Exercise-Based Training Strategies to Reduce the Incidence or Mitigate the Risk Factors of Anterior Cruciate Ligament Injury in Adult Football (Soccer) Players: A Systematic Review

Anterior cruciate ligament (ACL) is one of the most concerning injuries for football players. The aim of this review is to investigate the effects of exercise-based interventions targeting at reducing ACL injury rate or mitigating risk factors of ACL injury in adult football players. Following PRISMA guidelines, a systematic search was conducted in CINAHL, Cochrane Library, PubMed, Scopus, SPORTDiscus and Web of Science. Studies assessing the effect of exercise-based interventions in ACL injury incidence or modifiable risk factors in adult football players were included. 29 studies evaluating 4502 male and 1589 female players were included (15 RCT, 8 NRCT, 6 single-arm): 14 included warm-up, 7 resistance training, 4 mixed training, 3 balance, 1 core stability and 1 technique modification interventions. 6 out of 29 studies investigated the effect of interventions on ACL injury incidence, while the remaining 23 investigated their effect on risk factors. Only 21% and 13% studies evaluating risk of injury variables reported reliability measures and/or smallest worthwhile change data. Warm-up, core stability, balance and technique modification appear effective and feasible interventions to be included in football teams. However, the use of more ecologically valid tests and individually tailored interventions targeting specific ACL injury mechanisms are required

How does curve sprint evolve across different age categories in soccer players?

: Research has shown that soccer players regularly execute curved sprints during matches. The purpose of this study was to determine the age-related effects on curve sprint (CS) performance to both sides, asymmetry, and association with linear sprint (LS). Eighty-four soccer players (aged 16.1 ± 1.6 categorized in U15, U17, and U20) were recruited, who performed CS and LS tests. One-way analysis of variance (ANOVA) and effect size (ES) were used to compare CS performance between age categories, and relationships between physical performance measures were calculated using Pearson’s correlation coefficient. The main findings of this study were that: 1) there were significant differences in the “good” side CS among age groups (p < 0.001; ES from moderate to large), but not in the “weak” side CS, 2) curve asymmetry was significantly higher in U20 than U15 (p < 0.05; ES large) and U17 players (p < 0.05; ES moderate), and 3) relationships between CS and LS times decreased with age (from significant and very large [p 0.05]). This study highlights the importance of assessing and training CS in different age categories, an action that becomes less correlated with LS as age increases, with the aim of mitigating the increase in asymmetries as a result of the specialization process, focusing interventions mainly on improving the CS “weak” sideThanks to all the participants in this study, to Football Science Institute, and to the soccer clu

a living systematic review

Background: Hamstrings injuries are common in sports and the reinjury risk is high. Despite the extensive literature on hamstrings injuries, the efectiveness of the diferent conservative (i.e., non-surgical) interventions (i.e., modalities and doses) for the rehabilitation of athletes with acute hamstrings injuries is unclear. Objective: We aimed to compare the efects of diferent conservative interventions in time to return to sport (TRTS) and/or time to return to full training (TRFT) and reinjury-related outcomes after acute hamstrings injuries in athletes. Data Sources: We searched CINAHL, Cochrane Library, EMBASE, PubMed, Scopus, SPORTDiscus, and Web of Science databases up to 1 January, 2022, complemented with manual searches, prospective citation tracking, and consultation of external experts. Eligibility Criteria: the eligibility criteria were multi-arm studies (randomized and non-randomized) that compared conservative treatments of acute hamstrings injuries in athletes. Data Analysis: We summarized the characteristics of included studies and conservative interventions and analyzed data for main outcomes (TRTS, TRFT, and rate of reinjuries). The risk of bias was judged using the Cochrane tools. Quality and completeness of reporting of therapeutic exercise programs were appraised with the i-CONTENT tool and the certainty of evidence was judged using the GRADE framework. TRTS and TRFT were analyzed using mean diferences and the risk of reinjury with relative risks. Results Fourteen studies (12 randomized and two non-randomized) comprising 730 athletes (mostly men with ages between 14 and 49 years) from diferent sports were included. Nine randomized studies were judged at high risk and three at low risk of bias, and the two non-randomized studies were judged at critical risk of bias. Seven randomized studies compared exercise-based interventions (e.g., L-protocol vs C-protocol), one randomized study compared the use of low-level laser therapy, and three randomized and two non-randomized studies compared injections of platelet-rich plasma to placebo or no injection. These low-level laser therapy and platelet-rich plasma studies complemented their interventions with an exercise program. Only three studies were judged at low overall risk of inefectiveness (i-CONTENT). No single intervention or combination of interventions proved superior in achieving a faster TRTS/TRFT or reducing the risk of reinjury. Only eccentric lengthening exercises showed limited evidence in allowing a shorter TRFT. The platelet-rich plasma treatment did not consistently reduce the TRFT or have any efect on the risk of new hamstrings injuries. The certainty of evidence was very low for all outcomes and comparisons. Conclusions: Available evidence precludes the prioritization of a particular exercise-based intervention for athletes with acute hamstrings injuries, as diferent exercise-based interventions showed comparable efects on TRTS/TRFT and the risk of reinjuries. Available evidence also does not support the use of platelet-rich plasma or low-level laser therapy in clinical practice. The currently available literature is limited because of the risk of bias, risk of inefectiveness of exercise protocols (as assessed with the i-CONTENT), and the lack of comparability across existing studies. Clinical Trial Registration PROSPERO CRD42021268499 and OSF (https://osf.io/3k4u2/).9513-E3E4-C5C9 | Sílvia Fernanda Rocha RodriguesN/

Exercise-Based Training Strategies to Reduce the Incidence or Mitigate the Risk Factors of Anterior Cruciate Ligament Injury in Adult Football (Soccer) Players: A Systematic Review

Anterior cruciate ligament (ACL) is one of the most concerning injuries for football players. The aim of this review is to investigate the effects of exercise-based interventions targeting at reducing ACL injury rate or mitigating risk factors of ACL injury in adult football players. Following PRISMA guidelines, a systematic search was conducted in CINAHL, Cochrane Library, PubMed, Scopus, SPORTDiscus and Web of Science. Studies assessing the effect of exercise-based interventions in ACL injury incidence or modifiable risk factors in adult football players were included. 29 studies evaluating 4502 male and 1589 female players were included (15 RCT, 8 NRCT, 6 single-arm): 14 included warm-up, 7 resistance training, 4 mixed training, 3 balance, 1 core stability and 1 technique modification interventions. 6 out of 29 studies investigated the effect of interventions on ACL injury incidence, while the remaining 23 investigated their effect on risk factors. Only 21% and 13% studies evaluating risk of injury variables reported reliability measures and/or smallest worthwhile change data. Warm-up, core stability, balance and technique modification appear effective and feasible interventions to be included in football teams. However, the use of more ecologically valid tests and individually tailored interventions targeting specific ACL injury mechanisms are required.</jats:p

Exercise-Based Training Strategies to Reduce the Incidence or Mitigate the Risk Factors of Anterior Cruciate Ligament Injury in Adult Football (Soccer) Players: A Systematic Review

Anterior cruciate ligament (ACL) is one of the most concerning injuries for football players. The aim of this review is to investigate the effects of exercise-based interventions targeting at reducing ACL injury rate or mitigating risk factors of ACL injury in adult football players. Following PRISMA guidelines, a systematic search was conducted in CINAHL, Cochrane Library, PubMed, Scopus, SPORTDiscus and Web of Science. Studies assessing the effect of exercise-based interventions in ACL injury incidence or modifiable risk factors in adult football players were included. 29 studies evaluating 4502 male and 1589 female players were included (15 RCT, 8 NRCT, 6 single-arm): 14 included warm-up, 7 resistance training, 4 mixed training, 3 balance, 1 core stability and 1 technique modification interventions. 6 out of 29 studies investigated the effect of interventions on ACL injury incidence, while the remaining 23 investigated their effect on risk factors. Only 21% and 13% studies evaluating risk of injury variables reported reliability measures and/or smallest worthwhile change data. Warm-up, core stability, balance and technique modification appear effective and feasible interventions to be included in football teams. However, the use of more ecologically valid tests and individually tailored interventions targeting specific ACL injury mechanisms are required

Prevención de lesión de ligamento cruzado anterior en futbolistas: protocolo de campo e intervenciones eficientes

La lesión de ligamento cruzado anterior (LCA) es una de las que mayor preocupación genera. A nivel de club, porque supone perder un jugador para el resto de temporada, con sus correspondientes implicaciones económicas y de rendimiento. A nivel de jugador, por sus devastadores consecuencias, como el riesgo acrecentado de sufrir una segunda lesión, de no volver a competir al nivel previo o de sufrir osteoartritis temprana. La lesión de LCA ocurre principalmente en mecanismos de no contacto o contacto indirecto con la pierna lesionada (80%), comúnmente al realizar maniobras de cambio de dirección (CDD) o aterrizaje de salto en situaciones defensivas, con incertidumbre. Se han asociado muchos factores de riesgo a la lesión de LCA, aunque ninguno de forma contundente por las limitaciones metodológicas de los diseños de investigación utilizados. Se han propuesto multitud de programas de intervención para su prevención, si bien pocos han considerado el contexto característico del fútbol, lo que se ha traducido en una muy baja implementación de dichos programas. El objetivo general de la tesis fue diseñar un protocolo integral de campo dirigido a evaluar los factores de riesgo de lesión de LCA en futbolistas, así como a mitigarlos mediante estrategias preventivas fácilmente aplicables, considerando las frecuentes limitaciones de equipamiento, espacio y tiempo presentes en el contexto de un equipo de fútbol. El objetivo se abordó mediante cuatro artículos, tres de ellos publicados (artículos 2, 3 y 4) en revistas indexadas en el Journal of Scitation Reports. Artículo 1. Mediante esta revisión sistemática se pretendió encontrar todas aquellos test que, mediante maniobras de aterrizaje y CDD, trataran de evaluar los riesgos de jugadores de fútbol de sufrir una lesión de LCA. Se halló que existen una gran variedad de test con dicho propósito tanto para aterrizajes (i.e. saltos con y sin contramovimiento, drop landings, drop jumps (DVJ), saltos con carrera de aproximación, saltos horizontales y consecutivos) como para CDD (i.e. de angulación leve, moderada y agresiva), aunque pocos se han asociado apropiadamente a la lesión de LCA y donde raramente se han ofrecido los niveles de fiabilidad de las métricas evaluadas. Artículo 2. El objetivo de la segunda revisión sistemática fue el de recopilar todas aquellas intervenciones basadas en ejercicio físico, de más de 4 semanas, diseñadas para reducir la incidencia o los riesgos de lesión de LCA en futbolistas adultos. Se encontró que algunos programas de calentamiento, como el “FIFA 11+” o el “PEP Program” se han mostrado eficaces para la reducción de la incidencia, aunque los mecanismos mediante los que lo consiguen no están claros. Otras intervenciones basadas en modificación técnica, trabajo lumbopélvico y equilibrio mostraron efectos prometedores, con programas de entrenamiento resistido revelándose eficaces, aunque difícilmente implementables en el contexto de un equipo de fútbol. Destaca la escasez de intervenciones que fueron evaluadas por su capacidad para reducir los riesgos asociados a los principales mecanismos de lesión de LCA, así como la escasa, cuando no ausente descripción de los programas y test utilizados (i.e. niveles de fiabilidad y supervisores de la intervención no reportados, poca claridad en los métodos o enfoques estadísticos inapropiados). Artículo 3. En este artículo transversal se evaluó a 42 futbolistas semiprofesionales con el objetivo de determinar si las escalas Landing Error Scoring System (LESS) y Cutting Movement Assessment Score (CMAS) para valorar la calidad de movimiento de DVJ y CDD, respectivamente, son fiables en este cohorte de futbolistas, además de dilucidar si aportan un perfil de riesgo compartido. Los resultados demostraron que ambas poseen niveles de moderados a sustanciales de fiabilidad interobservador (ICC = 0.58-0.71) y de sustanciales a casi perfectos de fiabilidad intraobservador (ICC = 0.68-0.87). Además, no se encontró relación alguna entre el perfil de riesgo obtenido para una y otra escala, lo que sugiere que el riesgo para sufrir una lesión de LCA es dependiente de la tarea. El segundo aterrizaje del DVJ manifestó peores niveles de calidad de movimiento que el primero (ES = 0.80-0.83) justificando así el uso de ambos, junto al CMAS, para una panorámica más detallada del perfil de riesgo del jugador. Artículo 4. En el último artículo se evaluó la capacidad del Safe Landing, un programa de intervención basado en aterrizajes, pliometría y CDD con un énfasis en la corrección técnica, llevado a cabo durante 6 semanas, 3 veces por semana e incluido como parte del calentamiento para mejorar la calidad de movimiento del DVJ y el CDD, evaluadas mediante las escalas LESS y CMAS. El grupo experimental (GE, n = 15) mostró mejoras de magnitudes moderadas a grandes en ambos aterrizajes del DVJ (LESS1 y LESS2) y en el CMAS (p < 0.082, ղ2 = 0.137–0.272) respecto del grupo control (GC, n = 11), sin una merma en el rendimiento en dichas maniobras, que se mantuvo estable antes y después de la intervención (p > 0.05, ES = 0.039–0.420). Dado el escaso equipamiento (i.e. conos y balones) y el poco tiempo necesario para su implementación (~ 9 minutos / sesión), el Safe Landing se propone como una intervención efectiva y fácilmente implementable (con una adherencia superior al 93%) para mejorar la calidad de movimiento de jugadores de fútbol semiprofesionales. Asimismo, mediante la presente tesis doctoral se proporcionaron herramientas válidas y fiables para la identificación de riesgos de lesión de LCA en sus principales mecanismos predisponentes a profesionales médicos y de rendimiento, así como estrategias eficientes para la reducción efectiva de dichos riesgos. Un proceso que se abordó intentando mantener un equilibrio entre la rigurosidad metodológica que exige el método científico y la realidad contextual que caracteriza a equipos de fútbol.The anterior cruciate ligament (ACL) injury is one of the most concerning. At the club level, because it leads to lose a player for the rest of the season, with its corresponding economic and performance implications. At the player level, due to its devastating consequences, such as the increased risk of suffering a second injury, not being able to compete at the previous level, or suffering early osteoarthritis. ACL injuries mainly occur in non-contact or indirect contact mechanisms with the injured leg (80%), commonly when performing either change of direction (COD) manoeuvres or landings from a jump in defensive situations, under uncertainty. Many risk factors have been related to ACL injury, although usually through weak associations due to the methodological limitations of the research designs traditionally used. Numerous intervention programs have been proposed for its prevention, although few have considered the characteristic context of football, resulting in very low implementation levels of such programs. The general aim of the thesis was to develop a comprehensive protocol to both evaluating the risk factors of ACL injuries of football players, as well as mitigating them through easily implementable preventative programs. For that purpose, the equipment, space and time restrictions frequently observed in football teams was always considered. To achieve the aim four scientific articles were carried out, of which 3 were published (articles 2, 3 and 4) in journals indexed in the Journal of Citation Reports. Article 1. Through this systematic review, we aimed to find all those tests that were developed to assess the risks of football players suffering an ACL injury through either landing or cutting manoeuvres. It was found that there is a wide variety of tests for this purpose both for landings (i.e. jumps with and without countermovement, drop landings, drop jumps (DVJ), running approach jumps, horizontal and consecutive jumps) and cuttings (i.e. of shallow, moderate, and sharp angulations), although very few have been appropriately associated with ACL injury, and where the levels of reliability of the metrics evaluated have rarely been offered. Article 2. The aim of the second systematic review was to compile all those exercisebased interventions, lasting more than 4 weeks, that were designed to reduce the incidence or risks of ACL injury in adult footballers. It was found that some warm-up programs, such as “FIFA 11+” or the “PEP Program” were effective in reducing the incidence, although the mechanisms by which they achieved this reduction are not clear. Other interventions based on technical modification, lumbopelvic strengthening, and balance showed promising effects, with resistance training programs proving effective, although difficult to implement in a football team context. Noteworthy is the scarcity of interventions evaluated for their ability to reduce the risks associated with the main ACL injury mechanisms, as well as the scarce and/or poor description of the programs and tests used (i.e., levels of reliability and supervisors of the intervention not reported, lack of clarity in the methods or inappropriate statistical approaches). Article 3. In this cross-sectional article, 42 semi-professional footballers were evaluated to determine if the Landing Error Scoring System (LESS) and Cutting Movement Assessment Score (CMAS) scales are reliable for assessing the quality of movement in DVJ and COD, respectively, as well as to elucidate whether they provide a shared ACL risk profile of the players. The results showed that they possess moderate to substantial levels of intra-observer reliability (ICC = 0.58-0.71), and substantial to almost perfect inter-observer reliability (ICC = 0.68-0.87). In addition, no relationship was found between the risk profile obtained for one scale and the other, suggesting that the risk of suffering an ACL injury is task-dependent. The second landing of the DVJ (LESS2) displayed a riskier pattern than the first (LESS1) (ES = 0.80-0.83) justifying the use of both, along with the CMAS, for a more detailed overview of the player's risk profile. Article 4. In the last article, the capability of the Safe Landing, a technique-modification intervention based on landings, plyometrics, and COD exercises, to improve the movement quality of DVJ and COD was evaluated through the LESS and CMAS scales. It was carried out for 6 weeks, 3 times a week, and included as part of the warm-up. The experimental group (EG, n = 15) showed moderate to large improvements in both landings of the DVJ (LESS1 and LESS2) and in the CMAS (p < 0.082, ղ2 = 0.137–0.272) compared to the control group (CG, n = 11), without a decline in performance in such manoeuvres, which remained stable pre- to post-intervention (p > 0.05, ES = 0.039– 0.420). Given the little equipment (i.e., cones and balls), and the short time required for its implementation (~9 minutes/session), the Safe Landing is proposed as an effective and easily implementable intervention (with compliance levels above 93%) to improve the movement quality of semi-professional football players. By this way, through this doctoral thesis, practitioners working in medical and performance staffs were provided by valid and reliable screening tools for the identification of their football players’ injury risk in the main mechanisms predisposing to ACL injury, as well as by efficient strategies for the effective reduction of these risks. To properly address the process, the approach was based on an attempt to keep a balance between the methodological rigor required by the scientific method and the reality that characterises the football’s context.Tesis Univ. Granada.HumanLabInstituto Universitario Deporte y Salud (iMUDS)Football Science Institute (FSI

Curve sprinting in Soccer: Kinematic and Neuromuscular Analysis

Sprinting in curvilinear trajectories is an important soccer ability, corresponding to ~85 % of the actions performed at maximum velocity in a soccer league. We compared the neuromuscular behavior and foot contact-time between outside leg and inside leg during curve sprinting to both sides in soccer players. Nine soccer players (age = 23 ± 4.12 years) performed: 3 × Sprint linear, 3 × Sprint right curve, and 3 × Sprint left curve. An ANOVA with repeated measures was used to compare the differences between inside and outside leg, and Cohen’s d was used to calculate the effect-size. Considering the average data, the performance classification (from best to worst) was as follows: 1. Curve “good” side (2.45 ± 0.11 s), 2. Linear (2.47 ± 0.13 s), and 3. Curve “weak” side (2.56 ± 0.17 s). Comparing linear with curve sprinting, inside leg recorded significant differences (“good” and “weak”; effect size = 1.20 and 2, respectively); in contrast, for outside leg, there were no significant differences (“good” and “weak”; effect size = 0.30 and 0.49, respectively). Electromyography activity showed significant differences (p ≤ 0.05) during curve sprinting between outside (higher in biceps femoris and gluteus medius) and inside leg (higher activity in semitendinosus and adductor). In summary, inside and outside leg play different roles during curved sprints, but inside leg is more affected by the change from straight to curve sprint

The Safe Landing warm up technique modification programme: An effective anterior cruciate ligament injury mitigation strategy to improve cutting and jump-movement quality in soccer players

The objective of the study was to evaluate the effectiveness of the Safe Landing (SL), a 6-week technique-modification (TM) programme, on cutting and jump-landing movement quality in football players. In a non-randomized design, 32 male semi-professional football players from two Spanish clubs participated in the study: one served as the control group (CG, n = 11), while the other performed the SL (n = 15). Performance and movement quality of drop vertical jump and 70º change of direction (COD70) were evaluated through 2D video footage pre- and post-intervention. In such tasks, the Landing Error Scoring System for first (LESS1) and second (LESS2) landings, and the Cutting Movement Assessment Score (CMAS) were used for assessing movement quality. Pre-to-post changes and baseline-adjusted ANCOVA were used. Medium-to-large differences between groups at post-test were shown in CMAS, LESS1 and LESS2 (p  0.05) pre-to-post. In COD70 performance, large differences were found between groups (p  0.05, ES=0.039–0.420), while CG moderately decreasing performance (p = 0.024, ES=0.753) pre-to-post. The SL is a feasible and effective TM program to improve movement quality and thus potential injury risk in cutting and landing, while not negatively affecting performance

High-intensity actions in elite soccer: current status and future perspectives

Over the years, soccer has become more physically demanding; the number and frequency of high-intensity actions have increased, and these activities are decisive in determining the match outcome. Importantly, the reductionist approach commonly used to analyze high-intensity actions does not contemplate a more contextualized perspective on soccer performance. Traditionally, most investigations have only provided quantitative data regarding sprints (i. e. time, distances, frequency) without examining "how" (e. g. type of trajectory or starting position) and "why" (e. g. tactical role) soccer players sprint. In fact, other high-intensity actions, apart from running, are not even mentioned (i. e. curve sprints, change of direction, and specific-jump tasks). This has led to the use of tests and interventions that do not accurately reflect real game actions. Given the true technical-tactical-physical demands of each playing position, this narrative review collected a wide-spectrum of current soccer-related articles and provided a discussion regarding high-intensity actions, with a positional-based approach. In this narrative review, practitioners are encouraged to contemplate and consider the different elements that characterize high-intensity actions in soccer, in order to assess and train soccer players under a more sport-specific and integrative perspective

Effect of Ball Inclusion on Jump Performance in Soccer Players: A Biomechanical Approach

Objective: In soccer, vertical jump means jumping toward a ball. Since no vertical jump test includes the ball as a reference element, the effect that the ball would have in a vertical jump test is unknown. The aim of this study was to examine the biomechanical differences between run-up vertical jump measurements without (Run-up Vertical Jump) and with ball inclusion (Heading Test). Methods: Twelve semi- and professional soccer players were recruited. Athletes performed both jump tests in a biomechanical laboratory, where kinetic and spatiotemporal variables were collected and compared using a Student’s dependent t-test for paired samples. Results: Overall, players performed a different jumping strategy during the heading test compared to the run-up vertical jump, exhibiting: 1) higher horizontal velocity during initial contact (+45.3%, P ≤ .001), 2) shorter contact time, greater rate of force development, and total impulse during push-off (+27.5%, +53%, and +10.6%, respectively, P ≤ .008), 3) higher CoM horizontal and resultant velocity during take-off (+76.1% and 20.5%, respectively, P ≤ .001), 4) better vertical jump performance (+4.3%, P ≤ .0001), and 5) larger body angle rotation during landing (+63.3%, P = .006), compared to run-up vertical jump (effect size: 0.78 to 3.7). Conclusion: In general, soccer players display greater vertical jump heights in heading test, which highlights the importance of including an overhead ball during soccer-specific jump tests. Coaches and practitioners are encouraged to assess, and perhaps develop, the jumping ability of soccer players using a suspended ball as a specific target