Abstract
This study systematically reviewed scientific literature regarding the effects of the FIFA 11+ intervention on the change of direction (COD) performance in soccer and futsal players. We conducted a keyword search on June 30, 2020, in SPORTDiscus, PubMed, Web of Science, Academic Search Complete, Scopus, CINAHL, and Google Scholar. We performed a meta-analysis to estimate the pooled effect size of FIFA 11+ interventions on COD performance. Sixteen RCTs studies met the eligibility criteria and were included in this review. Compared to the control group, the FIFA 11+ intervention yielded a 0.87 standard deviation (95% CI = 0.52, 1.21; I2 = 96.2%) decrease in the time of COD task completion in soccer and futsal players. In addition, there were no differential effects of the FIFA 11+ intervention compared to the control group in COD performance enhancement among age, gender, athletic level, sport, intervention frequency, intervention duration, and measure covariates. In conclusion, the FIFA 11+ intervention is effective in improving the COD performance of soccer and futsal players. Future studies should recruit large representative samples from professional soccer or futsal teams and examine the effectiveness of the FIFA 11+ intervention on the COD performance among population subgroups (e.g., by age and gender). Studies focusing on different COD tests are warranted to deepen the understanding of the FIFA 11+ intervention effects on the COD performance.
Introduction
Futsal is the indoor version of soccer that is officially sanctioned by soccer's international governing body (Fédération de Football Association, FIFA). Futsal originated in South America and is played on a smaller pitch than indoor soccer, with the number of players reduced to five-a-side (i.e., one goalkeeper and four outfield players). During both soccer and futsal games, the vast majority of the players’ actions involve a significant change of direction (COD) as the players attempt to mark opponents closely, evade opposition defenders, and gain positional advantages.1,2 In sports, COD is a component of agility that refers to the athletes’ ability to instantly decelerate in a specific direction, and change the direction of movement, then reaccelerate in a new direction with the shortest time possible. 3 Agility performance largely relies on cognitive processes; however, COD requires no reaction to a stimulus and focuses on the physical components of agility. 4
Since soccer and futsal players are usually performing the COD movements under high-intensity conditions, it is easy to cause sports injuries. In 2006, FIFA Medical Research and Evaluation Center launched the FIFA 11+ injury prevention program to prevent soccer players’ injuries. 5 The FIFA 11+ program consists of three parts to help prevent injuries. 6 Part one of the FIFA 11+ program includes running at a slow pace and active stretching, and controlled partner contacts. Part two of the FIFA 11+ program has core stabilization, eccentric thigh muscle training, proprioceptive training, dynamic stabilization, and plyometric exercises, all performed with proper postural alignment. Lastly, part three of the FIFA 11+ program contains running exercises and cutting movements. Notwithstanding the FIFA 11+ program’s effectiveness in reducing sport injuries,7,8 it may be challenging to convince coaches and athletes to solely conduct this injury prevention training unless the FIFA 11+ has a positive effect on physical performance.
Furthermore, while several studies have shown the FIFA 11+ training programs have made positive changes in COD performance;9,10 other studies have failed to demonstrate positive changes.11,12 For example, Zarei et al. have shown that the FIFA 11+ intervention had no significant effect on improving teen soccer players’ COD performance. 13 Similarly, Impellizzeri et al. have reported that the FIFA 11+ training did not affect the COD performance for male amateur soccer players. 12 In sum, compared with traditional warm-up routines, the potential COD performance gained from the FIFA 11+ intervention remains inconclusive.
Therefore, this systematic review with meta-analysis examines whether the FIFA 11+ interventions effectively improve futsal and soccer players’ COD performance compared with their regular warm-up routines. The study also aims to identify which variables (i.e., age, gender, sport, level, intervention frequency, intervention duration, and measure) contribute most significantly to improve COD performance.
Methods
A systematic review was conducted by following the Preferred Reporting Items for Systematic Reviews and Meta-analysis. 14
Study selection criteria
Studies that have met all of the following criteria are included in the review: (1) Study design: randomized controlled trial and randomized crossover trial; (2) Study subjects: healthy soccer and futsal players without a history of injury; (3) Intervention type: FIFA 11+ intervention; (4) Intervention duration: four weeks or longer; (5) Outcome: COD performance; (6) Article type: peer-reviewed publication; (7) Time search window: 2006 to June 30, 2020; FIFA 11+ was launched by FIFA in 2006; 15 and (8) Language: English.
Studies that have met any of the following criteria are excluded from the review: (1) FIFA 11+ interventions that incorporated no outcome of COD performance; (2) FIFA 11+ interventions that included no control group; (3) Intervention duration shorter than four weeks; (4) Intervention frequency less than two times per week; (5) Letters, editorials, study protocols, conference proceedings, books, or review studies; and (6) Studies not written in English.
Search strategy
We performed a keyword search in seven electronic bibliographic databases: PubMed, Web of Science, Scopus, CINAHL, SPORTDiscus, Academic Search Complete, and Google Scholar. The search algorithm has included all possible combinations of keywords from the following two groups: (1) “FIFA 11+”, “FIFA 11 plus”; and (2)“agility”, “change of direction”, “COD”, “505 test”, “505 agility”, “Illinois agility test”, “IAT”, “Zigzag test”, “Zig-zag test”, “side step”, “side stepping”, “triangle sprint”, “cutting maneuver”, “shuttle run”, “shuttle sprint”, “sideways shuffle”, “T-test”, “T-drill”, “Y-shaped drill”, “Y-drill”, “L-drill”, “L-shaped drill”, “Pro-agility”, “arrowhead test”, “arrowhead agility”, “Balsom test”, “Balsom agility”, “3 Cone drill”, “3-Cone test”, “spider agility”, “Slalom sprint”, “up and back test”, “physical fitness”, “physical performance”, “motor performance”, “fitness performance”, and “sport performance”. We screened titles and abstracts of the studies identified through the keyword search against the study selection criteria. We retrieved the potentially relevant studies for an evaluation of the full-text. Two co-authors independently conducted a title and abstract screening and identified potentially relevant studies for the full-text review. We were using Cohen’s kappa (κ = 0.91) to assess the inter-rater agreement. The co-authors resolved discrepancies through face-to-face discussions and jointly determined the final pool of studies included in the review.
We conducted a reference list search (i.e., backward reference search) and a cited reference search (i.e., forward reference search) based on the full-text studies identified from the keyword search that met the study selection criteria. Studies identified from the backward and forward reference search were further screened and evaluated using the same study selection criteria. The co-authors repeated a reference search on all newly identified studies until no additional relevant articles were found.
Data extraction
We used a standardized data extraction form to collect methodological and outcome variables from each included study, including authors, publication year, study design, sample size, age, gender, sport, level, intervention frequency, intervention duration, measures, and main results.
Statistical analysis
We performed a meta-analysis to estimate the pooled effect of the FIFA 11+ intervention on the COD performance. Standardized pooled effect sizes (i.e., Hedge’s g), denoted by the difference in standard deviations in the time of COD task completion between the FIFA 11+ and the control group, were estimated. The I2 index was used to assess study heterogeneity. 16 A fixed-effect model (FE) was estimated when I2 ≤ 50%, and a random-effect model (RE) was estimated when I2 > 50%. Using Begg's and Egger's tests to assess publication bias.17,18 We used Stata 16 SE version (Stata Corp, College Station, TX) to conduct statistical analysis. All analyses have used two-sided tests, and a p-value of less than 0.05 was considered statistically significant. The standardized effect size was interpreted following Hopkins’s recommendations: 0.0–0.19: trivial, 0.2–0.59: small, 0.6–1.19: moderate, 1.2–2.0: large, and >2.0: very large. 19 Subgroup analyses were conducted to determine the potential covariates that may affect the effectiveness of CT intervention.
Study quality assessment
We have used the National Institutes of Health’s Quality Assessment Tool for Controlled Intervention Studies to assess each included study’s quality. 20 This assessment tool rates each study based on 14 criteria. For each criterion, a score of one is assigned if “yes” is the response, whereas a score of zero is assigned otherwise. A study-specific global score ranging from zero to 14 is calculated by summing up scores across all criteria. The study quality assessment helped measure the strength of scientific evidence but is not used for determining the inclusion of studies.
Results
Study selection
Figure 1 shows the study selection flowchart. We have identified 151 studies by the keyword search, including 11 studies from PubMed, 26 studies from Web of Science, 20 studies from SPORTDiscus, 24 studies from Scopus, 23 studies from CINAHL, 20 studies from Academic Search Complete, 27 studies from Google Scholar, and eight studies from forward/backward search. After removing duplicates, 66 unique studies entered title and abstract screening, from which 93 studies have been excluded. After the title and abstract screening, 42 articles were excluded. The full texts of the remaining 24 studies were reviewed against the study selection criteria. Of the 24 studies, eight studies have been excluded. The reason is that two of the studies were without COD measures, two studies have had a FIFA 11+ intervention durations that are less than four weeks, two studies did not recruit futsal or soccer players, and the remaining two studies have adopted a modified version of FIFA 11+ intervention. In total, 16 studies have met the selection criteria and are included in the qualitative synthesis, and 15 studies were included in the meta-analysis; one study has been excluded during the data extraction due to difficulties in calculating the effect size.

Study selection flowchart.
Basic characteristics of the included studies
Table 1 summarizes the basic characteristics of the 16 studies included in the review.9,10,12,13,21,22–32 All of these studies are randomized controlled trials. The sample size ranges from 20 to 122, with a mean of 23 participants. Subject age ranges from 10 to 27. Nine studies have focused on adolescent athletes between the ages of 10 and 16, and the other seven studies have focused on young adults aged from 17 and older.9,10,21,23,24,30,32 Moreover, ten studies have included only male athletes, two studies included only female athletes,25,26 three do not report on gender distribution,13,21,32 and the remaining one study had a female percentage of 5%. 31 Fourteen studies recruited amateur players, and the remaining two studies recruited elite players.9,29 Eleven studies recruited soccer players, and the remaining five studies recruited futsal players.10,13,21,24,32 Intervention duration in these 17 studies varies from four to 30 weeks, with a median follow-up period of ten weeks. A total of seven interventions have taken place three times per week, six interventions two times per week, and the remaining three interventions that have taken place five times per week. Regarding COD measures, nine studies have adopted the Illinois agility test, five studies have adopted the agility T-test, one study has adopted the V-cut test, one study has adopted the Zigzag test, one study has adopted the Arrowhead agility test, and the remaining one study has adopted the 180° COD test.
Basic characteristics of the studies included in the review.
180°COD: 180° change of direction test.
aNumber of participants at the end of the studies.
Meta-analysis
Figure 2 reports the results from the meta-analysis. Compared to the control group, the FIFA 11+ interventions yielded a 0.87 standard deviation (SD; 95% CI = 0.52, 1.21; I2 = 96.2%) reduction in the time of COD task completion. No publication bias has been identified based on Egger’s test and Begg’s test (p-values >0.05).

Effect size (ES) of all studies meeting the inclusion criteria. Diamonds represent the pooled ES across trials.
Table 2 reports results from the subgroup analyses. No differential effect of FIFA 11+ intervention was found compared to the control group in COD performance enhancement among age, gender, athletic level, sports, intervention frequency, intervention duration, and measure covariates (p-value > 0.05).
Subgroup analysis assessing potential moderating factors for the COD performance of the FIFA 11+ intervention vs. control group.
No.: number of the included studies; CI: confidence interval; I2: heterogeneity; ES: effect size; p: test for overall effect; pdiff, test for subgroup differences.
Study quality assessment
Table 3 reports criterion-specific and global ratings from the study quality assessment. The included studies, on average, have scored 10.8 out of 14, with a range from nine to 13. All studies have used adequate RCT designs, which state that the control and intervention arms were similar at baseline on key characteristics that could affect outcomes. All studies have strictly adhered to the pre-specified intervention protocols and assessed outcomes using valid and reliable measures. 33 Seven of the 16 studies have assessed outcomes blinded to participants’ group assignments and concealed treatment allocations. Fourteen of the 16 studies have an overall dropout rate lower than 20%. Sixteen studies have analyzed the results based on their original random treatment allocation. Eight of the 16 studies have used an intention-to-treat analysis. Out of the 16 studies, only four have reported a power analysis.
Study quality assessment.
1 denotes Yes and 0 denotes No.
Discussion
This systematic review assessed FIFA 11+ intervention’s effectiveness on futsal and soccer players’ COD performance. Seventeen RCTs studies have met the pre-determined eligibility criteria and are included in the review. Compared to the control group, the FIFA 11+ intervention effectively improves the COD performance in futsal and soccer players. No differential effect of the FIFA 11+ intervention has been found compared to the control group in COD enhancement among age, gender, athletic level, sports, intervention frequency, and intervention duration covariates.
One potential explanation for the present findings could be that the FIFA 11+ interventions included the essential components for enhancing COD. For instance, the exercise across the pitch (consisting of sprint training over 30 m) in Part 2 of the FIFA 11+ intervention may positively affect the COD performance. 34 Furthermore, most of the players recruited in the included studies were amateur; they may have less sprint training background than professional players. Therefore, the sprint training exercises in Part two of the FIFA 11+ interventions work more efficiently to improve the players’ speed and COD performance. Also, the plyometric exercises in Part two of the FIFA 11+ interventions can improve the muscle force and power output, as well as the ability of deceleration and acceleration, resulting in COD enhancement. 35 Core exercises in part two of the FIFA 11+ interventions, can contribute to enhancing the athlete’s COD performance. By focusing on improving the core stability, players can generate, transfer, and control force and motion in the distal segments of the kinetic chain.36,37 Moreover, Nordic hamstring movement and squats in Part two of the FIFA 11+ intervention may have a positive effect on hamstring muscle contraction during striking, accelerations/decelerations, cutting, and sidestepping maneuvers.10,35 Furthermore, the Nordic hamstring movement and squats have increased hamstring eccentric and concentric strengths, which may directly contribute to improving COD performance. 10 The plant and cut (i.e., agility exercise) in Part three of the FIFA 11+ intervention can directly develop COD performance in terms of neuromuscular control when changing direction, acceleration, and deceleration. The FIFA 11+ program exercises have positively impacted the COD performances of soccer and futsal players.
Since the FIFA 11+ intervention’s main purpose was to facilitate neuromuscular control during all exercises while ensuring correct postures, another possible explanation for the FIFA 11+ intervention induced enhancement in COD performance may be associated with the increase of neuromuscular control ability. The FIFA 11+ interventions can be considered additional neuromuscular training that could help athletes achieve COD movements. Evidence shows that neuromuscular training interventions, including plyometric training, balancing training, and lumbar pelvic stabilization training, can enhance an athlete’s COD performance through enhanced neuromuscular control ability.45 Additionally, the effectiveness of the FIFA 11+ intervention on COD performance may be associated with the modifications in kinematics variables such as contact time, braking time, and impulse. The FIFA 11+ interventions focus on appropriate biomechanical techniques and enhanced consciousness and movement control during diverse activities such as standing, running, planting, and cutting, 6 which may, in turn, strengthen athlete’s COD performance.
In this study, subgroup analysis was conducted to identify possible covariates (including age, gender, athletic level, sports, intervention frequency, intervention duration, and measures) that may moderate the effectiveness in COD performance between the FIFA 11+ intervention and the control group. No differential effect of the FIFA 11+ intervention on COD performance was observed among these covariates. This null finding may be due to the relatively small subgroup studies (i.e., only five studies recruiting adults, three studies recruiting females, four studies recruiting futsal players, and three studies recruiting elite players).
A few limitations pertaining to this review and the included studies should be noted. First of all, a small and heterogeneous set of studies have been included in the review. The included studies were conducted with relatively small samples of different age groups (e.g., adolescents vs. adults), genders, and athletic levels (e.g., amateur vs. elite). Second, the intervention frequencies and durations have varied across the studies. Another important note is that different COD tests used in the studies cover different aspects or task-specific characteristics of the COD. 39 Therefore, the specific characteristics that are needed for the Illinois agility test might be affected to a different extent compared to the characteristics required for the 180° COD test through the FIFA 11+ intervention. In sum, these study heterogeneities have confined the generalizability of review findings.
Conclusions
The present study showed that the FIFA 11+ intervention has effectively improved soccer and futsal players’ COD performance. No differential effect of FIFA 11+ intervention was found compared to the control group in COD performance enhancement among age, gender, athletic level, sports, intervention frequency, intervention duration, and measure covariates. Future studies should recruit large representative samples from elite soccer or futsal teams and examine the effects of the FIFA 11+ intervention on COD performance among population subgroups (e.g., by age and gender). Studies focusing on different COD tests are warranted to deepen the understanding of the FIFA 11+ intervention effects on COD performance.
Practical applications
Despite the success of the FIFA 11+ program in reducing sport injuries, it may be challenging, in practical terms, to convince coaches and athletes to conduct this program regularly solely to prevent injuries. This study aimed to prove that the FIFA 11+ program positively and directly impacts soccer and futsal players' physical performance (i.e., COD). We have conducted a systematic review and meta-analysis regarding the effectiveness of the FIFA 11+ intervention on soccer and futsal players’ COD performance. The current study’s findings reinforce that even short-term adherence to the FIFA 11+ program elicits substantial improvements (compared with its paired control group) in COD performance. Thus, we would advocate coaches exchanging traditional warm-up plans with the FIFA 11+ in futsal and soccer players.
Furthermore, in practical terms, the FIFA 11+ program usually performs in three parts with a total duration of 20 minutes with a precisely programmed exercise load and precisely scheduled rests between sets. The first part included warming up by running with performing tasks; the second part included various strength development exercises, plyometrics and stabilization, and balance exercises; and the third part also covered running, including specific tasks. According to the FIFA 11+ manual's instructions, the program comprises three levels (low, moderate, and high) of difficulty depending on the soccer and futsal athlete's age and preparedness level. The manual can be found on the official website for detailed instructions for the FIFA 11+ warm-up program (www.f-marc.com/11 plus). The FIFA 11+ program focuses on correct techniques throughout jumping, landing, and cutting movements by giving feedback about improper movement patterns. Therefore, the FIFA 11+ program is essential for movement competency in young soccer and futsal athletes.
It is also worth noting that the FIFA 11+ intervention for improving COD performance depends on the team’s compliance, which is a factor in the motivation, decisions, and actions of the head coach. The head coach is often responsible for implementing pre-activity warm-up and stretching practices. However, some of these coaches may be unaware of the FIFA 11+ injury prevention programs' current recommendations. Thus, there is a need for futsal and soccer head coaches' comprehensive education concerning the importance of implementing the FIFA 11+ program. 40 Coach education should play an essential role in how the FIFA 11+ program is delivered to teams and individual players. Thus, the FIFA 11+ program has the potential to serve as not only an injury prevention program but also as an efficient on-field warm-up before the competition. Coaches and athletic trainers should acknowledge this and consider familiarizing themselves with the program and including similar movements into the warm-ups and exercises for the athletes to become comfortable with the movement patterns, thus allowing for more seamless integration.
Footnotes
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was supported by the National Social Science Fund of China (NO.16BTY065) and the Leading Talents of Independent Research Program of Tsinghua University (NO.2016THZWLJ12). The funder has no role in the design, execution, interpretation, or writing of the study.
