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. 2022 Oct 20;17(10):e0275545. doi: 10.1371/journal.pone.0275545

Effects of the FIFA 11+ and a modified warm-up programme on injury prevention and performance improvement among youth male football players

Mojtaba Asgari 1,*, Mohammad Hossein Alizadeh 2,#, Shahnaz Shahrbanian 3,#, Kevin Nolte 1,#, Thomas Jaitner 1,#
Editor: Rafael Franco Soares Oliveira4
PMCID: PMC9584367  PMID: 36264894

Abstract

Introduction

The effects of the FIFA11+ programme (the 11+) on ankle and groin injuries and performance have remained questionable. The latter, particularly, has potentially reduced the implementation rate and applicability of the programme. This study aimed to evaluate the mid-to-long-term effects of the 11+ and a modified programme including football-specific exercises on injury prevention and performance improvement.

Materials and methods

Three teams of the Iranian Youth League (division two) volunteered to participate in this study and were randomly assigned to two intervention groups (F11+; n = 29, M11+; n = 31) and a control group (n = 30). The F11+ followed the FIFA 11+ programme, whereas the M11+ performed modified exercises three times weekly as a warm-up protocol before training and competition through a football season. The control group carried out its routine warm-ups, including joggings, basic football drills, and static stretches, while having no injury prevention approaches. Lower extremity injuries, as well as exposure time for each player, were recorded. The football-specific performance was assessed using the Illinois Agility and Slalom Dribbling tests. ANOVA, Fisher Freeman Halton, and chi-square tests were used to analyze the data.

Results

Injury incidences differed significantly between groups (p = 0.02, C = 0.40), with M11+ reporting the lowest incidence. Significant differences between the pre- and posttest as well as differences between the groups for development over time were revealed for the Illinois agility and dribbling speed (p≤0.01). Both performance tests demonstrated a large time effect, as the effect sizes for time in agility and dribbling speed were 0.74 (CI = [0.66; 0.79]) and 0.86 (CI = [0.79; 0.87]), respectively. The effect size for the interaction can be categorized as medium, with 0.38 (CI = [0.25; 0.49]) for agility and 0.52 (CI = [0.40; 0.61]) for dribbling speed. M11+ showed the largest improvement in both.

Discussion

Mid-to-long-term application of a structured dynamic warm-up that integrates injury prevention and performance approaches may lower injury incidences and improve youth subelite players’ performance. Although additional studies with larger samples are needed to prove the results of the current study, the amateur clubs/teams could integrate such twofold dynamic warm up into their routine training plan and benefit its advantages on injury prevention and performance improvement.

Introduction

Football accounts for nearly 300 million participants and is labeled the most popular but one of the riskiest Olympic sports [1, 2]. Missing training with a consecutive reduction in performance, dropout of young talent, early retirement, high socioeconomic costs, and increased risk of osteoarthritis are known as the consequences of sustaining injury [35]. Hence, mitigating football-related injuries has turned into the main focus of scientific inquiries. The FIFA 11+ programme (the 11+) was launched in 2006, aiming to integrate injury risk-mitigating exercises into a warm-up protocol. Given the advantages it entails in preventing injuries, it has been widely investigated and named a well-established injury prevention programme (IPP). The 11+ consists of three parts with an overall duration of 25 minutes and three difficulty levels. It aims to tackle the key elements of effective injury prevention programmes, such as neuromuscular control, static and dynamic balance, and the hamstring/quadriceps strength ratio [6].

The available literature strongly supports that the 11+ mitigates overall, thigh, and knee injuries among amature/subelite players [69]. More specifically, in men’s subelite football, it reduces injury burden by up to 40% [10]. However, the efficacy of the 11+ in the prevention of ankle and groin injuries [6, 7, 11] and players’ performance [12] has remained questionable. The latter, in addition to barriers such as prolonged duration, concerns regarding some exercises, and lack of a link to football-specific targets [13, 14], has been discussed as a potential reason for low compliance and less application of the programme [14]. Although high compliance has shown a strong correlation with the success of the IPPs and team success [15], O’Brien et al. (2017) reported that the 11+ was only implemented in 12% of the training sessions, while the modified forms were implemented in 28% of the sessions [14]. The most frequent reasons trainers gave for the modifications were adding variation, progression, challenge, and individualization [14, 16]. Additionally, Veith et al. suggested that part two of the FIFA11+ can be used outside of the training sessions since the trainers do not want to invest in it [17].

Although ankle injuries are among the most prevalent injuries in football [1820], lower effects of the 11+ on such injuries have been observed [6, 7]. One possible explanation for this lack of efficacy could be the low volume of dynamic exercises in the first part, followed by extensive static exercises in the second part of the programme. Nonprogressive and static exercises may not stimulate control mechanisms of the postural system and therefore may not reduce the risk of lower extremity injuries [21]. Studies by Veith et al. (2021) and Lopes et al. (2020) would precisely support this assumption, where they found no improvement in ankle stability, proprioception, and ankle evertors time latency following performing part two and the whole programme, respectively [17, 22, 23]. Hence, rescheduling the 11+ has been taken into account and appears to mitigate severe injuries and increase compliance [14].

Further, a lack of clarity exists regarding the effects of the 11+ on technical abilities and physical performance [12, 2427]. Although it is widely accepted that an appropriate warm-up programme should improve performance [28], more recent studies indicated that the 11+ programme does not improve players’ performance acutely but may reduce sprinting and agility compared to a dynamic warm-up programme. Another additional experiment demonstrated that the 11+ has no impact on kicking accuracy [29, 30].

Taken together, the main challenges regarding the 11+ correspond to low compliance and implementation rates, lower effects on ankle and groin injuries, and unclear effects on players’ performance. Considering that the 11+ is a verified warm-up, a new framework is needed to incorporate different training components into this programme. Thus, modernizing and modifying the 11+ based on football-specific demands may properly tackle these challenges and become essential, as it has not been updated since its launch (2006). Therefore, this study aims to evaluate the effects of the 11+ (F11+) and a modified programme (M11+), including more football-specific exercises on injury prevention and performance improvement. We expect that (i) players in the F11+ and M11+ groups suffer fewer lower extremity injuries than players in the control group, (ii) M11+ results in a lower incidence of lower extremity injuries than F11+, and (iii) M11+ improves performance, while F11+ does not affect it.

Methods

Study design

This prospective study involved two interventions and a control group (CG). The F11+ and M11+ groups performed the 11+ and the modified 11+, respectively, three times weekly for warming up before training sessions. The CG continued its routine warm-up, including basic football drills, running, cutting movements, and static stretch without any specific injury prevention approaches. The intervention lasted four months (June to October), corresponding to a complete season, as only a few teams attended the league. At baseline, players performed agility and slalom dribbling tests as described below; the tests were then repeated by the end of the season before the last match. According to the consensus statement on injury definitions and data collection in prospective studies, injuries and exposure time were documented during the study period [32]. The ethics committee of the Sport Sciences Research Institute of Iran approved the study design and research methods (ID IR.SSRI.REC.1397.257).

Participants and inclusion criteria

To calculate the sample size, we set the G-power Software version 3.1.9.4 (Universität Düsseldorf, Germany) as the exact test family, 2 tails, power of 80, alpha error 0.05, proportion 1 = 0.5, and proportion 2 = 0.15. The results revealed that 31 players per group are needed. Nevertheless, we asked all seven football clubs participating in Iranian youth league division three (northwest subdivision) to attend the study. The inclusion criteria were as follows: (i) competition in youth league division two, (ii) age range of 16 to 19 years at baseline, and (iii) at least two training sessions plus a match per week. Players were excluded if they (i) suffered severe lower extremity injury and trauma (exposure time ≥28 days) four months before the study, (ii) had a history of any musculoskeletal surgery, head concussion, or severe cardiovascular problems six months before the study, (iii) participated in other sports simultaneously or (iv) missed over 10% of the training sessions. Teams were also excluded if they were already applying an IPP as a part of their daily routine training, which resulted in one exclusion. Consequently, only four teams (124 players altogether) were eligible to attend the study, one of which (26 players) declined the invitation. As a result, three teams involving 98 players agreed to attend the study, eight of which were then excluded based on the exclusion criteria. The 90 volunteered participants signed a written consent letter and were free to leave the study at any time. Further, using an automat block randomized algorithm, three blocks were created (block1 = F11+, block2 = M11+, and block three = CG), and each team was randomly assigned to a block. Before the study commencement, trainers and players of the F11+ and M11+ were instructed to become familiar with their specific IPP in separate sessions. Further, they received adequate supportive materials (the video clips and manual of the 11+ and photoslides of the M11+ exercises).

Data collection and supervision

Medical assistants (licensed by the Sport-Medicine Federation of Iran) were responsible for diagnosing and documenting injuries. We defined an injury as "any complaint that results in a player being unable to take a full part in future football training or match play" [31]. Furthermore, we instructed trainers to record the exposure time using particular forms. While blinding each other and the study outcomes, two assistants were responsible for visiting the training sessions randomly and checking the accurate application of the interventions. Assessing compliance with the interventions was carried out by a threefold descriptive rating scale based on the percentage of fully completed warm-up sessions (HIGH>67% MOD<66%/LOW<33%) according to self-report data of trainers of the intervention groups.

Performance assessment

We recruited Illinois Agility (IA), as well as Slalom Dribbling (SD), tests to evaluate Football-specific performance [32, 33]. Within-subject and between-subject differences in pre vs posttest were considered as the interventions’ effects on those parameters. The IA performs in a rectangle of 10×5 m. The players start in the prone position, run toward the barrier at 10 m at maximum speed, return, and perform a zigzag run around four barriers, each 3.3 m apart. The test ends with another straight run to the end of the rectangle. For the SD, players dribble the ball after a starting signal in a zigzag shape around seven poles with a distance of one meter each and return a straight path of 10 meters. Each subject performed the test three times, and the best time, recorded through time gates, was considered for analysis.

The modified programme

M11+ consists of four parts (seven, four, four, and five minutes) and follows the structure of F11+. The first part includes core exercises (prone, supine, and dynamic plank), balance exercises, and M. iliopsoas strengthening. The second part involves straight running, controlled contacts, hip in and hip out (with higher frequency than the F11+), a dynamic stretch of hamstring and rotational, and cutting movements. The third part consists of Nordic Hamstring Exercise, single-leg standing with a heel-to-toe movement cycle (to optimize the stimulation of mechanoreceptors of the ankle), and throwing a ball to the partner simultaneously as well as squats (lunges, squat and single-leg squat). The last part includes agility and plyometric exercises, drop jumps, and countermovement jumps, as proposed by Thomas et al. [34]. The exercises are categorized into three difficulty levels and would adapt every 2–3 weeks depending on the players’ abilities and progress. By this, players may practice in a consecutive chain of static, dynamic, and intensive exercises and therefore should be ready for the main training body.

Data analysis and statistics

Injury incidence and rate ratios of total lower extremity injuries and thigh, knee, and ankle injuries served as primary outcomes. We calculated injury incidence based on the overall number of injuries per group divided by time exposure in players’ total hours of competition and training. Differences between pre- and posttest measures of IA and SD served as the secondary outcome. Chi-square and Fisher’s Freeman Halton tests were used to analyze the injury incidences and rate ratios of the three groups [35]. If the chi-square test was applicable, the corrected contingency coefficients (C) were calculated. For the performance parameters, Kolmogorov-Smirnoff and Leven’s tests were applied to verify the normality of the data and between-group homogeneity of variance, respectively. Repeated measures ANOVA analyzed differences between the interventions and the control group and the effect of the training period. The corresponding effect sizes (ESs) were determined by calculating η² and its 90% confidence interval (CI). Data were analyzed using SPSS software version 25, and the level of significance for all variables was set at p≤0.05.

Results

Over the football season, 6381 hours of training and matches were recorded, indicating that each player participated in approximately 56 hours of training (1675.66 ± 229.32 min) and 15 hours of matches (451.33 ± 92.64 min). Overall, 31 lower extremity injuries affected 24 players (26.6%). ANOVA revealed no differences between groups in age (p = 0.18), height (p = 0.07), weight (p = 0.11) or BMI (p = 0.06), as presented in detail in Table 1. The injury incidences of the lower extremities for the M11+, F11+, and CG were 2.00, 5.79, and 7.55 per 1000 h, respectively, demonstrating that compared to the M11+, players of the F11+ had 2.89 times higher lower extremities. The risk ratios for the CG were 3.77 and 1.30 times higher than those for the M11+ and F11+ groups, respectively. The chi-square test derived a significant dependence for the overall number of injuries and the prevention programmes (p = 0.02, C = 0.40), illustrating the lowest value for the M11+ and the highest for the CG. The follow-up chi-square analysis produced no significant difference in the number of injuries between the F11+ and CG (p = 0.50, C = 0.12).

Table 1. Anthropometric data of all players (mean and std dev).

Parameter M11+ F11+ CG Sig
Age (year) 16.98±0.7 16.96±0.68 16.69±0.58 0.18
Height (cm) 176±7.06 171.24±8.73 173.13±8.36 0.07
Weight (kg) 64.35±8.53 62.03±8.00 59.83±9.19 0.11
BMI (kg/m2) 20.70±1.69 21.06±1.08 19.85±1.79 0.06

Separately, for thigh (p = 0.70), knee (p = 0.10), and ankle (p = 0.09) injuries, no dependency on the interventions was found. Compared to the F11+ group, the M11+ group revealed on average 2.33 times fewer thigh, knee, and ankle injuries, including no injury incidences for the knee and ankle (Table 2).

Table 2. Lower extremity, thigh, knee, and ankle injuries.

Variable Total (n) Control (n) M11+ (n) F11+ (n)
Lower extremity (iir) Injured 31 (4.86) 15 (7.55) 5 (2.0) 11 (5.79)
Non-injured 59 15 26 18
Thigh Injured 13 5 3 5
Non-injured 77 25 28 24
Knee Injured 6 4 0 2
Non-injured 84 26 31 27
Ankle Injured 7 4 0 3
Non-injured 83 26 31 26

*iir = injury incidence ratio

Fig 1 illustrates the pre- and posttest results of the three groups. All three groups started on a similar level, as the group means were within 0.1 s in dribbling speed and agility during the pretest. All three groups improved during the training period. Agility and dribbling speed displayed the same hierarchy in improvement and differences between the three groups. The M11+ group showed the most considerable improvements in group means, with 1.09 s and 1.04 s, followed by the F11+ group, with 0.57 s and 0.52 s for agility and dribbling speed, respectively. The average times in the CG decreased by 0.35 s and 0.36 s, respectively.

Fig 1. Comparison pretest post-test in agility and dribbling speed.

Fig 1

A repeated-measure ANOVA supported these findings, as the effect of time and the interaction effect of group and time were significant (p≤0.01) for agility and dribbling speed. Both tests reveal a large time effect, as the effect size for time in agility is 0.74 (CI = [0.66;0.79]) and 0.86 (CI = [0.79;0.87]) in dribbling speed. The effect size for the interaction can be categorized as medium, with 0.38 (CI = [0.25;0.49]) for agility and 0.52 (CI = [0.40;0.61]) for dribbling speed (Table 3).

Table 3. Descriptive values and ANOVA results.

Agility [s] Dribbling speed [s]
Descriptive Pretest Posttest Pretest Posttest
 Modified 11+ 17.30 ± 0.66 16.21 ± 0.61 14.15 ± 1.15 13.11 ± 1.12
 Regular 17.27 ± 0.55 16.70 ± 0.77 14.16 ± 1.29 13.64 ± 1.29
 Control 17.27 ± 0.58 16.92 ± 0.54 14.25 ± 1.38 13.89 ± 1.37
ANOVA p-value p-value
 Group 0.082 0.396
 Time <0.001 <0.001
 time*group <0.001 <0.001

Discussion

This study aimed to compare the effects of the FIFA11+ and a modified warm-up programme, including dynamic and football-specific exercises, on the prevention of injuries and performance improvement among young subelite male players. Overall, players who performed the F11+ as a warm-up routine suffered nearly 27% fewer lower extremity injuries than those who performed their routine warm-up, including basic football drills, running and cutting movements, and static stretch. However, this difference was not statistically significant, which conflicts with the previous studies of Soligard et al. (2008), Owoeye et al. (2014), and Granelli et al. (2015) but supports the study of Hammes et al. (2015), which observed similar results in veteran players [6, 9, 36, 37]. A possible explanation for such a nonsignificant difference could be the small sample size, short monitoring period, and consequently lower number of lower extremity injuries over the study period. Furthermore, many injuries in football occur during matches. However, our study participants were only involved in 15 hours of matches during a complete football season and were at lower risk of sustaining injury. Additionally, this study focused on lower extremity injuries, while other studies considered full-body injuries and reported significant differences.

On the other hand, modernizing and modifying the F11+ according to football-specific demands could optimize its effect on lower extremity injuries and improve the performance of young male football players. Players who performed the M11+ suffered significantly lower extremity injuries (up to 55%) than both the F11+ and control groups (p≤0.05). Along this line, Al Attar et al. (2017) showed that combining the 11+ with highly intensive posttraining exercises improves the programme’s efficacy in preventing injuries [8]. In addition, the latest review on the literature pertaining to injury prevention strategies reported that football-related injuries can be mitigated by participating in dynamic warm-up programmes, including preventive exercises and adding strength, balance, and mobility exercises to the training sessions [38].

More specifically, our study revealed minor effects of F11+ on the prevention of ankle injuries, in line with the available literature. Lope et al. (2019 & 2020) reported that the 11+ produces no impacts on improving ankle stability and ankle evertor latency time [22, 23]. The dynamic stability of the ankle is mainly provided through the activity of the calf muscles. Additionally, most ankle injuries occur in the inversion position where the least joint stability exists, and the ankle is prone to injury. Therefore, delay in activation of ankle evertors that resist inversion and draw the ankle back to the upright position would reduce joint stability and put the athletes at higher risk of sustaining ankle injuries. Therefore, integrating plyometric, perturbation, and dynamic exercises that may properly stimulate proprioception into the warm-up strategy could be more beneficial in preventing ankle injuries. In the F11+ programme, there are more static than dynamic exercises, particularly in part two. The static structure of the F11+ could not stimulate feedback and control mechanisms of the postural system [22]. In contrast, dynamic exercises may adequately optimize the neuromuscular system and reduce severe ankle and knee injuries by improving proprioception [39]. Interestingly, the current study precisely addressed this assumption, where no ankle or knee injuries were observed in the M11+ group, albeit the differences were not statistically significant. Thus, further studies with larger sample sizes and better monitoring periods are required to prove our outcomes.

Neither F11+ nor M11+ could significantly reduce the risk of groin and hip injuries. Such lack of efficacy can be explained by the fact that no specific exercise for groin muscles is included in these warm-up modalities. This is an alarming deficiency and needs to be properly addressed, as up to 12% of subelite football injuries occur in the groin region [40]. Harøy et al. suggested that using Copenhagen adductor exercises may fill this gap by providing missing eccentric hip adduction strength [41]. The Copenhagen exercises appear to be highly adaptable to the 11+, as they require no specific equipment and have three levels of difficulties [41]. The better efficacy of the M11+ in preventing hip injuries, however, might be due to increasing the volume of hip dynamic stretch exercise, namely, hip-in, in addition to alteration of core area exercises.

According to agility and dibbling performance, the pretest results did not show significant differences between the groups, meaning that the groups were averaged at the same level of expertise before the intervention. Post test results at the end of the intervention course revealed a significant difference between the groups. The M11+ group showed better performance in agility and dribbling speed tests (p≤0.05). There were no significant differences between the FIFA 11+ and CG (p≥0.05). From the performance standpoint, the present study supports the studies of Ayala et al. [30], Parsons et al. [24] and Dunsky et al. [29], which also addressed the lack of performance improvement followed by performing the 11+ programme but are in contrast to the studies of Bizzini et al. (2013), Zarei et al., and Hwang et al. [26, 27, 42]. Players of the M11+ group performed the agility test significantly better than the F11+ and control groups. However, differences in dribbling speed were only significant between M11+ and F11+. Along with this, Daneshjoo et al. (2013) illustrated that F11+ might not improve the dribbling technique among youth players. Ayala et al., through their investigation of three different neuromuscular warm-up programmes, highlighted that F11+ would acutely decrease player sprinting compared to dynamic warm-ups [30]. Parameters such as agility and sprinting depend on the training features [43], so using exercises similar to real football’s movement patterns/tasks may enhance these parameters. Most likely, the negative effect of F11+ on agility and dribbling is due to the static structure of the programme. The volume of the plyometric and anaerobic exercises in the M11+ players was twice as high as that in the F11+ players, which could be the main reason for the improved agility and dribbling speed among the M11+ players. In this regard, Thomas et al. (2009) indicated that plyometric exercises could improve football players’ muscular power and agility [34]. As a result, implementing highly dynamic exercises as a part of warm-up routines but at a controlled intensity may be useful for the performance improvement of youth players.

As compliance with both programmes was calculated by MOD to HIGH, the study was not powered by compliance. However, another potential benefit of the M11+ might be increasing the compliance and implementation rate. According to the trainers’ self-reports, the completion rate of the M11+ programme was slightly better than that of F11+ (66% vs. 61%). This statistic, parallel with the study of O’Brien et al. (2016), indicates that both trainers and players would prefer to implement dynamic warm-up protocols to be well prepared for the further intensive and competitive parts of the training and competition [44].

Limitations

This study lacks a large sample size. Although we aimed to provide the most significant sample, three potential teams failed to meet the inclusion criteria and could not attend the study, and another team declined the invitation. This, alongside the short monitoring period caused by the small number of teams participating in the league, noticeably restricted us to manage a randomized controlled trial and somehow powered the outcomes.

Conclusion

Incorporating performance-specific and injury prevention-specific exercises into a structured warm-up programme provides a twofold warm-up modality, which may not only mitigate injuries but also improve the performance of youth subelite football players simultaneously. Therefore, it would be practical for daily routine training and competitions and, as a result, can be better accepted and implemented by football administrations. The amateur clubs/teams are highly recommended to integrate such warm up into their routine training plan.

Supporting information

S1 Data

(XLSX)

Acknowledgments

The authors would like to express their gratitude to Sahar Soheili for her comprehensive support in the data gathering and analysis phases.

Data Availability

*** PA @ ACCEPT: Please follow up with authors for data availabile at Accept *** We note that your Data Availability Statement reads: "The dataset is uploaded on Kaggle, a public repository platform for placing data sets. URL:www.kaggle.com/dataset/1f3df0f9ccf87f9dbeaca960baf76527376189128948699c4dec7eb056098834 https://doi.org/10.34740/KAGGLE/DSV/4054705.

Funding Statement

The authors received no specific funding for this work.

References

  • 1.Engebretsen L, Soligard T, Steffen K, Alonso JM, Aubry M, Budgett R, et al. Sports injuries and illnesses during the London Summer Olympic Games 2012. British journal of sports medicine. 2013;47(7):407–14. doi: 10.1136/bjsports-2013-092380 [DOI] [PubMed] [Google Scholar]
  • 2.Soligard T, Steffen K, Palmer D, Alonso JM, Bahr R, Lopes AD, et al. Sports injury and illness incidence in the Rio de Janeiro 2016 Olympic summer games: a prospective study of 11274 athletes from 207 countries. British Journal of Sports Medicine. 2017;51(17):1265–71. doi: 10.1136/bjsports-2017-097956 [DOI] [PubMed] [Google Scholar]
  • 3.Dvorak J, Junge A, Derman W, Schwellnus M. Injuries and illnesses of football players during the 2010 FIFA World Cup. British journal of sports medicine. 2011;45(8):626–30. doi: 10.1136/bjsm.2010.079905 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Junge A, Lamprecht M, Stamm H, Hasler H, Bizzini M, Tschopp M, et al. Countrywide campaign to prevent soccer injuries in Swiss amateur players. The American journal of sports medicine. 2011;39(1):57–63. doi: 10.1177/0363546510377424 [DOI] [PubMed] [Google Scholar]
  • 5.Valderrabano V, Hintermann B, Horisberger M, Fung TS. Ligamentous posttraumatic ankle osteoarthritis. The American journal of sports medicine. 2006;34(4):612–20. doi: 10.1177/0363546505281813 [DOI] [PubMed] [Google Scholar]
  • 6.Soligard T, Myklebust G, Steffen K, Holme I, Silvers H, Bizzini M, et al. Comprehensive warm-up programme to prevent injuries in young female footballers: cluster randomised controlled trial. Bmj. 2008;337. doi: 10.1136/bmj.a2469 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 7.Al Attar WSA, Soomro N, Pappas E, Sinclair PJ, Sanders RH. How effective are F-MARC injury prevention programs for soccer players? A systematic review and meta-analysis. Sports medicine. 2016;46(2):205–17. doi: 10.1007/s40279-015-0404-x [DOI] [PubMed] [Google Scholar]
  • 8.Al Attar WSA, Soomro N, Pappas E, Sinclair PJ, Sanders RH. Adding a post-training FIFA 11+ exercise program to the pre-training FIFA 11+ injury prevention program reduces injury rates among male amateur soccer players: a cluster-randomised trial. Journal of physiotherapy. 2017;63(4):235–42. doi: 10.1016/j.jphys.2017.08.004 [DOI] [PubMed] [Google Scholar]
  • 9.Silvers-Granelli H, Mandelbaum B, Adeniji O, Insler S, Bizzini M, Pohlig R, et al. Efficacy of the FIFA 11+ injury prevention program in the collegiate male soccer player. The American journal of sports medicine. 2015;43(11):2628–37. doi: 10.1177/0363546515602009 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 10.Thorborg K, Krommes KK, Esteve E, Clausen MB, Bartels EM, Rathleff MS. Effect of specific exercise-based football injury prevention programmes on the overall injury rate in football: a systematic review and meta-analysis of the FIFA 11 and 11+ programmes. British journal of sports medicine. 2017;51(7):562–71. doi: 10.1136/bjsports-2016-097066 [DOI] [PubMed] [Google Scholar]
  • 11.Whalan M, Lovell R, Thorborg K, Sampson JA. The 11+ of the future: a primary injury prevention framework for sub-elite football. BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine; 2021. [DOI] [PubMed] [Google Scholar]
  • 12.Asgari M, Nazari B, Bizzini M, Jaitner T. Effects of the FIFA 11+ program on performance, biomechanical measures, and physiological responses: A systematic review. Journal of Sport and Health Science. 2022. doi: 10.1016/j.jshs.2022.05.001 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Donaldson A, Callaghan A, Bizzini M, Jowett A, Keyzer P, Nicholson M. A concept mapping approach to identifying the barriers to implementing an evidence-based sports injury prevention programme. Injury Prevention. 2019;25(4):244–51. doi: 10.1136/injuryprev-2017-042639 [DOI] [PubMed] [Google Scholar]
  • 14.O’Brien J, Young W, Finch C. The use and modification of injury prevention exercises by professional youth soccer teams. Scandinavian journal of medicine & science in sports. 2017;27(11):1337–46. doi: 10.1111/sms.12756 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 15.Eirale C, Tol J, Farooq A, Smiley F, Chalabi H. Low injury rate strongly correlates with team success in Qatari professional football. British journal of sports medicine. 2013;47(12):807–8. doi: 10.1136/bjsports-2012-091040 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.O’Brien J, Young W, Finch CF. The delivery of injury prevention exercise programmes in professional youth soccer: Comparison to the FIFA 11+. Journal of science and medicine in sport. 2017;20(1):26–31. doi: 10.1016/j.jsams.2016.05.007 [DOI] [PubMed] [Google Scholar]
  • 17.Veith S, Whalan M, Williams S, Colyer S, Sampson JA. Part 2 of the 11+ as an effective home-based exercise programme in elite academy football (soccer) players: a one-club matched-paired randomised controlled trial: Submission type. Science and Medicine in Football. 2021. [DOI] [PubMed] [Google Scholar]
  • 18.Brito J, Malina RM, Seabra A, Massada JL, Soares JM, Krustrup P, et al. Injuries in Portuguese youth soccer players during training and match play. Journal of athletic training. 2012;47(2):191–7. doi: 10.4085/1062-6050-47.2.191 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Stubbe J, Schmikli S, van de Port I, Backx F. Differences in injury risk and characteristics between Dutch amateur and professional soccer players. Journal of science and medicine in sport. 2015;18(2):145–9. doi: 10.1016/j.jsams.2014.02.004 [DOI] [PubMed] [Google Scholar]
  • 20.Horan D, Blake C, Hägglund M, Kelly S, Roe M, Delahunt E. Injuries in elite‐level women’s football—a two‐year prospective study in the Irish Women’s National League. Scandinavian journal of medicine & science in sports. 2022;32(1):177–90. doi: 10.1111/sms.14062 [DOI] [PubMed] [Google Scholar]
  • 21.Delahunt E. Neuromuscular contributions to functional instability of the ankle joint. Journal of Bodywork and Movement Therapies. 2007;11(3):203–13. [Google Scholar]
  • 22.Lopes M, Rodrigues JM, Monteiro P, Rodrigues M, Costa R, Oliveira J, et al. Effects of the FIFA 11+ on ankle evertors latency time and knee muscle strength in amateur futsal players. European Journal of Sport Science. 2020;20(1):24–34. doi: 10.1080/17461391.2019.1609588 [DOI] [PubMed] [Google Scholar]
  • 23.Lopes M, Lopes S, Patinha T, Araújo F, Rodrigues M, Costa R, et al. Balance and proprioception responses to FIFA 11+ in amateur futsal players: short and long-term effects. Journal of sports sciences. 2019;37(20):2300–8. doi: 10.1080/02640414.2019.1628626 [DOI] [PubMed] [Google Scholar]
  • 24.Parsons JL, Carswell J, Nwoba IM, Stenberg H. Athlete perceptions and physical performance effects of the fifa 11+ program in 9–11 year-old female soccer players: a cluster randomized trial. International journal of sports physical therapy. 2019;14(5):740. [PMC free article] [PubMed] [Google Scholar]
  • 25.Daneshjoo A, Mokhtar AH, Rahnama N, Yusof A. Effects of the 11+ and Harmoknee warm-up programs on physical performance measures in professional soccer players. Journal of sports science & medicine. 2013;12(3):489. [PMC free article] [PubMed] [Google Scholar]
  • 26.Bizzini M, Impellizzeri FM, Dvorak J, Bortolan L, Schena F, Modena R, et al. Physiological and performance responses to the “FIFA 11+” (part 1): is it an appropriate warm-up? Journal of sports sciences. 2013;31(13):1481–90. doi: 10.1080/02640414.2013.802922 [DOI] [PubMed] [Google Scholar]
  • 27.Zarei M, Abbasi H, Daneshjoo A, Barghi TS, Rommers N, Faude O, et al. Long-term effects of the 11+ warm-up injury prevention programme on physical performance in adolescent male football players: a cluster-randomised controlled trial. Journal of sports sciences. 2018;36(21):2447–54. doi: 10.1080/02640414.2018.1462001 [DOI] [PubMed] [Google Scholar]
  • 28.Abade E, Sampaio J, Gonçalves B, Baptista J, Alves A, Viana J. Effects of different re-warm up activities in football players’ performance. PLoS One. 2017;12(6):e0180152. doi: 10.1371/journal.pone.0180152 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 29.Dunsky A, Barzilay I, Fox O. Effect of a specialized injury prevention program on static balance, dynamic balance and kicking accuracy of young soccer players. World Journal of Orthopedics. 2017;8(4):317. doi: 10.5312/wjo.v8.i4.317 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 30.Ayala F, Calderón-López A, Delgado-Gosálbez JC, Parra-Sánchez S, Pomares-Noguera C, Hernández-Sánchez S, et al. Acute effects of three neuromuscular warm-up strategies on several physical performance measures in football players. PloS one. 2017;12(1):e0169660. doi: 10.1371/journal.pone.0169660 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 31.Fuller CW, Ekstrand J, Junge A, Andersen TE, Bahr R, Dvorak J, et al. Consensus statement on injury definitions and data collection procedures in studies of football (soccer) injuries. Scandinavian journal of medicine & science in sports. 2006;16(2):83–92. [DOI] [PubMed] [Google Scholar]
  • 32.Hachana Y, Chaabene H, Ben Rajeb G, Khlifa R, Aouadi R, Chamari K, et al. Validity and reliability of new agility test among elite and subelite under 14-soccer players. PloS one. 2014;9(4):e95773. doi: 10.1371/journal.pone.0095773 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 33.Russell M, Benton D, Kingsley M. Reliability and construct validity of soccer skills tests that measure passing, shooting, and dribbling. Journal of sports sciences. 2010;28(13):1399–408. doi: 10.1080/02640414.2010.511247 [DOI] [PubMed] [Google Scholar]
  • 34.Thomas K, French D, Hayes PR. The effect of two plyometric training techniques on muscular power and agility in youth soccer players. The Journal of Strength & Conditioning Research. 2009;23(1):332–5. doi: 10.1519/JSC.0b013e318183a01a [DOI] [PubMed] [Google Scholar]
  • 35.Freeman G, Halton JH. Note on an exact treatment of contingency, goodness of fit and other problems of significance. Biometrika. 1951;38(1/2):141–9. [PubMed] [Google Scholar]
  • 36.Owoeye OB, Akinbo SR, Tella BA, Olawale OA. Efficacy of the FIFA 11+ warm-up programme in male youth football: a cluster randomised controlled trial. Journal of sports science & medicine. 2014;13(2):321. [PMC free article] [PubMed] [Google Scholar]
  • 37.Hammes D, Aus der Fünten K, Kaiser S, Frisen E, Bizzini M, Meyer T. Injury prevention in male veteran football players–a randomised controlled trial using “FIFA 11+”. Journal of sports sciences. 2015;33(9):873–81. [DOI] [PubMed] [Google Scholar]
  • 38.Pérez-Gómez J, Adsuar JC, Alcaraz PE, Carlos-Vivas J. Physical exercises for preventing injuries among adult male football players: A systematic review. Journal of Sport and Health Science. 2020. doi: 10.1016/j.jshs.2020.11.003 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 39.Hübscher M, Zech A, Pfeifer K, Hänsel F, Vogt L, Banzer W. Neuromuscular training for sports injury prevention: a systematic review. Medicine & Science in Sports & Exercise. 2010;42(3):413–21. [DOI] [PubMed] [Google Scholar]
  • 40.Whalan M, Lovell R, McCunn R, Sampson JA. The incidence and burden of time loss injury in Australian men’s sub-elite football (soccer): a single season prospective cohort study. Journal of science and medicine in sport. 2019;22(1):42–7. doi: 10.1016/j.jsams.2018.05.024 [DOI] [PubMed] [Google Scholar]
  • 41.Harøy J, Thorborg K, Serner A, Bjørkheim A, Rolstad LE, Hölmich P, et al. Including the Copenhagen adduction exercise in the FIFA 11+ provides missing eccentric hip adduction strength effect in male soccer players: a randomized controlled trial. The American journal of sports medicine. 2017;45(13):3052–9. doi: 10.1177/0363546517720194 [DOI] [PubMed] [Google Scholar]
  • 42.Hwang J, Kim J, Hwang J, Kim J. Effect of FIFA 11+ Training Program on Soccer-Specific Physical Performance and Functional Movement in Collegiate Male Soccer Players: A Randomized Controlled Trial. Exercise Science. 2019;28(2):141–9. [Google Scholar]
  • 43.Young WB, McDOWELL MH, Scarlett BJ. Specificity of sprint and agility training methods. The Journal of Strength & Conditioning Research. 2001;15(3):315–9. [PubMed] [Google Scholar]
  • 44.O’Brien J, Finch CF. Injury prevention exercise programmes in professional youth soccer: understanding the perceptions of programme deliverers. BMJ open sport & exercise medicine. 2016;2(1):e000075. doi: 10.1136/bmjsem-2015-000075 [DOI] [PMC free article] [PubMed] [Google Scholar]

Decision Letter 0

Rafael Franco Soares Oliveira

6 Jul 2022

PONE-D-22-14375Effects of the FIFA 11+ and a modified warm-up programme on injury prevention and performance improvement among youth male football players.PLOS ONE

Dear Dr. Asgari,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

==============================

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Viewing your abstract, we can see that it was previously published by Springer:

"Al Attar, W.S.A., Soomro, N., Pappas, E. et al. How Effective are F-MARC Injury Prevention Programs for Soccer Players? A Systematic Review and Meta-Analysis. Sports Med 46, 205–217 (2016). " ext-link-type="uri" xlink:type="simple">https://doi.org/10.1007/s40279-015-0404-x"

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Additional Editor Comments:

Dear authors,

The work is interesting but some improvements can be made before further consideration. There are some sentence that lack support (references). Some limitations should be added/highlighted as well as some pratical applications for coaches.

Thank you

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

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The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: I Don't Know

**********

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Reviewer #1: Yes

Reviewer #2: No

**********

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Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Dear authors,

I believe they did a good job and deserve credit for that.

The study is well designed, the introduction is robust, the methods are well explained and the discussion supports the results.

However, the conclusion can and should be improved, and should be presented with practical applications for the coach.

Furthermore, I believe that the limitations should be inserted at the end of the discussion.

Reviewer #2: The proposed manuscript is very interesting and has an noteworthy objective. Congratulations to the authors.

My suggestions follow below.

P.8

Comment 1:

Please rephase the “Background”, specifically “…the latter has potentially reduced compliance and

implementation of the programme”

Comment 2:

Keywords: I suggest not repeating the keyword that already exists in the title to enhance search results.

Comment 3:

“static stretches” in the warm-up? Or did the authors mean “dynamic stretches”?

Comment 4:

Is the discussion the conclusion in the abstract?

P.9

Comment 4:

I suggest rephrasing the sentence “It aims to tackle modifiable injury risk factors such as

neuromuscular control, static and dynamic balance, and the hamstring/quadriceps strength

ratio[8].” as they are not risk factors. They can be considred as “key elements of effective injury prevention programmes…”

Comment 5:

Please rephrase the sentence “The latter, along with barriers such as prolonged duration, concerns regarding some exercises, and lack of a link to football-specific targets[14, 18], has been discussed as a potential reason for low compliance and poor implementation of the programme[14, 19].”

Comment 6:

Please state the reference for the sentence “Although it is widely accepted that an appropriate warm-up programme should improve performance, more recent studies indicated that the 11+ programme does not improve players' performance acutely but may reduce sprinting and agility compared to a dynamic warm-up programme.”

P.10

Comment 7:

In the abstract the authors stated that the CG did not perform injury prevention studies, however in the methods section, the contrary is stated.

Comment 7:

Was static stretching really used?

P.11

Comment 8:

Please add further information of how the instructions to perform the 11+ and the M11+ were carried out.

Comment 9:

Data collection and supervision: How where the assistants “blinding each other”?

Comment 10:

Why was the “M. iliopsoas strengthening” and the “single-leg standing with a heel-to-toe movement cycle” selected? Can the authors support these choices with evidence? It would be great as the M11+ group showed few injuries.

P.12

Comment 11:

A table with Injury incidence/1000h and rate ratios for each group would enhance the manuscript.

Comment 12:

Further detail on injuries would also be of great interest for the study: (Fuller et al, 2006).

p.13

Comment 13:

The second manuscript from (Lopes et al.) is not in the references section. In the sentence extracted from other manuscripts as the numbered references are of other studies?

p.14

Comment 14:

“Neither F11+ nor M11+ could significantly reduce the risk of groin and hip injuries.”

Can these stats be shown in a table?

Comment 15:

The paragraph below is very important, however the message is not clear. Please rephrase.

“Neither F11+ nor M11+ could significantly reduce the risk of groin and hip injuries. In addition to the reasons mentioned above, they could not mitigate hip and groin injuries since they provided no specific exercise for groin muscles. This appears to be a noticeable gap, as up to 12% of subelite football injuries occur in the groin region [41]. Wahlan et al. suggested that using Copenhagen adductor exercises may fill this gap and would be fit for inclusion in the FIFA11+ programme, as it requires no specific equipment and has three levels of difficulties [41]. The better efficacy of the M11+ in preventing hip injuries, however, might be due to increasing the volume of hip dynamic stretch exercise, namely, hip-in, in addition to manipulating how core area muscles are being trained. “

P.15

Comment 16:

Limitations

In fact the study did not recruit the expected number of teams to manage a randomized sample. It is not clear that the authors did recognize this limitation.

Comment 17:

Was the trial registered in a clinical trials platform?

**********

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Reviewer #1: No

Reviewer #2: No

**********

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PLoS One. 2022 Oct 20;17(10):e0275545. doi: 10.1371/journal.pone.0275545.r002

Author response to Decision Letter 0


10 Aug 2022

Dear Editor,

Thank you so much for your great eyes to our work and highlighting those important points. We believe that the points you have raised would greatly enhance the quality of the manuscript. Thus, we tried to follow them in full and revise the manuscript accordingly. More specifically, regarding the data availability policy, we have now uploaded a minimized dataset as per your request. you will find the URL and DOI:

URL:www.kaggle.com/dataset/1f3df0f9ccf87f9dbeaca960baf76527376189128948699c4dec7eb056098834

https://doi.org/10.34740/KAGGLE/DSV/4054705

All means and standard deviations have already been mentioned in the manuscript. The changes we made based on your comments are highlighted in red throughout the manuscript.

More importantly, regarding your following comment ‘’Viewing your abstract, we can see that it was previously published by Springer: "Al Attar, W.S.A., Soomro, N., Pappas, E. et al. How Effective are F-MARC Injury Prevention Programs for Soccer Players? A Systematic Review and Meta-Analysis. Sports Med 46, 205–217 (2016). https://doi.org/10.1007/s40279-015-0404-x" We believe that there must be a mistake simply because any part of this manuscript has not been published up to this point. Further, the link you referred belongs to a systematic review which was first appeared in the literature 6 years ago, whereas this project has only one year old.

Reviewer #1: Dear authors,

I believe they did a good job and deserve credit for that.

The study is well designed, the introduction is robust, the methods are well explained and the discussion supports the results.

However, the conclusion can and should be improved, and should be presented with practical applications for the coach.

Furthermore, I believe that the limitations should be inserted at the end of the discussion.

Response: Dear Reviewer, we thank you so much for your positive review and for the positive and useful comments. We revised the conclusion and added recommendations for practitioners and trainers. Additionally, we inserted the limitation at the end of the discussion. The changes we made based on your comments are highlighted in light brown.

Reviewer #2: The proposed manuscript is very interesting and has a noteworthy objective. Congratulations to the authors.

My suggestions follow below.

Response: Dear Reviewer, we thank you very much for your positive feedback on our work and for the detailed, supportive and constructive comments. They are very helpful to improve the manuscript’s quality. Therefore, our effort was to integrate the comments throughout the manuscript accurately. The changes based on your comments are highlighted in light blue.

P.8

Comment 1:

Please rephase the “Background”, specifically “…the latter has potentially reduced compliance and

implementation of the programme”

Response: Thank you. We revised the background accordingly.

Comment 2:

Keywords: I suggest not repeating the keyword that already exists in the title to enhance search results.

Response: Thank you very much. We removed the keywords that are already a part of the title

Comment 3:

“static stretches” in the warm-up? Or did the authors mean “dynamic stretches”?

Response: Thank you very much for your great eyes to the important words. According to the reports of our research assistant who was visiting the CG, athletes indeed performed some static stretches within the warm-up phase, with each stretch lasting approximately 12 seconds.

Comment 4:

Is the discussion the conclusion in the abstract?

Response: Thank you for your comment. We added a one-sentence conclusion to the abstract.

P.9

Comment 4:

I suggest rephrasing the sentence “It aims to tackle modifiable injury risk factors such as

neuromuscular control, static and dynamic balance, and the hamstring/quadriceps strength

ratio[8].” as they are not risk factors. They can be considered “key elements of effective injury prevention programmes…”

Response: Thank you so much. We revised the sentence accordingly.

Comment 5:

Please rephrase the sentence “The latter, along with barriers such as prolonged duration, concerns regarding some exercises, and lack of a link to football-specific targets[14, 18], has been discussed as a potential reason for low compliance and poor implementation of the programme[14, 19].”

Response: Thank you so much. We revised the sentence accordingly.

Comment 6:

Please state the reference for the sentence “Although it is widely accepted that an appropriate warm-up programme should improve performance, more recent studies indicated that the 11+ programme does not improve players' performance acutely but may reduce sprinting and agility compared to a dynamic warm-up programme.”

Response: Thank you so much. We cited a suitable reference to support the sentence’s content.

P.10

Comment 7:

In the abstract the authors stated that the CG did not perform injury prevention studies, however in the methods section, the contrary is stated.

Response: Thank you so much for your great eyes to the manuscript. The phrase ‘’without any’’ specific injury prevention exercises… was missing. We rewrote the sentence.

Comment 7:

Was static stretching truly used?

Response: Well, it was used and, to my knowledge, is still being used even in some developed countries and on a roughly large scale, unfortunately.

P.11

Comment 8:

Please add further information of how the instructions to perform the 11+ and the M11+ were carried out.

Response: Thank you. We would be glad to present further details here and in the manuscript. First, we instructed the trainer and players on how to perform the programmes. Furthermore, we provided the 11+ group with the 11+manual (it was already translated in Persian by IF-MARC, Iran branch of FIFA Medical Assessment and Research Centre) and asked them to familiarize themselves with the 11+. In addition, we provided them with the YouTube link to watch out the 11+ exercises. For the M11+, we provided the trainers and the players with a series of photo slides including all exercises embedded in the programme. Meanwhile, to assure accuracy of the application of the 11+, a research assistant was responsible for visiting the training sessions of the M11+ and F11+ groups and checking the implementation of the warm-up modalities.

Comment 9:

Data collection and supervision: How where the assistants “blinding each other”?

Response: Thank you so much for highlighting these important points. We applied that approach to minimize any potential risk of bias during data collection. Three research assistants were responsible for their subsequent groups while having no idea about the study aims, the interventions, occurred injuries of the other groups, etc. They were only in touch with the research group leader and remained anonymous across the project.

Comment 10:

Why was the “M. iliopsoas strengthening” and the “single-leg standing with a heel-to-toe movement cycle” selected? Can the authors support these choices with evidence? It would be great as the M11+ group showed few injuries.

Response: Thank you very much for your detailed and beneficial comments. We are pleased to briefly explain it for your perusal:

The idea of strengthening M. iliopsoas muscles and single-leg standing with a heel-to-toe movement cycle and also modifying some core exercises comes from Janda’s approach, namely, the muscular chain, which is also known as upper/lower cross syndromes, as well as Shirley Sahrmann’s approach:

Izraelski, J., Assessment and treatment of muscle imbalance: The Janda approach. The Journal of the Canadian Chiropractic Association, 2012. 56(2): p. 158.

Sahrmann, S., D.C. Azevedo, and L. Van Dillen, Diagnosis and treatment of movement system impairment syndromes. Brazilian journal of physical therapy, 2017. 21(6): p. 391-399.

P.12

Comment 11:

A table with Injury incidence/1000 h and rate ratios for each group would enhance the manuscript.

Response: Thank you for your suggestion. We appreciate your support for enhancing the manuscript and considering them all. In this case, however, as we already have three tables in the manuscript, we taught that having another table could be too much. Therefore, we just added a row to table two, including IIC rates.

Comment 12:

Further detail on injuries would also be of great interest for the study: (Fuller et al, 2006).

Response: Thank you. We added additional information.

p.13

Comment 13:

The second manuscript from (Lopes et al.) is not in the references section. In the sentence extracted from other manuscripts as the numbered references are of other studies?

Response: Thank you so much for highlighting that mistake. Following your comment, we went through the reference list and found some errors by the meaning of false matching the numbers and references. Thus, all references were updated and matched accurately.

p.14

Comment 14:

“Neither F11+ nor M11+ could significantly reduce the risk of groin and hip injuries.”

Can these stats be shown in a table?

Response: Thank you for your attention. Given the few injuries that occurred in the hip and groin, we considered them and reported all as thigh injuries.

Comment 15:

The paragraph below is very important, however the message is not clear. Please rephrase.

“Neither F11+ nor M11+ could significantly reduce the risk of groin and hip injuries. In addition to the reasons mentioned above, they could not mitigate hip and groin injuries since they provided no specific exercise for groin muscles. This appears to be a noticeable gap, as up to 12% of subelite football injuries occur in the groin region [41]. Wahlan et al. suggested that using Copenhagen adductor exercises may fill this gap and would be fit for inclusion in the FIFA11+ programme, as it requires no specific equipment and has three levels of difficulties [41]. The better efficacy of the M11+ in preventing hip injuries, however, might be due to increasing the volume of hip dynamic stretch exercise, namely, hip-in, in addition to manipulating how core area muscles are being trained.

Response: Thank you for your comment. We revised the paragraph and hope that the readers now can clearly follow the argumentation and get the message.

P.15

Comment 16:

Limitations

In fact the study did not recruit the expected number of teams to manage a randomized sample. It is not clear that the authors did recognize this limitation.

Response: Thank you. We revised the limitation and pointed out the lack of a recruiting sample in addition to the short monitoring period.

Comment 17:

Was the trial registered in a clinical trials platform?

Response: Thank you. It was not registered

Attachment

Submitted filename: response to reviewers.docx

Decision Letter 1

Rafael Franco Soares Oliveira

12 Sep 2022

PONE-D-22-14375R1Effects of the FIFA 11+ and a modified warm-up programme on injury prevention and performance improvement among youth male football players.PLOS ONE

Dear Dr. Asgari,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

==============================Dear authors,

The authors made a great work in improving the work by following suggestion made by both reviewers. Reviewer 1 already recommend acception. Even so, I agree with the opinion of the second reviewers and for that reason, I suggest another round to improve the topic about static stretching being considered a good strategy for injury prevention.

Thank you

==============================

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PLOS ONE

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Additional Editor Comments:

Dear authors,

The authors made a great work in improving the work by following suggestion made by both reviewers. Reviewer 1 already recommend acception. Even so, I agree with the opinion of the second reviewers and for that reason, I suggest another round to improve the topic about static stretching being considered a good strategy for injury prevention.

Thank you

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

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Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

**********

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Reviewer #1: Yes

Reviewer #2: Yes

**********

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Reviewer #1: Yes

Reviewer #2: I Don't Know

**********

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Reviewer #1: Yes

Reviewer #2: Yes

**********

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Reviewer #2: Yes

**********

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Reviewer #1: Dear author, thank you for submitting the manuscript.

I believe that the authors did a good job of reformulating the manuscript according to the reviewers' requests. In that sense, I have no further reservations about the manuscript.

Reviewer #2: I thank the authors for their great effort in replying adequately to all the suggestion made. I have one final concern. I recommend a like a deeper discussion around the topic “static stretching” to be reflected in this manuscript. We understand that static stretching is not recommended to initiate sports practice. It reduces strength. How can the authors defend this modification to widely accepted injury prevention program. Please state this clearly in the manuscript.

**********

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Reviewer #1: No

Reviewer #2: No

**********

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PLoS One. 2022 Oct 20;17(10):e0275545. doi: 10.1371/journal.pone.0275545.r004

Author response to Decision Letter 1


16 Sep 2022

Dear respected editor/ reviewers

On behalf of our research group, I do thank you so much again for your positive reviews and commentary on our work. We do believe that the comments you made have widely improved the quality of our paper, so we highly appreciate your efforts. Just to reflect well to the last comment provided by the second reviewer which is a kind of misunderstanding/miscommunication, I do refer to the first revision round where I clearly stated that based on the research assistant, the Control Group (CG) used some static stretches as part of their routine warm up before main training. So, there was no any kind of static stretches neither in 11+ nor in the modified 11+ and as you accurately mentioned, it has been scientifically proven that static stretches must not be used for warming up.

To eliminate such misunderstanding, bellow you’ll find the original comments and the responses from the first revision round:

Comment 3:

“static stretches” in the warm-up? Or did the authors mean “dynamic stretches”?

Response: Thank you very much for your great eyes to the important words. According to the reports of our research assistant who was visiting the CG, athletes indeed performed some static stretches within the warm-up phase, with each stretch lasting approximately 12 seconds.

Comment 7:

Was static stretching truly used?

Response: Well, it was used and, to my knowledge, is still being used even in some developed countries and on a roughly large scale, unfortunately.

Given that there is no other comments to be reflected, I assume that this clarification suffices and therefore, we did not provide any changes on the manuscript.

Attachment

Submitted filename: Response to the reviewers second round.docx

Decision Letter 2

Rafael Franco Soares Oliveira

19 Sep 2022

Effects of the FIFA 11+ and a modified warm-up programme on injury prevention and performance improvement among youth male football players.

PONE-D-22-14375R2

Dear Dr. Asgari,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Rafael Franco Soares Oliveira

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Dear authors,

Congratulations on your work! After the clarification of the authors on the previous comments, I believe that this work can be accepted for publication.

Thank you.

Best regards

Reviewers' comments:

Acceptance letter

Rafael Franco Soares Oliveira

22 Sep 2022

PONE-D-22-14375R2

Effects of the FIFA 11+ and a modified warm-up programme on injury prevention and performance improvement among youth male football players.

Dear Dr. Asgari:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Rafael Franco Soares Oliveira

Academic Editor

PLOS ONE

Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 Data

    (XLSX)

    Attachment

    Submitted filename: response to reviewers.docx

    Attachment

    Submitted filename: Response to the reviewers second round.docx

    Data Availability Statement

    *** PA @ ACCEPT: Please follow up with authors for data availabile at Accept *** We note that your Data Availability Statement reads: "The dataset is uploaded on Kaggle, a public repository platform for placing data sets. URL:www.kaggle.com/dataset/1f3df0f9ccf87f9dbeaca960baf76527376189128948699c4dec7eb056098834 https://doi.org/10.34740/KAGGLE/DSV/4054705.


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