Influence of Substitutions and Roles on Kinematic Variables in Professional Soccer Players.

In soccer, roles, and substitutions could make unclear how different physical capacities decrease over time and impact performance. This investigation aimed to analyze kinematic parameters and their changes over game time and provide information to effectively prescribe training programs. Data from four professional teams were analyzed, and all the teams competed in the Premier Division championship. Average metabolic power and high-intensity activities associated with critical moments in the match were considered in the comparisons. The video analysis system STATS SportVU collected the data during official matches. Players were assigned to a specific group according to their time played, categorized as follows: 0-15', 15-30', 30-45', 45-60', 60-75', 75-90', and > 90 min. Different roles, including forwards and wingers (FW), midfielders (MF), center-backs (CB), and side-backs (SB) were also considered. Significant differences (p<0.05) were found in different roles and within roles at different times played. The results highlighted how MF performance decreased over time, whereas CB was unaffected by time. SB spent more time at very high velocity than other roles, independently from the time played. These findings provide valuable information about the physical demands of official soccer games and could be used to review training prescriptions.

Relationship between aerobic fitness and metabolic power metrics in elite male soccer players.

The aim was to assess the relationship between aerobic fitness and metabolic power metrics in elite male soccer players, and the possible differences that playing positions might impose during match play over new metabolic power metrics. Sixty-two elite professional male soccer players (13 central backs, 13 side backs, 22 midfielders, and 14 forwards) took part in the study. Players were monitored during eleven months of full training (including pre-season and in-season) and over all official matches (Serie A matches, Italy Cup matches). Aerobic fitness tests were conducted one week after the start of the preseason, and 8, 24 and 36 weeks after the beginning of the Championship. Players' aerobic fitness and metabolic power metrics were considered as the mean of all seasonal testing and of pooling data of 38 championship matches and 3 or 6 Italy Cup matches for all the calculations respectively. The velocity at 4 mmol·L-1 (VL4) was significantly related to metabolic power metrics match variables with correlation ranging from trivial to very large (r = 0.32 to r = 0.89). Receiver-operating-characteristic (ROC) analysis showed that speed at VL4 was sensitive in detecting high metabolic power distance (HMPD) changes in all but central back players as revealed by area under the curve (central back .78, 95%CI .47 to .95; full back .93, 95%CI .64 to 0.99; midfielder .88, 95%CI .67 to 0.98; forward .90, 95%CI .62 to 0.99). This study's findings provide further evidence for the ecological validity of aerobic fitness in elite male soccer players. Players having a HMPD cut-off equal to or higher than > 1450 m for central backs, > 1990 m for full backs, > 2170 m for midfielders and > 1670 m for forwards may be considered as possessing superior aerobic fitness status. In light of this study's findings, the VL4 test may be considered a valid test to evaluate meaningful information for direct generic aerobic training in soccer players.

Injury prevention in professional soccer players: can re-warmup training be organized in the post-warmup and half-time during a soccer game in a short time?

INTRODUCTION: Passive time, during the post-warmup and half-time, decreases athletes' performance and increases injury risk factors in the active phases of the soccer match. OBJECTIVE: This narrative review aims to research and synthesize existing evidence to identify brief re-warmup strategies that may find applicability in the post-warmup and half-time of a soccer match. EVIDENCE ACQUISITION: The analysis was conducted on PubMed, Web of Science, PEDro, SPORTDiscus and Google Scholar. Due to the lack of evidence, no temporal time was established, preferring most up-to-date articles. The data were synthesized in relation to the objectives, following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. EVIDENCE SYNTHESIS: Our research yielded a total of 753 studies, 463 related to re-warmup, 136 articles on re-warmup in soccer, and 154 articles on re-warmup during half-time. Of these, 26 met the inclusion objectives and were included in this research. Our findings confirm that a re-warmup can mitigate the decremental effect of static rest on performance. From the studies considered, we have identified a work that emphasizes how a 1-minute warmup of high-intensity exercise at speed corresponding to 90% of VO2max can prevent decreases related to passive time, in sprint performance and muscle strength, as well as improve muscle temperature. These results could apply to both post-warmup and half-time scenarios of a soccer match. CONCLUSIONS: From this narrative review, it has been possible to highlight a one-minute high-intensity re-warmup that improved sprint performance, increased core temperature, and enhanced muscle activation, not leading to additional physiological or psychological fatigue.

Return to training in soccer players after anterior cruciate ligament reconstruction: reflections and considerations.

This clinical and rehabilitative overview focuses on the return to unrestricted sporting activity, aiming to consolidate the scientific evidence surrounding the structural progression of athletes, particularly footballers, undergoing anterior cruciate ligament reconstruction (ACLR). A multidisciplinary approach necessitates a shared language and standardized methodologies. Unfortunately, significant disparities persist in the structural strategies guiding the decision-making process for returning to on-field activities, the latter stages of rehabilitation, and subsequent restoration of technical and tactical football abilities. Divergences in definitions, terminologies, and rehabilitation protocols can substantially influence final outcomes. Presently, scientific consensus studies regarding the decision-making process during the final stages of on-field rehabilitation are lacking. Nevertheless, this overview outlines and defines pivotal language parameters crucial for effective communication and the seamless integration of clinical and rehabilitative data among the diverse professionals involved in facilitating the athlete's return to peak performance. In conclusion, the successful resumption of competitive sporting activities for footballer's post ACLR demands a collaborative decision-making approach encompassing various professionals. Additionally, it necessitates a cohesive transition from rehabilitation to on-field work, aiming at reinstating athleticism, technical prowess, and tactical acumen.

Prevention of Secondary Injury after Anterior Cruciate Ligament Reconstruction: Relationship between Pelvic-Drop and Dynamic Knee Valgus.

(1) Background: Optimal neuromuscular, Lumbo-Pelvic-Hip Complex, and lower extremity control are associated with decreased risk factors for secondary anterior cruciate ligament (ACL) injury. This study aimed to analyze any asymmetries and malalignments in the Lumbo-Pelvic-Hip Complex and the lower limbs at 6 months after ACL reconstruction (ACLR). (2) Methods: We conducted an exploratory retrospective observational single-center study in patients during the outpatient postoperative rehabilitation program at ICOT (Latina, Italy). From January 2014 to June 2020, 181 patients were recruited, but only 100 patients (86 male 28 ± 0.6 years, 178 ± 0.5 height; 14 female 24 ± 2.0 years, 178 ± 3.0 height) were eligible for the inclusion criteria and studied 6 months after ACL reconstruction surgery. (3) Statistical analysis: Student's t-tests and Pearson's product-moment correlation coefficient were used to determine significant differences between affected and non-affected limbs and variables' association. (4) Results: The study shows a decrease in neuromuscular control of the Lumbo-Pelvic-Hip Complex and dynamic adaptive valgus of the knee at 6 months after ACLR (mean difference between pathological and healthy limb of dynamic adaptive valgus was -10.11 ± 8.19° 95% CI -14.84 to -9.34; mean value was 16.3 ± 6.8° 95% CI 14.04 to 18.55 for healthy limb and 4.2 ± 3.1° 95% CI 3.15 to 5.21 for pathological limb, p < 0.0001). The results also showed a relationship between dynamic adaptive valgus and contralateral pelvic drop (r = 0.78, 95% CI 0.62 to 0.88, magnitude of correlation very large). (5) Conclusions: The analysis showed an associative correlation between decreased postural control of the pelvic girdle and dynamic adaptive valgus of the knee in 38% of patients; this study highlights the usefulness of the Single-Leg Squat Test (SLST) as a clinical/functional assessment to evaluate the rehabilitation process and as a preventive tool to reduce the risk of second ACL injuries during the return to sport.

Effects of three different stretching protocols on hamstring muscle flexibility in professional soccer players: a randomized study.

BACKGROUND: The current study aimed to investigate and compare the influences of global postural rieducation techniques (GPR), stretching exercises on a whole-body vibration platform (WBV), and static stretching exercises on hamstrings flexibility in elite soccer players. METHODS: 24 professional soccer players were randomly assigned to either global postural re-education (N.=8), stretching on whole-body vibration group (N.=8) or static stretching (N.=8), during the first 4 weeks of the precompetitive season. Assessment of hamstring muscle flexibility was performed using a straight leg raise test. All participants were assessed three times: at baseline, at the end of the study protocol and 14 days after the end of the study protocol. RESULTS: The short-term increase in hamstring muscle flexibility was observed in all 3 groups, without significant differences among groups. However, after 14 days from the end of the interventions only the WBV group maintained the flexibility level achieved just at the end of the protocol with no significant changes in both legs whereas a significant decrease in the SLRT in GPR and SS groups, in right and left legs (GPR, P=0.002; P=0.015; SS, P=0.0001; P=0.0001), was observed. CONCLUSIONS: These results would suggest that GPR, static stretching on whole-body vibration and static stretching techniques all improve hamstring muscle flexibility, but only stretching on WBV maintains the effect over time in professional soccer players.

Examining and comparing the health and performance indices of university undergraduate students according to year of study and gender.

This study examined and compared, based on year of study and gender, the health and performance indices of university undergraduate students. Eighty-nine students (mean±standard deviation age, 22.47±2.22 years) were randomly selected for assessment prior to second semester examination of 2015/2016 academic year. body mass index, resting metabolic rate, visceral fat, skeletal muscle mass, body fat, systolic & diastolic blood pressure, resting heart rate, upper & lower body endurance, handgrip strength, and lower back and hamstring flexibility were assessed. The students had sedentary heart rate, low skeletal muscle mass, average upper and lower body endurance, and weak handgrip strength. Significant difference existed in the visceral fat (P=0.008) between third and fourth year students. There were significant gender differences in resting metabolic rate (P=0.000), skeletal muscle mass (P=0.000), body fat (P=0.000), systolic blood pressure (P=0.001), heart rate (P=0.005) and handgrip strength (P=0.000). There are gender differences in association between health and performance indices. Dependable health education and pragmatic involvement of undergraduate university students in structured exercise programmes are recommended.