Elite Soccer Players Research Articles

Cognitive training in elite soccer players: evidence of narrow, but not broad transfer to visual and executive function

Visual and executive functions have been suggested to be crucial in high-demanding team sports. Consequently, the interest in evaluating training possibilities of these functions is relatively high. However, easily applicable training tools, as well as evidence of their efficacy, especially in the present group of age (i.e. 17–21 years) and performance level, are scarce. Therefore, the present study aimed to evaluate the effectiveness and transfer of an essential cognitive training tool (i.e. NeuroTracker [NT] three dimensional [3D] multiple-object tracking [MOT]) in youth elite soccer players. Visual and executive functions were analyzed in a pre–post test design with an intervention and a control group after 10 weeks of training twice a week. Physical activity was included as a possible covariate. Results show meaningful benefits in the trained ability (i.e. MOT) besides small but negligible improvements in visual clarity and inhibition for the intervention group. Consequently, strict single-task NT 3D-MOT seems to have little transfer to other visual or executive functions. However, future studies should investigate the effects of sport-specific dual-task NT 3D-MOT to analyze possible multitasking adaptations further.

The effect of a weekly flywheel resistance training session on elite U-16 soccer players’ physical performance during the competitive season. A randomized controlled trial

ABSTRACT This study investigated the effects of a weekly flywheel resistance training session over a 10-week period on U16 soccer players’ physical performance with special attention to change of direction ability (e.g., deficit [CODdef]). Twenty elite young soccer players were assigned to an experimental (EG, n = 10) or control (CG, n = 10) group. Unilateral countermovement jumps with dominant (CMJd) and non-dominant (CMJnd) leg, 10, 20, and 30-m linear sprint test and change of direction sprint test in 5 + 5 (COD10) and 10 + 10 m (COD20) were performed before and after flywheel training period. Significant within-group differences were found in CG in COD10 (p = 0.01; effect size [ES] = large) and CODdef10 (p = 0.03; ES = small) with dominant leg, while differences in EG were observed in CMJ (p = 0.001–0.01; ES = moderate-large) and in all COD and CODdef variables (p = 0.001–0.04; ES = large). Between-groups analysis revealed differences in favour of the EG in CMJ (p = 0.03–0.05) and COD and CODdef variables (p = 0.001–0.05). These findings suggest a weekly flywheel training session is suitable for improving jumping and COD abilities in U16 elite soccer players in season.

Morning Priming Exercise Strategy to Enhance Afternoon Performance in Young Elite Soccer Players.

To compare the effects of different modalities of morning priming exercise on afternoon physical performance with the associated hormonal and psychophysiological responses in young soccer players. In a randomized counterbalanced crossover design, 12 young soccer players completed 3 different morning conditions on 3 different days: repeated-sprint running (6 × 40m), easy exercise (4 × 12 fast half squats, 6 speed ladder drills, and 20-m sprints), and control (no exercise). Blood testosterone and cortisol concentrations were assessed upon arrival (approximately 8:30AM) and approximately 5hours and 30minutes later. Body temperature, self-reported mood, quadriceps neuromuscular function (maximal voluntary contraction, voluntary activation, rate of torque development, and twitch contractile properties), jump, and sprint performance were evaluated twice per day, while rating of perceived exertion, motivation, and the Yo-Yo Intermittent Recovery level 2 (IR2) tests were assessed once per day. Compared with the control, repeated-sprint running induced a possible positive effect on testosterone (+11.6%) but a possible to very likely negative effect on twitch contractile properties (-13.0%), jump height (-1.4%), and Yo-Yo IR2 (-7.1%). On the other hand, easy exercise had an unclear effect on testosterone (-3.3%), resulted in lower self-reported fatigue (-31.0%) and cortisol (-12.9%), and had a possible positive effect on the rate of torque development (+4.3%) and Yo-Yo IR2 (+6.5%) compared with the control. Players' testosterone levels were positively influenced by repeated-sprint running, but this did not translate into better physical function, as both muscular and endurance performance were reduced. Easy exercise seemed to be suitable to optimize the physical performance and psychophysiological state of young soccer players.

The design fluency test: a\xa0reliable and valid instrument for the assessment of game intelligence?

The design fluency test (DFT) has been reported to predict successful sports performance of soccer players and has therefore been in the spotlight of sport psychology research. There is, however, a lack of research regarding the psychometric properties of the DFT in elite sports. Thus, the aim of this research was to provide findings of test–retest reliability, practice effects and the diagnostic power of the DFT. Multiple studies of youth and adult elite athletes, as well as nonathlete students, were conducted in applied settings. Test–retest relationship demonstrated poor to acceptable short-term and long-term correlations. Furthermore, significant changes between test and retest were obtained in some variables that differed among samples. The differential value of the DFT was corroborated by significant differences between adolescent students and adolescent elite soccer players. Regarding the prospective value, significant partial correlation coefficients were found between DFT scores and volleyball performance in adult elite players. Although our research partially confirmed previous findings on the differential and prospective power of the DFT, the findings on test–retest reliability indicate that the DFT cannot be recommended for application in sports. The psychometric properties—in particular the findings on test–retest reliability—of the DFT have to be improved before research can be carried out on the application for the selection of team sport athletes and for the prediction of future success in team sports. Further research is needed to develop a scientific instrument for the assessment of game intelligence.

Sustained Passing Performance of Elite and Subelite Female Soccer Players Following a Female Match-Specific Exercise Protocol.

This study examined the maintenance of passing performance following soccer-specific high-intensity intermittent exercise in elite (n = 9) and subelite (n = 11) Western Australian female soccer players (19.5 [2.5]y). A total of 20 participants completed the Loughborough Soccer Passing Test (LSPT) prior to, during, and following 90 minutes of a modified, female-specific, individualized exercise protocol (Loughborough Intermittent Shuttle Test [LIST]) to simulate 2 halves of a soccer match. Performance in the LSPT was calculated by adding "raw time" to the accumulated "penalty time" for each test. Elite players recorded greater distances (t58 = 4.671, P < .001, effect size [ES] = 1.21) and higher derived VO2max values (t58 = 4.715, P < .001, ES = 1.20) for the LIST exercise protocol over the subelite players. The total performance times for each LSPT were longer in the subelites in comparison with the elites, with a very large ES difference seen in post-LIST1 (t18 = -6.64, P < .001, ES = 2.99) and post-LIST2 (t18 = -9.143, P < .001, ES = 4.12). No between-groups differences were identified for "raw time" at any time point. Hence, all reported LSPT performance differences are attributed to "penalty time." These data suggest that elite players can sustain their passing performance more efficiently throughout match play that can subelite female soccer players. These findings may contribute to future talent-identification testing by helping to distinguish between elite- and subelite-level players through sustained passing performance. Coaches may also use this information to better inform best-practice training methods through modification of male soccer-specific high-intensity intermittent exercise to a female cohort.

SMILE: A verbal and graphical user interface tool for speech-control of soccer robots in Ghana

SMILE (Smartphone Intuitive Likeness and Engagement) application, a portable Android application that allows a human to control a robot using speech input. SMILE is a novel open source and platform independent tool that will contribute to the robot soccer research by allowing robot handlers to verbally command robots. The application resides on a smartphone embedded in the face of a humanoid robot, using a speech recognition engine to analyze user speech input while using facial expressions and speech generation to express comprehension feedback to the user. With the introduction of intuitive human robot interaction into the arena of robot soccer, we discuss a couple specific scenarios in which SMILE could improve both the pace of the game and autonomous appearance of the robots. The ability of humans to communicate verbally is essential for any cooperative task, especially fast-paced sports. In the game of soccer, players must speak with coaches, referees, and other players on either team. Therefore, if humanoids are expected to compete on the same playing field as elite soccer players in the near future, then we must expect them to be treated like humans, which include the ability to listen and converse. SMILE (Smartphone Intuitive Likeness and Engagement) is the first platform independent smartphone based tool to equip robots with these capabilities. Currently, humanoid soccer research is heavily focused on walking dynamics, computer vision, and intelligent systems; however human-robot interaction (HRI) is overlooked. We delved into this area of robot soccer by implementing SMILE, an Android application that sends data packets to the robot's onboard computer upon verbal interaction with a user.

Muscle strength capacities in elite football players after anterior cruciate ligament reconstruction

The aim of this study was to explore the strength capacities of the injured and non-injured leg following a unilateral anterior cruciate ligament reconstruction. Eight elite soccer players (age = 25.5 ± 3.9 years; height = 1.83 ± 0.04 m; body mass = 78.9 ± 4.5 kg) volunteered to participate in this study. Nine months after the anterior cruciate ligament reconstruction and just before initiating the full training process, the maximal peak torque of the quadriceps and hamstring muscles were measured at 60 and 180 degrees/ second using isokinetic dynamometry. Obtained peak torques were used for calculating hamstring-to-quadriceps ratio, limb symmetry index, and to estimate maximal torque capacity using a two-velocity method (i.e., linear torque-velocity relationship modeled considering peak torque obtained at 60 and 180 degrees/second). No differences were found between hamstring-to- -quadriceps ratios of the injured and non-injured leg ( p = 0.165), nor between limb symmetry index of the quadriceps and hamstring muscles ( p = 0.985), regardless of the angular velocity applied during tests. The two-point method revealed significant differences between quadriceps and hamstring muscle groups both in the injured and non-injured leg ( p < 0.001; maximal estimated torque was higher for quadriceps compared to hamstring muscles), while the differences between same muscle groups of the different legs were not significant. Collectively, these findings indicate that 9 months were enough for reaching a certain strength level of the injured leg that permits a safe return to play.

Monitoring of overtraining and motivation in elite soccer players

Aim: This study aimed to monitor the behavior of the overtraining and motivations dimensions, as well as to verify whether these dimensions correlate in the preparatory and competitive periods over the season. Methods: Professional soccer players (n = 32) answered the Stress and Recovery Questionnaire for Athletes (RESTQ-Sport 76) and the Sport Motivation Scale (SMS) during the preparatory and competitive periods. Results: Intrinsic amotivation and sport-specific recovery were lower in the competitive period than in the preparatory period. In the preseason, motivation presented a strong and negative correlation with overall recovery (p = 0.001; r = −0.75; r2 = 0.56) and sport-specific recovery (p = 0.001; r = −0.72; r2 = 0.52). The amotivation explained in 56% the variance of the results of the overall recovery and 52% of the sport-specific recovery. During the competitive phase, amotivation showed a strong and positive correlation with overall stress (p = 0.001; r = 0.70; r2 = 0.49) and sport-specific stress (p = 0.001; r = 0.79; r2 = 0.62). The amotivation accounted for 49% of the variance in the results of the overall stress and 62% of sport-specific stress in soccer players. Conclusion: There are associations between overtraining and motivation during the investigated periods. Through longitudinal monitoring in professional soccer, it was verified that the dimensions of amotivation, overall recovery, and sport-specific stress could be related to the prevention symptoms of overtraining in a professional soccer team.

The impact of COVID-19 lockdown on professional soccer players' body composition and physical fitness.

During the COVID-19 lockdown, professional soccer players ceased their regular team training sessions and were provided with exercise programs to follow independently. This investigation assessed the impact of a 7-week COVID-19 lockdown and home-based individual physical training on professional soccer players’ body composition and physical fitness. The study consisted of nineteen division 1 elite soccer players (age 27.68 ± 5.99 years, height 178.47 ± 5.44 cm) and compared the anthropometric and physical fitness parameters obtained post-transition period to those obtained post-COVID-19 lockdown. The statistical analysis indicated that body fat percentage was significantly higher after the lockdown period [t(18) = -5.59, p < 0.01, d = 0.56]. Furthermore, VO2max [t(17) = -11.54, p < 0.01, d = 0.57] and running time [t(17) = 3.94, p < 0.01, d = 0.76] values were significantly higher after the COVID-19 lockdown than those obtained after the transition period. In addition, significantly higher level of performance was demonstrated on squat jump [t(18) = -4.10, p < 0.01, d = 0.30], countermovement jump [t(18) = -7.43, p < 0.01, d = 1.11] and sit and reach tests [t(19) = -5.33, p < 0.01, d = 0.32]. Concurrently, lower body strength was indicated to be significantly greater (p < 0.01) following the COVID-19 lockdown. The training protocol provided during the confinement, due to the COVID-19 outbreak, was effective in keeping physical fitness at a significantly higher level compared to the transition period. Coaches and trainers are encouraged to examine the effectiveness of this protocol, as it may help them develop effective periodization programs during the transition period. This protocol may aid in the development of effective periodization programs that require minimal equipment and can be followed in similar situations.

Asymptomatic Foot and Ankle Abnormalities in Elite Professional Soccer Players.

Background:Professional soccer players are often evaluated with asymptomatic lesions of the ankle and foot, and such abnormalities may eventually become clinically relevant.Purpose:To ascertain the prevalence of foot and ankle abnormalities in elite professional adult soccer players.Study Design:Case series; Level of evidence, 4.Methods:Professional adult male elite soccer players (n = 37) underwent magnetic resonance imaging (MRI) scans of both their feet and ankles. All competed for their respective national junior or adult soccer teams. MRI scans were performed with 1.5-T scanners and analyzed independently by 2 experienced radiologists.Results:The MRI scans of 86.5% of the players showed degenerative joint disease (DJD) in at least 1 of the joints of the foot and ankle. Articular cartilage lesions in the joints of the foot and ankle were evident in 42% of the scans. Of all lesions, 17% were grade 3 or 4 (Noyes and Stabler classification) cartilage lesions and accompanied by subchondral bone marrow edema. The greater the age, weight, and height of the players, the greater was the odds ratio of DJD of the ankle joint. Synovitis in at least 1 of the joints of the foot was detected in 64% of the MRI scans. Leg dominance significantly correlated with bone marrow edema of the talus.Conclusion:Elite professional soccer players are often evaluated with a high prevalence of asymptomatic osteochondral lesions with subchondral bone marrow edema in the foot and ankle. These osteochondral lesions may remain asymptomatic or, with the continuing high-intensity stresses that modern professional soccer demands of its athletes, may evolve and cause foot and ankle pain. It is unclear whether and which interventions can be implemented to prevent the occurrence of these abnormalities in the first place.

대학 엘리트 축구선수의 긍정심리자본이 직무열의와 조직시민행동에 미치는 영향

이 연구의 목적은 대학 엘리트 축구선수의 긍정심리자본이 직무열의와 조직시민행동에 어떠한 영향을 미치는지 를 규명하는데 있으며, 이를 위해 전국 대학 엘리트 축구선수를 대상으로 총 261부의 자료를 수집하였다. 자료분석은 SPSS 21.0 프로그램을 활용하였으며, 빈도분석과 탐색적 요인분석, 신뢰도 분석, 상관분석, 다중회귀분석을 실시하였 다. 이상의 분석방법을 사용하여 다음과 같은 결론을 얻었다. 첫째, 긍정심리자본과 직무열의의 하위요인인 몰두의 회귀 분석 결과 긍정심리자본의 하위요인인 자기효능감과 희망, 회복탄력성, 낙천성 등 모든 변인에서 유의한 영향을 미치는 것으로 나타났으며, 활력과 헌신은 긍정심리자본의 하위요인인 자기효능감과 희망, 회복탄력성에서 유의한 영향을 미치 는 것으로 나타났고, 낙천성은 유의한 영향을 미치지 않는 것으로 나타났다. 둘째, 긍정심리자본과 조직시민행동의 회귀 분석 결과 긍정심리자본의 하위요인인 자기효능감과 희망, 회복탄력성에서 통계적으로 유의한 영향을 미치는 것으로 나타났으며, 낙천성은 유의한 영향을 미치지 않는 것으로 나타났다. 셋째, 직무열의와 조직시민행동의 회귀분석 결과 직무열의의 하위요인인 활력, 헌신, 몰두 등 모든 변인에서 통계적으로 유의한 영향을 미치는 것으로 나타났다.

The effects of residential environment on the condition and fitness of soccer players in the summer.

Exercise performance is reduced in hot environments due to physiological responses caused by increased body temperature. A proper residential environment is important for improving the performance and maintaining physical condition of soccer players in the summer. The purpose of this study was to determine the effect of indoor temperature of the resting space during the summer on the fitness and condition of soccer players. A total of 12 K-3 League semiprofessional players without serious injuries in the last 3 months voluntarily participated in the study. Participants performed speed (10 m, 20 m, and 30 m), soccer-specific coordination skill (dribbling), agility, repeated sprints, Yo-Yo intermittent level 2, vertical jump, and questionnaire (fatigue, sleep quality, muscle soreness, stress, and mood) after staying indoor temperature at 20°C, 26°C, and 30°C for one night, respectively. There was no difference among groups in physical fitness (speed, agility, jump, coordination, Yo-Yo intermittent level 2, and repeated sprints). The differences in fatigue and sleep quality were not statistically significant among groups, but they tended to be different. Muscle soreness was similar among all groups. Significant differences were observed between the 20°C and 30°C groups in stress and mood levels. The present study concluded that, while the physical fitness did not differ among groups, the 30°C residential environment was shown to have a negative psychological effect. Considering that many diseases associated with hot weather occur in low residential temperatures, a room temperature of 26°C is recommended for elite soccer players in hot summer weather.

Are There Differences in Concentric Isokinetic Strength Perfor-Mance Profiles between International and Non-International Elite Soccer Players?

The purpose of this study is to evaluate the differences in concentric isokinetic strength characteristics of the knee extensor and knee flexor musculature between international (IL) and non-international level (N-IL) soccer players. The second aim is to establish strength symmetry status in knee muscles for dominant (DL) and non-dominant (NDL) legs for both within and between groups. 100 male top elite soccer players (IL: n = 36, age = 27.5 ± 3.4 years and N-IL: n = 64, age = 27.7 ± 6.4 years) underwent concentric isokinetic strength tests, using a Biodex System 3 dynamometer. Results indicate that statistically significant differences between groups were noted for peak torque of hamstrings (PT-H), hamstrings/quadriceps (H/Q) ratio, and total work of hamstrings (TW-H), where mean values for the IL were similarly higher than for the N-IL group (p = 0.006, p < 0.001, and p = 0.012, respectively). Our results also showed statistically significant differences for peak torque of quadriceps (PT-Q), PT-H, total work of quadriceps (TW-Q) and TW-H between legs, where mean values noted for the DL were higher than for the NDL for both groups (p = 0.021, p < 0.001, p = 0.006, and p = 0.004, respectively). Additional results show that IL players presented more symmetrical strength between legs than N-IL. The results of this study indicate that that the greatest differences in isokinetic strength performance across players at different soccer levels relate to the hamstring muscle. As a result, systematic strength training of these muscle groups is strongly recommended.

Do elite soccer players cover longer distance when losing? Differences between attackers and defenders

This study aimed to evaluate the effects playing position, match location (home or away), quality of opposition (strong or weak), effective playing time (total time minus stoppages), and score-line on physical match performance in professional soccer players using a large-scale analysis. A total of 10,739 individual match observations of outfield players competing in the Spanish La Liga during the 2018–2019 season were recorded using a computerized tracking system (TRACAB, Chyronhego, New York, USA). The players were classified into five positions (central defenders, players = 94; external defenders, players = 82; central midfielders, players = 101; external midfielders, players = 72; and forwards, players = 67) and the following match running performance categories were considered: total distance covered, low-speed running (LSR) distance (0–14 km · h−1), medium-speed running (MSR) distance (14–21 km · h−1), high-speed running (HSR) distance (&gt;21 km · h−1), very HSR (VHSR) distance (21–24 km · h−1), sprint distance (&gt;24 km · h−1) Overall, match running performance was highly dependent on situational variables, especially the score-line condition (winning, drawing, losing). Moreover, the score-line affected players running performance differently depending on their playing position. Losing status increased the total distance and the distance covered at MSR, HSR, VHSR and Sprint by defenders, while attacking players showed the opposite trend. These findings may help coaches and managers to better understand the effects of situational variables on physical performance in La Liga and could be used to develop a model for predicting the physical activity profile in competition.

Elite Soccer Players Do Not Cover Less Distance in the Second Half of the Matches When Game Interruptions Are Considered.

Rey, E, Kalén, A, Lorenzo-Martínez, M, López-Del Campo, R, Nevado-Garrosa, F, and Lago-Peñas, C. Elite soccer players do not cover less distance in the second half of the matches when game interruptions are considered. J Strength Cond Res 38(4): 709-713, 2024-This study aimed to analyze quantitative differences in the physical demands of male elite soccer players between the first and second halves during official matches, accounting for effective playing time (the duration of play after subtracting the game interruptions) and playing positions. A total of 4,249 individual match observations of 412 outfield players competing in the Spanish first division league (LaLiga) were undertaken during the 2018-2019 season, using a computerized tracking system (TRACAB, Chyronhego, New York, NY). The players were classified into 5 positional roles: central defenders (CD), external defenders (ED), central midfielders (CM), external midfielders (EM), and forwards (F). The main results showed that in contrast to those observed when total playing time was considered, independent of playing position, there were no significant differences on high-speed running (HSR) (5.5 ± 2.4 vs. 5.5 ± 2.4 m·min -1 ) and sprint (5.3 ± 3.3 vs. 5.4 ± 3.3 m·min -1 ) distances between the first and second halves in professional soccer players when the effective playing time was considered. However, differences in match running performance at HSR and sprint distances between the first and second halves were dependent on players' playing position. Whereas ED and EM maintained HSR and sprint efforts during the second half, CD and CM significantly increased ( p < 0.001) the distance covered at sprint during the second period of the match. Contrarily, F were unable to maintain their HSR (6.2 ± 2.3 vs. 5.9 ± 3.3 m·min -1 ) and sprint (7.0 ± 3.5 vs. 6.5 ± 3.4 m·min -1 ) match running performances during the second half. Such findings demonstrate that total playing time could overestimate fatigue-induced performance declines. Thus, effective playing time and playing position should be taken into account when interpreting the match running performance of professional soccer players.

Rethinking training in elite soccer players: comparative evidence of small-sided games and official match play in kinematic parameters.

The aim of this study was to compare kinematics parameters among official matches and SSGs of an Italian premier league soccer team. Eighteen elite professional male soccer players (4 central defenders, 4 wide defenders, 3 central midfielders, 3 box-to-box midfielders, 2 wingers and 2 strikers) took part in the study. Players were monitored during four months of full training (including preseason and in-season) and over 26 matches (14 Serie A matches, 9 Europa League matches, and 3 friendly matches), from July 2017 until November 2017. The kinematic parameters during official matches and SSGs were evaluated through video match analysis. The kinematic data analysis shows that the metabolic power, that constitutes an integrated measure of acceleration and velocity, fails to reflect what occurs during actual match-play. An increased attention should be place in planning SSGs during training to better reproduce actual match situations.

The Association Between Training Load Indices and Injuries in Elite Soccer Players.

Tiernan, C, Comyns, T, Lyons, M, Nevill, AM, and Warrington, G. The association between training load indices and injuries in elite soccer players. J Strength Cond Res 36(11): 3143-3150, 2022-To investigate the association between contact injuries, noncontact injuries, and training load indices, across different lag periods in elite soccer players. Internal load (session rate of perceived exertion) was collected from 15 elite soccer players over 1 season (40-weeks). Acute (7 days), chronic (28 days), acute:chronic workload ratio (ACWR) (uncoupled), exponentially weighted moving averages (EWMA) ACWR, and 2-, 3-, and 4-week cumulative load were calculated on a rolling weekly basis. Multilevel logistic regression was used to analyze the associations between contact, noncontact injuries, and training load indices, across different lag periods (5 and 7 days). A player was at a significantly higher risk of a noncontact injury 5 days later, if week-to-week acute load changes increased (odds ratio [OR] = 1.97). An increase in EWMA ACWR was associated with an increased risk of both a contact (OR = 1.30) and noncontact injury (OR = 1.35), 5 days later. An increase in 2-week cumulative load (OR = 1.77) was associated with an increased risk of a contact injury 7 days later and 3-week cumulative load (OR = 1.55) 5 days later. These findings suggest that to reduce the potential risk of a noncontact injury, training load should be gradually increased, avoiding an increase in week-to-week acute load change (≥9%) or EWMA ACWR (>1.20). Findings indicated that EWMA ACWR may be a more sensitive measure for detecting a player at a higher risk of an injury than ACWR. Furthermore, a high 2- and 3-week cumulative load was associated with an increased risk of a contact injury, which may indicate accumulated fatigue. Practitioners must note that this study investigated associations with injury risk and not injury prediction.

Effects of the COVID-19 confinement period on physical conditions in young elite soccer players.

The rapid spread of the SARS-CoV-2 infection required general confinement measures reducing or even preventing sport practice, which was a risk of detraining in athletes. In adolescents, detraining is poorly known as well as its prevention by home-exercises. This article aimed to assess the effects of COVID-19 confinement on detraining in young high-level soccer players despite a multimodal training program conducted at home. Twenty-five elite soccer players, aged 14, were included to perform physical exercises at home during the COVID-19 confinement. Two cardio-training sessions and two upper and lower limb muscle strengthening sessions were performed per week. The exercise program was monitored remotely via the web. Hooper, training and mental indexes allowed a psychological follow-up. The effect of COVID-19 confinement on aerobic capacity was measured using a pre- and postconfinement Yo-Yo Test. Out of the 25 adolescences who completed the exercises program, 19 performed the postconfinement Yo-Yo Test. The running distance decreased by 614+/-630 m (-25%) (P=0001) and the maximal running speed by 0.97+/-1 km/h (-5%) (P=0.001), confirming detraining. Hooper, training and mental indexes remained stable showing a well-supported home COVID-19 confinement. The 2-month period of strict home confinement due to the SARS-CoV-2 pandemic was responsible for a decrease of aerobic abilities in adolescent soccer players, despite a remotely monitored multimodal exercises program.

Do elite soccer players cover less distance when their team spent more time in possession of the ball?

ABSTRACT Purpose: The aim of this study was to examine the association between the time spent in possession by teams and the match-running performance in elite soccer matches. Methods: Match performance data were collected from players in Spanish LaLiga (8,468 individual match observations of 412 outfield players) using a multiple-camera computerised tracking system. A k-means cluster analyses classified teams depending on time spent in possession of the ball: very high-percentage ball possession teams (VHPBPT), high-percentage ball possession teams (HPBPT), low-percentage ball possession teams (LPBPT) and very low-percentage ball possession teams (VLPBPT). Results: Overall, physical indicators were highly associated with ball possession. Distances covered in VHPBPT were lower than HPBPT, LPBPT and VLPBPT, especially at low and medium speed. Position-specific changes were also evident for physical profiles. Attackers (central midfielders, external midfielders and forwards) in VHPBPT covered fewer meters per minute at any speed than their counterparts in HPBPT, LPBPT or VLPBPT. However, defenders (Central defenders and External defenders) in VLPBPT covered lower distances. Conclusion: These findings may have a great deal of practical implications and may help coaches to better understand match-running variations according to ball possession strategies and could be used to develop a model for predicting the physical activity profile in competition.

The Validity of an Updated Metabolic Power Algorithm Based upon di Prampero's Theoretical Model in Elite Soccer Players.

The aim of this study was to update the metabolic power (MP) algorithm (, W·kg−1) related to the kinematics data (PGPS, W·kg−1) in a soccer-specific performance model. For this aim, seventeen professional (Serie A) male soccer players ( 55.7 ± 3.4 mL·min−1·kg−1) performed a 6 min run at 10.29 km·h−1 to determine linear-running energy cost (Cr). On a separate day, thirteen also performed an 8 min soccer-specific intermittent exercise protocol. For both procedures, a portable Cosmed K4b2 gas-analyzer and GPS (10 Hz) was used to assess the energy cost above resting (C). From this aim, the MP was estimated through a newly derived C equation (PGPSn) and compared with both the commonly used (PGPSo) equation and direct measurement (). Both PGPSn and PGPSo correlated with (r = 0.66, p < 0.05). Estimates of fixed bias were negligible (PGPSn = −0.80 W·kg−1 and PGPSo = −1.59 W·kg−1), and the bounds of the 95% CIs show that they were not statistically significant from 0. Proportional bias estimates were negligible (absolute differences from one being 0.03 W·kg−1 for PGPSn and 0.01 W·kg−1 for PGPSo) and not statistically significant as both 95% CIs span 1. All variables were distributed around the line of unity and resulted in an under- or overestimation of PGPSn, while PGPSo routinely underestimated MP across ranges. Repeated-measures ANOVA showed differences over MP conditions (F1,38 = 16.929 and p < 0.001). Following Bonferroni post hoc test significant differences regarding the MP between PGPSo and /PGPSn (p < 0.001) were established, while no differences were found between and PGPSn (p = 0.853). The new approach showed it can help the coaches and the soccer trainers to better monitor external training load during the training seasons.