty model was created using forward selection. The model's discriminative ability was tested in the validation phase (2015-2016, 31 injuries, 98 observations) using Harrell's C index. RESULTS: Five SNP were found to be significantly associated with hamstring injury in a multivariable model: matrix metalloproteinase 3 rs679620 (A vs G, hazard ratio [HR] = 2.06, 95% confidence interval [CI] = 1.51-2.81), tenascin C rs2104772 (A vs T, HR = 1.65, 95% CI = 1.17-2.32), interleukin 6 rs1800795 (GG vs GC + CC, HR = 1.68, 95% CI = 1.11-2.53), nitric oxide synthase 3 rs1799983 (G vs T, HR = 1.35, 95% CI = 1.01-1.79), and hypoxia-inducible factor-1α rs11549465 (CC vs CT, HR = 2.08, 95% CI = 1.00-4.29). Age also entered the model (≥24 vs <24 yr, HR = 2.10, 95% CI = 1.29-3.42). The model showed acceptable discrimination in the discovery phase (C index = 0.74), but not in the validation phase (C index = 0.52). CONCLUSION: Genetic variants appear to be involved in the etiology of hamstring injuries but were not found to have predictive value by themselves. Further research, increasing the number of genetic variants and including environmental factors in complex multifactorial risk models, is necessary.

I-DNASE21 system: development and SWGDAM validation of a new STR 21-plex reaction.

I-DNASE21 is a new STR multiplex system that amplifies 21 STR autosomal loci, plus the amelogenin locus in one reaction. This system has been designed to analyze all the STR loci included in the Combined DNA Index System (CODIS), Interpol Standard Set of Loci (ISSL), Extended European Standard Set (ESS-Extended), UK National Criminal Intelligence DNA Database (NDNAD) and German Core loci (GCL). This manuscript presents the validation of the I-DNASE21 system according to the revised guidelines issued by the Scientific Working Group on DNA Analysis Methods (SWGDAM). The results of this validation, added to the extremely high discriminatory power showed, suggest that I-DNASE21 could be a potentially helpful tool for identification and kinship determination even in complex paternity cases.