Factors Affecting Submaximal Running Economy in Children

The research conducted in this study has helped to clarify a number of important methodological and physiological questions in submaximal paediatric exercise physiology. The work was sub-divided into three major sections: methodological aspects of measuring submaximal running economy, factors affecting submaximal running economy and possible methods of manipulation of submaximal running economy

Facilitators and barriers associated with youth player transition to professional first team football:a key stakeholder perspective

The transition of elite youth footballers through academy systems towards the first team is highly complex, competitive, and often unsuccessful. A myriad of factors including technical competence, physical prowess, and the development environment combine to determine youth player progression. Current research has focused on broad investigations of multiple clubs and stakeholders, providing a valuable overview of the key aspects associated with elite youth player transition. This study aimed to provide an in-depth, context-specific investigation of key stakeholders within an elite level club in the United Kingdom (UK). Seven key stakeholders including the head of the academy (n = 1), the head of sports science (n = 1), coaches (n = 3), and lead sports scientists (n = 2) were recruited. Framework analysis led to the development of a practical framework outlining the key facilitators and barriers of youth-to-first-team transition. Facilitators of transition included overcoming adversity, high-level physical prowess, exceptional technical competence, and possessing at least one elite-level attribute. Barriers to transition included a lack of opportunity, lucrative youth player contracts and a lack of development-specific coaching. In addition, the developmental environment and developing individuals within a team environment were key influences on youth-to-first-team transition. This study complements recent broad investigations of the UK and global stakeholders by corroborating many of their findings while providing transferable, context-specific accounts of applied issues related to successful transition to first-team football

Decision-making accuracy of soccer referees in relation to markers of internal and external load

This study examined the relationships between the decision-making performances of soccer referees and markers of physiological load. Following baseline measurements and habituation procedures, 13 national-level male referees completed a novel Soccer Referee Simulation whilst simultaneously adjudicating on a series of video-based decision-making clips. The correctness of each decision was assessed in relation to the mean heart rate (HR), respiratory rate (RR), minute ventilation (VE), perceptions of breathlessness (RPE-B) and local muscular (RPE-M) exertion and running speeds recorded in the 10-s and 60-s preceding decisions. There was a significant association between decision-making accuracy and the mean HR (p = 0.042; VC = 0.272) and RR (p = 0.024, VC = 0.239) in the 10-s preceding decisions, with significantly more errors observed when HR ≥ 90% of HRmax (OR, 5.39) and RR ≥ 80% of RRpeak (OR, 3.34). Decision-making accuracy was also significantly associated with the mean running speeds performed in the 10-s (p = 0.003; VC = 0.320) and 60-s (p = 0.016; VC = 0.253) preceding decisions, with workloads of ≥250 m·min−1 associated with an increased occurrence of decisional errors (OR, 3.84). Finally, there was a significant association between decision-making accuracy and RPE-B (p = 0.021; VC = 0.287), with a disproportionate number of errors occurring when RPE-B was rated as “very strong” to “maximal” (OR, 7.19). Collectively, the current data offer novel insights into the detrimental effects that high workloads may have upon the decision-making performances of soccer referees. Such information may be useful in designing combined physical and decision-making training programmes that prepare soccer referees for the periods of match play that prove most problematic to their decision-making

“He’s Just a Wee Laddie”: The Relative Age Effect in Male Scottish Soccer

Significant structural, developmental, and financial constraints exist in Scottish soccer that may predicate a different approach to talent identification and development. To our knowledge, no published reports exist evaluating the prevalence of the relative age effect (RAE) in Scottish soccer players. Consequently, the aim of this study was to investigate the prevalence of the RAE among varied playing levels and ages of male Scottish youth soccer players. Birthdates of male youth players (n = 1,230) from U10 to U17 age groups and from playing levels: “Amateur” (n = 482), “Development” (n = 214), and “Performance” (n = 534), alongside a group of male Scottish senior professional players (n = 261) were recorded and categorized into quartiles (Q1 = January–March; Q2 = April–June; Q3 = July–September; and Q4 = October–December) and semesters (S1 = January–June and S2 = July–December) from the start of the selection year. Birthdates were analyzed for: (a) each playing level and (b) each age group irrespective of playing level. For the varied playing levels examined, an RAE was evident in “Development” and “Performance” playing levels only at youth level. When examining each age group, an RAE was observed in U12–U17 players only. While there was a slight asymmetry favoring Q1 born senior professional players, the RAE was not present within this group of our sample. Results from our study suggest that a bias in selecting individuals born earlier in the selection year may exist within male soccer academy structures, but not at amateur level. The asymmetry favoring chronologically older players at youth but not professional level questions the efficacy of this (un)conscious bias within male Scottish soccer players

Selected, Deselected, and Reselected: A Case Study Analysis of Attributes Associated With Player Reselection Following Closure of a Youth Soccer Academy

Considering the perceived benefit of early recruitment and the time and resources spent developing youth players, individuals released from talent development programmes are often re-recruited by rival academies. However, due to the contractual nature of many talent development programmes, limited empirical data exists on players deselected from (or reselected to) youth soccer academies. Adopting a novel case study approach, differences in skill, psychological, and physical attributes associated with reselection following closure of a junior-elite soccer academy were explored. Overall subjective coach ratings for skill, psychological, and physical abilities; subjective coach ratings for skill and psychological attributes; and physical fitness test performance of 79 junior-elite soccer players (U11–U17) were assessed as part of regular scheduled testing and monitoring practices prior to the academy closure. Reselection status was monitored and recorded for all players in the 6 months following the academy closure and was classified as a persistence/progression (“Reselected”) or attrition (“Deselected”) in playing level. Of the 79 released players, a total of 60 players (76%) were re-signed to a junior-elite academy within 6 months. Differences were observed for overall ratings of skill, psychological, and physical abilities in favor of the “Reselected” player group. “Reselected” players were also rated higher by coaches for all attributes categorized as skill and psychological, as well as performing better at all physical fitness tests. However, “Reselected” players were lesser in stature and body mass and less mature than “Deselected” players. Our findings suggest that reselection is not a product of anthropometric criteria and, therefore, a pathway for selection remains open for later maturing players. We also inform upon desirable qualities associated with player reselection and provide a case study approach of a unique, yet highly relevant, scenario for talent identification and development in youth soccer

Reliability, familiarization effect, and comparisons between a predetermined and a self-determined isometric-squat testing protocol

Purpose: This study examined the interday reliability of a predetermined and a self-determined isometric-squat test among youth soccer players. Familiarization effects were evaluated to determine the minimum number of trials necessary to obtain consistent outputs. Finally, differences between protocols were evaluated.Methods: Thirty-one youth soccer players (mean [SD] age: 13.2 [1.0] y; body mass: 54.1 [3.4] kg; stature: 166.3 [11.2] cm; percentage of estimated adult height: 92.6% [3.6%]) from a top-tier professional academy completed 4 experimental sessions for each protocol: familiarization 1, familiarization 2, test, and retest sessions. Peak force; relative peak force; impulse from 0 to 50 milliseconds, 0 to 100 milliseconds, 0 to 150 milliseconds, and 0 to 200 milliseconds; and rate of force development from 0 to 50 milliseconds, 0 to 100 milliseconds, 0 to 150 milliseconds, and 0 to 200 milliseconds were measured. Results: Both protocols displayed acceptable (intraclass correlation coefficient >=.75 and coefficient of variation ≤10%) reliability statistics for all metrics apart from rate of force development of any time epoch. Differences were found between familiarization 2 and both test and retest sessions for peak force (P = .034 and .021, respectively) and relative peak force (P = .035 and .005, respectively) across both protocols. Conclusions: The isometric-squat test is a reliable test among youth soccer players. Two familiarization sessions seem to be sufficient to ensure data stabilization. Outputs between the self-determined and predetermined are comparable; however, the latter seems preferable due to improved testing time efficiency

The effect of long-term soccer training on left ventricular structure and function in elite male youth soccer players

AimsCardiac adaptations in elite, male adolescent youth soccer players have been demonstrated in relation to training status. The time course of these adaptations and the delineation of the influence of volatile growth phases from the training effect on these adaptations remain unclear. Consequently, the aims of the study were to evaluate the impact of 3 years of elite-level soccer training on changes in left ventricular (LV) structure and function in a group of highly trained elite youth male soccer players (SP) as they transitioned through the pre-to-adolescent phase of their growth.MethodsTwenty-two male youth SP from the highest Level of English Premier League Academy U-12 teams were evaluated once a year for three soccer seasons as the players progressed from the U-12 to U-14 teams. Fifteen recreationally active control participants (CON) were also evaluated over the same 3-year period. Two-dimensional transthoracic echocardiography was used to quantify LV structure and function.ResultsAfter adjusting for the influence of growth and maturation, training-induced increases in Years 2 and 3 were noted for: LV end diastolic volume (LVEDV; p = 0.02) and LV end systolic volume (LVESV; p = 0.02) in the SP compared to CON. Training-induced decrements were noted for LV ejection fraction (LVEF; p = 0.006) and TDI-S′ (p < 0.001).ConclusionsAn increase in training volume (Years 2 and 3) were aligned with LV volumetric adaptations and decrements in systolic function in the SP that were independent from the influence of rapid somatic growth. Decrements in systolic function were suggestive of a functional reserve for exercise

Decision-making accuracy of soccer referees in relation to markers of internal and external load

Rosie Arthur - ORCID: 0000-0003-0651-4056 https://orcid.org/0000-0003-0651-4056Supplementary data for this paper is available at: https://eresearch.qmu.ac.uk/handle/20.500.12289/13683 .AM replaced with VoR 2024-03-18.This study examined the relationships between the decision-making performances of soccer referees and markers of physiological load. Following baseline measurements and habituation procedures, 13 national-level male referees completed a novel Soccer Referee Simulation (SRS) whilst simultaneously adjudicating on a series of video-based decision-making clips. The correctness of each decision was assessed in relation to the mean heart rate (HR), respiratory rate (RR), minute ventilation (V̇E), perceptions of breathlessness (RPE-B) and local muscular (RPE-M) exertion, and running speeds recorded in the 10-s and 60-s preceding decisions. There was a significant association between decision-making accuracy and the mean HR (P=0.042; VC=0.272) and RR (P=0.024, VC=0.239) in the 10-s preceding decisions, with significantly more errors observed when HR ≥90% of HRmax (OR, 5.39) and RR ≥80% of RRpeak (OR, 3.34). Decision-making accuracy was also significantly associated with the mean running speeds performed in the 10-s (P=0.003; VC=0.320) and 60-s (P=0.016; VC=0.253) preceding decisions, with workloads of ≥250 m·min-1 associated with an increased occurrence of decisional errors (OR, 3.84). Finally, there was a significant association between decision-making accuracy and RPE-B (P=0.021; VC=0.287), with a disproportionate number of errors occurring when RPE-B was rated as “very strong” to “maximal” (OR, 7.19). Collectively, the current data offer novel insights into the detrimental effects that high workloads may have upon the decision-making performances of soccer referees. Such information may be useful in designing combined physical and decision-making training programmes that prepare soccer referees for the periods of match play that prove most problematic to their decision-making.aheadofprintaheadofprin

Physiological Characteristics of Female Soccer Players and Health and Performance Considerations: A Narrative Review

From Springer Nature via Jisc Publications RouterHistory: accepted 2021-03-22, registration 2021-03-22, online 2021-04-12, pub-electronic 2021-04-12, pub-print 2021-07Publication status: PublishedAbstract: Female soccer has seen a substantial rise in participation, as well as increased financial support from governing bodies over the last decade. Thus, there is an onus on researchers and medical departments to develop a better understanding of the physical characteristics and demands, and the health and performance needs of female soccer players. In this review, we discuss the current research, as well as the knowledge gaps, of six major topics: physical demands, talent identification, body composition, injury risk and prevention, health and nutrition. Data on female talent identification are scarce, and future studies need to elucidate the influence of relative age and maturation selection across age groups. Regarding the physical demands, more research is needed on the pattern of high-intensity sprinting during matches and the contribution of soccer-specific movements. Injuries are not uncommon in female soccer players, but targeting intrinsically modifiable factors with injury prevention programmes can reduce injury rates. The anthropometric and physical characteristics of female players are heterogeneous and setting specific targets should be discouraged in youth and sub-elite players. Menstrual cycle phase may influence performance and injury risk; however, there are few studies in soccer players. Nutrition plays a critical role in health and performance and ensuring adequate energy intake remains a priority. Despite recent progress, there is considerably less research in female than male soccer players. Many gaps in our understanding of how best to develop and manage the health and performance of female soccer players remain

Oxygen uptake kinetics in trained adolescent females

Little evidence exists with regard to the effect that exercise training has upon oxygen uptake kinetics in adolescent females. PURPOSE: The aim of the study was to compare [Formula: see text] and muscle deoxygenation kinetics in a group of trained (Tr) and untrained (Utr) female adolescents. METHOD: Twelve trained (6.4 ± 0.9 years training, 10.3 ± 1.4 months per year training, 5.2 ± 2.0 h per week) adolescent female soccer players (age 14.6 ± 0.7 years) were compared to a group (n = 8) of recreationally active adolescent girls (age 15.1 ± 0.6 years) of similar maturity status. Subjects underwent two, 6-min exercise transitions at a workload equivalent to 80 % of lactate threshold from a 3-min baseline of 10 W. All subjects had a passive rest period of 1 h between each square-wave transition. Breath-by-breath oxygen uptake and muscle deoxygenation were measured throughout and were modelled via a mono-exponential decay with a delay relative to the start of exercise. RESULT: Peak [Formula: see text] was significantly (p < 0.05) greater in the Tr compared to the Utr (Tr: 43.2 ± 3.2 mL kg(-1 )min(-1) vs. Utr: 34.6 ± 4.0 mL kg(-1 )min(-1)). The [Formula: see text] time constant was significantly (p < 0.05) faster in the Tr compared to the Utr (Tr: 26.3 ± 6.9 s vs. Utr: 35.1 ± 11.5 s). There was no inter-group difference in the time constant for muscle deoxygenation kinetics (Tr: 8.5 ± 3.0 s vs. Utr: 12.4 ± 8.3 s); a large effect size, however, was demonstrated (-0.804). CONCLUSION: Exercise training and/or genetic self-selection results in faster kinetics in trained adolescent females. The faster [Formula: see text] kinetics seen in the trained group may result from enhanced muscle oxygen utilisation