Latest research in football - week 43 - 2022

#1 An evidence-based approach to assessing the effectiveness of training regimen on athlete performance: Youth soccer as a case study

Reference: PLoS One. 2022 Nov 1;17(11):e0276762. doi: 10.1371/journal.pone.0276762. eCollection 2022.

Authors: Cam M K Rechenmacher, Michael Keating, James D Nichols, Jonathan M Nichols

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9624410/pdf/pone.0276762.pdf

Summary: Athletic performance data are modeled in an effort to better understand the relationship between both hours spent training and a measurement of "commitment" to that training, and improvements in performance. Both increased training time and greater commitment were predicted to produce larger increases in performance improvement, and commitment was predicted to be the more important determinant of improvement. The performance of 108 soccer players (ages 9-18) was quantified over a 10-week training program. Hours spent training ranged from 16 to 90 during the course of the study, while commitment scores ranged from 0.55 to 2.00, based on a scale from 0.00 to 2.40. A model selection approach was used to discriminate among models specifying relationships between training hours and improvement, and commitment and improvement. Despite considerable variability in the data, results provided strong evidence for an increase in performance improvement with both training hours and commitment score. The best models for hours and commitment were directly compared by computing an evidence ratio of 5799, indicating much stronger evidence favoring the model based on commitment. Results of analyses such as these go beyond anecdotal experience in an effort to establish a formal evidentiary basis for athletic training programs.

 

 

#2 Effects of long-term detraining on muscle performance in young soccer players

Reference: J Sports Med Phys Fitness. 2022 Nov 2. doi: 10.23736/S0022-4707.22.13948-4. Online ahead of print.

Authors: Giovanni Melchiorri, Valerio Viero, Daniele Lentini, Giuseppe Annino, Virginia Tancredi, Tamara Triossi

Summary: Long-term detraining consists of a physiological partial or total reduction of the adaptations induced by training caused by a suspension period of the training itself longer than 4 weeks. The aim of this study was to analyze a group of young soccer players by assessing the effects of long-term detraining on neuromuscular performance. A study sample of 35 young soccer players of sub-elite level (age 14.5 ± 0.5 years) was recruited. The subjects were tested 7 days before the interruption of training for the summer break (T0), and at the end of the 7-week detraining period (T1). No statistically significant differences were found for BMI (p=0.283) and percentage of fat mass (p=0.273) between T0 and T1. PUSH UP (p=0.016; ES=effect size 0.2) and SIT UP (p=0.001; ES 1.2) test values show statistically significant increase, those of CHIN UP (p=0.05; ES -0.2), instead, a statistically significant worsening. Statistically significant but moderate differences on Speed Running Test 30 meters (p=0.001; ES: 0.3) are observed as well as trivial differences on 50 meters (p=0.001; ES: 0.2), while differences on 10, 15 and 20 meters are irrelevant. As for the jump tests, values show a slight worsening (p=0.135; ES 0.2) in Squat Jump and Counter Movement Jump (p=0.153; ES 0.2) without statistical significance. A 7-week-long detraining period does not seem to produce any appreciable changes on neuromuscular performance of the lower limb (trained muscle) in young soccer players. As regards the analyzed age group, coaches should not focus their attention on neuromuscular efficiency maintenance exercises in the off-season period.

 

 

#3 Penalty feet positioning rule modification and laterality effect on soccer goalkeepers' diving kinematics

Reference: Sci Rep. 2022 Nov 2;12(1):18493. doi: 10.1038/s41598-022-21508-6.

Authors: Rafael Luiz Martins Monteiro, Bruno Luiz Souza Bedo, Pedro Henrique Martins Monteiro, Felipe Dos Santos Pinto de Andrade, Felipe Arruda Moura, Sergio Augusto Cunha, Ricardo da Silva Torres, Daniel Memmert, Paulo Roberto Pereira Santiago

Download link: https://www.nature.com/articles/s41598-022-21508-6.pdf

Summary: In 2019, a new rule was applied in soccer. It allows the goalkeeper to have only one foot or part of it on the goal line when the kicker hits the ball, unlike the previous rule that determined the goalkeeper should have both feet on the line. The purpose of the present study was to analyze how the change in the rule and the lower limbs laterality influences on the diving save kinematic performance in penalties. Six goalkeepers, two professionals and four amateurs, performed a total of 20 dives in the laboratory and had their force and impulse exerted by the lower limb and displacement/velocity data from the center of body mass collected through force plates and kinematic analysis. The side preference was collected through an inventory. The results showed that goalkeepers dive further (p < 0.001) and faster (p < 0.001) when diving according to the new rule. Dives for the non-dominant side presented higher values than the trials for the dominant side in mediolateral (p = 0.02) and resultant (p = 0.03) displacements. Concluding, the goalkeepers performed better with the new rule in the analyzed variables and the lower limb preference has influenced only the mediolateral and resultant displacement.

 

 

#4 Preliminary results indicate that regular training induces high protection against oxidative stress in basketball players compared to soccer

Reference: Sci Rep. 2022 Nov 2;12(1):18526. doi: 10.1038/s41598-022-23351-1.

Authors: Simone Luti, Rosamaria Militello, Tania Fiaschi, Francesca Magherini, Tania Gamberi, Matteo Parri, Riccardo Marzocchini, Simone Pratesi, Riccardo Soldaini, Alessandra Modesti, Pietro A Modesti

Download link: https://www.nature.com/articles/s41598-022-23351-1.pdf

Summary: In elite athlete several metabolic changes occur during regular training. These modifications are associated with changes in blood metabolic profile and can lead to adaptive mechanisms aimed at establish a new dynamic equilibrium, which guarantees better performance. The goal of this study was to characterize the plasma metabolic profile and redox homeostasis, in athletes practicing two different team sports such as soccer and basketball in order to identify potential metabolic pathways underlying the differences in training programs. A cohort of 30 male, 20 professional players (10 soccer and 10 basketballs) and 10 sedentary males as control were enrolled in the study. Plasma redox balance, metabolites and adiponectin were determined. The results show low levels of oxidative species (25.5%), with both high antioxidant capacity (17.6%) and adiponectin level (64.4%) in plasma from basketball players, in comparison to soccer players. Metabolic analysis indicates in basketball players a significant high plasma level of amino acids Valine and Ornithine both involved in redox homeostasis and anti-inflammatory metabolism.

 

 

#5 Two-dimensional and three-dimensional multiple object tracking learning performance in adolescent female soccer players: The role of flow experience reflected by heart rate variability

Reference: Physiol Behav. 2022 Oct 29;258:114009. doi: 10.1016/j.physbeh.2022.114009. Online ahead of print.

Authors: Xiang Che, Yu Zhang, Jingkang Lin, Kun Zhang, Weiqun Yao, Jijun Lan, Jie Li

Summary: Three-dimensional multiple object tracking (3D-MOT) has been used in various fields to mimic real-life tracking, especially in perceptual-cognitive skills training for soccer. Yet, the learning efficiency in 3D-MOT tasks has not been compared with 2D-MOT. Further, whether the advantage can be reflected by heart rate variability (HRV) based on the neurovisceral integration model should also be examined. Therefore, we used both 2D- and 3D-MOT in a brief adaptive task procedure for adolescent female soccer players with HRV measurement. A faster tracking speed threshold of participants was found in the 3D- compared to 2D-MOT, as well as average tracking speed in the last training period of 3D-MOT. Moreover, lower low frequency (LF) components of HRV in the 3D-MOT indicated a flow experience, demonstrating the provision of more attentional resources. Therefore, we observed that adolescent female soccer players demonstrated higher learning efficiency in 3D-MOT tasks in virtual reality (VR) through a higher flow experience. This study examined the learning efficiency between the two MOT tasks in the soccer domain using evidence from HRV and highlighted the utility and applicability of 3D-MOT application.

 

 

#6 Quantifying Exposure and Intra-Individual Reliability of High-Speed and Sprint Running During Sided-Games Training in Soccer Players: A Systematic Review and Meta-analysis

Reference: Sports Med. 2022 Nov 4. doi: 10.1007/s40279-022-01773-1. Online ahead of print.

Authors: Antonio Dello Iacono, Shaun J McLaren, Tom W Macpherson, Marco Beato, Matthew Weston, Viswanath B Unnithan, Tzlil Shushan

Summary: Sided games (i.e., small sided, medium sided, large sided) involve tactical, technical, physical, and psychological elements and are commonly implemented in soccer training. Although soccer sided-games research is plentiful, a meta-analytical synthesis of external load exposure during sided games is lacking. The objective of this systematic review and meta-analysis was to: (1) synthesize the evidence on high-speed and sprint running exposure induced by sided games in adult soccer players, (2) establish pooled estimates and intra-individual reliability for high-speed and sprint running exposure, and (3) explore the moderating effects of game format and playing constraints. A literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Four databases (PubMed/MEDLINE, Scopus, SPORTDiscus, Web of Science Core Collection) were systematically searched up to 25 January, 2022. Eligibility criteria were adult soccer players (population); training programs incorporating sided games (intervention); game manipulations including number of players, pitch dimension, and game orientation (comparator); and high-speed, very high-speed, and sprint relative (m[Formula: see text]min-1) running distances and associated intra-individual reliability (outcome). Eligible study risk of bias was evaluated using RoBANS. Pooled estimates for high-speed and sprint running exposure, and their intra-individual reliability, along with the moderating effect of tracking device running velocity thresholds, pitch dimension (i.e., area per player), and game orientation (i.e. score or possession), were determined via a multi-level mixed-effects meta-analysis. Estimate uncertainty is presented as 95% compatibility intervals (CIs) with the likely range of relative distances in similar future studies determined via 95% prediction intervals. A total of 104 and 7 studies met our eligibility criteria for the main and reliability analyses, respectively. The range of relative distances covered across small-sided games, medium-sided games, and large-sided games was 14.8 m[Formula: see text]min-1 (95% CI 12.3-17.4) to 17.2 m[Formula: see text]min-1 (95% CI 13.5-20.8) for high-speed running, 2.7 m[Formula: see text]min-1 (95% CI 1.8-3.5) to 3.6 m[Formula: see text]min-1 (95% CI 2.3-4.8) for very high-speed running, and 0.2 m[Formula: see text]min-1 (95% CI 0.1-0.4) to 0.7 m[Formula: see text]min-1 (95% CI 0.5-0.9) for sprinting. Across different game formats, 95% prediction intervals showed future exposure for high-speed, very high-speed running, and sprinting to be 0-46.5 m[Formula: see text]min-1, 0-14.2 m[Formula: see text]min-1, and 0-2.6 m[Formula: see text]min-1, respectively. High-speed, very high-speed running, and sprinting showed poor reliability with a pooled coefficient of variation of 22.8% with distances being moderated by device speed thresholds, pitch dimension, and game orientation. This review is the first to provide a detailed synthesis of exposure and intra-individual reliability of high-speed and sprint running during soccer sided games. Our estimates, along with the moderating influence of common programming variables such as velocity thresholds, area per player, and game orientation should be considered for informed planning of small-sided games, medium-sided games, and large-sided games soccer training.

 

 

#7 Individual-Specific Relationship Between External Training and Match Load and Creatine-Kinase Response in Youth National Team Soccer Players

Reference: Sports Health. 2022 Oct 30;19417381221128822. doi: 10.1177/19417381221128822.

Authors: Gabor Schuth, Gyorgy Szigeti, Gergely Dobreff, Alija Pasic, Tim Gabbett, Adam Szilas, Gabor Pavlik

Summary: Previous studies have examined the relationship between external load and creatine-kinase (CK) response at the team level. This study aimed to build individualized CK prediction models for elite youth national team soccer players. We hypothesized that the CK response of youth soccer players can be categorized as being sensitive to micromovements (MM), high-velocity (HV) parameters, or the combination of both, measured during training sessions and matches. A total of 25 U16-U17 youth national team soccer players were monitored during training sessions and matches using global positioning system (GPS) units. Individual CK values were measured every morning from whole blood. The data set consisted of 57 ± 17 individual datapoints per player. Individual prediction models were used to examine the relationship between external load and consecutive CK changes. Numerous models were built for each player using MM, HV parameters, or the combination of both. The performance of the models was described by the R2 and the root mean square error (RMSE, U/l for CK values). The MM models were superior for 8 players (R2 = 0.68; RMSE = 113 U/l), followed by HV (8 players; R2 = 0.69; RMSE = 88 U/l) and the combined models (2 players; R2 = 0.64; RMSE = 141 U/l). For the remaining 7 players, the R2 of the models was <0.5. The recovery time between efforts was more important in the HV model. Players could be categorized on sensitivity to MM, HV movements, or the combination of both. These findings can be used to individualize postmatch recovery strategies and to optimize weekly training periodization to maximize match performance.

 

 

#8 A review of the essential visual skills required for soccer: Beyond 20-20 optometry

Reference: Front Sports Act Living. 2022 Oct 12;4:965195. doi: 10.3389/fspor.2022.965195. eCollection 2022.

Authors: Lourens Millard, Gerrit Jan Breukelman, Nonkululeko Mathe, Ina Shaw, Brandon S Shaw

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9596797/pdf/fspor-04-965195.pdf

Summary: In ball sports such as soccer, the visual system is critical in guiding a player's search for crucial information that underpins skillful behavior, which requires the incorporation of all of the relevant information in the environment in order to make successful decisions under pressure. However, vision in sport, and focusing on the specific visual skills required to be successful in a particular sport has largely been a practice ignored by experts and coaches as being an essential component of athletic performance. This is the first attempt to summarize and compile the necessary visual skills for soccer. This review's evidence suggests that, while current research still tends to focus on visual skills as a whole, there is a need to streamline this focus to the necessities of a particular sport. Furthermore, in identifying the visual skills essential for soccer, it allows for the effective training and testing of these skills, as well as for talent identification.

 

 

#9 Positive association of lean mass and negative association of protein intake on bone mass and bone geometry of adolescent soccer players

Reference: Nutrition. 2022 Sep 30;105:111857.  doi: 10.1016/j.nut.2022.111857. Online ahead of print.

Authors: Raiany Rosa Bergamo, Mauro Alexandre Páscoa, Jefferson Eduardo Hespanhol, Anderson Marques de Moraes, Gil Guerra-Júnior

Summary: The aim of this study was to evaluate the association of food consumption and body composition on bone parameters in adolescent soccer players. There were 148 male soccer players 12 to 18 y who participated in the study. Body composition was assessed by dual energy x-ray absorptiometry, comprising bone mineral density (BMD) and bone mineral content (BMC) of total body without head (TBLH), lumbar spine (L1-L4), and right femoral neck (RFN). The bone geometry variables measured were femoral strength index (FSI), buckling ratio (BR), section modulus (Z), cross-sectional moment of inertia (CSMI), and cross-sectional area (CSA). Food intake was analyzed using the 24-h food recall. Somatic maturation was estimated by the peak height velocity equation. For the statistical analysis, the stepwise multiple linear regression was used, with P < 0.05. Regarding food consumption, there was a high protein intake and low calcium intake. Lean mass was a predictor of BMC of TBLH (R2 = 0.524), L1-L4 (R2 = 0.492), and RFN (R2 = 0.405); BMD of L1-L4 (R2 = 0.407) and RFN (R2 = 0.27); Z (R2 = 0.683), CSMI (R2 = 0.630), and CSA (R2 = 0.640). There was a negative correlation between protein intake with bone mass and bone geometry parameters. In adolescent soccer players, lean mass was a predictor of bone parameters, and high protein intake was negatively associated with bone mass and geometry.

 

 

#10 A neural network for the detection of soccer headers from wearable sensor data

Reference: Sci Rep. 2022 Oct 28;12(1):18128. doi: 10.1038/s41598-022-22996-2.

Authors: Jan Kern, Thomas Lober, Joachim Hermsdörfer, Satoshi Endo

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9616946/pdf/41598_2022_Article_22996.pdf

Summary: The aim was to investigate the proposed association between soccer heading and deleterious brain changes, an accurate quantification of heading exposure is crucial. While wearable sensors constitute a popular means for this task, available systems typically overestimate the number of headers by poorly discriminating true impacts from spurious recordings. This study investigated the utility of a neural network for automatically detecting soccer headers from kinematic time series data obtained by wearable sensors. During 26 matches, 27 female soccer players wore head impacts sensors to register on-field impact events (> 8 g), which were labelled as valid headers (VH) or non-headers (NH) upon video review. Of these ground truth data, subsets of 49% and 21% each were used to train and validate a Long Short-Term Memory (LSTM) neural network in order to classify sensor recordings as either VH or NH based on their characteristic linear acceleration features. When tested on a balanced dataset comprising 271 VHs and NHs (which corresponds to 30% and 1.4% of ground truth VHs and NHs, respectively), the network showed very good overall classification performance by reaching scores of more than 90% across all metrics. When testing was performed on an unbalanced dataset comprising 271 VHs and 5743 NHs (i.e., 30% of ground truth VHs and NHs, respectively), as typically obtained in real-life settings, the model still achieved over 90% sensitivity and specificity, but only 42% precision, which would result in an overestimation of soccer players' true heading exposure. Although classification performance suffered from the considerable class imbalance between actual headers and non-headers, this study demonstrates the general ability of a data-driven deep learning network to automatically classify soccer headers based on their linear acceleration profiles.

 

 

#11 Extended Knee Control programme lowers weekly hamstring, knee and ankle injury prevalence compared with an adductor strength programme or self-selected injury prevention exercises in adolescent and adult amateur football players: a two-armed cluster-randomised trial with an additional comparison arm

Reference: Br J Sports Med. 2022 Oct 31;bjsports-2022-105890. doi: 10.1136/bjsports-2022-105890.

Authors: Hanna Lindblom, Sofi Sonesson, Kalle Torvaldsson, Markus Waldén, Martin Hägglund

Summary: The aim was to evaluate the preventive efficacy of an extended version of the Knee Control injury prevention exercise programme (IPEP) compared with an adductor strength programme and to a comparison group using a self-selected IPEP in amateur adolescent and adult male and female football players. Two-armed cluster-randomised trial with an additional non-randomised arm. All 251 amateur teams (players 14-46 years) in one regional football district were approached. Teams meeting inclusion criteria were randomised to (1) extended Knee Control or (2) an adductor strength programme. Teams already using an IPEP were allocated to a comparison group and received no new intervention. Players responded to weekly questionnaires about football exposures and injuries during a 7-month season. Seventeen teams in the extended Knee Control, 12 in the adductor and 17 in the comparison group participated, with 502 players. For the primary outcomes, no difference in injury incidence in three lower-limb injury locations combined (hamstring, knee and ankle) was seen between extended Knee Control and the adductor group, whereas extended Knee Control had 29% lower incidence than the comparison group (incidence rate ratio 0.71, 95% CI 0.52 to 0.98). No between-group differences in groin injury incidence were seen. The weekly injury prevalence rates in the three lower limb locations combined (hamstring, knee and ankle) were 17% lower (prevalence rate ratio (PRR) 0.83, 95% CI 0.69 to 1.00) and 26% lower (PRR 0.74, 95% CI 0.63 to 0.87) in extended Knee Control compared with the adductor and comparison groups, respectively. No difference in injury incidence was seen between the extended Knee Control and the adductor programme whereas extended Knee Control reduced injury incidence by nearly one-third compared with a self-selected IPEP. Players in extended Knee Control had lower injury prevalence compared with an adductor or self-selected IPEP.

 

 

#12 "Benched" The effect of the COVID-19 lockdown on injury incidence in sub-elite football in Australia: A retrospective population study using injury insurance records

Reference: Sci Med Footb. 2022 Nov 3. doi: 10.1080/24733938.2022.2143551. Online ahead of print.

Authors: Andrew G Ross, Marnee J McKay, Evangelos Pappas, Nazim Bhimani, Kerry Peek

Summary: The primary aim of this study was to compare injury rates pre- and post- COVID-19 lockdown in sub-elite football (soccer) players by analysing the full season and the first month of each season between 2018-2020. Secondary aims were to describe the incidence, location and type of injuries and to compare injuries by age group and sex. A de-identified insurance database was retrospectively coded using the Orchard Sports Injury Classification System. Injury incidence per 1000 hours as well as incidence rate ratios (IRR) with confidence intervals were calculated. No significant difference was found in the overall incidence rate in 2020 compared with the 2018 and 2019 seasons (IRR, 1.04 [95% CI, 0.96-1.13]; p= 0.294). However, overall injuries increased by 26% (IRR: 1.26 [95% CI 1.07- 1.47]; p<0.005) and joint sprains increased by 45% (IRR: 1.45 [95% CI 1.14- 1.84]; p<0.005) in the first month of 2020 compared with 2018-2019. Between 2018-2020 there were 4149 injury insurance claims, with anterior cruciate ligament (ACL) ruptures accounting for 19% of all injuries. When comparing sex, female players had significantly more ankle sprains whilst male players suffered more dental injuries. This study adds to a growing body of evidence investigating injury rates post COVID-19 lockdowns in sport. Sub-elite players appear to be at higher risk of joint injuries within the first month of training following a period of lockdown. Overall, stakeholders involved in sub-elite football should prioritise knee and ankle joint injury prevention.

 

 

#13 Injury-Inciting Activities in Male and Female Football Players: A Systematic Review

Reference: Sports Med. 2022 Oct 31. doi: 10.1007/s40279-022-01753-5. Online ahead of print.

Authors: Francesco Aiello, Franco M Impellizzeri, Susan J Brown, Andreas Serner, Alan McCall

Download link: https://link.springer.com/content/pdf/10.1007/s40279-022-01753-5.pdf

Summary: A comprehensive examination of the sport-specific activities performed around the time of injury is important to hypothesise injury mechanisms, develop prevention strategies, improve management, and inform future investigations. The aim of this systematic review is to summarise the current literature describing the activities performed around the time of injury in football (soccer). A systematic search was carried out in PubMed, Web of Science, SPORTDiscus, and OpenGrey. Studies were included if participants were football players aged > 13 years old and the activities performed at the time of injury were reported together with the total number of injuries. Risk of bias was assessed using an adapted version of checklists developed for prevalence studies. The activities reported by the studies were grouped to account for inconsistent reporting, and the proportion of each injury activity was calculated. Data were not meta-analysed due to high heterogeneity of methods and classification criteria. We included 64 studies reporting on 56,740 injuries in total. ACL injures were analysed by 12 studies, ankle/foot and knee injuries were analysed by five studies, thigh injuries were analysed by four studies, hip/groin injuries were analysed by three studies, and hamstring injuries were analysed by two studies. Five studies analysed more than one type of injury and 38 studies did not specify the type of injuries analysed. Running and kicking were the predominant activities leading to thigh and hamstring injuries. Changing direction and kicking were the predominant activities leading to hip and groin injuries and duels were the predominant activities leading to ankle injuries. Duels and pressing seem the predominant activities leading to ACL injuries, while results for other knee and general injuries were inconsistent. A qualitative summary of the activities performed at the time of injury has been reported. The results need to be interpreted carefully due to the risk of bias observed in the included studies. If we are to meaningfully progress our knowledge in this area, it is paramount that future research uses consistent methods to record and classify injuries and activities leading up to and performed at the time of injury.

 

 

#14 Examining karate and football perceptions and their links with athlete engagement and quality of life

Reference: Front Sports Act Living. 2022 Oct 13;4:971677. doi: 10.3389/fspor.2022.971677. eCollection 2022.

Authors: Teresa Limpo, Gabriela Rödel, Sid Tadrist

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9606457/pdf/fspor-04-971677.pdf

Summary: The importance of perceptions as determinants of people's behavior has been well-established, but little is known about athletes' perceptions of their sport and the links of these perceptions with other correlates. In this study, we compared karate (n = 51) and football (n = 49) athletes' perceived benefits and aggressiveness risks from their sports and examined whether these perceptions predicted athletes' engagement and quality of life (QoL). Participants completed perception measures of karate and football, and engagement and QoL measures. Results showed that karateka perceived more benefits and fewer risks in karate than football, but footballers generally perceived equal benefits and risks in both sports. Both athlete groups perceived similar physical and psychological benefits in their own sport, but deemed physical benefits as prominent outcomes in the other sport. Notably, karateka's perceived benefits about karate predicted engagement directly and QoL indirectly via vigor. Overall, karate athletes' perceptions seemed to be relevant to experiencing fulfillment in training and general well-being.

 

 

#15 Shortcomings of applying data science to improve professional football performance: Takeaways from a pilot intervention study

Reference: Front Sports Act Living. 2022 Oct 12;4:1019990. doi: 10.3389/fspor.2022.1019990. eCollection 2022.

Authors: Mat Herold, Matthias Kempe, Ludwig Ruf, Luis Guevara, Tim Meyer

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9597494/pdf/fspor-04-1019990.pdf

Summary: Positional tracking data allows football practitioners to derive features that describe patterns of player behavior and quantify performance. Existing research using tracking data has mostly focused on what occurred on the pitch, such as the determinants of effective passing. There have yet to be studies attempting to use findings from data science to improve performance. Therefore, 24 professional players (mean age = 21.6 years, SD = 5.7) were divided into a control team and an intervention team which competed against each other in a pre-test match. Metrics were gathered via notational analysis (number of passes, penalty box entries, shots on goal), and positional tracking data including pass length, pass velocity, defensive disruption (D-Def), and the number of outplayed opponents (NOO). D-Def and NOO were used to extract video clips from the pre-test that were shown to the intervention team as a teaching tool for 2 weeks prior to the post-test match. The results in the post-test showed no significant improvements from the pre-test between the Intervention Team and the Control Team for D-Def (F = 1.100, p = 0.308, η2 = 0.058) or NOO (F = 0.347, p = 0.563, η2 = 0.019). However, the Intervention Team made greater numerical increases for number of passes, penalty box entries, and shots on goal in the post-test match. Despite a positive tendency from the intervention, results indicate the transfer of knowledge from data science to performance was lacking. Future studies should aim to include coaches' input and use the metrics to design training exercises that encourage the desired behavior.