Elite Male Soccer Players Research Articles

Hormonal (Cortical-Gonadotropic Axis) and Physical Changes With Two Years Intense Exercise Training in Elite Young Soccer Players.

Hammami, MA, Ben Abderrahman, A, Hackney, AC, Kebsi, W, Owen, AL, Nebigh, A, Racil, G, Tabka, Z, and Zouhal, H. Hormonal (cortical-gonadotropic axis) and physical changes with two years intense exercise training in elite young soccer players. J Strength Cond Res 31(9): 2388-2397, 2017-The aim of this study was to investigate the effects of 2 soccer-training seasons on physical fitness and hormone concentrations in elite youth soccer players. Twenty male elite soccer players (SP, age 14.5 ± 0.4 years) and 20 male control subjects (CS, age 14.3 ± 0.3 years) participated in the study. Anthropometric measurements, aerobic (Yo-Yo Intermittent Recovery Test Level 1 [YYIRT1]) and anaerobic soccer relevant performances (jump and sprint tests), blood testosterone (T), cortisol (C), sex hormone binding globulin (SHBG), and T/C ratio were assessed 5 times (from T0 to T4) during 2 competitive seasons. Significant differences from basal values (Δ) of T, SHBG, and C between SP and CS were observed (p < 0.01). Additionally, T and T/C ratio changes were positively correlated with physical performance (p ≤ 0.05). In conclusion, as expected, higher T concentration and greater power performance were observed in the soccer players group compared with controls. Our findings also show that the T concentrations and power performance outcomes co-vary positively over the 2 soccer seasons in soccer players.

Perceptions of psychological momentum of elite soccer players

The purpose of this research was to investigate elite soccer players’ perceptions and experiences of psychological momentum (PM) using a mixed methodological approach. Specifically, by comparing responses, the study aimed to provide coaches with a more appropriate method for collecting PM data. Interviews and focus groups were conducted with 10 English Academy, elite male soccer players. In addition, 75 professional male soccer players completed a 49-item measure about their experiences of PM. Interviews and focus groups were manually analysed using a combination of inductive and deductive approaches with Chi-square tests used to assess differences between responses to the PM measure. The majority of questionnaire responses were supported by themes highlighted by players interviewed. Scoring and conceding goals were the most frequently reported match variables associated with positive and negative PM, respectively. In addition, “feeling confident”, “having a positive attitude” and “being cohesive as a team” were important aspects of positive PM. A “perceived lack of ability” and “feeling anxious” were the most frequently reported experiences of negative PM. The similarity of results from both methods support the measure as a useful tool for coaches to collect data pertaining to players’ experiences and perceptions of PM. Overall, findings suggest that PM is a complex (dynamic) process whereby triggers, characteristics, and consequences can hardly be separated. By understanding players’ experiences and perceptions of PM, coaches may incorporate specific training methods to help players maximise positive PM, reduce negative PM as well as develop strategies to optimise PM.

The phase angle of bioelectric impedance in elite male soccer players in Taiwan

The phase angle of bioelectric impedance in elite male soccer players in Taiwan

The bone mineral density in lumber spine and upper limbs in elite male soccer players in Taiwan

The bone mineral density in lumber spine and upper limbs in elite male soccer players in Taiwan

Differences between the sexes in athletes' body composition and lower limb bioimpedance values.

The differences between the sexes in body composition are well established, although sports activity at an elite level seems to reduce them. The aim of this study is a comparison of the sexes in terms of athletes' body composition with a three-compartment model and a localized bioimpedance analysis in elite soccer players. 18 female and 18 male elite soccer players of the same age were matched (female=26.2±2.4, male 26.9±2.5; p=0.87). An assessment of body composition was performed through the integration of anthropometrics parameters, skinfold thickness and bioimpedance data. The evaluations were carried out in the morning on a group of athletes who were in a rested condition, having not exercised in the previous 12 hours and having fasted for breakfast. A body composition assessment shows higher values in females for hip circumference/ height (female: 0.55±0.03, male: 0.52±0.02; p<0.01) and fat mass index (female: 3.7±0.7 kg/m2, male: 2.4±0.4 kg/m2; p<0.001), while there is no difference between the genders in the extra cellular mass index (female: 7.1±1.2 kg/m2, male: 7.6±0.4 kg/m2; p=0.11). A localized bioimpedance analysis describes well-defined differences in the thighs, while in the calves these differences are reversed for the reactance values. Sports activity seems to slightly reduce differences in the whole body. The different adaption at the same physical effort appears to be mainly related to cellular mass. This study shows for the first time localized bioimpedance values in female athletes. II b.

Consistency of Field-Based Measures of Neuromuscular Control Using Force-Plate Diagnostics in Elite Male Youth Soccer Players.

Read, P, Oliver, JL, Croix, MD, Myer, GD, and Lloyd, RS. Consistency of field-based measures of neuromuscular control using force-plate diagnostics in elite male youth soccer players. J Strength Cond Res 30(12): 3304-3311, 2016-Deficits in neuromuscular control during movement patterns such as landing are suggested pathomechanics that underlie sport-related injury. A common mode of assessment is measurement of landing forces during jumping tasks; however, these measures have been used less frequently in male youth soccer players, and reliability data are sparse. The aim of this study was to examine the reliability of a field-based neuromuscular control screening battery using force-plate diagnostics in this cohort. Twenty-six pre-peak height velocity (PHV) and 25 post-PHV elite male youth soccer players completed a drop vertical jump (DVJ), single-leg 75% horizontal hop and stick (75%HOP), and single-leg countermovement jump (SLCMJ). Measures of peak landing vertical ground reaction force (pVGRF), time to stabilization, time to pVGRF, and pVGRF asymmetry were recorded. A test-retest design was used, and reliability statistics included change in mean, intraclass correlation coefficient, and coefficient of variation (CV). No significant differences in mean score were reported for any of the assessed variables between test sessions. In both groups, pVGRF and asymmetry during the 75%HOP and SLCMJ demonstrated largely acceptable reliability (CV ≤ 10%). Greater variability was evident in DVJ pVGRF and all other assessed variables, across the 3 protocols (CV range = 13.8-49.7%). Intraclass correlation coefficient values ranged from small to large and were generally higher in the post-PHV players. The results of this study suggest that pVGRF and asymmetry can be reliably assessed using a 75%HOP and SLCMJ in this cohort. These measures could be used to support a screening battery for elite male youth soccer players and for test-retest comparison.

A critical evaluation of the aerobic capacity demands of elite male soccer players

The present review investigate whether aerobic capacity of elite male soccer players has changed over the past 30-40 years, and sought to establish an improved estimate of aerobic capacity based on results reported in the literature. A systematic review of manuscripts reporting the match distance covered and/or the VO2max of elite male soccer players was performed. Eighteen studies (published between 1967 and 2010) reporting the total distance covered and representing 14 countries (3,833 players), and 25 studies (published between 1975 and 2012) reporting VO2max and representing 22 countries (1,921 players) were selected for analysis. Little, if any, relationship existed between the mean match play distance covered/VO2max and the year of measurement/reporting. An improved estimate of the match play distance covered was calculated as 10,418 m with a pooled standard deviation of ± 933 m (95% confidence interval [CI] = 10,053 - 10,783 m) and a maximum mean of 12,650 m and minimum of 8,638 m. In addition, the improved estimate of the VO2max was calculated as 59.38 mL · kg-1 ·min-1, with a pooled standard deviation of ± 3.74 mL·kg-1 ·min-1 (95% CI = 57.99 - 60.78 mL·kg-1 ·min-1) and a maximum mean of 67.6 mL · kg-1 · min-1, and a minimum of 52.1 mL · kg-1 · min-1. The results suggest that distance covered and VO2max in elite male soccer players have been stable over the period from 1967 to 2012 and that aerobic metabolism is the major source of energy during the match. Thus, soccer players must possess a minimum aerobic capacity to cover the total match distances and to recover from high-intensity action.

The relationship between physical match performance and 48-h post-game creatine kinase concentrations in English Premier League soccer players

The aim of the investigation was to determine the relationship between blood creatine kinase and physical match performance in 15 elite male soccer players competing in the English Premier League. Blood samples were collected 48 h following a competitive match and analysed for creatine kinase concentration immediately after collection. Physical match performance data were collected using a computerised tracking system (Prozone®) from &gt;6 matches for each player. Mean ± S.D creatine kinase concentration 48 h post-match was 520 ± 224 µ.mol.l−1. Large individual variation in creatine kinase response at this time point was observed (184 µ.mol.l−1 to 1573 µ.mol.l−1). No significant correlation coefficients were observed between the chosen indicators of physical match performance and creatine kinase concentration 48 h post-match. These data suggest that creatine kinase concentrations are elevated as a consequence of playing a soccer match. Creatine kinase may also be of limited value in supporting important decisions in the coaching process.

No Association Between Return to Play After Injury and Increased Rate of Anterior Cruciate Ligament Injury in Men's Professional Soccer.

Background:Studies have shown that previous injury, not necessarily anatomically related, is an important injury risk factor. However, it is not known whether a player runs an increased risk of anterior cruciate ligament (ACL) injury after returning to play from other injury types.Purpose:To analyze whether professional soccer players are more susceptible to ACL injury after returning to play from any previous injury.Study Design:Case-control study; Level of evidence, 3.Methods:A total of 101 elite male soccer players suffering a first-time complete ACL injury between 2001 and 2014 were included and matched according to team, age, and playing position with control players who did not have a current injury (1:1 match). For each injured player, the 90-day period prior to the ACL injury was analyzed for injuries and compared with that of control players by using odds ratios (ORs) and 95% CIs.Results:The odds of a player with an ACL injury sustaining a previous injury in the 90-day period did not differ significantly from that of controls (OR, 1.20; 95% CI, 0.66-2.17; P = .65). Testing the frequency of absence periods due to injury between the groups revealed that the odds of a player with an ACL injury having a previous period of absence due to injury did not differ compared with controls (OR, 1.14; 95% CI, 0.64-2.01; P = .77).Conclusion:Players with ACL injury did not have a greater occurrence of absence due to injury in the 3 months preceding their ACL injury compared with matched controls. This indicates that previous injury of any type does not increase the risk of suffering an ACL injury.

Evidence-based strength and conditioning in soccer

Background . Competitive soccer is complex and acyclical in nature. In addition to the necessary technical and tactical skills, a number of well-developed physiological characteristics are required to perform successfully. Soccer is not a science, but evidence-based practice based on scientific literature can improve performance. Strength and conditioning (S&C) practitioners are now emerging as essential members of a multidisciplinary coaching team. Purpose . To review the physiological demands of soccer and provide S&C coaches with evidence-based training recommendations for elite male soccer players. Methods . To gather information on soccer match-play and effective training prescriptions, a narrative review of literature was conducted using Ovid/Medline, Pub-Med and Google Scholar data-bases. This was supplemented by a review of relevant reference lists. Results . During a 90 minute match, elite soccer players cover 10-12 km mostly by walking or jogging. High-intensity actions occur during important periods of play and are critical to the result of the match. The elite soccer player is required to complete almost 3000 actions during a match, including sprinting, jumping, turning, and decelerating. These activities are dynamic and occur in an unpredictable pattern. Conclusion . Wherever possible, S&C in soccer must replicate match-play so that specific movement patterns can be developed. Small-sided games should be manipulated to improve aerobic endurance, repeated sprint ability, and agility, while also promoting a direct transfer to the competitive environment. Strength and power sessions must prescribe varying loads to develop the full strength-power continuum. Coaches should consider the scientific evidence when implementing S&C programs in soccer.

Muscular and neuromuscular control following soccer-specific exercise in male youth: Changes in injury risk mechanisms.

Poor neuromuscular control has been proposed as a risk factor for non-contact injuries, thus this study aimed to explore the effects of soccer-specific fatigue on leg muscle activation, reactive strength, leg stiffness, and functional hamstring/quadriceps ratio (H/QFUNC ) in elite male youth soccer players. Outcome measures were determined in 18 youth players (age 14.4±0.5years; stature 169.4± 9.9cm; mass 59.3±8.9kg; maturity offset 0.86±0.88 years) pre and post simulated soccer match play (SAFT90 ). There was no fatigue-related change in the H/QFUNC ; however, reactive strength and leg stiffness were both compromised (P<0.001) after soccer-specific fatigue. Muscle activation was also locally compromised (P<0.001) in the medial hamstring and quadriceps but not in the lateral muscles. Where statistically significant changes were observed, the effect sizes ranged from small to large (0.33-0.97). Compromised stiffness when fatigue is present suggests an increased yielding action, greater ground contact times, greater center of mass displacement, and less efficient movement when the limb comes into contact with the ground. This combined with a reduction in medial quadriceps muscle activation may reflect poor kinetic chain control at the hip and an increase in knee injury risk.

Reliability of the Tuck Jump Injury Risk Screening Assessment in Elite Male Youth Soccer Players.

Read, PJ, Oliver, JL, de Ste Croix, MBA, Myer, GD, and Lloyd, RS. Reliability of the tuck jump injury risk screening assessment in elite male youth soccer players. J Strength Cond Res 30(6): 1510-1516, 2016-Altered neuromuscular control has been suggested as a mechanism for injury in soccer players. Ligamentous injuries most often occur during dynamic movements, such as decelerations from jump-landing maneuvers where high-risk movement patterns are present. The assessment of kinematic variables during jump-landing tasks as part of a preparticipation screen is useful in the identification of injury risk. An example of a field-based screening tool is the repeated tuck jump assessment. The purpose of this study was to analyze the within-subject variation of the tuck jump screening assessment in elite male youth soccer players. Twenty-five pre-peak height velocity (PHV) and 25 post-PHV elite male youth soccer players from the academy of a professional English soccer club completed the assessment. A test-retest design was used to explore the within-subject intersession reliability. Technique was graded retrospectively against the 10-point criteria set out in the screening protocol using two-dimensional video cameras. The typical error range reported for tuck jump total score (0.90-1.01 in pre-PHV and post-PHV players respectively) was considered acceptable. When each criteria was analyzed individually, kappa coefficient determined that knee valgus was the only criterion to reach substantial agreement across the two test sessions for both groups. The results of this study suggest that although tuck jump total score may be reliably assessed in elite male youth soccer players, caution should be applied in solely interpreting the composite score due to the high within-subject variation in a number of the individual criteria. Knee valgus may be reliably used to screen elite youth male soccer players for this plyometric technique error and for test-retest comparison.

Convergent Validity of the Flight Time and Impulse-Momentum Methods of Calculating Countermovement Jump Height

The countermovement jump test is considered to be one of the best assessments of lower body power in athletic populations. Impairments in jump height have been previously shown to be indicative of acute and chronic exercise-induced fatigue. There are a number of different methods to calculate vertical jump height utilizing a force platform including the flight time and impulse-momentum methods. However, there has been limited research comparing vertical jump heights derived from either method in elite-level athletes. PURPOSE: To examine the convergent validity between flight time and impulse-momentum methods of calculating countermovement jump height in elite male soccer players. METHODS: Thirty-four collegiate Division-1 men’s soccer players (age 20.4 ± 1.5 years; height 181.7 ± 6.1 cm; body mass, 80.2 ± 8.1 kg) were assessed for vertical jump height using a force plate (Bertec AM 651x Force Plate, Bertec Corporation, Columbus, OH). Each subject completed three attempts of the countermovement jump test with 1-min rest intervals. RESULTS: No significant bias was detected between methods (mean, 0.25 cm; 95% CI, -0.11 to 0.61 cm; p > 0.05). Furthermore, there was a very strong correlation observed between methods (r = 0.93; p < 0.01). CONCLUSION: The flight time and impulse-momentum methods possess convergent validity and each provide an accurate measurement of vertical jump height in elite-level athletes. However, the flight time method may be more preferable for practical applications due to its relative simplicity.

The scientific foundations and associated injury risks of early soccer specialisation

ABSTRACTEarly specialisation is characterised by formal participation in a single sport at the exclusion of others. Limited data are available to support this approach in the development of soccer players who attain elite status later in life. Of growing concern is the associated increased risk of injury and suggestions that single sport specialisation is a risk factor independent of age, growth, biological maturation and training volumes. In the United Kingdom, elite soccer organisations have recently adopted an early sport specialisation approach following the introduction of the Elite Player Performance Plan. A key tenet of this programme is increased opportunities for training through a marked rise in the specified on-pitch hours per week. The accumulation of high training hours may be less of a relevant marker for success, and the impact of such a significant increase in training volume for young athletes who are experiencing a range of growth and maturational processes is currently unknown. This critical commentary includes an evidence-based discussion of the effectiveness of early sport specialisation and the potential injury risks associated with such programmes placing a specific focus on elite male youth soccer players. Available data indicate that modifications to the existing Elite Player Performance Plan framework could enhance players’ development and reduce injury risk. Proposed alterations include reduced volume of soccer-specific training at key stages of growth and maturation and guidelines for the provision of a greater variety of physical activities that are integrated within other programme components.

Injury profile among elite male youth soccer players in a Swedish first league.

This study investigated the injury profile among elite male youth soccer players in a Swedish first league during two seasons. The present cohort study is based on data collected during the 2013–2014 seasons. In total, 43 young elite male soccer players, aged 15 to 19 yr, were prospectively followed regarding injuries, time of exposure, injury location, type of injury, and injury severity. The overall incidence of injury in the present study was estimated to 6.8 injuries per 1,000 exposure hours and 15.5 and 5.6 injuries per 1,000 hr for matches and training, respectively. The single most common injury subtype was muscle strain (53%). The hip and groin were the most common locations for injuries. Thirty-one percent of the injuries were classified as severe injury and caused >28 days absence from training and match play. Both the injury incidence and the number of serious injury seems to be relatively high in youth elite players according to this study. Although the injury incidence seems to be slightly lower than in adult elite players the injuries seem to be more traumatic in youth elite players.

Muscle Strength and Speed Performance in Youth Soccer Players.

This study aimed to examine the relationship between maximum leg extension strength and sprinting performance in youth elite male soccer players. Sixty-three youth players (12.5 ± 1.3 years) performed 5 m, flying 15 m and 20 m sprint tests and a zigzag agility test on a grass field using timing gates. Two days later, subjects performed a one-repetition maximum leg extension test (79.3 ± 26.9 kg). Weak to strong correlations were found between leg extension strength and the time to perform 5 m (r = -0.39, p = 0.001), flying 15 m (r = -0.72, p < 0.001) and 20 m (r = -0.67, p < 0.001) sprints; between body mass and 5 m (r = -0.43, p < 0.001), flying 15 m (r = -0.75, p < 0.001), 20 m (r = -0.65, p < 0.001) sprints and agility (r =-0.29, p < 0.001); and between height and 5 m (r = -0.33, p < 0.01) and flying 15 m (r = -0.74, p < 0.001) sprints. Our results show that leg muscle strength and anthropometric variables strongly correlate with sprinting ability. This suggests that anthropometric characteristics should be considered to compare among youth players, and that youth players should undergo strength training to improve running speed.

Association Between MCT1 A1470T Polymorphism and Fat-Free Mass in Well-Trained Young Soccer Players.

The aim of this study was to investigate the association between the MCT1 A1470T polymorphism and fat-free mass in young Italian elite soccer players. Participants were 128 Italian male soccer players. Fat-free mass was estimated for each of the soccer player using age- and gender-specific formulas with plicometry. Genotyping for the MCT1 A1470T polymorphism was performed using polymerase chain reaction. The MCT1 A1470T genotypes were in agreement with the Hardy-Weinberg equilibrium distribution. The percentage of fat-free mass was significantly higher in soccer players with the TT genotype and in the T-allele-dominant model group (TT + AT) compared with the soccer players with the AA genotype. The MCT1 T allele is associated with the percentage of fat-free mass in young elite male soccer players. Elucidating the genetic basis of body composition in athletes could potentially be used as an additional tool for strength and conditioning professionals in planning and adjusting training. However, these results are preliminary and need to be replicated in more cohorts.

The within-participant correlation between perception of effort and heart rate-based estimations of training load in elite soccer players

ABSTRACTThe measurement of relative physiological stress during training is important because this is the stimulus for the long-term adaptive response. Measurements of perceived exertion (RPE) have been reported to correlate with the heart rate during field-based training sessions. Nevertheless, there are few studies on how well RPE tracks with the heart rate over repeated training sessions in elite soccer players. Therefore, we aimed to quantify the within-participant correlations between variability in session-RPE (sRPE) and the heart rate in elite male soccer players, and to determine whether the playing position moderated these correlations. The field-based training of four central defenders, four wide defenders, six central midfielders, two wide midfielders and three attackers from an elite English Premier League squad were monitored over an entire in-season competitive period, giving a total of 1010 individual training sessions for study. Correlations between session-RPE and heart rates were quantified using a within-participant model. The correlation between changes in sRPE and heart rates was r = 0.75 (95% CI: 0.71–0.78). This correlation remained high across the various player positions (wide-defender, r = 0.81; central-defender, r = 0.74; wide midfielder, r = 0.70; central midfielder, r = 0.70; attacker, r = 0.84; P < 0.001). The correlation between changes in RPE and heart rates, measured during a season-long period of field-based training, is high in a sample of elite soccer players.

Preseason preparation training and endothelial function in elite professional soccer players.

AimTo examine whether a high volume of soccer-specific training can lead to endothelial activation and/or dysfunction in professional soccer players due to exercise-induced oxidative stress.MethodsTwenty-three (15 nonsmokers and eight smokers) healthy, elite male professional soccer players (mean age: 25.2±4.3 years, BMI: 23.1±1.3 kg/m2, fat: 7.8%±2.6%) were selected for this study. All participants had a full clinical and laboratory evaluation. von Willebrand factor antigen (vWf Ag) plasma levels were measured on two different occasions: 1 day before the beginning of the preseason preparation period and after 7 weeks of strenuous exercise.ResultsMean vWf Ag plasma levels were significantly decreased from 95.1%±26% to 88.3%±27.2% at the end of the experimental period (P=0.018), suggesting a potential beneficial effect on the endothelium of these athletes. Further analysis showed that age greater than 29 years with an age range from 29 to 34 years can not impair this effect (P>0.05).ConclusionStrenuous exercise did not lead to endothelium activation or dysfunction in well-trained elite soccer players. On the contrary, it seemed to produce a beneficial effect on the endothelium of these players.

Lumbopelvic motor control and low back pain in elite soccer players: a cross-sectional study

ABSTRACTThis study aimed to investigate the relationship between the history of low back pain and quality of lumbopelvic motor control in soccer players. Forty-three male elite soccer players (mean age, 18.2 ± 1.4 years) filled in questionnaires related to low back pain and attended a session to assess lumbopelvic motor control by means of five tests (the bent knee fall out test, the knee lift abdominal test, the sitting knee extension test, the waiter’s bow and the transversus abdominis test). A physiotherapist, blinded to the medical history of the participants, scored (0 = failed, 1 = correct) the performance of the players for each of the tests resulting in a lumbopelvic motor control score ranging from 0 to 5. Forty-seven per cent of the soccer players reported a disabling low back pain episode lasting at least two consecutive days in the previous year. These players scored worse lumbopelvic motor control than players without a history of low back pain (lumbopelvic motor control score of 1.8 vs. 3.3, P < 0.01). The between-groups difference was particularly marked for the bent knee fall out test, the knee lift abdominal test and the transversus abdominis test (P < 0.01). In conclusion, most soccer players with a history of low back pain had an altered lumbopelvic motor control. Further research should examine whether lumbopelvic motor control is etiologically involved in low back pain episodes in soccer players.