Footballscience.net
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 Acute effects of the FIFA11+ and Football+ warm-ups on motor performance. A crossover randomized controlled trial
Reference: PLoS One. 2023 Apr 20;18(4):e0284702. doi: 10.1371/journal.pone.0284702. eCollection 2023.
Authors: Mojtaba Asgari, Marcus Schmidt, Benedikt Terschluse, Maximilian Sueck, Thomas Jaitner
Download link: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0284702
Summary: Few studies including contradictory results have addressed the acute effects of the 11+ on motor performance, indicating a potentially reduced applicability of the program for warming up before competitions. This study aims to compare the acute effects of a soccer-specific warm-up (Football+) and the 11+ on motor performance. Thirty-eight volunteer collegiate players (22 males; age = 21.1±1.9 years, height = 1.81± 0.06 m, weight = 73.4± 9.5 kg; 16 females; age = 21.3±1.5 years; height = 1.71± 0.07 m, weight = 67.8± 8.5 kg) underwent the 11+ and the Football+ in a randomized crossover design with a one-week washout. The Football+ starts with a self-estimated 40-50 percent running, followed by dynamic stretching of the hip muscles, shoulder contact, controlled lunge, Copenhagen exercise, and modified Nordic hamstring exercise. The second part involves roughly intensive small-sided games, followed by plyometric and anaerobic exercises in the third part. The warm ups' effects on performance were determined by a linear sprinting test (20 m), countermovement jump performance (CMJ), Illinois agility (IA), and dribbling speed (DS) tests. Within-subject differences were reported as the means and SD. Pairwise t tests at the significance level of p<0.05 were used to calculate the significant differences. Overall, except for the CMJ (mean = -0.43±3.20 cm, p = 0.21, d = -0.13), significant differences for the 20 m sprint (mean = 0.04±0.10 s, p = 0.005, d = 0.42), IA (mean = 0.65±0.45 s, p = 0.01, d = 1.43), and DS (mean = 0.60±1.58 s, p = 0.012, d = 0.38) were observed. In females, significant differences observed only for IA (mean difference = 0.52±0.42 s, p<0.001, d = 1.24) and DS (mean difference = 1.29±1,77 s, p = 0.005, d = 0.73), with the Football+ showing superiority. In males, significant differences were found only for 20 m sprinting (mean difference = 0.06±0.09, p = 0.005, d = 0.60) and IA (mean difference = 0.74±0.46, p<0.001, d = 1.62), with the Football+ having superiority. Although practicable for injury prevention, the 11+ may not optimize acute performance and prepare players for high-intensity physical tasks as well as a well-structured, roughly intensive warm-up. Further gender-specific studies should evaluate the long-term effects of the Football+ on performance and injury prevention.
#2 Using Deadlifts as a Postactivation Performance Enhancement Strategy in Warm-ups in Football
Reference: J Strength Cond Res. 2023 Apr 19. doi: 10.1519/JSC.0000000000004485. Online ahead of print.
Authors: Eduardo Abade, João Brito, Bruno Gonçalves, Luís Saura, Diogo Coutinho, Jaime Sampaio
Summary: Postactivation performance enhancement activities may be relevant warm-up strategies aiming to improve subsequent physical performance. The purpose of the current study was to investigate the effects of adding barbell deadlift or hex-bar deadlift exercises to current warm-up routines on running and jumping performances in football players. Ten highly trained male football players participated in the study during the competitive phase of the season. All players performed 3 protocols in the same week: a standard warm-up that included players' regular routines and 2 other protocols with the addition of barbell or hex-bar deadlift, after the end of the warm-up (3 sets of 3 reps, progressing set by set from 60% to 85% repetition maximum). All protocols had the same time interval between pretest (immediately after the warm-up) and posttest (15 minutes after the warm-up). Vertical jumping (countermovement jump [CMJ]; Abalakov jump [AJ]) and running performances (505 test) were impaired 15 minutes after the standard warm-up (CMJ: -6.7 ± 4.2%; AJ: -8.1 ± 8.4%; and 505 time: 1.4 ± 2.5%). For warm-up with the addition of barbell deadlift, vertical jump increased by 4.3 ± 5.6% (Cohen's dunb: 0.23 [0.02-0.47]) and 505 time decreased by -5.9 ± 3.6% (Cohen's dunb: 0.97 [-1.68 to -0.43]). The warm-up with hex-bar deadlift led to trivial changes for CMJ and AJ, but 505 time decrease by -2.7 ± 2.6% (Cohen's dunb: -0.53 [-1.01 to -0.13]). The deadlift exercise can be added to warm-up routines to maintain or even enhance acute physical performance. However, coaches and practitioners should be aware that performance enhancements resultant from deadlift may vary according to individual physical profiles.
#3 Predictors of linear sprint performance in professional football players
Reference: Biol Sport. 2023 Apr;40(2):359-364. doi: 10.5114/biolsport.2023.114289. Epub 2022 Jun 1.
Authors: Joel Barrera, António J Figueiredo, João Duarte, Adam Field, Hugo Sarmento
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10108761/pdf/JBS-40-114289.pdf
Summary: The purpose of this study was to analyze the relationship between sprint performance (time), and strength and power capabilities in football players. A total of 33 professional Portuguese football players performed isokinetic strength assessments, countermovement jumps (CMJ), squat jumps (SJ), and 10, 20 and 30 m sprints. Pearson's correlation (r) was used to determine the relationships between variables. Concentric knee extensor torque at 180° · s-1 was largely-to-very largely correlated with 10 m (r = -0.726), 20 m (-0.657) and 30 m sprints (r = -0.823). Moderate inverse correlation were observed between CMJ (r = -0.425 and r = -0.405) and SJ height (r = -0.417 and r = -0.430), and 20 m and 30 m sprint performance, respectively. Multiple linear regression combining KEcon 180° · s-1 and KFcon 180° · s-1 demonstrated that the model was significant for predicting 10 m sprint time (F (2, 8) = 5.886; R 2 = 0.595). The model combining SJ, CMJ and KEcon 180° · s-1 was also significant for predicting 20 and 30 m sprint times (F (3, 7) = 2.475; R 2 = 0.515 and F (3, 7) = 5.282; R 2 = 0.562; respectively). In conclusion, peak torque at higher velocities and vertical jump performance correlates significantly with linear sprint performance (time). For practitioners seeking to improve linear sprint performance in football players, evaluation of high speed strength and vertical jump indices should be undertaken.
#4 Mechanisms of ACL injuries in men's football: A systematic video analysis over six seasons in the Qatari professional league
Reference: Biol Sport. 2023 Apr;40(2):575-586. doi: 10.5114/biolsport.2023.118024. Epub 2022 Jul 21.
Authors: Raouf Nader Rekik, Roald Bahr, Flavio Cruz, Paul Read, Rod Whiteley, Pieter D'hooghe, Montassar Tabben, Karim Chamari
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10108748/pdf/JBS-40-118024.pdf
Summary: To assess the mechanisms of ACL injury in male professional football players in Qatar across multiple seasons using systematic video analysis. 15 ACL injuries occurred in competition among the professional football teams that participated in an injury Surveillance Programme during 6 seasons (2013/2014 to 2018/2019). High-definition broadcast videos of these injuries were analyzed (49 views; 34 slow motion) by five analysts who independently described the injury mechanisms (situation, behavior, biomechanical characteristics) using validated observational tools. A knee valgus mechanism was observed in two-thirds of the cases (1 with direct contact to the knee, 3 with indirect contact (other body parts) and 6 with no contact). No visible valgus was reported in 2 of the direct knee contact injuries, while 3 cases of non-contact and indirect contact injuries were unclear. We observed 4 main categories of injury situation among those (n = 12) classified as non-contact/ indirect contact (multiple combinations were possible): pressing (n = 6), tackling or being tackled (n = 4), blocking (n = 3) and screening (n = 2). Direct contact injuries (n = 3) were suffered by 2 players during tackling and 1 whilst being tackled. Contact injuries represented only 20% of ACL injuries occurring during competition in Qatari professional soccer players. Independent of the playing situation, knee valgus was frequently observed (10/15 cases). Pressing was the most common situation (6/15 cases) leading to injury. Landing after heading was not reported in any of these ACL injuries.
#5 Time-loss and recurrence rates after lateral ankle ligament sprains in male elite football players: summary of a systematic review and meta-analysis
Reference: Sportverletz Sportschaden. 2023 Apr 19. doi: 10.1055/a-2047-9031. Online ahead of print. [Article in German]
Authors: Zacharias Flore, Karen Hambly, Kyra De Coninck, Götz Welsch
Summary: A literature search was conducted to systematically review and meta-analyse time-loss and recurrence rates of lateral ankle sprains (LAS) in male professional football players. Six electronic databases were screened separately for time-loss and recurrence rates after lateral ankle sprains in elite football players. A total of 13 (recurrence) and 12 (time-loss) studies met the previously defined inclusion criteria. The total sample size of the recurrence studies was 36.201 participants (44.404 overall initial injuries, 7944 initial ankle sprain (AS) injuries, 1193 recurrent AS injuries). 16.442 professional football players (4893 initial AS injuries, 748 recurrent AS injuries) were subsequently meta-analysed. A recurrence rate of 17.11% (95% CI: 13.31-20.92%; df=12; Q=19.53; I2=38.57%) was determined based on the random-effects model. A total of 7736 participants were part of the time-loss studies (35.888 total injuries, 4848 total ankle injuries; 3370 AS injuries). Out of the 7736 participants, 7337 participants met the inclusion criteria with a total of 3346 AS injuries. The average time-loss was 15 days (weighted mean: 15.92, median: 14.95, min: 9.55; max: 52.9). A priori, we determined considerable heterogeneity (CI: 18.15-22.08; df=11; Q=158; I2=93%). There is an average time-loss of 15 days per LAS and a recurrence rate of 17%. LAS is one of the most common types of injury with high recurrence rates in professional football players. The high recurrence rates and long-term consequences show the necessity for research in the field of LAS in elite football. However, heterogeneous data lead to difficulties regarding the aspect of comparability.
#6 Hamstring muscle injury in football players. Part 2 : preventive strategies
Reference: Rev Med Liege. 2023 Apr;78(4):213-217. [Article in French]
Authors: François Delvaux, Jean-Louis Croisier, Christopher Carling, Emmanuel Orhant, Jean-François Kaux
Summary: Prevention of hamstring injuries represents an important issue for football players and clubs. Preventive strategies can be effective if they include multiple dimensions and are well-structured. Five points appear essential in order to obtain a high-quality preventive strategy: progressive muscle strengthening, optimal workload management, lumbopelvic stability exercises, development of physical condition and optimization of sprint technique. While recognizing the limitations of preventive screening and the difficulty of predicting future injury, screening tests appear relevant for the identification of an individual risk profile for each footballer and in defining each player's work priorities. Finally, secondary prevention starts with the implementation of rigorous and high-level rehabilitation, as well as a special attention to players with a history of hamstring injury.
#7 SARS-CoV-2 serological assay and viral testing: a report of professional football setting
Reference: Postgrad Med J. 2022 Jul 1;98(1161):529-532. doi: 10.1136/postgradmedj-2021-140176.
Authors: Bahar Hassanmirzaei, Zohreh Haratian, Ali Ahmadzadeh Amiri, Amir Ahmadzadeh Amiri, Navid Moghadam
Summary: PCR is the current standard test for the diagnosis of SARS-CoV-2 infection. However, due to its limitations, serological testing is considered an alternative method for detecting SARS-CoV-2 exposure. In this study, we measured the level of SARS-CoV-2 IgM and IgG antibodies of male professional football players and compared the results with the standard PCR test to investigate the association between the two tests. Participants were male professional football players and team officials. Nasopharyngeal swabs and peripheral blood samples were collected for the PCR and serological tests, respectively. Also, previous records of COVID-19 testing and symptoms were gathered. Those with previous positive PCR tests who tested negative for the second time were considered to be recovered patients. Of the 1243 subjects, 222 (17.9%) were seropositive, while 29 (2.3%) tested positive for the SARS-CoV-2 PCR test. Sixty percent of symptomatic cases with a negative PCR were found to be seropositive. The mean level of IgM was significantly higher in PCR-positive and symptomatic subjects, whereas the recovered cases showed significantly higher levels of IgG. Our study revealed an inconsistency of results between the two tests; therefore, although application of serological assays alone seems insufficient in diagnosing COVID-19 disease, the findings are beneficial in the comprehension and the management of the disease.
#8 Beyond physical ability-predicting women's football performance from psychological factors
Reference: Front Psychol. 2023 Mar 28;14:1146372. doi: 10.3389/fpsyg.2023.1146372. eCollection 2023.
Authors: Susann Dahl Pettersen, Monica Martinussen, Bjørn Helge Handegård, Lene-Mari Potulski Rasmussen, Roman Koposov, Frode Adolfsen
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10090955/pdf/fpsyg-14-1146372.pdf
Summary: Even though there is a clear agreement among researchers that psychological factors are a vital part of a football player's performance, the topic has not been investigated thoroughly. The present study aimed to examine the predictive value of psychological factors on female football players' match performance. A sample of 156 players from the top two leagues in Norway completed the following questionnaires: Perceived Motivational Climate in Sport Questionnaire 2 (PMCSQ-2), Big Five Inventory (BFI-20), Self-Regulated Learning questionnaire, and Grit-S and Sport Mental Toughness Questionnaire (SMTQ). Match performance data were collected from the online database of the performance analysis company InStat. Results from a linear mixed model analysis showed that perceived mastery climate and extraversion were the only significant predictors of performance. Other relevant indicators, such as mental toughness, self-regulated learning, and grit, did not predict performance. These findings suggest that the team climate facilitated by coaches may be more important for predicting match performance than individual psychological factors.
#9 Verbal Encouragement Improves Game Intensity, Technical Aspects, and Psychological Responses During Soccer-Specific Training
Reference: Int J Sports Physiol Perform. 2023 Apr 28;1-7. doi: 10.1123/ijspp.2022-0435. Online ahead of print.
Authors: Okba Selmi, Danielle E Levitt, Bilel Aydi, Waad Ferhi, Anissa Bouassida
Download link: https://www.frontiersin.org/articles/10.3389/fphys.2023.1167449/full
Summary: Soccer match outcomes rely on technical accuracy, intensity of play, and athlete motivation, and these parameters can be developed during sport-specific practice such as during small-sided games (SSGs). Verbal encouragement as a coaching technique improves exercise intensity and athlete enjoyment (indicative of motivation), but the impact on technical performance alongside these critical parameters remains unknown. The aim was to examine the effects of verbal encouragement on technical performance, exercise intensity, and enjoyment during SSGs. Sixteen male youth soccer players (mean [SD]; age: 17.2 [0.4] y; height: 176.3 [7.0] cm; body mass: 68.0 [4.1] kg; body fat: 11.9% [2.2%]) completed 4 sessions of 4-per-side SSG without a goalkeeper. Two sessions were conducted as SSGs with verbal encouragement and 2 without verbal encouragement. Each SSG lasted 25 minutes (4 × 4-min work, 3-min passive recovery between bouts) on a 25 × 35-m pitch. Heart rate (HR) was continuously recorded, and rating of perceived exertion was collected after each SSG. Video analysis was used to quantify technical actions during SSG. Enjoyment was assessed after each SSG using the Physical Activity Enjoyment Scale. Paired t tests revealed that SSGs with verbal encouragement induced higher HR (% maximum HR and mean HR), rating of perceived exertion, and Physical Activity Enjoyment Scale score than SSGs without verbal encouragement (all P < .001, all d ≥ 0.92, large). Compared with SSGs without verbal encouragement, SSGs with verbal encouragement resulted in an increased percentage of successful passes (P < .001, d = 0.73, medium) and number of interceptions (P < .001, d = 0.89, large) and fewer lost balls (P < .001, d = 0.68, medium). Coaches should use verbal encouragement during SSGs to improve physical effort, technical performance, and psychological status in soccer players.
#10 Changes in Hematological Parameters of Iron Status and Total Iron Concentrations in Different Biological Matrices during a Sports Season in Women's Soccer Players
Reference: Nutrients. 2023 Apr 11;15(8):1833. doi: 10.3390/nu15081833.
Authors: Víctor Toro-Román, María C Robles-Gil, Ignacio Bartolomé, Francisco J Grijota, Diego Muñoz, Marcos Maynar-Mariño
Summary: Iron (Fe) metabolism and concentrations change during a sports season. Fe deficiency affects a significant number of women athletes. The aims of the present study were: (i) to analyze changes in hematological parameters of Fe status and (ii) to analyze changes in Fe concentrations in different biological matrices (serum, plasma, urine, erythrocytes, and platelets) during a sports season. Twenty-four Spanish semi-professional women's soccer players (23.37 ± 3.95 years) participated in the present study. Three assessments were performed throughout the sports season (beginning, middle and end of the season). Nutritional intake was evaluated and female hormones, hematological parameters of Fe status and Fe concentrations in plasma, serum, urine, erythrocytes and platelets were determined. There were no differences in Fe intake. Hemoglobin and mean corpuscular hemoglobin concentrations increased at the end of the season compared to initial values (p < 0.05). There were no significant changes in extracellular Fe concentrations (plasma, serum, and urine). However, erythrocyte Fe concentrations were lower at the end of the season (p < 0.05). Hematological parameters of Fe status and intracellular Fe concentrations change throughout the sports season in women's soccer players.
#11 The Association between Training Frequency, Symptoms of Overtraining and Injuries in Young Men Soccer Players
Reference: Int J Environ Res Public Health. 2023 Apr 11;20(8):5466. doi: 10.3390/ijerph20085466.
Authors: Filipe Rodrigues, Diogo Monteiro, Ricardo Ferraz, Luís Branquinho, Pedro Forte
Summary: Overtraining is a prevalent issue among young men soccer players, particularly those who are driven to enhance their skills. While an intense training volume and effort might contribute to athletic growth, it can also have negative implications, including injury. The current study aimed at examining the association between training frequency, symptoms of overtraining and injuries in young men soccer players. A path analysis approach was used to examine the causal relationships between variables. The sample consisted of 189 young men soccer players aged 13-17 years old (age = 14.81, SD = 1.37). Participants reported that they were training, on average, 5.77 days (SD = 1.53) per week. Athletes were competing at a regional (n = 100) or national (n = 89) level. Concerning injuries, participants indicated, on average, 2.03 (SD = 1.16) injuries since they started practicing soccer. The results displayed a significant association, as theoretically expected, namely: (i) training frequency was significantly associated with overtraining symptoms (β = 0.15 [IC95% = 0.01, 0.29]); (ii) overtraining symptoms were significantly associated with the number of injuries (β = 0.19 [IC95% = 0.02, 0.35]). An indirect effect between training frequency and injuries was also observed (β = 0.15 [IC95% = 0.01, 0.29]). Thus, there is preliminary evidence that overtraining symptoms could play a mediating role. In conclusion, investigating the links between overtraining symptoms and injury in young men soccer players is critical, as it can assist in identifying overtraining warning signs, promote young players' health and safety, customize training regimens to individual needs, and contribute to a better understanding of sports-related injuries.
#12 Ability of Countermovement Jumps to Detect Bilateral Asymmetry in Hip and Knee Strength in Elite Youth Soccer Players
Reference: Sports (Basel). 2023 Mar 31;11(4):77. doi: 10.3390/sports11040077.
Authors: Hailey L Wrona, Ryan Zerega, Victoria G King, Charles R Reiter, Susan Odum, Devon Manifold, Karyn Latorre, Timothy C Sell
Download link: https://www.mdpi.com/2075-4663/11/4/77
Summary: Clinicians frequently assess asymmetry in strength, flexibility, and performance characteristics as a method of screening for potential musculoskeletal injury. The identification of asymmetry in countermovement jumps may be an ideal method to reveal asymmetry in other lower extremity characteristics such as strength that otherwise may require additional testing, potentially reducing the time and burden on both the athlete and clinicians. The present study aims to examine the ability of asymmetry in both the single-leg and two-leg countermovement jump tests to accurately detect hip abduction, hip adduction, and eccentric hamstring strength asymmetry. Fifty-eight young male elite soccer players from the same professional academy performed a full battery of functional performance tests which included an assessment of hip adductor and abductor strength profiles, eccentric hamstring strength profiles, and neuromuscular performance and asymmetries during countermovement jumps. Bilateral variables attained from both the single-leg and two-leg countermovement jump tests included concentric impulse (Ns), eccentric mean force (N), and concentric mean force (N) computed by the VALD ForceDecks software. Average maximal force (N) was calculated bilaterally for the strength assessments. Asymmetry was calculated for each variable using 100 × |(right leg - left leg)/(right leg)| and grouped into three categories: 0 to <10%, 10% to <20%, and 20% or greater. Analyses were performed for the two higher asymmetry groups. The accuracy to detect strength asymmetry was assessed as the sensitivity, specificity, and predictive values for positive and negative tests. The outcomes from the accuracy assessments suggest that the single-leg countermovement jump concentric impulse variable at the 20% threshold is indicative of a youth male soccer player having hip adduction strength asymmetry while also demonstrating more accuracy and applicability than the two-leg countermovement jump concentric impulse variable.
#13 Relative Individual Sprint in Most Demanding Passages of Play in Spanish Professional Soccer Matches
Reference: Sports (Basel). 2023 Mar 23;11(4):72. doi: 10.3390/sports11040072.
Authors: Juan Ángel Piñero, Marcos Chena, Juan Carlos Zapardiel, Alberto Roso-Moliner, Elena Mainer-Pardos, Miguel Lampre, Demetrio Lozano
Download link: https://www.mdpi.com/2075-4663/11/4/72
Summary: The objective of this research was to analyse the most demanding passages (MDP) considering the sprint variable relative to the maximum level of sprint ability of each player as a function of player position, final outcome and part of the match during the competitive phase of a professional soccer season. Global positioning system (GPS) data were collected from 22 players according to their playing position in the last 19 match days of the Spanish La Liga professional soccer in the 2020/2021 season. MDP were calculated from 80% of the maximum sprint speed of each player. Wide midfielders covered the greatest distance at >80% of the maximum speed (2.4 ± 1.63 seg) and the longest duration (21.91 ± 13.35 m) in their MDP. When the whole team was losing, it demonstrated greater distances (20.23 ± 13.04 m) and longer durations (2.24 ± 1.58 seg) compared to games in which it was winning. When the team ended up drawing, the relative sprint distance covered in the second half was significantly greater than in the first (16.12 ± 21.02; SD = 0.26 ± 0.28 (-0.03/-0.54). Different demands of MDP, according to the sprint variable relative to the maximum individual capacity in competition, are required when contextual game factors are considered.
#14 Effect of Heading a Soccer Ball as an External Focus During a Drop Vertical Jump Task
Reference: Orthop J Sports Med. 2023 Apr 17;11(4):23259671231164706. doi: 10.1177/23259671231164706. eCollection 2023 Apr.
Authors: Hadi Akbari, Satoshi Kuwano, Yohei Shimokochi
Summary: Research has demonstrated that performing a secondary task during a drop vertical jump (DVJ) may affect landing kinetics and kinematics. The aim was to examine the differences in the trunk and lower extremity biomechanics associated with anterior cruciate ligament (ACL) injury risk factors between a standard DVJ and a DVJ while heading a soccer ball (header DVJ). Participants comprised 24 college-level soccer players (18 female and 6 male; mean ± SD age, 20.04 ± 1.12 years; height, 165.75 ± 7.25 cm; weight, 60.95 ± 8.47 kg). Each participant completed a standard DVJ and a header DVJ, and biomechanics were recorded using an electromagnetic tracking system and force plate. The difference (Δ) in 3-dimensional trunk, hip, knee, and ankle biomechanics between the tasks was analyzed. In addition, for each biomechanical variable, the correlation between the data from the 2 tasks was calculated. Compared to the standard DVJ, performing the header DVJ led to significantly reduced peak knee flexion angle (Δ = 5.35°; P = .002), knee flexion displacement (Δ = 3.89°; P = .015), hip flexion angle at initial contact (Δ = -2.84°; P = .001), peak trunk flexion angle (Δ = 13.11°; P = .006), and center of mass vertical displacement (Δ = -0.02m; P = .010), and increased peak anterior tibial shear force (Δ = -0.72 N/kg; P = .020), trunk lateral flexion angle at initial contact (Δ = 1.55°; P < .0001), peak trunk lateral flexion angle (Δ = 1.34°; P = .003), knee joint stiffness (Δ = 0.002 N*m/kg/deg; P = .017), and leg stiffness (Δ = 8.46 N/kg/m; P = .046) compared to those in standard DVJs. In addition, individuals' data for these variables were highly and positively correlated between conditions (r = 0.632-0.908; P < .001). The header DVJ task showed kinetic and kinematic parameters that suggested increased risk of ACL injury as compared with the standard DVJ task. Athletes may benefit from acquiring the ability to safely perform header DVJs to prevent ACL injury. To simulate real-time competition situations, coaches and athletic trainers should incorporate such dual tasks in ACL injury prevention programs.
#15 Kinematic parameters and metabolic power in elite soccer players: A small sided a large sided games comparison
Reference: Front Physiol. 2023 Apr 7;14:1150713. doi: 10.3389/fphys.2023.1150713. eCollection 2023.
Authors: Nemanja Zlojutro, Serdar Eler, Marko Joksimovic, Nebahat Eler, Saša Marković, Aleksandar Kukrić, Kosta Goranovic
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10119402/pdf/fphys-14-1150713.pdf
Summary: The goal of this paper is to determine what happens in one minute (on average) in kinematic parameters and metabolic power in small sided games (SSG) (3v3; 5v5) and large sided games (LSG) (10v10) and in which games kinematic parameters and metabolic power are best developed. The participants of this study were 22 professional football players, height 182.95±6.52 cm, mass 77.17±8.21 kg, body mass index (BMI) 22.97±1.47 kg/m2, body fat 9.85±2.55 %, aged 27.1±5.4 yrs, who played in the Premier League of Bosnia and Herzegovina. Data total distance (TD), maximum speed (MS), number of accelerations (nAcc), number of decelerations (nDec), number of sprints (nS), high intensity distance (Z4≥19.8 km/h), sprint distance (Z5≥25.2 km/h) and movements requiring a certain metabolic power (Pmet), were collected using a 20 Hz Global positioning system (GPS) system Pro2 (GPEXE, Exelio srl, Udine, Italy), on a total of 307 individual observations. The results showed that the average total distance was significantly higher in the 5v5 (135.16±18.78 m) and 10v10 (133.43±20.06 m) games (F=64.26, p<0.001) compared to the 3v3 (108.24±11.26 m). Furthermore, the values of the variables Z4 (8.32±3.38 m, F=97.59), Z5 (1.84±1.53 m, F=123.64), nS (0.13±0.10 n, F=96.14) as well as Maxspeed (27.06±1.90 km/h, F=139.33), are statistically significantly higher (p<0.001) in the 10v10 game compared to the other two game formats. The average number of nAcc (0.40±0.32 n, F=9.86, p<0.001) and nDec (0.62±0.36 n, F=6.42, p<0.001) is statistically significantly higher in the 5v5 game. The results showed that the 5v5 game is significantly more metabolically demanding Pmet (2.76±0.67 W•kg-1, F=66.08, p<0.001) compared to the other two game formats. The data presented in this paper can be used as a basis for the construction of specific exercises based on kinematic and physiological requirements, and for planning and programming microcycles in football.
#16 Septic retrocalcaneal bursitis in a young soccer player treated with hindfoot endoscopic bursectomy: a case report
Reference: J Surg Case Rep. 2023 Apr 19;2023(4):rjad169. doi: 10.1093/jscr/rjad169. eCollection 2023 Apr.
Authors: Morimoto Shota, Tachibana Toshiya, Iseki Tomoya
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10115463/pdf/rjad169.pdf
Summary: Septic retrocalcaneal bursitis (RB) is extremely rare with no reports on surgical treatment. Here, we describe a rare case of septic RB in a 14-year-old male soccer player who was treated with hindfoot endoscopic bursectomy. A 14-year-old male soccer player complained of right heel pain without trauma histories when he was playing a soccer. Based on physical examination, radiological findings and laboratory results, we diagnosed the patient with septic RB and started to treat with conservative treatment including a non-weightbearing splint and intravenous antibiotics therapy. However, his symptoms and laboratory results did not improve at 4 days after starting intravenous antibiotics therapy, and so we applied hindfoot endoscopic bursectomy for him. At 4 weeks after the surgery, he could return to the original sport at preinjury level without symptoms and complications. Septic RB in a 14-year-old male soccer player was successfully treated with hindfoot endoscopic bursectomy.
#17 Identifying Soccer Teams' Styles of Play: A Scoping and Critical Review
Reference: J Funct Morphol Kinesiol. 2023 Mar 30;8(2):39. doi: 10.3390/jfmk8020039.
Authors: Spyridon Plakias, Serafeim Moustakidis, Christos Kokkotis, Themistoklis Tsatalas, Marina Papalexi, Dionysios Plakias, Giannis Giakas, Dimitrios Tsaopoulos
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10123610/pdf/jfmk-08-00039.pdf
Summary: Identifying and measuring soccer playing styles is a very important step toward a more effective performance analysis. Exploring the different game styles that a team can adopt to enable a great performance remains under-researched. To address this challenge and identify new directions in future research in the area, this paper conducted a critical review of 40 research articles that met specific criteria. Following the 22-item Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines, this scoping review searched for literature on Google Scholar and Pub Med database. The descriptive and thematic analysis found that the objectives of the identified papers can be classified into three main categories (recognition and effectiveness of playing styles and contextual variables that affect them). Critically reviewing the studies, the paper concluded that: (i) factor analysis seems to be the best technique among inductive statistics; (ii) artificial intelligence (AI) opens new horizons in performance analysis, and (iii) there is a need for further research on the effectiveness of different playing styles, as well as on the impact of contextual variables on them.
#18 The seven phases of match status differentiate the running performance of soccer players in UEFA Champions League
Reference: Sci Rep. 2023 Apr 24;13(1):6675. doi: 10.1038/s41598-023-33910-9.
Authors: Marek Konefał, Łukasz Radzimiński, Jan Chmura, Toni Modrić, Michał Zacharko, Alexis Padrón-Cabo, Damir Sekulic, Sime Versic, Paweł Chmura
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10126199/pdf/41598_2023_Article_33910.pdf
Summary: The purpose of this research was to investigate the running performance of professional soccer players in relation to seven phases which resulted in the changing or maintaining the match status in the UEFA Champion League games during season 2020/2021. Moreover, we aimed to define which match status phases occur at the earliest stage of regular game time. This study involved professional soccer players from 24 teams participating in the group stage of UEFA Champions League in season 2020/21. The match status was divided into seven phases that result in changing or maintaining the match outcome: DW (Drawing to Winning); LD (Losing to Drawing); WW (Winning to Winning); DD (Drawing to Drawing); LL (Losing to Losing); DL (Drawing to Losing); WD (Winning to Drawing). Such running performance variables as: total distance covered (TDC) and distance covered in high-intensity running (HIR) were analyzed. Players participating in the UEFA Champions League matches cover the longest TDC in DW, DL and DD phases. TDC in these stages was between 111 and 123 m min-1. The highest HIR was recorded during phases: DW, DL and LL (range between 9.91 and 10.82 m min-1). In contrast, the lowest total distance and distance in HIR is covered during WD phase (only 105.57 ± 1.89 m min-1 and 7.34 m min-1 respectively). On average, phases resulting in the change of the match status occur during the first half, while all phases maintaining the result in the second half. Coaching staffs should consider registering and analysing the physical match performance in relation to described seven match status phases. Such information allows to prepare team-specific training drills, that players should perform more often in order to change or maintain the status of the game.
