Latest research in football - week 28 - 2020

As previous literature updates, I have performed a PubCrawler search looking for football articles in NCBI Medline (PubMed) and GenBank databases.

Following studies were retrieved for this week:

#1 Financial Awards and Their Effect on Football Players' Anxiety and Coping Skills
Reference: Front Psychol. 2020 Jun 10;11:1148. doi: 10.3389/fpsyg.2020.01148. eCollection 2020.
Authors: Adriana Kaplánová
Summary: Financial awards can be an important factor affecting athletes' mental preparation and various skills to manage stress. Since such a link has not yet been studied, the study has been designed to evaluate the moderation effect of financial awards in relation to football players' anxiety and coping skills. The study consists of 110 male football players aged 18-32 years old (mean ± SD: 23.98 ± 3.01 years) who were divided into two groups: financial awarded (n = 48) and financial unawarded for sports performance (n = 62). The anxiety of football players was measured by the Sport Anxiety Scale SAS-2. Coping strategies to manage stress were assessed by the Athletic Coping Skills Inventory ACSI-28. The effect of financial awards in relation to football players' anxiety and coping skills was evaluated by the mediators' model using the PROCESS software (Hayes, 2018). The results suggest that financial awards are important factors that influence football players' anxiety and coping skills. The financial awards increase the motivation of football players to better prepare for sports performance, which has been proven, through better setting of performance goals and more careful mental preparation. Financially awarded football players seem to respect the coach and follow his instructions to a greater extent than unawarded football players, which may be due to the financial benefits and the commitment they have confirmed by signing to the football club. In another aspect, the financial awards are likely to increase the cognitive trait of the anxiety of football players. It seems that financial players are more concerned about the failure of the match, which increases their anxiety, especially since it is a cognitive part and affects their sports performance. For this reason, we encourage sports organizations to focus more on the mental preparation of football players. It is important to provide football players the opportunity to graduate from short- or long-term mental training conducted by a trained sports psychologist not only at the time of the athlete's failure but also as a preventive measure against increasing cognitive anxiety. We recommend sports organizations to train coaches in the field of mental training, preferably through annual short training sessions with a sports psychologist, to influence the development of desirable athletes' coping skills.

#2 Effect of Weekly Training Frequency With the Nordic Hamstring Exercise on Muscle-Strain Risk Factors in Football Players: A Randomized Trial
Reference: Int J Sports Physiol Perform. 2020 Jun 24;1-8. doi: 10.1123/ijspp.2018-0780. Online ahead of print.
Authors: Thales M Medeiros, João B Ribeiro-Alvares, Carolina G Fritsch, Gabriel S Oliveira, Lucas Severo-Silveira, Evangelos Pappas, Bruno M Baroni
Summary: The purpose was to examine the differences between performing Nordic hamstring exercises once or twice a week on hamstring eccentric strength and other muscle-strain risk factors in high-level football players. In this randomized trial, 32 football players (18-23 y old) completed an 8-week Nordic hamstring exercise training program in 1 of 2 experimental groups: group 1 (once a week; n = 15) and group 2 (twice a week; n = 17). Knee-flexor/extensor peak torques and biceps femoris long-head muscle architecture were assessed through isokinetic dynamometry and ultrasonography, respectively, before and after the training programs. Analysis of covariance, effect sizes (ESs), and t tests for percentage change were used to assess the effect of the 2 interventions on the outcome measures. Group 2 demonstrated higher hamstring concentric peak torque than group 1 posttraining (155-164 vs 149-158 N·m; P = .043; ES = 0.27), although there was also a statistical trend for higher hamstring eccentric peak torque (212-234 vs 198-221 N·m; P = .098; ES = 0.37), hamstring-to-quadriceps conventional ratio (0.56-0.59 vs 0.54-0.57; P = .089; ES = 0.31), and hamstring-to-quadriceps functional ratio (0.76-0.84 vs 0.71-0.79; P = .076; ES = 0.50). No between-groups differences were found for muscle thickness (P = .864; ES = 0.12), pennation angle (P = .289; ES = 0.18), fascicle length (P = .406; ES = 0.03), and quadriceps concentric peak torque (P = .340; ES = 0.02). Only the Nordic hamstring exercise training program performed twice a week strengthened the hamstrings of high-level football players, while similar changes in muscle architecture occurred with both once- and twice-weekly sessions.

#3 Football Can Tackle Type 2 Diabetes: A Systematic Review of the Health Effects of Recreational Football Practice in Individuals With Prediabetes and Type 2 Diabetes
Reference: Res Sports Med. 2020 Jun 22;1-19. doi: 10.1080/15438627.2020.1777417. Online ahead of print.
Authors: Ana Barbosa, João Brito , Pedro Figueiredo, André Seabra, Romeu Mendes
Summary: This work aimed to summarize the health effects of recreational football practice in individuals with prediabetes and type 2 diabetes (T2D), through a systematic review. An electronic search was performed in PubMed, Scopus, Web of Science, LILACS and list of references of the available reviews, until July 2019. Studies were eligible if they included any form of football practice, in patients diagnosed with prediabetes or T2D. After recreational football practice, participants with prediabetes or T2D improved fasting glucose, total and LDL cholesterol, triglycerides, body mass, body fat percentage, waist circumference, blood pressure, and maximal oxygen uptake. Further benefits were found in fat-free mass and resting heart rate for participants with prediabetes, and in glycated haemoglobin, body mass index and fat mass in individuals with T2D. This systematic review showed promising benefits of recreational football practice on both the prevention and control of T2D and related cardiovascular risk.

#4 Ankle Osteoarthritis and Its Association With Severe Ankle Injuries, Ankle Surgeries and Health-Related Quality of Life in Recently Retired Professional Male Football and Rugby Players: A Cross-Sectional Observational Study
Reference: BMJ Open. 2020 Jun 21;10(6):e036775. doi: 10.1136/bmjopen-2020-036775.
Authors: Liam D A Paget, Haruhito Aoki, Simon Kemp, Mike Lambert, Clint Readhead, Keith A Stokes, Wayne Viljoen, Gustaaf Reurink, Johannes L Tol, Gino M M J Kerkhoffs, Vincent Gouttebarge
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Summary: The objective was to determine (1) the prevalence of ankle osteoarthritis (OA) among former professional football and rugby players, (2) assess the association between ankle injuries or ankle surgeries with ankle OA, and (3) compare the mental and physical quality of life (QoL) between former professional football and rugby players with and without OA. We conducted a questionnaire-based observational study with a cross-sectional design. Former professional football and rugby players were recruited by the Football Players Worldwide and the International Rugby Players. Information concerning ankle OA, sustained ankle injuries and ankle surgeries was gathered (medical record or most recent medical professional). Health-related QoL was assessed using the Patient-Reported Outcomes Measurement Information System (PROMIS) physical and mental health scores. Overall, 553 former professional football (n=401) and rugby (n=152) players were enrolled in the study (response rate of 56%). Ankle OA prevalence among former professional football and rugby players was 9.2% and 4.6%, respectively. Football players were more likely to suffer from ankle OA following every ankle injury and/or surgery. Football and rugby players with ankle OA had similar PROMIS physical and mental health scores to the norm for the general population. Former professional football and rugby players had higher ankle OA prevalence than the general population (3.4%). Football players are more likely to suffer from ankle OA following every ankle injury and/or surgery. No clinically relevant difference was seen for physical or mental health-related QoL among football and rugby players. Preventive measures for ankle injuries are recommended.

#5 Medial Epicondyle Avulsion After Elbow Dislocation in an Adolescent Non-Professional Soccer Player Treated With a Cannulated Screw: A Case Report
Reference: Acta Biomed. 2020 May 30;91(4-S):271-275. doi: 10.23750/abm.v91i4-S.9578.
Authors: Alessio Pedrazzini, Alberto Visigalli, Piergiulio Valenti, Nicola Bertoni, Henry Yewo Simo, Roberto Bisaschi, Vanni Medina, Bianca Pedrabissi, Francesco Ceccarelli, Francesco Pogliacomi
Summary: Medial epicondyle fractures of the humerus account for 11-20% of all elbow injuries in children and in 30-55% of cases they are associated with an elbow dislocation. Undisplaced fractures are usually treated conservatively but literature is controversial regarding the treatment of displaced fractures (≥5mm) in paediatric fractures. In recent years, there is an emerging consensus that such patients may benefit more from open reduction and internal fixation. Authors report a case of a 15 years old nonprofessional soccer player who suffered of an elbow dislocation with an intra-articular fragment derived from avulsion of the medial epicondyle. Clinical and instrumental evaluation confirmed elbow dislocation with an intra-articular fragment derived of the medial epicondyle. After the reduction an open reduction and internal fixation with cannulated screw was performed. Clinical evaluation after 90 days showed resolution of pain and almost complete ROM and complete recovery of strength and of functionality of the operated limb. Furthermore, x-rays demonstrated consolidation of the fracture. this case confirms that a precise evaluation of the fracture and its displacement is at the base of satisfactory outcomes. If fracture is displaced≥5mm and patient is near skeletal maturity open reduction and fixation is indicated.

#6 Long-term Test-Retest Evaluation of the King-Devick Test in Youth Soccer Athletes
Reference: J Neurol Sci. 2020 Jun 6;416:116951. doi: 10.1016/j.jns.2020.116951. Online ahead of print.
Authors: Abigail C Bretzin, Morgan Anderson, Ryan N Moran, Tracey Covassin
Summary: Despite the clinical utility of baseline comparisons during concussion assessments, little evidence exists on long-term test-retest reliability of baseline tests in youth athletes. In addition, sex differences in baseline performance are inconsistent in youth athletes, warranting further research. The purpose was to examine sex differences, prevalence of false-positive scores, and long-term test-retest reliability of the King-Devick (KD) test. Healthy youth athletes (23 males, 28 females) completed the KD test prior to the Spring 2016 and Fall 2017 seasons. Two-way random-effects intraclass correlation coefficients (ICCs) were utilized to determine test-retest reliability. A mixed between-within ANOVA with post-hoc t-tests were used to identify the interaction between sex and season, and frequencies were used to determine abnormal test score prevalence. The KD test demonstrated good test-retest reliability (0.77[95% CI, 0.43-0.89]), with 11.8% of youth athletes having clinically meaningful improvements between Season 1 to Season 2. There was a significant sex*season interaction (F(1,49) = 4.67, p = .04), with significantly greater improvements between seasons in male youth athletes compared to female youth athletes. However, 33-35% of youth athletes displayed abnormal test scores in Season 2 relative to Season 1. The KD test demonstrated good reliability and only a small percentage had clinically meaningful changes, however a high prevalence of false-positive scores were observed in this sample.

#7 Match Demands of Women's Collegiate Soccer
Reference: Sports (Basel). 2020 Jun 12;8(6):E87. doi: 10.3390/sports8060087.
Authors: Andrew R Jagim, Jason Murphy, Alexis Q Schaefer, Andrew T Askow, Joel A Luedke, Jacob L Erickson, Margaret T Jones
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Summary: Research describing the match and specific positional demands during match play in women's collegiate soccer is limited. The purpose of the study was to quantify the match demands of National Collegiate Athletic Association (NCAA) Division III soccer and assess position differences in movement kinematics, heart rate (HR), and energy expenditure. Twenty-five Division III women soccer players (height: 1.61 ± 0.3 m; body mass: 66.7 ± 7.5 kg; fat-free mass: 50.3 ± 6.5 kg; body fat%: 25.6 ± 5.1%) were equipped with a wearable global positioning system to assess the demands of 22 matches throughout a season. Players were categorized by position (goal keepers (GK), center defenders (CB), flank players (FP), forwards (F), and center midfielders (CM)). Players covered 9807 ± 2588 m and 1019 ± 552 m at high speeds (>249.6 m·m-1), with an overall average speed of 62.85 ± 14.7 m·m-1. This resulted in a mean HR of 74.2 ± 6% HR max and energy expenditure of 1259 ± 309 kcal. Significant and meaningful differences in movement kinematics were observed across position groups. CM covered the most distance resulting in the highest training load. FP covered the most distance at high speeds and mean HR values were highest in CM, CB, and FP positions.

#8 Predicting the Timing of the Peak of the Pubertal Growth Spurt in Elite Youth Soccer Players: Evaluation of Methods
Reference: Ann Hum Biol. 2020 Jun 16;1-23. doi: 10.1080/03014460.2020.1782989. Online ahead of print.
Authors: James Parr, Keith Winwood, Emma Hodson-Tole, Frederik J A Deconinck, Les Parry, James P Hill , Robert M Malina, Sean P Cumming
Summary: Three commonly used non-invasive protocols are implemented to estimate the timing at which PHV most likely occurs. Accurate estimation of circumpubertal years can aid in managing training load of adolescent athletes. Three protocols were compared against observed age at PHV: an estimate of 13.8 ± 1.0 years - generic age at PHV (from longitudinal measures); an estimate based on the maturity offset equation, predicted age at PHV ±1.0 year; a window of PHV based on 85 - 96% of predicted adult height at time of observation. A final sample of 23 (from 28) adolescent participants who were selected from the academy of an English Premier League club. Anthropometric measures were collected across five playing seasons; age at PHV was estimated with Super-Imposition by Translation and Rotation (SITAR). The three protocols were compared based on measures at 13.0 years. An age window based on predicted maturity offset did not improve estimation of PHV compared to generic age method; however, the percentage of predicted adult height window showed improvement in performance shown by the following results. Predicted age at PHV correctly assigned 15 participants (65%) as experiencing PHV, while the percentage height correctly assigned 17 participants (74%). Generic age and predicted age at PHV correctly predicted observed age at PHV for 14 participants (61%), percentage of adult height window correctly predicted 22 participants (96%).

#9 Psychosocial Outcomes Associated With Soccer Academy Involvement: Longitudinal Comparisons Against Aged Matched School Pupils
Reference: J Sports Sci. 2020 Jun 16;1-12. doi: 10.1080/02640414.2020.1778354. Online ahead of print.
Authors: Fieke Rongen, Jim McKenna, Stephen Cobley, Jason Cameron Tee, Kevin Till
Summary: Despite literature highlighting numerous risks to the healthy psychosocial development of youth elite academy soccer players, little of this research is based on high-quality research designs. This study employed a prospective longitudinal cohort design to track psychosocial outcomes of academy involvement within male youth elite soccer players (n = 33, U12-U16 age groups) compared to age-matched soccer-active school pupils (n = 44) over 12 months. Participants completed questionnaires assessing the most commonly raised psychosocial concerns at four equally spaced data collection periods (T1-T4). Repeated measures multivariate analysis of variance (MANOVAs) indicated that, over the year, both groups reported a healthy and improving stress and recovery balance, as well as positive and stable needs satisfaction and physical, psychological and social well-being. Academy players reported stable positive school-related quality of life, whereas school pupils reported increases from T3 to T4. Academy players reported consistent significantly higher total athletic identity and exclusivity of identity. Findings suggest that many concerns around negative psychosocial impacts of soccer academy involvement did not materialise in this context. However, heightened athletic identities remained a concern

#10 A Comparison of Bilateral vs. Unilateral-Biased Strength and Power Training Interventions on Measures of Physical Performance in Elite Youth Soccer Players
Reference: J Strength Cond Res. 2020 Jun 10. doi: 10.1519/JSC.0000000000003659. Online ahead of print.
Authors: Darren Stern, Oliver Gonzalo-Skok, Irineu Loturco, Anthony Turner, Chris Bishop
Summary: The aim of the present study was to compare the effects of bilateral and unilateral-biased strength and power training programs on measures of physical performance in male youth soccer players. Twenty-three elite youth players (age: 17.6 ± 1.2 years) were randomly assigned to either a unilateral (n = 11) or a bilateral (n = 12) group, who completed a strength and power intervention, twice per week for 6 weeks. The unilateral group completed rear foot elevated split squats (RFESS), single-leg countermovement jumps (SLCMJs), single-leg drop jumps (SLDJs), and single-leg broad jumps (SLBJs). The bilateral group intervention performed back squats, CMJs, drop jumps (DJ), and broad jumps (BJ). A 2 × 2 repeated measures analysis of variance showed no between-group differences. However, within-group differences were evident. The bilateral training group showed significant (p < 0.05) improvements in back squat strength (d = 1.27; %Δ = 26.01), RFESS strength (d = 1.64; %Δ = 23.34), BJ (d = 0.76; %Δ = 5.12), 10-m (d = -1.17; %Δ = 4.29), and 30-m (d = -0.88; %Δ = 2.10) performance. The unilateral group showed significant (p < 0.05) improvements in RFESS strength (d = 1.40; %Δ = 33.29), SLCMJ on the left leg (d = 0.76; %Δ = 9.84), SLBJ on the left leg (d = 0.97; %Δ = 6.50), 10 m (d = -1.50; %Δ = 5.20), and 505 on the right leg (d = -0.78; %Δ = 2.80). Standardized mean differences showed that bilateral training favored improvements in back squat strength and unilateral training favored improvements in RFESS strength, SLDJ on the right leg and 505 on the right leg. These results show that although both training interventions demonstrated trivial-to-large improvements in physical performance, the notion of training specificity was evident with unilateral training showing greater improvements in unilateral test measures.

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