Latest research in football - week 47 - 2019

#1 An Evaluation of Heart Rate Variability in Female Youth Soccer Players Following Soccer Heading: A Pilot Study
Reference: Sports (Basel). 2019 Nov 4;7(11). pii: E229. doi: 10.3390/sports7110229.
Authors: Harriss AB, Abbott K, Kimpinski K, Holmes JD, Johnson AM, Walton DM, Dickey JP
Download link: https://www.mdpi.com/2075-4663/7/11/229/pdf
Summary: Most head impacts in soccer occur from purposeful heading; however, the link between heading and neurological impairment is unknown. Previous work suggests concussion may result in an uncoupling between the autonomic nervous system and cardiovascular system. Accordingly, heart rate variability (HRV) may be a sensitive measure to provide meaningful information regarding repetitive heading in soccer. The purpose of this pilot study assesses the feasibility of measuring HRV to evaluate autonomic function following soccer heading. Sixteen youth female participants underwent heart rate monitoring during a heading and footing condition. Participants completed a five minute resting supine trial at the start and end of each testing session. Standard 450 g soccer balls were projected at 6 m/s towards participants. Participants performed five headers, for the header condition, and five footers for the footer condition. The HRV for resting supine trials, pre- and post-header and footer conditions were assessed for both time and frequency domains. HRV effect sizes were small when comparing conditions, except absolute low frequency (d = 0.61) and standard deviation of the normal-normal (NN) intervals (d = 0.63). Participant retention and adherence were high, without adverse events. Findings suggest HRV is a feasible measure for evaluating the effects of heading on autonomic function.


#2 Combined Anterolateral, Anterior, and Anteromedial Ankle Impingement in an Adolescent Soccer Player: A Case Report and Review of the Literature
Authors: Cosma DI, Vasilescu DE, Corbu A, Todor A, Valeanu M, Ulici A
Summary: A unique case of combined anterolateral, anterior, and anteromedial ankle impingement in an adolescent soccer player is presented in this article. To the best of our knowledge, this is the only report of circumferential, massive, anterior ankle impingement in children described in the literature. The importance of proper diagnosis and treatment of such a lesion is illustrated in this case report. We also emphasize that clinical examination combined with 3D computed tomography scan reconstruction is an excellent and cost-effective imaging modality that can help with the diagnosis of anterior ankle impingement. Finally, open surgical treatment showed excellent results in an elite athlete.


#3 Defining the Process of a Cardiovascular Risk Assessment Program: Lessons Learned From Cardiac Assessment of Elite Soccer Players in the United Kingdom
Reference: Clin J Sport Med. 2019 Nov;29(6):500-505. doi: 10.1097/JSM.0000000000000534.
Authors: Speers C, Seth AN, Patel KC, Rakhit DJ, Gillett MJ
Summary: Retrospectively analyze the cardiac assessment process for elite soccer players, and provide team physicians with a systematic guide to managing longitudinal cardiac risk. Cardiac assessments incorporating clinical examination, 12-lead ECG, echocardiography, and health questionnaire were utilized in this study.  Soccer players at 5 professional clubs in England, the United Kingdom participated. Data was retrospectively collected, inspected, and analyzed to determine their clinical management and subsequent follow-up. Over 2 years, 265 soccer players, aged 13 to 37 years with 66% of white European ethnicity, were included in the cohort. Eleven percent had "not-normal" assessments, of these assessments, 83% were considered gray screens, falling into three broad categories: structural cardiac features (including valvular abnormalities), functional cardiac features, and electrocardiogram changes. After cardiology consultation, all assessments were grouped into low, enhanced and high-risk categories for ongoing longitudinal risk management. Overall clear-cut pathology was identified in 2%. Cardiovascular assessment is a vital tool in identifying athletes at risk of sudden cardiac death to mitigate their risk through surveillance, intervention, or participation restriction. The decision whether a player is fit to play or not requires a robust risk assessment followed by input from a multidisciplinary team that includes both the team physician and cardiologist. This educational article proposes a clinical management pathway to aid clinicians with this process. Sudden cardiac death is the important medical cause of death during exercise. The team physician should assume responsibility for the management of the longitudinal risk of their players' cardiac assessments in conjunction with sports cardiologist.


#4 Effects of a Computerized Training on Attentional Capacity of Young Soccer Players
Reference: Front Psychol. 2019 Oct 21;10:2279. doi: 10.3389/fpsyg.2019.02279. eCollection 2019.
Authors: Reigal RE, González-Guirval F, Morillo-Baro JP, Morales-Sánchez V, Juárez-Ruiz de Mier R, Hernández-Mendo A
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6816454/pdf/fpsyg-10-02279.pdf
Summary: The purpose of this work was to analyze the effects of a computerized training on attentional capacity in a group of young soccer players. Seventy-five male adolescents from two soccer clubs in the city of Malaga (Spain) and aged between 14 and 18 (15.45 ± 1.43 years) participated in the investigation. A quasi-experimental design was used, and the adolescents were divided into control (n = 38) and experimental (n = 37) groups. The experimental group underwent a computerized training (Rejilla 1.0) of their attention during 9 weeks and 27 sessions. In addition, the D2 attention test was used to analyze the evolution of participants after the intervention program. The results showed positive effects of the computerized intervention program on selective attention, observing changes both in the executions of the software used (p < 0.001, Cohen's d = 1.58, 95% CI [1.06, 2.11]) and in the main measures of the D2 test, total effectiveness (p < 0.001, Cohen's d = 0.62, 95% CI [0.15, 1.08]) and concentration (p < 0.01, Cohen's d = 0.48, 95% CI [0.02, 0.94]).


#5 Growth pattern of lumbar bone mineral content and trunk muscles in adolescent male soccer players
Reference: J Bone Miner Metab. 2019 Nov 7. doi: 10.1007/s00774-019-01060-6. [Epub ahead of print]
Authors: Takei S, Taketomi S, Tanaka S, Torii S
Summary: Previous studies have reported that the peak in lean body mass (LBM) precedes the peak in bone mineral content (BMC). However, it is unknown whether the trunk region growth is similar. We investigated the difference between pubertal peak age in the increase of LBM in the trunk (trunk LBM) and pubertal peak age in the increase of BMC in the lumbar spine (lumbar BMC) in a longitudinal study of 201 Japanese male adolescent soccer players. The age of peak height velocity (PHV) and the developmental age were calculated. The participants were followed over a 2-year period, with height and dual-energy X-ray absorptiometry scans taken every 6 months. The trunk LBM (ρ = 0.732, p < 0.0001) and the lumbar BMC (ρ = 0.621, p < 0.0001) significantly correlated with the developmental age. The increase of trunk LBM and lumbar BMC was significantly different according to the developmental stages (Kruskal-Wallis test; p < 0.0001 and p < 0.001, respectively). We used a cubic spline to estimate the developmental age, when the increase reached its peak: the peak age of the increase in trunk LBM was estimated to be - 0.08 years (approximately - 1 month) prior to PHV age, whereas the peak age of the increase in lumbar BMC was estimated to be 0.42 years (approximately 5 months) after the PHV age. The maximal increase in trunk LBM occurs just before PHV age and approximately 6 months before the maximal increase in lumbar BMC during the pubertal growth spurt in the Japanese adolescent male soccer players.


#6 The impact of endurance training and table soccer on brain metabolites in schizophrenia
Reference: Brain Imaging Behav. 2019 Nov 5. doi: 10.1007/s11682-019-00198-1. [Epub ahead of print]
Authors: Rauchmann BS, Ghaseminejad F, Keeser D, Keller-Varady K, Schneider-Axmann T, Takahashi S, Karali T, Helms G, Dechent P, Maurus I, Hasan A, Wobrock T, Ertl-Wagner B, Schmitt A, Malchow B, Falkai P
Summary: Higher glutamate and glutamine (together: Glx) and lower N-acetyl-aspartate (NAA) levels were reported in schizophrenia. Endurance training normalizes NAA in the hippocampus, but its effects on other metabolites in the brain and the relationship of metabolites to clinical symptoms remain unknown. For 12 weeks, 20 schizophrenia inpatients (14 men, 6 women) and 23 healthy controls (16 men, 7 women) performed endurance training and a control group of 21 schizophrenia inpatients (15 men, 6 women) played table soccer. A computer-assisted cognitive performance training program was introduced after 6 weeks. We assessed cognitive performance, psychopathological symptoms, and everyday functioning at baseline and after 6 and 12 weeks and performed single voxel magnetic resonance spectroscopy of the hippocampus, left dorsolateral prefrontal cortex (DLPFC), and thalamus. We quantified NAA, Glx, total creatine (tCr), calculated NAA/tCr and Glx/tCr and correlated these ratios with physical fitness, clinical and neurocognitive scores, and everyday functioning. At baseline, in both schizophrenia groups NAA/tCr was lower in the left DLPFC and left hippocampus and Glx/tCr was lower in the hippocampus than in the healthy controls. After 6 weeks, NAA/tCr increased in the left DLPFC in both schizophrenia groups. Brain metabolites did not change significantly in the hippocampus or thalamus, but the correlation between NAA/tCr and Glx/tCr normalized in the left DLPFC. Global Assessment of Functioning improvements correlated with NAA/tCr changes in the left DLPFC. In our study, endurance training and table soccer induced normalization of brain metabolite ratios in the brain circuitry associated with neuronal and synaptic elements, including metabolites of the glutamatergic system.


#7 Maximal oxygen consumption and oxygen muscle saturation recovery following repeated anaerobic sprint test in youth soccer players
Reference: J Sports Med Phys Fitness. 2019 Oct 28. doi: 10.23736/S0022-4707.19.10162-4. [Epub ahead of print]
Authors: Michailidis Y, Chatzimagioglou A, Mikikis D, Ispirlidis I, Metaxas T
Summary: The purpose of the study was to examine whether differences in aerobic capacity (VO2max) influence muscle reoxygenation following repeated anaerobic sprint test (RAST) in soccer players. We hypothesized that muscle reoxygenation is faster in players with higher aerobic capacity. Ten male, youth soccer players participated in the study and performed RAST on a synthetic grass field. Oxygen saturation in muscle (StO2) of the right vastus lateralis muscle was measured by near-infrared spectroscopy. Half the time that was required for StO2 recovery (T1/2 StO2) after RAST was used to evaluate the reoxygenation in the recovery period after testing. The T1/2 StO2 was defined as the time from the end of RAST testing to the time of reaching 50% of StO2. Aerobic capacity (VO2max) was estimated by the Yo-Yo intermittent recovery test level 1 (YYIR1). The T1/2 StO2 had a significant inverse correlation with VO2max (r=-0.71; P=0.021) and with the distance which was covered by players on YYIR1 test (r=-0.71; P=0.021). In contrast, StO2 recovery rate showed no significant correlations with the VO2max in subjects. These results indicate that aerobic capacity can influence vastus lateralis reoxygenation following RAST in youth soccer players.


#8 Match Performance of Soccer Teams in the Chinese Super League-Effects of Situational and Environmental Factors
Reference: Int J Environ Res Public Health. 2019 Nov 1;16(21). pii: E4238. doi: 10.3390/ijerph16214238.
Authors: Zhou C, Hopkins WG, Mao W, Calvo AL, Liu H
Download link: https://www.mdpi.com/1660-4601/16/21/4238/pdf
Summary: The purpose of the study was to investigate the effects of situational factors (match location, strength of team and opponent) and environmental factors (relative air humidity, temperature and air quality index) on the technical and physical match performance of Chinese Soccer Super League teams (CSL). The generalized mixed modelling was employed to determine the effects by using the data of all 240 matches in the season 2015 collected by Amisco Pro®. Increase in the rank difference would increase the number of goal-scoring related, passing and organizing related actions to a small-to-moderate extent (Effect size [ES]: 0.37-0.99). Match location had small positive effects on goal-scoring related, passing and organizing related variables (ES: 0.27-0.51), while a small negative effect on yellow card (ES = -0.35). Increment in relative air humidity and air quality index would only bring trivial or small effects on all the technical performance (ES: -0.06-0.23). Increase in humidity would decrease the physical performance at a small magnitude (ES: -0.55--0.38). Teams achieved the highest number in the physical performance-related parameters at the temperature between 11.6 and 15.1 °C. In the CSL, situational variables had major effects on the technical performance but trivial effects on the physical performance, on the contrary, environmental factors affected mainly the physical performance but had only trivial or small impact on the technical performance.


#9 Psychological Intervention Program to Control Stress in Youth Soccer Players
Reference: Front Psychol. 2019 Oct 16;10:2260. doi: 10.3389/fpsyg.2019.02260. eCollection 2019.
Authors: Olmedilla A, Moreno-Fernández IM, Gómez-Espejo V, Robles-Palazón FJ, Verdú I, Ortega E
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6805695/pdf/fpsyg-10-02260.pdf
Summary: The influence on the psychological well-being of the players and their sports performance seems to be one of the keys to the current sports practice. The purpose of this study was to determine the effectiveness of a psychological intervention program for stress control in youth soccer players. A total sample of 19 male youth soccer players (age: 16.3 ± 0.99 years; years playing soccer: 10.89 ± 1.56 years) completed the current research. The Psychological Characteristics Questionnaire related to Sports Performance (CPRD) was used to assess stress factors related to sports competition. A program based on Cognitive-Behavioral Therapy was implemented during eight sessions of approximately 50 min each. A pre-post design was used and statistical differences between pre- and post-measures were checked through dependent sample t-tests. The results indicated that the post-test scores were higher than the pre-tests in "Influence of the Evaluation of Performance" and "Mental Skills" factors, which supposes a significant improvement of the stress management related to performance evaluation, as well as the use of psychological resources and techniques. In addition, the post-test scores were also higher in the "Stress Control" factor, although in this case the differences were not statistically significant. Practical indications deriving from the findings of this study can help youth soccer players to manage the stress of competition using a psychological training program.


#10 The effectiveness of a practical half-time re-warm-up strategy on performance and the physical response to soccer-specific activity
Reference: J Sports Sci. 2019 Nov 2:1-10. doi: 10.1080/02640414.2019.1686941. [Epub ahead of print]
Authors: Fashioni E, Langley B, Page RM
Summary: The aim of this study was to assess the influence of a half-time (HT) re-warm up (RWU) strategy on measures of performance and the physical and perceptual response to soccer-specific activity. Ten male soccer players completed a control (CON) and RWU trial, in which participants completed 60 min (4 x 15-min periods with a 15-min HT interspersing the third and fourth periods) of a soccer-specific exercise protocol. The CON trial comprised a passive 15-min HT, whilst the RWU trial comprised a passive 12-min period, followed by a 3-min RWU. The RWU elicited an improvement in 20 m sprint times (d= 0.6; CON: 3.42 ± 0.20 s; RWU: 3.32 ± 0.12 s), and both squat (d= 0.6; CON: 26.96 ± 5.00 cm; RWU: 30.17 ± 5.13 cm) and countermovement jump height (d= 0.7; CON: 28.15 ± 4.72 cm; RWU: 31.53 ± 5.43 cm) following the RWU and during the initial stages of the second half. No significant changes were identified for 5 m or 10 m sprint performance, perceived muscle soreness, or PlayerLoadTM. Ratings of perceived exertion were however higher (~2 a.u) following the RWU. These data support the use of a HT RWU intervention to elicit acute changes in performance.


#11 The adolescent motor performance development of elite female soccer players: A study of prognostic relevance for future success in adulthood using multilevel modelling
Reference: J Sports Sci. 2019 Nov 2:1-10. doi: 10.1080/02640414.2019.1686940. [Epub ahead of print]
Authors: Leyhr D, Raabe J, Schultz F, Kelava A, Höner O
Summary: Considering the scarce empirical evidence regarding talent predictors in female youth soccer, the present study aimed to investigate the long-term prognostic validity of elite female soccer players' adolescent motor performance for future success in adulthood. Additionally, the three-year development of highly talented girls' motor performance and the predictive value of this motor development for reaching a professional adult performance level (APL) was analysed.Overall, N = 737 female players participated in nationwide motor diagnostics (sprinting, agility, dribbling, ball control, shooting) within the German Soccer Association's talent identification and development programme at least twice between the age groups Under-12 (U12) and U15. Based on their APL at least four years later, participants were assigned to a professional (first German division, 6.2%) or non-professional group (lower divisions, 93.8%).Multilevel regression analyses revealed a general prognostic relevance for the investigated parameters with respect to players' APL. In addition, there was a non-linear improvement in participants' motor performance across all variables from U12 to U15. However, non-significant interactions between APL and these improvements indicate motor performance development itself cannot adequately predict players' future success in adulthood. Findings provide insightful information that can help coaches foster optimal support for young female soccer players' development.