Aerobic Capacity Differences among Elite and Sub-elite Young Female Soccer Players: A Longitudinal Comparison by Competition Level and Playing Position

BackgroundUnderstanding the hip adduction and abduction strength in female soccer players is crucial for performance enhancement and injury prevention. This study compares the strength profiles in these muscle groups between elite and sub-elite female soccer players and assesses the impact of leg limb-dominance.MethodsA descriptive-comparative study was employed. Eighty-two female soccer players were evaluated. Isometric hip-adduction and abduction strength were measured using a handheld dynamometer.ResultsFemale elite and sub-elite soccer players displayed a mean and standard deviation (SD) on isometric hip-adductor strength for dominant (3.19 Nm/kg ± 0.69 vs. 2.40 Nm/kg ± 0.67) and non-dominant leg (3.32 Nm/kg ± 0.76 versus 2.42 Nm/kg ± 0.70), respectively. For isometric hip-abductor strength in elite and sub-elite players, a mean and SD of dominant (2.86 Nm/kg ± 0.56 vs. 2.07 Nm/kg ± 0.50) and non-dominant (2.80 Nm/kg ± 0.59 vs. 2.04 Nm/kg ± 0.43). In essence, elite players were stronger than sub-elite players on isometric hip-adduction (mean difference [MD] = 0.82 Nm/kg, CI95% = 0.42–1.12) and abduction (MD = 0.83 Nm/kg, CI95% = 0.54- 1.12) both in dominant and non-dominant, leg, whereas no differences existed for hip adduction:abduction ratios between groups and legs.ConclusionsElite female athletes exhibited greater strength than sub-elite female players in both hip adduction and abduction, whereas adduction:abduction ratio values did not differ between the two groups or between different legs.

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.

Mental toughness (MT) is seen as an important psychological factor in the athletic success of elite athletes. Research on the subject has usually concerned male athletes. Our purpose was to investigate whether there are differences in mental toughness between female players who compete in an elite league and those who play at lower levels. In total, 298 female soccer players (M = 20.7 years, SD = 3.7 years) from three levels of Norwegian soccer responded to the Sports Mental Toughness Questionnaire. The MT Constancy subscale was removed from analysis due to an unacceptable Cronbach alpha (0.57). The results revealed that elite league players had significantly higher MT Global scores than those in lower leagues. The elite players had higher scores than the third league players on the MT Confidence subscale. For MT Control, the elite league players had a significantly higher score than the second league players, but the elite players did not differ significantly from the third league players on this subscale. These results partially confirm a relationship between mental toughness and playing level among female soccer players.

Acute whole body vibration training (WBVT) is a tool used amongst coaches to improve performance prior to activity. Its effects on other fitness components, such as balance and stability, along with how different populations respond are less well understood. The aim of the current research is to determine the effect of acute WBVT on balance and stability amongst elite and amateur soccer players. Forty-four healthy male soccer players (22 elite and 22 amateur) were assigned to a treatment or control group. The intervention group then performed 3 × 60 seconds static squat on vibration platform at 40 Hz (±4 mm) with Y balance test (YBT) scores and dynamic postural stability index (DPSI) measured pre and post. DPSI was significantly lower in the elite players in the acute WBVT compared to amateur players (F1, 40= 6.80; P = 0.013). YBT anterior reach distance showed a significant improvement in both amateur and elite players in the acute WBVT group (F1, 40= 32.36; P < 0.001). The improvement in DPSI amongst the elite players indicates a difference in responses to acute high frequency vibration between elite and amateur players during a landing stability task. The results indicate that acute WBVT improves anterior YBT reach distances through a possible improvement in flexibility amongst both elite and amateur players. In conclusion, acute WBVT training appears to improve stability amongst elite soccer players in comparison to amateur players, the exact reasoning behind this difference requires further investigation.

Ankle dorsiflexion range of motion (DF-ROM) has been shown to be associated with poor landing posture. This study aimed to model the relationship between DF-ROM and landing quality during the Soccer-Specific Jump-Landing task (SSJL) on the non-dominant extremity in elite and amateur female soccer players using a quantile regression approach. 55 amateur and 47 professional female soccer players participated in the study. The relationship between DF-ROM and SSJL quality was evaluated using Pearson's product-moment correlation analysis and Quantile regression modelling. There was a statistically significant negative correlation between DF-ROM and SSJL landing quality among female soccer players (r = - 0.33, p = 0.001). Moreover, there was a statistically significant negative correlation between DF-ROM and SSJL landing quality in amateur female soccer players (r = - 0.63, p = 0.001), no significant correlation was found in elite female soccer players (r = 0.22, p = 0.13). Quantile regression results for amateur female soccer players indicate that the association between ankle DF-ROM and landing quality is stronger in athletes with higher SSJL landing quality scores (e.g., Q75 and Q90) compared to those with lower scores (e.g., Q10 and Q25). This suggests that ankle DF-ROM plays a more critical role in achieving higher-quality landing techniques than in poorer techniques. Higher quality landing techniques in female soccer players are associated with larger ranges of ankle DF-ROM. Therefore, ankle DF-ROM level may be a functional clinical measurement for amateur female athletes in determining landing-related injury risk factors during SSJL.

Aerobic capacity and heart rate variability (HRV) reflect a player's level of the cardiopulmonary fitness and could be used as indicators for predicting the outcome of a player's performance. In this study, we aimed to investigate the differences of aerobic capacity and HRV between the elite and college soccer players. The male elite (n=8) and college (n=18) soccer players, aged from 18 to 25 years, were recruited in this study. Aerobic capacity was determined by the incremental treadmill exercise test. HRV was measured by the short‐range radio telemetry by Polar Electro S810. This study was approved by the Ethics Committee of Taipei Physical Education College, and the informed consent was obtained from all subjects. The body mass index, body fat, and muscular strength were not significantly different between the two groups. The maximal oxygen consumption of the elite players was significantly higher than the college players (p&lt;0.05). Also, the time of 3000 meters running was significantly shorter in the elite group (p&lt;0.05). HRV measures showed that no significant difference of the interbeat interval variability was found between the two groups, but low‐frequency power was lower in the elite players. Our results may provide useful information for assessing the exercise performance in different levels of soccer players.

In learning and development, self-regulation can be described as the extent to which individuals are metacognitively, motivationally, and behaviourally proactive participants in their learning process (Zimmerman, 1989, 2006). We examined the relationship between self-regulation and performance level in elite (n = 159) and non-elite (n = 285) youth soccer players aged 11–17 years (mean 14.5 years, s = 1.4). The players completed a questionnaire that assessed planning, self-monitoring, evaluation, reflection, effort, and self-efficacy. A logistic regression analysis was performed (controlling for age) to determine which self-regulatory aspects were associated with players' performance level (elite vs. non-elite). High scores on reflection and effort were associated with a higher level of performance. Findings suggest that elite players may be more aware of their strong and weak points as well as better able to translate this awareness into action. In addition, elite players appear to be more willing to invest effort into practice and competition. It is suggested that these better developed self-regulatory skills may translate into a more effective learning environment and ultimately result in an increased capacity for performance in elite players relative to their non-elite peers.

Although cross-sectional evidence exists regarding the association between sport specialization and health outcomes, sport-specific, prospective research is lacking. The aim of this study was to determine the relationship between sport specialization status and in-season injury and illness risk in elite female adolescent soccer players. 80 female youth soccer players (ages 13-18) from a local youth soccer organization underwent preseason evaluation of maximal aerobic capacity (VO<inf>2max</inf>) and sport specialization and provided self-reporting of daily training load (session-rating of perceived exertion), injury and illness for two four-month competitive soccer seasons. Mixed effects logistic regression models were used to predict individual injury and illness (yes/no) during the study period, using sport specialization, age, and training load as fixed effects and individual athlete as a random effect. Specialized (N.=46) athletes did not differ from non-specialized (N.=34) athletes with respect to age, preseason physical activity, VO<inf>2max</inf> or in-season training load (all P>0.05). 28 athletes participated in both years, representing 108 player-years. No differences were seen in the proportion of individuals from each group that reported an in-season injury (specialized = 25% vs. 20%, P=0.55) or illness (46% v 38%, P=0.41). After adjusting for age and training load, individual injuries (OR=0.86 [0.26, 2.8], P=0.81) and illnesses were not significantly predicted by specialization (OR=1.06 [0.45, 2.5], P=0.89). After adjusting for age and training load, late sport specialization was not associated with in-season injury or illness risk in elite female soccer players.

The purpose of this investigation was to compare sprint and countermovement-jump (CMJ) performance among female competitive soccer players as a function of performance level, field position, and age. In addition, the authors wanted to quantify the evolution of these physical characteristics among elite players over a 15-y period. 194 female elite players (22± 4.1 y, 63 ± 5.6 kg), including an Olympic winning squad, tested 40-m sprint with electronic timing and CMJ on a force platform at the Norwegian Olympic training center from 1995 to 2010. Moderate to large velocity differences across performance levels and positions were observed. National-team players were 2% faster than 1st-division players (P = .027, d = 0.5) and 5% faster than 2nd-division players (P < .001, d = 1.3) over 0-20 m. National-team players jumped 8-9% higher than 1st-division players (P = .001, d = 0.6) and junior elite players (P = .023, d = 0.5). Forwards were 3-4% faster than midfielders (P < .001, d = 0.8) and goalkeepers (P = .003, d = 0.9) over 0-20 m. No differences in velocity or CMJ height were observed among the age categories. Players from 2006-2010 were 2% faster (P < .05, d = 0.6) than players from 1995-1999 over 20 m, whereas no differences in 20- to 40-m velocity or CMJ performance were observed. This study provides effect-magnitude estimates for the influence of performance level, age, and player position on sprint and CMJ performance in female soccer players. While 20- to 40-m velocity and CMJ performance have remained stable over the time, there has been a moderate but positive development in 0- to 20-m velocity among elite performers.

Methods of assessing soccer players' performance have developed significantly in recent times. The fitness profiles and skill levels of a prospective elite soccer player is a valuable resource for coaches in the process of identifying talent. Traditional means to measure aerobic fitness have centred on the 'aerobic capacity' or '&OV0312;O(2max)' test (also known as the maximal oxygen consumption test) but, over time, this has been shown not to be a sensitive measure for specific aspects of soccer in a match situation. Therefore, numerous soccer-specific simulations have been designed to re-create exercise patterns similar to those experienced during a match. Some of these studies have yet to be validated, while others have been shown to result in a similar physiological load to that encountered during regular match play. Further developments have led to specifically designed intermittent sprint tests, which are used as a sensitive tool to accurately measure the fluctuations in players' ability both between and within soccer seasons. Testing procedures have also been developed that incorporate elements of both skill and physical ability. Soccer-specific field tests have been designed, incorporating skill and dynamic movements, and this opens up the possibility of teams testing the aerobic capacity of their elite players using soccer-specific movements. Valid studies assessing soccer-specific skills in an ecologically sound environment have been quite rare until recently. Some test protocols have been deemed largely irrelevant to soccer match play, while others have had limited impact on scientific literature. More recently, skill tests have been developed and shown to be valid and reliable methods of assessing soccer skill performance. Many new skill tests continue to be developed, and some have been shown to be highly reliable, but further study of these relatively novel concepts is required before a more solid recommendation can be made. Overall, while significant work has been completed to date, there is still a need for further focused investigations, which can more closely assess the physiological demands of an elite soccer player, with a particular emphasis on sport-specific exercises during the execution of soccer skills. In this regard, more reliable and specific performance tests can be designed to more efficiently assess soccer players in the future.

Objective: To summarize risk factors for injury in elite women’s soccer. Methods: Ten electronic databases were searched for studies that explored risk factors for injury in elite women soccer players. Study cohorts were required to consist of adult (?18 years) elite players defined as ‘the best performers in their country in a certain sport who are competing at national or international levels’ [1]. Two reviewers independently assessed articles for eligibility. The CASP checklist was used for quality assessment of included studies, and the Oxford Center of Evidence-Based Medicine guidelines were used to determine their level of evidence. Results: Eight studies were included in this review. Findings indicated an association between an increased injury risk and previous injury and increased joint laxity. There is additional evidence to support a relationship between injuries and higher soccer exposure, playing position, increased BMI, low H/Q ratio, player’s level of balance and co-ordination, as well as various psychological issues. However, there were conflicting findings for the effect of postural control. Individual differences in Q-angle, intercondylar notch width or pelvic width measurements were not found to be associated with injury. The incidence of injury was higher in the dominant limb. Conclusion: The risk of injury in elite female soccer players is multifactorial, complex, and associated with a range of intrinsic, and extrinsic factors. More high-quality studies are needed to investigate each identified risk factor in order to inform effective injury screening.

The relationship between the vitamin D receptor (VDR) gene and muscle strength has been extensively investigated; however, the findings of this research remain inconclusive. The aim of this study was to evaluate the association between VDR variants (ApaI rs797523, BsmI rs1544410, and FokI rs2228570 genotypes) and athletic performance in youth soccer players in China. A total of 142 male soccer players (73 from an elite group and 69 from a sub-lite group) aged 13-15 years, and 107 controls (13- to 14-year-old students) were recruited for this study. We measured height, weight, speed, explosive power, anaerobic endurance, and aerobic endurance in both the elite and sub-elite athletes. ApaI, BsmI and FokI genotypes were detected in controls, elite, and sub-elite soccer players with the single-nucleotide polymorphism (SNP) technique. The χ 2 test was applied to analyze the correlation between genotype distribution and allelic frequency in elite and sub-elite athletes and controls. One-way analysis of variance and Bonferroni's post hoc test were implemented to analyze the differences in parameters among groups, and statistical significance was set at p≤0.05. (1) The genotype distributions of the ApaI, BsmI, and FokI in controls, elite, and sub-elite soccer players were consistent with the Hardy-Weinberg equilibrium (HWE) results, except for the BsmI genotype distribution in control s (χ 2=7.396, df = 1, p=0.025). (2) The BsmI AG frequency in the controls and sub-elite players was significantly higher than in the elite players (χ 2=6.4, df = 1, p=0.011; χ 2=4.50, df = 1, p=0.034, respectively). The frequency of the FokI TT genotype in the controls was significantly higher than in the elite and sub-elite players (χ 2=12.737, df = 1, p<0.001, χ 2=8.805, df = 1, p=0.003, respectively). The frequency of the ApaI A in the elite players was significantly lower than that in the controls and sub-elite players (χ 2=3.765, df = 1, p=0.05; χ 2=12.19, df = 1, p<0.001 respectively). (3) ApaI CC players had longer distances in the standing long jump (SLJ) (p=0.026) and shorter times in the 30-m run (p=0.003) than ApaI AC players. Additionally, ApaI AA players had significantly longer Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) running distances compared to ApaI AC players (p=0.002). Chinese elite youth soccer players are more likely to possess the ApaI CC genotype and are less likely than sub-elite players to have the BsmI A alleles. Additionally, the ApaI CC genotype is associated with better speed and explosive power among Chinese elite youth soccer players.

Background and Objectives: Research on female soccer players that analyzes playing status is scarce and has previously only examined load monitoring, while other markers, such as physical (i.e., strength, power, and agility), physiological (i.e., maximal oxygen uptake), and body composition (i.e., body fat mass, fat-free mass, body water, and phase angle) markers, warrant further investigation. Thus, the study aims were to (a) compare physical, physiological, body composition, and load markers between starters and non-starters; (b) compare measurements pre- and post-training intervention (five weeks); and (c) analyze any relationships between physical, physiological, body composition, and load markers in an elite female soccer team. Materials and Methods: Fourteen first-team players participated in the study (age 23.29 ± 3.19 years, weight 59.14 ± 6.87 kg, height 1.66 ± 0.08 m). Several physical (n = 15), physiological (n = 1), body composition (n = 11), and load markers (n = 14) were collected. In addition, participants were sub-divided into starters (n = 7) and non-starters (n = 7). Results: No differences were revealed between starters and non-starters in any of the examined variables. Moreover, following the training intervention, a significantly lower value was found for total body water/fat-free mass ratio (p = 0.043; ES = 0.582). In addition, there were several correlations detected between load and physical/physiological markers (n = 28); load and body composition markers (n = 6); physical/physiological and body composition markers (n = 34); and physical and physiological markers (n = 42). Conclusions: In conclusion, only a slight tendency of higher load values for starters than non-starters was observed. In addition, no differences in physical, physiological, and body composition markers were found between starters and non-starters, possibly suggesting that five weeks were not enough to improve such variables. Finally, the present results provide novel information assessing the effects of the pre-season in elite female Portuguese soccer players and contribute to a better understanding of the associations between different types of measurements.

BackgroundPrevious studies have shown controversial relationships between ACE I/D and ACTN3 R577x polymorphisms and athletic performance. Therefore, the aim of this study was to assess athletic performance indicators of Chinese youth male football players with different ACE and ACTN3 gene profiles.Methods and MaterialsThis study recruited 73 elite (26 13-year-olds, 28 14-year-olds, and 19 15-year-olds) and 69 sub-elite (37 13-year-olds, 19 14-year-olds, and 13 15-year-olds) and 107 controls (63 13-year-olds, and 44 14-year olds aged 13–15 years, all participants were of Chinese Han origin. We measured height, body mass, thigh circumference, speed, explosive power, repeat sprints ability, and aerobic endurance in elite and sub-elite players. We used single nucleotide polymorphism technology to detect controls elite and sub-elite players’ ACE and ACTN3 genotypes, Chi-squared (χ2) tests were employed to test for Hardy-Weinberg equilibrium. χ2 tests were also used to observe the association between the genotype distribution and allele frequencies between controls and elite and sub-elite players. The differences in parameters between the groups were analyzed using one-way analysis of variance and a Bonferroni’s post-hoc test, with statistical significance set at p ≤ 0.05.Results(1) The genotype distribution of the ACE I/D and ACTN3 R577x polymorphisms in controls, elite and sub-elite football players were consistent with Hardy-Weinberg equilibrium, except for the ACE genotype distribution of sub-elite players. (2) The RR and DD genotypes were significantly different between elite and sub-elite players (p = 0.024 and p = 0.02, respectively). (3) Elite players were more likely to have the RR genotype and less likely to have the DD genotype compared with sub-elite players. (4) Both elite and sub-elite RR players’ Yo-yo intermittent recovery level 1 (YYIR1) running distance was significantly longer than that of RX players (p = 0.05 and p = 0.025, respectively). However, there was no significantly different in YYIR1 running distance between elite and sub-elite RR players. (5) Elite XX players’ VO2 max was significantly higher than that of RX and sub-elite players.ConclusionThese results indicate that ACE I/D and ACTN3 R577x polymorphisms are not associated with muscle power in Chinese elite and sub-elite players. The XX genotype of ACTN3 is associated with the aerobic endurance of elite players.

Landing from a jump has been identified as a common situation of increased risk in sport and the tuck jump assessment (TJA) has been proposed for a comprehensive examination of landing mechanics. However, group-specific data on female athletes are limited. The purpose of this study was to examine the movement mechanics during a TJA in Spanish female soccer players and to explore potential differences between players of different performance levels. A total of 96 (elite and non-elite) female soccer players performed a TJA, and a rater visually graded the technique using the modified 10-item scoring system (0, 1, or 2 for "none", "small", or "large" flaws). Descriptive statistics were calculated. The association between the flaws and performance groups was assessed using the chi-square test. Almost 90% of all players involved were categorized with small and large flaws for the item "Lower extremity valgus at landing". The proportion of players categorized with technical flaws was also high for "Foot contact timing not equal" (85%) and "Does not land in same footprint" (82%). Differences between elite and non-elite players were only found for "Foot placement not parallel" and "Excessive landing contact noise" (p < 0.008). These results reveal the importance of implementing training programs to reduce jumping and landing deficits in female soccer players, independently of the players' level of performance.