Soccer is the most popular sport in the world and is performed by men and women, children and adults with different levels of expertise. Soccer performance depends upon a myriad of factors such as technical/biomechanical, tactical, mental and physiological areas. One of the reasons that soccer is so popular worldwide is that players may not need to have an extraordinary capacity within any of these performance areas, but possess a reasonable level within all areas. However, there are trends towards more systematic training and selection influencing the anthropometric profiles of players who compete at the highest level. As with other activities, soccer is not a science, but science may help improve performance. Efforts to improve soccer performance often focus on technique and tactics at the expense of physical fitness. During a 90-minute game, elite-level players run about 10 km at an average intensity close to the anaerobic threshold (80-90% of maximal heart rate). Within this endurance context, numerous explosive bursts of activity are required, including jumping, kicking, tackling, turning, sprinting, changing pace, and sustaining forceful contractions to maintain balance and control of the ball against defensive pressure. The best teams continue to increase their physical capacities, whilst the less well ranked have similar values as reported 30 years ago. Whether this is a result of fewer assessments and training resources, selling the best players, and/or knowledge of how to perform effective exercise training regimens in less well ranked teams, is not known. As there do exist teams from lower divisions with as high aerobic capacity as professional teams, the latter factor probably plays an important role. This article provides an update on the physiology of soccer players and referees, and relevant physiological tests. It also gives examples of effective strength- and endurance-training programmes to improve on-field performance. The cited literature has been accumulated by computer searching of relevant databases and a review of the authors' extensive files. From a total of 9893 papers covering topics discussed in this article, 843 were selected for closer scrutiny, excluding studies where information was redundant, insufficient or the experimental design was inadequate. In this article, 181 were selected and discussed. The information may have important implications for the safety and success of soccer players and hopefully it should be understood and acted upon by coaches and individual soccer players.

http://carlocapelli.it/ftp/didattica/master calcio/bibliografia_essenziale/stolen_et_al_2005.pdf

Physiology of Soccer: An Update

Exercise Metabolism and the Molecular Regulation of Skeletal Muscle Adaptation

Exercise Physiology: Energy, Nutrition and Human Performance

Global trends in insufficient physical activity among adolescents: a pooled analysis of 298 population-based surveys with 1·6 million participants.

An ever-growing volume of peer-reviewed publications speaks to the recent and rapid growth in both scope and understanding of exercise immunology. Indeed, more than 95% of all peer-reviewed publications in exercise immunology (currently >2, 200 publications using search terms "exercise" and "immune") have been published since the formation of the International Society of Exercise and Immunology (ISEI) in 1989 (ISI Web of Knowledge). We recognise the epidemiological distinction between the generic term "physical activity" and the specific category of "exercise", which implies activity for a specific purpose such as improvement of physical condition or competition. Extreme physical activity of any type may have implications for the immune system. However, because of its emotive component, exercise is likely to have a larger effect, and to date the great majority of our knowledge on this subject comes from exercise studies.

Position statement. Part one: Immune function and exercise.

© 2021 The Authors. Published by Springer. This is an open access article available under a Creative Commons licence. 
The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1007/s00421-021-04793-3

/pdf/bone-mineral-density-in-high-level-endurance-runners-part-a-26rhpdth69.pdf

Bone mineral density in high-level endurance runners: part A-site-specific characteristics.

Gene differences predisposing to atherosclerosis disease are important to identify and allow us to understand cellular processes involved in the progression and development of atherosclerotic disease. This protocol describes the experimental procedure for multiplex amplicon sequencing using barcoded primers. The procedures included in this chapter focus on amplicon library preparation (including polymerase chain reaction (PCR) conditions), DNA library quantitation options, next generation pyrosequencing with the 454 GS Junior system and data analysis. The process from DNA to sequencing data can be completed within 5 days.

Protocol for Multiplex Amplicon Sequencing Using Barcoded Primers

/pdf/draft-version-of-a-bases-position-stand-2s12b8prtp.pdf

Draft Version of a BASES Position Stand

Objectives The titin gene (TTN) encodes the largest described protein to date and, due to its size, provides a molecular blueprint for the organisation and assembly of the muscle sarcomere. Differences in sarcomere length, due to the expression of different titin isoforms, have been observed previously and may influence muscle fascicle length, which could provide an advantage for running performance. Thus, the aim of this study was to investigate if the TTN rs10497520 polymorphism was associated with muscle fascicle length in recreationally active men and marathon personal best time in elite male marathon runners, and to investigate any differences in genotype frequency between RA and MR. Methods The sample comprised 278 healthy, unrelated Caucasian men who all gave written consent to take part. Participants were categorised as either recreationally active [RA; n = 137; age = 20.7 (2.7) yr; height = 1.79 (0.06) m; mass = 75.3 (10.1) kg] or marathon runners [MR; n = 141; age = 34.9 (7.8) yr; height = 1.79 (0.07) m; mass = 66.5 (6.7) kg]. MR comprised Olympic, international and national level athletes, who had all achieved marathon personal best times under 2 hr 36 mins. Resting fascicle length of the vastus lateralis muscle was assessed in vivo using B-mode ultrasonography at 50% of muscle length in RA only. All participants provided either a whole blood, saliva or buccal cell sample, from which DNA was isolated and genotyped using real-time polymerase chain reaction. Independent samples t-tests were used to determine any genotype-dependent differences in fascicle length in RA and marathon personal best time in MR. Pearson’s chi-square tests were conducted to compare genotype frequencies between RA and MR. Results Vastus lateralis fascicle length was 10.4% longer in CC homozygotes than CT heterozygotes (P = 0.003) in RA. In the absence of any TT homozygotes, reflective of the low T-allele frequency within Caucasian populations, it is unclear if fascicle length for this group would have been smaller still. No differences in genotype frequency between the RA and MR groups were observed (P = 0.500), however, within the MR group the T-allele carriers demonstrated marathon personal best times 2 min 25 s faster than CC homozygotes (P = 0.020). Conclusions These results suggest that the T-allele at rs10497520 in the TTN gene is associated with shorter skeletal muscle fascicle length and conveys an advantage for marathon running performance in habitually trained men.

/pdf/titin-genotype-is-associated-with-skeletal-muscle-fascicle-j7ke81sx5w.pdf

Titin genotype is associated with skeletal muscle fascicle length in recreationally active men and running performance in habitually trained marathon runners

Alun G. Williams

Papers

Bone mineral density in high-level endurance runners: part A-site-specific characteristics.

Protocol for Multiplex Amplicon Sequencing Using Barcoded Primers

Draft Version of a BASES Position Stand

Titin genotype is associated with skeletal muscle fascicle length in recreationally active men and running performance in habitually trained marathon runners

union player status and playing position