Latest research in football - week 34 - 2022

#1 Cold Water Immersion Improves the Recovery of Both Central and Peripheral Fatigue Following Simulated Soccer Match-Play

Reference: Front Physiol. 2022 Aug 15;13:860709. doi: 10.3389/fphys.2022.860709. eCollection 2022.

Authors: Mustapha Bouchiba, Nicola Luigi Bragazzi, Slim Zarzissi, Mouna Turki, Firas Zghal, Mohamed Amine Grati, Wael Daab, Fatma Ayadi, Haithem Rebai, Hassen Ibn Hadj Amor, Thomas J Hureau, Mohamed Amine Bouzid

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9420968/pdf/fphys-13-860709.pdf

Summary: The present study aimed to investigate the effect of cold water immersion (CWI) on the recovery of neuromuscular fatigue following simulated soccer match-play. In a randomized design, twelve soccer players completed a 90-min simulated soccer match followed by either CWI or thermoneutral water immersion (TWI, sham condition). Before and after match (immediately after CWI/TWI through 72 h recovery), neuromuscular and performance assessments were performed. Maximal voluntary contraction (MVC) and twitch responses, delivered through electrical femoral nerve stimulation, were used to assess peripheral fatigue (quadriceps resting twitch force, Qtw,pot) and central fatigue (voluntary activation, VA). Performance was assessed via squat jump (SJ), countermovement jump (CMJ), and 20 m sprint tests. Biomarkers of muscle damages (creatine kinase, CK; Lactate dehydrogenase, LDH) were also collected. Smaller reductions in CWI than TWI were found in MVC (-9.9 ± 3%vs-23.7 ± 14.7%), VA (-3.7 ± 4.9%vs-15.4 ± 5.6%) and Qtw,pot (-15.7 ± 5.9% vs. -24.8 ± 9.5%) following post-match intervention (p < 0.05). On the other hand, smaller reductions in CWI than TWI were found only in Qtw,pot (-0.2 ± 7.7% vs. -8.8 ± 9.6%) at 72 h post-match. Afterwards, these parameters remained lower compared to baseline up to 48-72 h in TWI while they all recovered within 24 h in CWI. The 20 m sprint performance was less impaired in CWI than TWI (+11.1 ± 3.2% vs. +18 ± 3.6%, p < 0.05) while SJ and CMJ were not affected by the recovery strategy. Plasma LDH, yet no CK, were less increased during recovery in CWI compared to TWI. This study showed that CWI reduced both central and peripheral components of fatigue, which in turn led to earlier full recovery of the neuromuscular function and performance indices. Therefore, CWI might be an interesting recovery strategy for soccer players.

 

 

#2 Analysis of the most demanding passages of play in elite youth soccer: a comparison between congested and non-congested fixture schedules

Reference: Sci Med Footb. 2022 Aug 29;1-8. doi: 10.1080/24733938.2022.2117404. Online ahead of print.

Authors: Sergio L Jiménez, Nuno Mateus, Anthony Weldon, Álvaro Bustamante-Sánchez, Adam L Kelly, Jaime Sampaio

Summary: This study aimed to examine the most demanding passages of play in elite youth soccer for congested and non-congested fixture schedules. Seventeen elite youth male soccer players (18.2 ± 1.3 years old) participated in this study across 30 competitive matches. Assessed matches included congested (n = 12, three matches within eight consecutive days or less) and non-congested matches (n = 18, at least 5 days between matches). The players' activity profiles during matches were analysed using global positioning measurement units (GPS). Players activity included: distance covered, distance covered at different velocities, high-intensity accelerations and decelerations, and player load. The most demanding passages (MDP) of match play was calculated using a moving average method within three-time windows (i.e., 1, 5, and 10 min). Data were analysed using a Bayesian ANOVA. During congested fixtures, the players' distance covered and player load declined, with the former decreasing across all the MDP time windows, whereas the latter exclusively into the long-time windows (i.e., 5 and 10 min). Conversely, statistical differences in the remaining variables were anecdotal and in favour of the null hypothesis (i.e., Bayes factor <1), suggesting a non-influence of the competition fixture schedule. These findings provide insight into the MDP of youth soccer, helping practitioners to periodize training and recovery strategies during different competitive fixture schedules.

 

 

#3 Resumption of professional football league with spectators during the COVID-19 pandemic: The implementation of Bio-secure bubble protocol

Reference: Qatar Med J. 2022 Jul 26;2022(3):31. doi: 10.5339/qmj.2022.31. eCollection 2022.

Authors: Abdul Wahab Al Musleh, Naushad Ahmad Khan, Sameer Abdurahiman, Mohammad Asim, Ayman El-Menyar, Gordon Penney, Hassan Al-Thani

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9405165/pdf/qmj-2022-03-031.pdf

Summary: Elite professional sports events involving mass gatherings carry a high risk of viral transmission during the coronavirus disease of 2019 (COVID-19) pandemic. We describe the potential impact of resuming professional football leagues involving international participants adhering to a strict Bio-secure bubble protocol and investigate the consequences of spectators/fan attendance at such mass events during the ongoing COVID-19 pandemic in Qatar. We conducted a descriptive cohort study involving football players, referees, match officials, local organizing committee (LOC) members, hotel and security staff working in close coordination, and over 10,000 spectators from the Asian Football Confederation (AFC) Champions League (East) and the final match. The study covered almost four weeks of the event (November 19 to December 19, 2020) under a robust Bio-secure bubble protocol. It included extensive severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) RT-PCR (reverse transcription-polymerase chain reaction) every 3-6 days and clinical symptom monitoring on and off the field. Target variables included positive RT-PCR results and clinical symptom monitoring among participants, and rapid antigen testing for fan attendance to examine their safe return to the stadiums. A total of 12,250 RT-PCR tests involving 3158 individuals in the Bio-secure bubble were done over one month for all the AFC (East) matches, including the final match. Overall, 44 matches involving 16 teams were played. During the championship, only five individuals (three LOC members and two match officials) returned positive for COVID-19 infections. Four individuals (three team staff/officials and one person outside the Bio-secure bubble) had reactive results. None of the players tested positive for COVID-19 infection. All individuals testing positive were asymptomatic or had mild symptoms, with no one requiring hospitalization other than symptomatic treatment. The overall positivity rate was 0.15% for the entire duration of the AFC (East) Champions League. For the final match, a total of 10,320 rapid antigen tests were done for spectators, of which only one test was positive for COVID-19. This report shows a very low incidence rate of COVID-19 infections during mass gathering events at the international level. For the resumption of football with spectators, careful mitigation strategies should be considered to reduce the risk of transmission to a sufficiently safe level. This may require proper coordination and measures (i.e., physical distancing, testing, entry, and exit routes in the stadium, and seating arrangement inside the stadium with limited attendance). Based on this, during the ongoing COVID-19 pandemic, the supervised and controlled resumption of football matches with spectators can be done safely provided that a strict Bio-secure bubble protocol has been implemented.

 

 

#4 Influence Mechanism of the Home Advantage on Referees' Decision-Making in Modern Football Field - A Study From Sports Neuro-Decision Science

Reference: Front Psychol. 2022 Aug 11;13:873184. doi: 10.3389/fpsyg.2022.873184. eCollection 2022.

Authors: Li Zhang, Hongfei Zhang, Shaopeng Li, Jianlan Ding, Yuxiao Peng, Zeyuan Huang

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9407239/pdf/fpsyg-13-873184.pdf

Summary: As professional football stadiums continue to grow in popularity worldwide, fans are able to watch the game in closer proximity, but the design of professional football stadiums to shorten the distance between fans and the playing field also exacerbates the impact of the home advantage on the referee's decision to call a penalty. Studies have confirmed the existence of the home advantage and found that experienced referees can reduce the impact of this interference, but the neural mechanisms behind this phenomenon have not been adequately investigated. In this study, we designed a soccer referee decision making task based on a home field effect scenario in a real soccer game, and used event-related potentials (ERPs) to compare the decision making and EEG differences between individuals with different experience levels when faced with foul actions under spectator noise interference. The experiments showed that individuals with different experience levels triggered a significant ERN EEG component when performing the penalty decision task under the home field effect factor, suggesting that the interference of the home field effect may lead referees to correct their previous decision-making behavior patterns in the penalty decision and reduce unfavorable calls against the home team. In contrast, referees with officiating experience elicited smaller ERN amplitudes compared to other subjects, suggesting that experience factors may inhibit this tendency to change behavioral patterns. This study suggests that in response to the increasing trend of professional football stadiums, policy makers should place more emphasis on enhancing the experience level of referees in the training of referees to ensure the fairness of the game.

 

 

#5 Application of Image Processing Technology in the Diagnosis of Football Injury

Reference: Appl Bionics Biomech. 2022 Aug 5;2022:5926098. doi: 10.1155/2022/5926098. eCollection 2022.

Authors: Liyun Xu, Zhubo Xu

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9410979/pdf/ABB2022-5926098.pdf

Summary: With the hot development of football, sports injuries caused by football have also received special attention. In football games, although there are medical staff on and off the field always on call to protect the safety of players, because of the complexity of diagnosis work, medical staff can easily lead to diagnostic errors due to factors such as fatigue, which seriously affects the condition of athletes. Image processing is a technology that uses computer to process images, which can greatly overcome the uncertain factors brought by manual diagnosis. Based on this, this paper uses image processing technology and pattern recognition as technical means to explore the specific application of image processing in football injury diagnosis. This paper firstly takes football clubs as the main research object and analyzes and explores the specific utility of image segmentation and feature recognition in sports injury image processing. Then, starting from the relevant image features, the paper analyzes and compares the sensitivity of support vector machine pattern recognition and neural network pattern recognition in football injury diagnosis. This article comprehensively summarizes the application of image processing technology in the diagnosis of football injuries and puts forward constructive suggestions for its subsequent development. Experiments show that the effect of pattern recognition is often different for different injury parts of football. Among them, the sensitivity of pattern recognition based on image processing can reach 68.9%, and the detection rate of football injuries can also be maintained at about 81.2%. This fully shows that image processing technology can play an active role in the actual football injury diagnosis, and provide very valuable information for clinical diagnosis.

 

 

#6 Rate of torque development as a discriminator of playing level in collegiate female soccer players

Reference: J Musculoskelet Neuronal Interact. 2022 Sep 1;22(3):326-335.

Authors: Ty B Palmer, Kazuma Akehi

Download link: https://www.ismni.org/jmni/pdf/89/jmni_22_326.pdf

Summary: This study aimed to examine the efficacy of isometric knee extension and flexion peak torque and rate of torque development (RTD) variables to distinguish starters from non-starters in collegiate female soccer players. Eleven starters (20±2 years) and 13 non-starters (19±1 years) performed three isometric maximal voluntary contractions of the knee extensors and flexors. Peak torque, peak RTD, and RTD at 0-100 (RTD100) and 0-200 (RTD200) ms were obtained from each contraction. The starters produced significantly greater (P=0.002-0.015) knee extension and flexion peak RTD, RTD100, and RTD200 values than the non-starters. There were no significant differences (P>0.050) between the starters and non-starters for peak torque. Discriminant analysis revealed thresholds of 9.36, 7.98, and 6.97 Nm⋅s-1⋅kg-1 for knee extension RTD200 and knee flexion peak RTD and RTD100, respectively. These thresholds showed 81.8% sensitivity and 76.9 to 92.3% specificity for identifying playing group membership. Our findings indicate that RTD may be a better parameter than peak torque at differentiating between playing level in collegiate female soccer players. The discriminant analysis thresholds for the RTD variables demonstrated good sensitivity and specificity, and therefore, may be used as indices to identify players with a high degree of soccer playing ability.

 

 

#7 MAN v FAT Soccer: Feasibility Study and Preliminary Efficacy of a Sport-Based Weight-Loss Intervention for Overweight and Obese Men in Australia

Reference: J Sport Exerc Psychol. 2022 Aug 30;1-11. doi: 10.1123/jsep.2021-0165. Online ahead of print.

Authors: Timothy Budden, James A Dimmock, Michael Rosenberg, Mark R Beauchamp, Ian Fitzpatrick, Ben Jackson

Summary: MAN v FAT Soccer is a sport-based weight-loss program for overweight and obese men that originated in the United Kingdom (i.e., as MAN v FAT Football) and appears to successfully engage men with weight loss. We sought to explore whether the program would work in an Australian context by (a) establishing a foundation for the implementation of the program on a larger scale and (b) determining how large-scale implementation is most feasible. We conducted a nonrandomized, single intervention group feasibility trial of MAN v FAT Soccer in Australia with 418 male participants with a body mass index greater than 27.50 kg/m2. Results indicate that the program is acceptable, with participants reporting positive perceptions of the various components of the program and a high proportion reporting intentions to recommend the program to others (95.9%). Furthermore, preliminary effectiveness results indicate positive changes in weight (4.6% reduction) and physical activity (88.5% increase) and improvements in psychological outcomes such as depression (17.6% decrease), stress (19.0% decrease), and body appreciation (19.1% increase). Our findings provide general support for the feasibility of MAN v FAT Soccer and the notion that leveraging competition and masculinity may help drive men's health behavior change.

 

 

#8 Bilateral Training Improves Agility and Accuracy for Both Preferred and Non-Preferred Legs in Young Soccer Players

Reference: Percept Mot Skills. 2022 Sep 2;315125221124373. doi: 10.1177/00315125221124373.

Authors: Ahmed Ben Kahla, Yousri Elghoul, Achraf Ammar, Liwa Masmoudi, Khaled Trabelsi, Jordan M Glenn, Riadh Dahmen

Summary: As laterality of the lower limbs is regarded as a relevant influence on soccer performance, we assessed whether a bilateral training program for both the preferred leg (PL) and non-preferred leg (NPL) would improve soccer players' lateral asymmetry, agility, and accuracy. Sixty right-foot-dominant young soccer players were randomly assigned to either an experimental group (EXP) that underwent bilateral training or a control group (CONT) that performed their usual training schedule without bilateral exercise. We assessed the players' lateral asymmetries before and after training on four soccer skill tasks: a zigzag test with and without a ball, a receiving and direct volley-shooting accuracy test, and a passing accuracy test. Results showed post-test versus pre-test performance improvements for the EXP group on the index of technical skills and agility (p < .001). A post-hoc analysis further revealed a pre-test to post-test performance improvement on shooting and passing accuracy with both legs only for the EXP group (p < .001). These results support the role of bilateral practice in improving lateral asymmetries, agility, and accuracy.

 

 

#9 Melatonin supplementation alleviates cellular damage and physical performance decline induced by an intensive training period in professional soccer players

Reference: PLoS One. 2022 Sep 2;17(9):e0273719. doi: 10.1371/journal.pone.0273719. eCollection 2022.

Authors: Mohamed Amine Farjallah, Kais Ghattassi, Anis Kamoun, Ahmed Graja, Lobna Ben Mahmoud, Tarak Driss, Kamel Jamoussi, Zouheir Sahnoun, Nizar Souissi, Piotr Zmijewski, Omar Hammouda

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9439208/pdf/pone.0273719.pdf

Summary: Melatonin has been proved to have positive effects on cellular damage and metabolic regulation. The aim of the study was to determine the effect of melatonin supplementation during an intensive training period on physical performance decline, oxidative stress and cellular damage state. The investigation was conducted on 20 soccer players who participated in an exhaustive six-day training schedule associated with daily 5 mg oral melatonin or placebo ingestion. Resting blood samples and physical performance were measured before and after the training period. The mixed 2-way ANOVA (group x training camp) showed that compared to placebo, melatonin intake prevented an increase in advanced oxidation protein products (p>0.05) and increased the antioxidant enzyme activity (i.e., superoxide dismutase; p<0.001). In addition, melatonin prevented an increase of biomarkers of renal function (e.g., creatinine; p>0.05) and biomarkers of muscle (e.g., creatine kinase; p>0.05) and liver (e.g., gamma-glutamyltransferase; p>0.05) damage. Furthermore, melatonin alleviated the deterioration in physical performance (countermovement jump, five-jump test and 20-m sprint; p>0.05). In conclusion, the obtained data showed increased oxidative stress and renal, muscle and liver damage in professional soccer players during an exhaustive training schedule. Melatonin intake during the training period exerts beneficial effects on physical performance and protects tissues against the deleterious effects of reactive oxygen species and cellular damage.

 

 

#10 Inter-limb asymmetries and kicking limb preference in English premier league soccer players

Reference: Front Sports Act Living. 2022 Aug 17;4:982796. doi: 10.3389/fspor.2022.982796. eCollection 2022.

Authors: Gareth Nicholson, Tim Bennett, Aaron Thomas, Lysander Pollitt, Mike Hopkinson, Rubén Crespo, Tom Robinson, Rob J Price

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9428458/pdf/fspor-04-982796.pdf

Summary: The aims of this study were: (1) to quantify interlimb asymmetries in EPL soccer players in the context of kicking limb preference and (2) to establish the relationship between interlimb asymmetries and measures of physical performance. Twenty-two players (age: 21.8 ± 4.4 years) from an EPL club performed a running gait assessment (20 km/h) and unilateral countermovement jumps, a CoD assessment (modified 505 test), and an isokinetic knee extension/flexion protocol using each leg. Asymmetries were quantified using the percentage difference method and Pearson's correlations were used to quantify the association between variables. Players displayed the greatest level of asymmetry in isokinetic strength measures (5.9-12.7%) and lower levels of asymmetry in gait (1.6-7.7%), jump (0.9-7.0%) and CoD (1.9-3.5%) assessments. The influence of the preferred kicking limb was most evident in the isokinetic assessment with the players showing dominance in the preferred limb for knee flexor strength and in the non-preferred limb for knee extensor strength. These manifested in the asymmetry values calculated for the hamstring:quadricep (H:Q) ratios at 60°/s (8.80 ± 7.82%) and 240°/s (11.22 ± 7.04%) and in the functional H:Q ratio (12.67 ± 8.25%). The asymmetry values for peak extensor moment at 240°/s showed a significant correlation (ρ = -0.55, p = 0.034) with 10 m time in the CoD assessment. These findings provide benchmark asymmetry data for soccer practitioners and reveal that kicking limb preferences may bring about interlimb differences in the H:Q ratio which raises important considerations in the design of testing batteries and injury reduction interventions.

 

 

#11 Hip arthroscopy is a successful treatment for femoroacetabular impingement in under-16 competitive football players: a prospective study with minimum 2-year follow-up

Reference: Arch Orthop Trauma Surg. 2022 Sep 6.  doi: 10.1007/s00402-022-04584-1. Online ahead of print.

Authors: David Barastegui, Roberto Seijas, Eduard Alentorn-Geli, Alfred Ferré-Aniorte, Patricia Laiz, Ramon Cugat

Summary: Femoroacetabular impingement is considered a spectrum disease affecting multiple hip structures and it is especially prevalent in football players. Hip arthroscopy has shown good results in this population. However, little attention has been given to its efficacy in children and adolescent players. The aim of this study is to evaluate the outcomes of hip arthroscopy in under-16 football players. Between 2008 and 2019, all under-16 competitive football players who underwent hip arthroscopy for the treatment of femoroacetabular impingement were recruited for this prospective study. Hip pain and function were measured through the VAS, HOS, mHHS and WOMAC scores before the surgery, at 1-year after the surgery and at minimum 2-years after surgery. Preoperative and postoperative scores were compared to establish the evolution of hip pain and function. Additionally, rate and time to return to play were recorded. 14 subjects were included in the analysis. All subjects attended to the last follow-up, at mean 3.21 years after the surgery (range 2-10). Mean ± SD VAS (0-100) scores were 60.14 ± 15.88 before the surgery, 6.43 ± 5.19 at 1-year follow-up and 5.07 ± 4.05 at final follow-up (p < 0.05). Significant improvements were observed in HOS ADL, HOS SS, mHHS and WOMAC (p < 0.05) between preoperative values and 1-year follow-up. No significant differences were found in knee pain or function between 1-year and final follow-up assessments (p > 0.05). All subjects (100%) were playing football 1-year after the surgery, with a mean ± SD time to return to play of 5.93 ± 2.09 months. 13 subjects (92.86%) were still playing at final follow-up. Hip arthroscopy is a safe and effective surgical procedure for the treatment of FAI in under-16 competitive football players, improving hip pain and function with excellent rates to return to play.

 

 

#12 Effects of a shock microcycle after COVID-19 lockdown period in elite soccer players

Reference: Sci Sports. 2022 Aug 29. doi: 10.1016/j.scispo.2022.07.004. Online ahead of print.

Authors: L Vardakis, Y Michailidis, A Mandroukas, C Zelenitsas, G Mavrommatis, T Metaxas

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9420708/pdf/main.pdf

Summary: Decreases in physical fitness are inevitable after two to six week period of detraining in athletes. Lockdown period changed the characteristics of soccer players' training. The aim of our study was to apply a HIIT shock-microcycle (SM) after return to training and assess its effect on players' performance. Nineteen elite professional soccer players during the lockdown period (LP) from March to May 2020 (8 weeks) performed 3-4 individual training sessions per week. The training sessions included running boots of anaerobic short and aerobic prolonged duration intervals. Intensity was determined according to lab ergospirometry test 2 weeks before LP. All the players followed an indoor program, 3-6 sessions per week consisted of core, balance and flexibility exercises (∼45 minutes). SM training content was same for both groups and took place the first two weeks after LP, consisted by eight high intensity interval training sessions (HIIT), two technique, two tactical sessions and two days off. Repeated sprint ability mean time (RSAMeanTime) and Repeated sprint ability performance - sprint no 4,5,6 (RSA4,5,6S) improved after SM (p=0.025, Effect size:r2=0.331, p=0.010, Effect size:r2=0.411, p=0.009, Effect size:r2=0.418, p=0.037, Effect size:r2=0.293, respectively. Yo-Yo intermitted recovery test level 2 (YYIR2TotalDistance) that covered by players during the 2nd measurement was 10.8% longer (p=0.004, Effect size:r2=0.483). Also, the YYIR2HeartRateRecovery percentage was lower during the 2nd measurement (p=0.014, Effect size:r2=0.107). These results indicate that SM can improve YYIR2 and RSA performance thus it is a useful tool to regain physical attributes in a short period.

 

 

#13 Combined effect of game position and body size on network-based centrality measures performed by young soccer players in small-sided games

Reference: Front Psychol. 2022 Aug 22;13:873518. doi: 10.3389/fpsyg.2022.873518. eCollection 2022.

Authors: Paulo Henrique Borges, Julio Cesar da Costa, Luiz Fernando Ramos-Silva, Gibson Moreira Praça, Enio Ricardo Vaz Ronque

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9443843/pdf/fpsyg-13-873518.pdf

Summary: This study verified the effects of body size and game position on interactions performed by young soccer players in small-sided games (SSG). The sample consisted of 81 Brazilian soccer players (14.4 ± 1.1 years of age). Height, body mass, and trunk-cephalic height were measured. SSG was applied in the GK + 3v3 + GK format, and Social Network Analyses were carried out through filming the games to obtain the following prominence indicators: degree centrality, closeness centrality, degree prestige, and proximity prestige, in addition to network intensity and number of goals scored. Factorial ANCOVA (bone age as covariate) was used to test the effects of game position, body size, and respective interaction on centrality measurements (p < 0.05). Similarity between game positions in body size indicators (p > 0.05) was observed. The game position affected degree centrality (p = 0.01, η 2 = 0.16), closeness centrality (p = 0.01, η 2 = 0.11), and network intensity (p = 0.02, η 2 = 0.09), in which midfielders presented the highest network prominence values when compared to defenders and forwards. In conclusion, midfielders are players with high interaction patterns in the main offensive plays, which behavior is independent of body size.

 

 

#14 Hip and knee joint angle patterns and kicking velocity in female and male professional soccer players: A principal component analysis of waveforms approach

Reference: J Sports Sci. 2022 Sep 8;1-12. doi: 10.1080/02640414.2022.2121022. Online ahead of print.

Authors: Archit Navandar, Kristof Kipp, Enrique Navarro

Summary: This study used principal component analysis (PCA) of waveforms to extract movement patterns from hip and knee angle time-series data; and determined if the extracted movement patterns were predictors of ball velocity during a soccer kick. Twenty-three female and nineteen male professional soccer players performed maximal effort instep kicks while motion capture and post-impact ball velocities data were recorded. Three-dimensional hip and knee joint angle time-series data were calculated from the beginning of the kicking leg's backswing phase until the end of the follow-through phase and entered into separate PCAs for females and males. Three principal components (PC) (i.e., movement patterns) were extracted and PC scores were calculated. Pearson correlation coefficients were calculated to establish correlations between hip and knee PC scores and kicking velocity. Results showed better kicking performance in male players was associated with a greater difference between the hip extension at the end of the backswing/beginning of the leg cocking phases and hip flexion at the end of the follow-through phase (r = -0.519, p = 0.023) and a delayed internal rotation of the hip (r = 0.475, p = 0.040). No significant correlations between ball velocity and hip and knee kinematics were found for female players.

 

 

#15 Specific relations of visual skills and executive functions in elite soccer players

Reference: Front Psychol. 2022 Aug 25;13:960092. doi: 10.3389/fpsyg.2022.960092. eCollection 2022.

Authors: Antonia Knöllner, Daniel Memmert, Marec von Lehe, Johannes Jungilligens, Hans-Erik Scharfen

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9454603/pdf/fpsyg-13-960092.pdf

Summary: Visual and cognitive skills are key to successful functioning in highly demanding settings such as elite sports. However, their mutual influence and interdependencies are not sufficiently understood yet. This cross-sectional study examined the relationship between visual skills and executive functions in elite soccer players. Fifty-nine male elite soccer players (age: 18-34 years) performed tests assessing visual clarity (left-, right-, and both eyes), contrast sensitivity, near-far quickness, and hand-eye coordination. Executive function measures included working memory capacity, cognitive flexibility, inhibition and selective attention. Overall, visual abilities were largely correlated with executive functions. Near-far quickness performance showed a large correlation with an executive function total score as well as with cognitive flexibility, working memory, and especially selective attention. Visual clarity and contrast sensitivity were moderately correlated with the cognition total score. Most consistent correlations with the visual functions were present for working memory. These findings present an overall vision-cognition relationship but also very specific linkages among subcategories of these functions, especially meaningful relations between near-far quickness, selective attention and cognitive flexibility. Further studies are needed to investigate the neuropsychological mechanisms accounting for the correlations and possible improvements of the executive functions by training specific visual skills.

 

 

#16 CortexVR: Immersive analysis and training of cognitive executive functions of soccer players using virtual reality and machine learning

Reference: Front Psychol. 2022 Aug 23;13:754732. doi: 10.3389/fpsyg.2022.754732. eCollection 2022.

Authors: Christian Krupitzer, Jens Naber, Jan-Philipp Stauffert, Jan Mayer, Jan Spielmann, Paul Ehmann, Noel Boci, Maurice Bürkle, André Ho, Clemens Komorek, Felix Heinickel, Samuel Kounev, Christian Becker, Marc Erich Latoschik 

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9446155/pdf/fpsyg-13-754732.pdf

Summary: This paper presents an immersive Virtual Reality (VR) system to analyze and train Executive Functions (EFs) of soccer players. EFs are important cognitive functions for athletes. They are a relevant quality that distinguishes amateurs from professionals. The system is based on immersive technology, hence, the user interacts naturally and experiences a training session in a virtual world. The proposed system has a modular design supporting the extension of various so-called game modes. Game modes combine selected game mechanics with specific simulation content to target particular training aspects. The system architecture decouples selection/parameterization and analysis of training sessions via a coaching app from an Unity3D-based VR simulation core. Monitoring of user performance and progress is recorded by a database that sends the necessary feedback to the coaching app for analysis. The system is tested for VR-critical performance criteria to reveal the usefulness of a new interaction paradigm in the cognitive training and analysis of EFs. Subjective ratings for overall usability show that the design as VR application enhances the user experience compared to a traditional desktop app; whereas the new, unfamiliar interaction paradigm does not negatively impact the effort for using the application. The system can provide immersive training of EF in a fully virtual environment, eliminating potential distraction. It further provides an easy-to-use analyzes tool to compare user but also an automatic, adaptive training mode.

 

 

#17 The Effect of Sex, Sport, and Preexisting Histories on Baseline Concussion Test Performance in College Lacrosse and Soccer Athletes

Reference: Clin J Sport Med. 2022 Sep 1;32(5):e461-e468. doi: 10.1097/JSM.0000000000001018. Epub 2022 Feb 15.

Authors: Jason P Mihalik, Elizabeth F Teel, Cassie B Ford, Stephanie A Amalfe, Nikki E Barczak-Scarboro, Robert C Lynall, Kaitlin E Riegler, Erin B Wasserman, Margot Putukian

Summary: The aim was to study sex and sport differences in baseline clinical concussion assessments. A secondary purpose was to determine if these same assessments are affected by self-reported histories of (1) concussion; (2) learning disability; (3) anxiety and/or depression; and (4) migraine. Male and female soccer and lacrosse athletes (n = 237; age = 19.8 ± 1.3 years) participated in this study.  Sport, sex, history of (1) concussion; (2) learning disability; (3) anxiety and/or depression; and (4) migraine were assessed as risk factors. Sport Concussion Assessment Tool 22-item symptom checklist, Standardized Assessment of Concussion, Balance Error Scoring System (BESS), Generalized Anxiety Disorder 7-item scale, and Patient Health Questionnaire were main outcome measures. Female athletes had significantly higher total symptoms endorsed (P = 0.02), total symptom severity (P < 0.001), and BESS total errors (P = 0.01) than male athletes. No other sex, sport, or sex-by-sport interactions were observed (P > 0.05). Previous concussion and migraine history were related to greater total symptoms endorsed (concussion: P = 0.03; migraine: P = 0.01) and total symptom severity (concussion: P = 0.04; migraine: P = 0.02). Athletes with a migraine history also self-reported higher anxiety (P = 0.004) and depression (P = 0.01) scores. No other associations between preexisting histories and clinical concussion outcomes were observed (P > 0.05). Our findings reinforce the need to individualize concussion assessment and management. This is highlighted by the findings involving sex differences and preexisting concussion and migraine histories. Clinicians should fully inventory athletes' personal and medical histories to better understand variability in measures, which may be used to inform return-to-participation decisions following injury.

 

 

#18 Effects of a soccer-specific vertical jump on lower extremity landing kinematics

Reference: Sports Med Health Sci. 2022 Jul 20;4(3):209-214. doi: 10.1016/j.smhs.2022.07.003. eCollection 2022 Sep.

Authors: Sophia Mancini, D Clark Dickin, Dorice Hankemeier, Caroline Ashton, Jordan Welch, Henry Wang

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9453686/pdf/main.pdf

Summary: Anterior cruciate ligament (ACL) injury frequently occurs in female soccer athletes during deceleration movements such as landings. In soccer, landings mostly occur following jumping headers. Little research has been done to determine the mechanics that follow and how they compare to standard drop vertical jumps (DVJ). The purpose of this study was to analyze differences in kinematics between the DVJ and the soccer-specific vertical jump (SSVJ) in female soccer athletes to better assess the sport-specific risk for ACL injury. A secondary aim was to compare second landings (L2) to first landings (L1). Eight female recreational soccer athletes performed DVJs and SSVJs initiated from a 31 cm height. Motion capture was performed during landings and data were analyzed using repeated-measures ANOVA. SSVJs produced less peak hip flexion (p = 0.03) and less peak knee flexion (p = 0.002) than DVJs. SSVJs also demonstrated increased ankle plantarflexion at initial contact (IC) than DVJs (p = 0.005). L2s produced less peak hip (p = 0.007) and knee flexion (p = 0.002) than L1s. SSVJs and L2s displayed a more erect landing posture than the DVJs and L1s at the hip and knee, a known ACL risk factor. The significant results between jump styles show that the SSVJ displays mechanics that are different from the DVJ. The SSVJ may be a better sport-specific screening tool for ACL injury mechanisms than the DVJ in soccer athletes as it has a more direct translation to the sport.