Different endurance characteristics of female and male german soccer players

Comparison of usefulness of two tests measuring anaerobic performance of untrained and soccer-training girls U12

The study aimed to investigate the usefulness of the Running-based Anaerobic Sprint Test (RAST) in anaerobic performance estimation in trained and untrained girls U12, and the effect of an 8-week training period in female U12 soccer players on anaerobic performance. A comparative study of two structurally different anaerobic tests was performed to reach the goal. The study was designed as a non-randomized, controlled before-and-after trial. Fourteen female soccer players (FSP) and twelve untrained girls (UNT) participated in the study. During that time, all participants were subjected to school's physical education classes and the FSP additionally participated in regular soccer training. The anaerobic performance was evaluated twice, within 8-weeks period, using the traditional Wingate test (WAnT) and the RAST. A significant increase in the anaerobic performance of the FSP was noted (p < 0.05). In both tests peak, average, and relative power were significantly improved (p < 0.005). Nevertheless, strong, statistically significant (p < 0.05) correlation coefficients (0.50 < r < 0.70) were found for pre-training measurements between the WAnT and the RAST power parameters in absolute values. In UNT group significant improvement was found in peak, average and min power (p < 0.05) in the RAST. The improvement in anaerobic performance after training along with the strong correlation noted between the WAnT and the RAST power parameters prove the usefulness of the RAST in assessing anaerobic capacity in female youth athletes. Its simplicity encourages its use in monitoring anaerobic capacity in both trained and untrained girls.

Predicting Cardiorespiratory Fitness in Female Soccer Players: The Basque Female Football Cohort Study

PURPOSE

To develop gender-specific operational equations for prediction of cardiorespiratory fitness in female footballers.

METHOD

Forty-eight semiprofessional female footballers performed an intermittent progressive maximal running test for determination of fixed blood lactate concentration (FBLC) thresholds. Relationships between FBLC thresholds and the physiological responses to submaximal running were examined. Developed equations (n = 48) were compared with equations previously obtained in another investigation performed in males (n = 100).

RESULTS

Submaximal velocity associated with 90% maximal heart rate was related to FBLC thresholds (r = .76 to .79; P < .001). Predictive power (R2 = .82 to .94) of a single blood lactate concentration (BLC) sample measured at 10 or 11.5 km·h-1 was very high. A single BLC sample taken after a 5-minute running bout at 8.5 km·h-1 was related to FBLC thresholds (r = -.71; P < .001). No difference (P = .15) in the regression lines predicting FBLC thresholds from velocity associated with 90% maximal heart rate was observed between the female and male cohorts. However, regressions estimating FBLC thresholds by a single BLC sample were different (P = .002).

CONCLUSIONS

Velocity associated with 90% maximal heart rate was robustly related to FBLC thresholds and might serve for mass field testing independently of sex. BLC equations accurately predicted FBLC thresholds. However, these equations are gender-specific. This is the first study reporting operational equations to estimate the FBLC thresholds in female footballers. The use of these equations reduces the burden associated with cardiorespiratory testing. Further cross-validation studies are warranted to validate the proposed equations and establish them for mass field testing.

Sex Differences in Physical Capacities of German Bundesliga Soccer Players

Cardoso de Araújo, M, Baumgart, C, Jansen, CT, Freiwald, J, and Hoppe, MW. Sex differences in physical capacities of German Bundesliga soccer players. J Strength Cond Res 34(8): 2329-2337, 2020-Sex differences in physical capacities of elite soccer players have received limited attention. Therefore, this study investigated sex differences in linear and nonlinear sprint, squat and countermovement jump, core endurance, as well as incremental and intermittent endurance capacities in German Bundesliga soccer players. A total of 76 field players (29 women) were tested for the mentioned anaerobic- and aerobic-related physical capacities in a noninterventional cross-sectional design. The largest sex differences were evident in the explosive- and intermittent endurance-related capacities, with women presenting largely to extremely largely lower values in sprints, jumps, and intermittent endurance (effect size [ES] ≥1.77, p < 0.01). The differences in the total core endurance, running velocity at 2 and 4 mmol·L capillary blood lactate (v2 and v4), maximal heart rate (HR) (ES ≤ 0.72, p ≥ 0.06), and distance covered during the incremental endurance test (ES = 1.09, p = 0.01) were trivially to moderately lower for women. However, women had small to moderately higher ventral and dorsal core endurance (ES ≤ 0.69, p ≥ 0.07) and largely higher relative HR at the lactate thresholds (ES ≥ 1.54, p < 0.01). The individual data of female players showed more variability. Some individual data of women overlapped those of men, most evident in the total core endurance and v2. The findings indicate that there are sex differences in physical capacities according to the underlying amount of anaerobic and aerobic energy supply. The sex specificities should be considered to optimize training and testing procedures for soccer players.

Gender differences in instep soccer kicking biomechanics, investigated through a 3D human motion tracker system

BACKGROUND

This study aims at describing and comparing each other male and female soccer players kicking instep a stationary ball. The different measures we collected by the 3D motion capture system Movit G1 and the High-Speed Camera (240 fps) were considered as dependent variables, whereas the gender was considered as the independent one.

METHODS

Twenty soccer well trained non-professional players: 10 men (age: 25.3±6.5 yrs; height 1.80±0.07 m; body mass 76.9±13.2 kg) and 10 women (age: 19±3.34 yrs; height 1.64±0.07 m; body mass 58.2±7.2 kg) volunteered to participate in the study.

RESULTS

Gender differences were found, with a statistical significance (P<0.05) or interesting magnitude (Cohen d>0.5). The most relevant ones were the differences in hip extension of the kicking leg when the foot of the supporting one touches the ground, just before the impact on the ball (independent sample t-Test; P=0.03; Cohen d=1.64) and the speed of the ball, reached immediately after kicking (P<0.001;d=1.23).

CONCLUSIONS

These results, together with the greater pelvic acceleration shown by men compared to women, highlight the need to develop a gender-differentiated training model, in order to customize the kicking technique in women and to reduce the likelihood, currently higher than for men, of kicking related injuries.

Contextual factors influencing the characteristics of female football players

Women's football participation rates are projected to increase to 60 million worldwide by 2026, doubling the current participation. Growing investment and the increase in research in women's football has had a positive effect on the level of performance over the last 10 years. The present review aimed to examine the literature on the physical and physiological characteristics of female football players from 2010 to 2019 to reflect the recent changes in professionalism. Characteristics investigated include anthropometry, strength, speed, endurance, power, change of direction and repeated sprint ability. These characteristics are presented in relation to playing position, age and competition-level. Results revealed that goalkeepers (171 cm, 66 kg) and defenders (168 cm, 61 kg) were the tallest and had the greatest body mass, while attackers were the fastest players over 20 m (3.05 s) and 30 m (4.38 s) and midfielders had the highest endurance (55.4 mL∙kg^-1∙min^-1) (P<0.05). Characteristics tended to improve with age until full biological maturity around 17 to 18 years of age. Competition comparisons demonstrated international players have significantly greater speed, repeated sprint ability, power and endurance characteristics (P<0.05). By identifying influential factors, coaches may be able to optimize their training and physical assessment practices, to better expose players to the required stimulus to develop these characteristics considered crucial to improved performance.

Contrasts in intermittent endurance performance and heart rate response between female and male soccer players of different playing levels

This study compared intermittent endurance performance and heart rate (HR) response, as well as their relationship, by sex and competitive level in soccer. A total of 68 outfield (18 elite and 16 sub-elite female, 17 elite and 17 sub-elite male) soccer players performed the Interval Shuttle Run Test (ISRT) with monitored HR. Sex and level effects were evaluated by two-way analysis of variance (ANOVA) and the relationships between parameters using Pearson’s correlation coefficient. Female players presented lower performance (effect sizes [ES]: 2.12-4.71, p < 0.01) and higher submaximal HR during the ISRT (ES: 1.66-3.40, p < 0.01). Elite players showed higher performance and reduced submaximal HR compared with their sub-elite counterparts, with a large level effect only evident between the female groups (ES: 1.22-1.56, p < 0.01). The maximum and the HR recovery 1 min after the ISRT (HRR) did not differ among all groups (ES: 0.01-0.51, p ≥ 0.18). The HRR was slightly related to the test performance for all groups (r = 0.20, p = 0.12). Large to very large negative correlations were verified between HR at 6 and 9 min during the ISRT and the test performance for each group (r = -0.54 to -0.84, p ≤ 0.04). However, 16 (3 elite and 13 sub-elite) female players did not reach the 9^th minute of the test. The gap between competitive levels among female soccer players is greater than that observed for male players in intermittent endurance performance and submaximal HR response. The HRR had only a minor impact on performance and was influenced neither by sex nor by level.

Biceps femoris long head muscle fascicle length does not differ between sexes

Hamstring strain injury (HSI) rates are higher for males vs. females. This cross-sectional study investigated if inherent differences in biceps femoris long head (BF_LH) fascicle length (Lf) exist between recreationally active males and females (i.e., individuals without specific training practice history). Twenty-four young healthy participants (12 males; 12 females) had their BF_LH muscle architecture (Lf, pennation angle [θp], and muscle thickness [MT]) measured using B-mode ultrasonography. Eccentric and isometric knee flexion strength were also assessed. BF_LH Lf did not differ between sexes when expressed in absolute terms (males, 81.5 ± 14.7 mm; females, 73.6 ± 15.9 mm, P = 0.220, effect size (ES) = 0.52) or relative to femur length (0.140 ≤ P ≤ 0.220, ES = 0.63). Similarly, BF_LH θp did not differ between sexes (P = 0.650) but BF_LH MT was 18.9% larger for males vs. females (P = 0.024, ES = 0.99). Isometric and eccentric knee flexion strength was greater for males vs. females in absolute terms ([both] P < 0.001, 2.00 ≤ ES ≤ 2.27) and relative to body mass ([both] P < 0.001, 1.93 ≤ ES ≤ 2.13). In conclusion, factors other than BF_LH Lf seem likely to be implicated in higher male vs. female HSI rates.

Differences in Player Position Running Velocity at Lactate Thresholds Among Male Professional German Soccer Players

This study investigated the differences in running velocities at specific lactate thresholds among male German soccer players. One hundred fifty-two professional (3rd league: n = 78; 4th league: n = 74) male soccer players (mean ± SD; age: 24.7 ± 4.37 years, body mass: 80.8 ± 7.33 kg, body height: 1.83 ± 0.06 m) volunteered for the investigation. Players were categorized as goalkeepers, central defenders, central midfielders, wings and forward. Players completed a treadmill test, at incremental speeds, to determine running velocity at different blood lactate concentrations (v2 = 2 mmol/l; v4 = 4 mmol/l; and v6 = 6 mmol/l). In addition, the largest difference between positions for running velocity was found at the lactate threshold v2 (p = 0.005). The running data revealed that only goalkeepers had significantly lower velocities at the lactate thresholds compared to outfield players. The central midfielders showed the highest average performance level at the lactate thresholds (v2: 12.5 ± 1.20 km/h; v4: 15.2 ± 1.14 km/h; and v6: 16.6 ± 1.14 km/h). In conclusion, this study provides soccer and position-specific reference data for the running performance of male professional German soccer players to evaluate the endurance performance in a standardized way. In this context, future research should extend the database for the first and second leagues. Further research assessing running performance during competition matches over the entire season is required to validate the endurance test performance data.

Sprint Mechanical Properties of Female and Different Aged Male Top-Level German Soccer Players

This study compared the sprint mechanical properties of female and different aged male top-level soccer players. A total of 14 adult females (FEM) and 115 different aged male field players, competing at German top levels, participated in this study. The males belonged to teams of under 12, 13, 14, 15, 17, 19, and 23 years (U 12–23) and professionals (PRO). All players were tested for a 30 m linear sprint. From timing gate derived sprint times, force-velocity and power-velocity relationships, as well as theoretical maximum running velocity, force, and power data were computed by an inverse dynamic approach applied to the center of mass. The approach was optimized for taking the starting time into account, which is a progress in the present research field, when aiming to compute sprint mechanical properties by different methodological approaches under field conditions. Sprint mechanical properties of FEM were lower than those of PRO. Compared to other age groups, sprint mechanical properties of FEM were similar to those of U 14 and U 15. An increase in sprint mechanical properties was found from U 12 to U 17. The study shows that sprint mechanical properties differ according to gender and age in top-level soccer players.

Evaluation of Seasonal Changes in Fitness, Anthropometrics, and Body Composition in Collegiate Division II Female Soccer Players

Peart, AN, Nicks, CR, Mangum, M, and Tyo, BM. Evaluation of seasonal changes in fitness, anthropometrics, and body composition in collegiate division II female soccer players. J Strength Cond Res 32(7): 2010-2017, 2018-The purpose of this study was to investigate anthropometrics, body composition, aerobic and anaerobic fitness of collegiate Division II female soccer players throughout a calendar year. Eighteen (20 ± 0.9 years) National Collegiate Athletics Association division II female soccer players from the same team participated in the study. Anthropometrics and body composition variables were assessed in addition to the counter movement jump (CMJ), Wingate Anaerobic Test (WAT), and peak oxygen uptake (V[Combining Dot Above]O2peak). Data were collected over 5 time points: end of competitive seasons (ECS1 and ECS2), beginning of off-season (BOS), end of off-season (EOS), and preseason (PS). Repeated-measures analysis of variance was conducted to compare test scores among all 5 data collection points. Where appropriate, Bonferroni post hoc tests were used to determine which points were significantly different. Hip circumference decreased significantly (p < 0.001) from EOS (98.47 ± 6.5 cm) to PS (94.46 ± 6.8 cm). Fat mass (12.73 ± 5.4 kg) was significantly different in ECS2 compared with BOS and EOS means (p ≤ 0.05) and percentage of body fat (%BF) (20.08 ± 5.44) significantly different in ECS2 compared with ECS1, BOS, and EOS means (p ≤ 0.05), whereas fat-free mass (FFM) was maintained from ECS1 to ECS2. Counter movement jump, WAT, and V[Combining Dot Above]O2peak performance did not significantly change from ECS1 to ECS2. Anthropometrics and body composition results are similar to previous studies measuring Division II to professional female soccer players. Counter movement jump results remained consistent and are comparable to results on Division I female soccer players. Coaches and researchers can use these data to help design and evaluate training programs throughout a calendar year.

Profile of 1-month training load in male and female football and futsal players

The aim of this study was to analyse the variance of training load between male and female football and futsal players. The statistical analysis tested the variance between gender and type of sport during training sessions. Fifty-nine male and female amateur football and futsal amateur players were monitored during 48 training sessions. The heart rate (HR) responses and the percentage of time spent in zones of intensity were analysed during training sessions. Differences were found in football between the gender and the dependent variables of %HRmax (p value = 0.001; η (2) = 0.042; minimum effect), %time in Z2 (p value = 0.001; η (2) = 0.054; minimum effect), %time in Z4 (p value = 0.001; η (2) = 0.031; minimum effect) and %time in Z5 (p value = 0.001; η (2) = 0.053; minimum effect). The analysis in male players revealed differences between football and futsal in %HRmax (p value = 0.001; η (2) = 0.172; minimum effect). Similar results were found in female category (p value = 0.001; η (2) = 0.040; minimum effect). In this study it was possible to verify that female players spent more time in high intensity zones and that futsal training sessions are more intense than football sessions. Based on such results, coaches and fitness trainers may identify the physiological characteristics of training load imposed to different sports and genders and optimize the training plan for specific categories.

Aerobic fitness and performance in elite female futsal players

Despite its growing popularity, few studies have investigated specific physiological demands for elite female futsal. The aim of this study was to determine aerobic fitness in elite female futsal players using laboratory and field testing. Fourteen female futsal players from the Venezuelan National team (age =21.2±4.0 years; body mass =58.6±5.6 kg; height =161±5.0 cm) performed a progressive maximal treadmill test under laboratory conditions. Players also performed a progressive intermittent futsal-specific field test for endurance, the Futsal Intermittent Endurance Test (FIET), until volitional fatigue. Outcome variables were exercise heart rate (HR), VO₂, post-exercise blood lactate concentrations ([La]b) and running speeds (km · h^-1). During the treadmill test, VO₂max, maximal aerobic speed (MAS), HR and peak [La]b were 45.3±5.6 ml · kg^-1 · min^-1, 12.5±1.77 km · h^-1, 197±8 beats · min^-1 and 11.3±1.4 mmol · l^-1, respectively. The FIET total distance, peak running velocity, peak HR and [La]b were 1125.0±121.0 m, 15.2±0.5 km · h^-1, 199±8 beats · min^-1 and 12.5±2.2 mmol · l^-1, respectively. The FIET distance and peak speed were strongly associated (r= 0.85-87, p < 0.0001) with VO₂max and MAS, respectively. Peak HR and [La]b were not significantly different between tests. Elite female futsal players possess moderate aerobic fitness. Furthermore, the FIET can be considered as a valid field test to determine aerobic fitness in elite level female futsal players.