Effects of different strength and velocity training programs on physical performance in youth futsal players.

Futsal is a high intensity team sport with intermittent actions of short duration, so it is necessary to include different training strategies to improve explosive actions. There is a gap in the scientific literature regarding training programs that improve the performance of young futsal players. The aim of this study was to determine the effects of different strength and velocity training programs on lower body physical performance in youth futsal players. Forty-two youth futsal players were divided into control group (CG, n = 14) and a strength intervention group (SG, n = 14), which included a weekly session for 8 weeks of eccentric strength training, plyometrics and core strengthening, and a velocity intervention group (VG, n = 14), which included a weekly session during 8 weeks of training with linear speed exercises and with change of direction, accelerations with resistance bands and core strengthening. SG significantly improved horizontal jump (HJ) (p:0.02), V-CUT (p:0.91) and change of direction deficit (CODD) (p:0.01). VG showed significant improvements in HJ (p:0.01), in 25 m sprint (p:0.01), in total repeated sprint ability time (p:0.01), in V-CUT (p:0.01) and in CODD (p:0.01). SG showed significant intergroup differences (p:0.01) in COD variables with respect to CG and VG. In conclusion, SG and VG showed significant improvements in lower body performance variables in youth futsal players. In addition, the SG has substantial changes in COD compared to the other two groups, so it has a greater effect.

Analysing the Influence of Speed and Jumping Performance Metrics on the Percentage Change of Direction Deficit in Adolescent Female Soccer Players.

Studies show that although female soccer players often have shorter change of direction (COD) deficits than males, indicating different biomechanical profiles, there is a lack of research on the impact of physical metrics on COD performance in females. The purpose of this work was to analyse whether performance metrics based on speed and jumping could explain the variation in %CODD in young female soccer players. Thirty-three highly trained adolescent female soccer players with an age of 16 ± 0.95 years, a body mass of 55.7 ± 7.22 kg, and a height of 160.4 ± 5.22 cm performed COD180 tests, 10 m and 30 m sprint tests, single-leg countermovement, and horizontal jumps. Acceleration in the first 10 m of a sprint was identified as a significant predictor of COD180 performance (R2 = 28%), (R2 = 50%), (p < 0.01), indicating that early sprint performance may largely determine an individual's ability to change direction. However, no predictors were found for %CODD. Significant correlations were observed between COD180 performance and %CODD, acceleration, linear speed, and horizontal jump performance (r = -0.59 to 0.70; p < 0.05). The study suggests that specific physical performance metrics, particularly early acceleration, are crucial for enhancing COD skills in female soccer players, emphasizing the need for targeted training interventions.

Effects of a neuromuscular training program on the performance and inter-limb asymmetries in highly trained junior male tennis players.

Background: The objective of this study was to assess the effectiveness of neuromuscular training on the performance of highly trainer junior tennis players. Methods: Twelve male tennis players (age: 13.4 ± 0.36 years; weight: 50.2 ± 6.29 kg; height: 163 ± 4.41 cm) participated and were randomly divided into two groups. The experimental group (EG) performed neuromuscular training that included exercises for speed, strength, throws, agility, jumps and coordination twice a week for a duration of 10 weeks. Performance was evaluated using various variables, including bilateral and unilateral countermovement jump, 30 cm drop jump and horizontal jump, 505 change of direction test conducted with both the right and left legs, 20-m sprint, and overhead 3 kg medicine ball throw. Asymmetries were also evaluated during the unilateral tests. The impact of the training was assessed through the utilization of ANCOVA tests and effect size measurements. Results: The results indicated a significant enhancement in the EG, specifically in bilateral vertical jump and horizontal jump, as well as explosive strength and speed. Conversely, the control group (CG) did not display similar advancements. Furthermore, there was no increase in asymmetries. Conclusion: This suggests that the implementation of a neuromuscular training program could prove to be an effective approach in enhancing explosive power in the lower limbs among young competitive tennis players. Finally, this training program could contribute to the enhancement of their physical attributes in lower body of young tennis players.

Isometric and isokinetic strength of lower-limb muscles in female athletes during different phases of menstrual cycle: a causal-comparative study.

BACKGROUND: Muscle strength is affected by different stages of the menstrual cycle in women. Since the strength of the lower limb muscles plays a significant role in the occurrence of anterior cruciate ligament injury, it seems necessary to study the strength of the lower limb muscles at different stages of this cycle to take preventive measures. Therefore, this study aimed to compare the isometric and isokinetic strength of lower limb muscles in female athletes at different menstrual cycle stages. METHODS: The present study is of a causal-comparative type. Thirty-seven female athletes in anterior cruciate ligament injury high-risk disciplines participated in this study. Isometric and isokinetic knee extensors and flexors muscle strength status, including the traditional hamstrings/quadriceps (H/Q) ratios, were recorded at different stages of the menstrual cycle (follicular, ovulatory, luteal) by Biodex isokinetic dynamometry system 4. Then, the obtained results were analyzed by repeated measure analysis of variance. RESULTS: Analysis of variance with repeated measures showed isokinetic and isometric strength in the knee flexor and extensor muscles at an angular velocity of 60˚/s in the ovulatory phase are higher than the follicular and luteal ones. The strength of the muscles declined during the follicular and luteal phases (p ≤ 0.05). CONCLUSIONS: Due to the negative effect of the follicular and luteal stages of the menstrual cycle on the strength of the flexor and extensor muscles of the knee, the risk of anterior cruciate ligament injury may increase during this period. Therefore, it is recommended that all female coaches and athletes take preventive measures during this period.

Horizontal jump asymmetries are associated with reduced range of motion and vertical jump performance in female soccer players.

BACKGROUND: Performance in jumping and change of direction tests are good proxies to reflect the skill level during soccer-specific actions. Greater inter-leg asymmetries have been identified as a risk factor for developing acute and overuse injuries and jeopardizing soccer performance. The aim of this study was to assess the association between asymmetry in the unilateral vertical and horizontal jump tests, ankle range of motion, linear velocity, and change of direction in a sample of highly trained adult female soccer players. METHODS: Thirty-eight highly trained female soccer players underwent a testing protocol including ankle dorsiflexion, single leg jumps for height (CMJ), distance (HJ), 40 m sprint and 180° change of direction tests. RESULTS: Within-session reliability was acceptable (CV ≤ 7.9%), and relative reliability showed good to excellent (ICC: 0.83 to 0.99). The one-way ANOVA reported higher inter-limb differences for change of direction deficit (10.9 ± 8.04%) and single leg CMJ (5.70 ± 5.22%). Pearson correlations highlighted significant relationships between horizontal jump asymmetries and ankle dorsiflexion (r = -0.41), CMJ (r = -0.36 to -0.49) and HJ (r = -0.28 to -0.56). CONCLUSIONS: Assessing inter-limb asymmetries through different methods can help scientists understand the specificity of their detrimental effects on soccer performance. Practitioners should be aware of these specificities as well as the magnitude and direction of the asymmetries when aiming to improve specific on-field skills.

Effects of a neuromuscular training program on physical performance and asymmetries in female soccer.

Introduction: Women's football require optimal neuromuscular system development for injury prevention and performance optimization. Standardized neuromuscular training programs have shown promising results in reducing injuries and functional asymmetries, but evidence on their impact on performance is limited. Methods: This research examined the effects of a 10-week neuromuscular training program on physical performance and asymmetries in female football players. Thirty-eight female players from two Spanish Second Division women's football teams participated in the study. The physical performance tests used were: ankle dorsiflexion, bilateral and unilateral horizontal jump, bilateral and unilateral vertical countermovement jump, 40 m sprint including partial times at 10, 20 and 30 m and the 505 test for change of direction evaluation. For 10 weeks, players in the experimental group performed three weekly 24-min neuromuscular training sessions. Participants in the control group completed their normal 24-min strength and conditioning program. Results: The main results were that maximal linear velocity and change of direction skills showed the most notable improvements [effect size (ES), 0.46 to 0.59] after implementation of the training program, ankle dorsiflexion and jumping skills, also improved although, to a lesser extent (ES, <0.35) while asymmetries between limbs were reduced. Maximal running speed improved in the intervention group (p < 0.001) with a mean ES -0.59. Discussion: We conclude that a 10-week neuromuscular training program can be a sufficient stimulus to improve football-specific performance variables in high-level female football players. Therefore, female players and coaches should be aware that weekly inclusion of strength, power and dynamic balance exercises following a neuromuscular paradigm is helpful for football-specific performance improvement.

Relative Individual Sprint in Most Demanding Passages of Play in Spanish Professional Soccer Matches.

(1) Background: The objective of this research was to analyse the most demanding passages (MDP) considering the sprint variable relative to the maximum level of sprint ability of each player as a function of player position, final outcome and part of the match during the competitive phase of a professional soccer season. (2) Methods: Global positioning system (GPS) data were collected from 22 players according to their playing position in the last 19 match days of the Spanish La Liga professional soccer in the 2020/2021 season. MDP were calculated from 80% of the maximum sprint speed of each player. (3) Results: Wide midfielders covered the greatest distance at >80% of the maximum speed (2.4 ± 1.63 seg) and the longest duration (21.91 ± 13.35 m) in their MDP. When the whole team was losing, it demonstrated greater distances (20.23 ± 13.04 m) and longer durations (2.24 ± 1.58 seg) compared to games in which it was winning. When the team ended up drawing, the relative sprint distance covered in the second half was significantly greater than in the first (16.12 ± 21.02; SD = 0.26 ± 0.28 (-0.03/-0.54). (4) Conclusions: Different demands of MDP, according to the sprint variable relative to the maximum individual capacity in competition, are required when contextual game factors are considered.

Variations in cumulative workload and anaerobic power in adolescent elite male football players: associations with biological maturation.

BACKGROUND: It is considered that the maturity condition of young football players is related to their physical performance during short high-intensity efforts dependent on anaerobic power ability. Hence, the aim was to determine possible relationships between maturity status and training intensity by measuring the footballer´s peak height velocity (PHV), maturity offset and anaerobic power. METHODS: Seventeen youth male players of different playing positions participated in the study and performed tests at three different stages of the season (early-, mid- and end-season) All the anthropometric parameters and biomarkers related to maturation were controlled during the season. The training intensity and load was monitored and the anaerobic power of the players was assessed by a running-based anaerobic sprint test (RAST). RESULTS: The analysis of all the recorded data revealed a positive relationship between PHV and anaerobic power in the early- and end-season stages (p < 0.05). Maturity offset and anaerobic power (mean RAST) showed an absolute correlation in early- and end -season stages (r: - 0.39 to 0.91). The multiple linear regression analysis revealed that min RAST was the best predictor for both PHV and maturity offset. The analysis of the training intensity and workloads showed a positive effect on the performance in the fitness test (p < 0.05). Additionally, players experienced less fatigue at the end-season stage than at the early-season. CONCLUSIONS: The results show that coaches might benefit from monitoring training loads and the maturity status of the players in order to enhance their physical performance during the season.

Motoric performance variation from morning to evening: 80% intensity post-activation potentiation protocol impacts performance and its diurnal amplitude in basketball players.

Introduction: Post-activation potentiation (PAP) can be defined as the acute enhancement in muscle performance after preload stimulation that occurs during strength exercises or warm-up protocols, and the contractile history of any muscle group can directly influence the presented performance. The purpose of this study was to compare the results of motoric performance tests carried out at two different times of the day using three different PAP protocols. Methods: Thirty-two male basketball players with at least 2 years of training experience and who competed at the national level were recruited for this study [age: 21.80 ± 1.91 years; body height: 178.40 ± 6.85 cm; body mass: 72.50 ± 7.16 kg; body mass index (BMI): 22.81 ± 2.28]. After control and experimental-specific warm-up (SWU) sessions, participants completed a countermovement jump (CMJ) and seated medicine ball throw (SMBT). The SWU protocol was developed based on the athlete's typical warm-up routine. The experimental warm-ups included the same exercises as the SWU, with one set of bench presses for five repetitions at 80% (80% PAP) and one repetition at 100% of 1 RM (100% PAP). Each of the protocols consists of 15 min. The SWU and experimental warm-up sessions were completed in a random, counterbalanced order, completed in a period of 3-weeks. Results: According to the research findings, carrying out the protocols in the evening led to a larger improvement in SMBT than in the morning (F = 35.94, p < 0.001, η 2 p = 0.537). Additionally, the SMBT results were statistically more significant in the group that received 80% PAP compared to the SWU (p = 0.034), and the SMBT results were also higher in the group that received 100% PAP compared to the SWU (p = 0.002). Furthermore, the interaction effect (time × PAP) was statistically significant in SMBT (F = 6.39, p = 0.003, η 2 p = 0.17). Discussion: These results may provide more particular recommendations than previously thought to basketball coaches for the planning of basketball-specific PAP exercises prior to the start of training programs.

Variations in Accumulated-Training Load Parameters and Locomotor Demand with Consideration of Puberty in Elite Young Soccer Players.

The study's purposes were to examine the associations of training load parameters with locomotor demand and puberty status in elite young soccer players and to predict the percentage of changes in their performance ability with adjustments to the training load parameters, using multivariate regression analysis, while considering PHV and maturity offset. Seventeen male players (15−16 years old) participated in this study. Anthropometrics, body composition, maximal oxygen consumption (VO2max), and puberty status (for calculating PHV) and maturity offset were assessed. The results demonstrated substantial differences between the PHV, VO2max, and load parameters (acute and chronic workload (CWL)) over a soccer season. A substantial relationship existed between the workload parameters (VO2max, CWL, and training monotony (TM)) and maturity offset. All of the variables, except for training strain, demonstrated significant variances in relation to the differences between the first and second halves (p < 0.05). Aerobic performance can be estimated using the CWL, TM, and maturity offset values (R2 = 0.46). On the contrary, aerobic power performance can be explained using the acute:chronic workload, TM, and PHV values (R2 = 0.40). In conclusion, the biological maturity state of young soccer players has a substantial impact on their functional potential. Variations in accumulated load contribute significantly to aerobic resistance, whereas weight and height contribute significantly to sprint and vertical-jump performance, respectively.

Evaluation of 10-Week Neuromuscular Training Program on Body Composition of Elite Female Soccer Players.

(1) Background: This study was conducted to investigate the effects of a 10-week neuromuscular training program (NMT) on the sum of six skinfolds (Σ6S) and body composition variables in elite female soccer players. (2) Methods: Forty-four Spanish elite female soccer players (age: 24.0 ± 4.2 years; height: 164.3 ± 5.5 cm; body mass: 60.4 ± 5.5 kg; body mass index (BMI): 22.4 ± 2.2 kg/m2) were randomly assigned to a control group (CG) or to an experimental group (EG). Participants in the EG completed a specific NMT program of 24 min, three times per week, which included exercises from six different categories (mobility, dynamic stability, anterior chain strength, lumbopelvic control, posterior chain strength, and change of direction). The CG followed their normal strength and conditioning program. Pre- and post-intervention assessments included anthropometric measurements (weight, height, limb circumferences, and bone breadths), and subsequently, body composition factors BMI, Σ6S, body mass, muscle mass, and lean body mass were calculated. Nutrition was standardized by a nutritionist and also load monitored. (3) Results: A two-way mixed analysis of variance (group × time) revealed that there was a significant (p ≤ 0.001) group × time interaction between body mass, fat mass, and Σ6S in favor of NMT. A significant interaction was also observed for body skeletal muscle mass and lean body mass favoring NMT. (4) Conclusions: The application of an NMT program seems to be a useful strategy to improve body composition in elite female soccer players.

Investigation of obesity, eating behaviors and physical activity levels living in rural and urban areas during the covid-19 pandemic era: a study of Turkish adolescent.

BACKGROUND: The purpose of this study was to determine the eating behaviors, obesity and physical activity status of children of similar ages living in rural and urban areas and to examine these relationships during the coronavirus disease (COVID-19) pandemic process. METHOD: The research was conducted using the scanning model. The research group consists of children living in rural and urban areas in Turkey. The sample of the study consists of a total of 733 adolescent participants, 351 females (47.9%) and 382 males (52.1%). After anthropometric measurements were made, the Physical Activity Questionnaire for older children and the Yale Food Addiction Scale for children 2.0 were used to determine the food addiction and physical activity status of children during the COVID19 pandemic process. Since the groups were homogeneously distributed, independent samples t-test and Pearson correlation test were used. RESULT: In terms of food addiction and physical activity levels, children living in the urban have higher scores than children living in rural areas. In addition, children living in the urban were taller and have higher body mass values than those in rural areas. In terms of physical activity level and food addiction levels, while girls living in the urban had higher activity levels than those living in rural areas, no statistically significant difference was found between the physical activity levels of boys. When evaluated in terms of general and gender, it was determined that children living in rural areas were overweight and obese at a higher rate. Obese children had higher levels of food addiction and lower physical activity levels than non-obese children. CONCLUSION: In order to prevent childhood obesity, the level of food addiction should be reduced as well as increasing the level of physical activity. This study is limited in terms of cross-sectional evaluation. Future research can experimentally reveal how much obesity is reduced by methods such as exercise and diet interventions.

Acute effects of a 60-min time trial on power-related parameters in trained endurance runners.

BACKGROUND: The advent of power meters for running has raised the interest of athletes and coaches in new ways of assessing changes in running performance. The aim of this study is to determine the changes in power-related variables during and after a strenuous endurance running time trial. METHODS: Twenty-one healthy male endurance runners, with a personal record of 37.2 ± 1.2 min in a 10-km race, completed a 1-h run on a motorized treadmill trying to cover as much distance as they could. Before and after the time trial the athletes were asked to perform a 3-min run at 12 km h-1. Normalized mean power output, step frequency, form power and running effectiveness were calculated using the Stryd™ power meter. Heart rate (HR) and rating of perceived exertion (RPE) were monitored, and data averaged every 5 min. RESULTS: Despite high levels of exhaustion were reached during the time trial (HRpeak = 176.5 ± 9.8 bpm; RPE = 19.2 ± 0.8), the repeated measures ANOVA resulted in no significant differences (p ≥ 0.05), between each pair of periods for any of the power-related variables. The pairwise comparison (T test) between the non-fatigued and fatigued constant 3-min runs showed an increase in step frequency (p = 0.012) and a decrease in form power (p < 0.001) under fatigue conditions, with no meaningful changes in normalized mean power output and running effectiveness. CONCLUSIONS: Trained athletes are able to maintain power output and running effectiveness during a high demanding extended run. However, they preferred to reduce the intensity of vertical impacts under fatigue conditions by increasing their step frequency.

Associations between bio-motor ability, endocrine markers and hand-specific anthropometrics in elite female futsal players: a pilot study.

BACKGROUND: The second-to-fourth digit ratio (2D:4D) has been calculated for individual athletes and sports, but it has not been investigated in futsal performance. Therefore, the aim of this study was to investigate any relationships between 2D:4D of the dominant and non-dominant hands and physical capacity performances, selected functional variables and hormone concentrations in elite female futsal players. METHODS: Twenty-four elite female futsal players were measured for 2D:4D in the dominant (2D:4DD) and non-dominant (2D:4DND) hand. The futsal specific performance test (FSPT), hand-grip strength (HGS) and aerobic power were also assessed. In addition, selected circulatory hormones were measured (estradiol, cortisol, growth hormone and insulin like growth factor-1). Pearson's correlation test was used to identify correlational relationships. RESULTS: Total test-time and performance time (total time + penalty time) for the FSPT showed a significant correlation with 2D:4DD (r = 0.53, p = 0.005 and r = 0.55, p = 0.003, respectively). HGSND also displayed a significant correlation with the 2D:4DD (r = 0.59, p = 0.002). Aerobic power and time spent running on the treadmill also showed a significant relationship with 2D:4DND (both, r = 0.54, p = 0.006). Cortisol showed a significant correlation with 2D:4DD (- 0.58, p = 0.003) and 2D:4DND(- 0.52, p = 0.008). CONCLUSIONS: The measurement of 2D:4D ratio could be an important factor in determining potential performance attributes and talent identification of elite female futsal players. Further studies are needed in this area to further examine the results presented here.

The Influence of Stud Characteristics of Football Boots Regarding Player Injuries.

BACKGROUND: the main aim of this study was to analyze the relationship between sole pattern parameters of football boots with the frequency of injuries that occur in semiprofessional and amateur footballers. METHODS: The study sample was composed of 77 male football players. All were at least 18 years old, played at least 10 h per week, gave signed informed consent to take part and properly completed the Visual Analogue Scale. This study analysed data from each player's medical history, including age, injuries, years of practice, field type and surface condition information. RESULTS: The visual analogic score in semiprofessional players was higher (2.05 ± 2.43) than in amateur players (1.00 ± 1.1). A total of 141 lesions were collected, equivalent to 1.81 injuries for each football player studied (n = 77). The result of the ROC curve indicated that the player's years of practice could predict significantly (p < 0.05) the presence of lower limb injuries, with an area under the curve of 0.714. CONCLUSIONS: This study described the predictive capacity of sole pattern characteristics concerning lower limb injuries in amateur and semiprofessional footballers. Football boot variables associated with the number of studs were associated with foot and ankle overload injuries.

Influence of contextual factors on physical demands and technical-tactical actions regarding playing position in professional soccer players.

BACKGROUND: The aim of this study was to analyse the physical demands and technical-tactical actions for each playing position according to game location and final outcome in professional soccer players. METHODS: A convenience sample was obtained from twenty-one professional male soccer players, belonged to same soccer team of the Spanish Second Division. Players' physical demands were monitored during each match using a portable 18 Hz GPS unit and 600 Hz triaxial accelerometer. These analysed demands were total distance, moderate speed running distance (>14.4 km·h-1), high-speed running distance (>19.8. km·h-1), sprint distance (>25.0 km·h-1), number of accelerations between 2 and 4 m·s-2 and above 4 m·s-2, and number of decelerations between 2 and 4 m·s-2 and above 4 m·s-2. The data related to technical-tactical actions were obtained from WyScout®, a computerized multiple-camera tracking system based on the OPTA® track analysis tool. The obtained indicators were general, defensive and offensive. RESULTS: For all players, higher total distance (p = 0.045; effect size [ES] = 0.24, small effect) was covered and greater deceleration 2-4 m·ss-2 (p = 0.001; ES = 0.68, medium effect) was performed when the team plays at home and lose and for all players, playing at home and winning demanded higher defensive volume (p =0.014; ES = - 1.49, large effect) and nº interceptions (p =0.031; ES = - 1.40, large effect) in comparison to playing at home and losing. CONCLUSIONS: The physical demands and technical-tactical actions vary when contextual game factors (i.e., match location and final outcome) are considered. We can confirm that, although the training of physical demands does not influence the final result of the match, the training of technical tactical actions could help to achieve an optimal performance of the team to win matches.

Effect of Aerobic-Based Exercise on Psychological Well-Being and Quality of Life Among Older People: A Middle East Study.

The aimed to evaluate the effects of low and moderate-intensity aerobic exercise on psychological well-being (PWB) and quality of life (QoL) among older people. Forty-five male Iranian adults aged 65-80 years were selected according to the eligibility criteria and randomly assigned to a low-intensity group (LIG) (40-50% of maximum heart rate), moderate-intensity group (MIG) (60-70% of maximum heart rate) and control group (CG). The exercise protocols consisted of 12 weeks of aerobic exercise (two sessions per week). Psychological well-being and QoL were assessed through the Ryff's Psychological Well-being Scale and the World Health Organization QoL Questionnaire. The statistical analysis for psychological well-being indicated that a significant main group (between-group) (F = 11.777, p < 0.001, ηp2 = 0.359), time (within-group) (F = 58.983, p < 0.001, ηp2 = 0.584) and interaction effect (group × time) (F = 20.146, p < 0.001, ηp2 = 0.490) for PWB total score. Bonferroni post-hoc tests revealed that the PWB total score in the MIG group was more significant than both LIG (p = 0.003) and CG (p < 0.001). Results for PWB components including self-acceptance, positive relationships with others, autonomy, purposeful life, and environmental mastery revealed no significant differences (p > 0.05). While there was a significant difference between the groups for personal growth component. Bonferroni post-hoc tests revealed that the personal growth in the MIG group was more significant than both LIG (p = 0.028) and CG (p < 0.001). Result for QoL indicated significant differences for the main group (F = 13.277, p < 0.001, ηp2 = 0.387), time (F = 25.533, p < 0.001, ηp2 = 0.378) and interaction effect (F = 9.992, p < 0.001, ηp2 = 0.332) for QoL total scale. Bonferroni post-hoc tests revealed that the QoL total scale in the MIG group was more significant than both LIG (p = 0.003) and CG (p < 0.001). Results for QoL components including Physical health, Social relationships, Health environment revealed no significant differences (p > 0.05), while there was a significant difference between the groups for the Psychological health component. Bonferroni post-hoc tests revealed that the Psychological health in the MIG group was more significant than both LIG (p = 0.009) and CG (p = 0.002). Therefore, aerobic exercise improves PWB and QoL in older adults, moderate-intensity exercise seems to produce higher benefits than low-intensity, demonstrating a positive dose-response relationship.

Sprint Variables Are Associated with the Odds Ratios of Non-Contact Injuries in Professional Soccer Players.

Significant evidence has emerged that a high volume of sprinting during training is associated with an increased risk of non-contact injuries in professional soccer players. Training load has been reported as a modifiable risk factor for successive injury in soccer. Sprint workload measures and non-contact injuries were recorded weekly in twenty-one professional soccer players over a one season period. Odds ratio (OR) and relative risk (RR) were calculated based on the weeks of high and low load of total distance (TD), high-speed distance (HSD), sprint distance (SPD). and repeated sprints (RS). The Poisson distribution estimated the interval time between the last injury and the new injury. The weeks with high-load levels increased the risk of non-contact injury associated with TD (OR: 4.1; RR: 2.4), HSD (OR: 4.6; RR: 2.6), SPD (OR: 6.9; RR: 3.7), and RS (OR: 4.3; RR: 2.7). The time between injuries was significantly longer in weeks of low-load in TD (rate ratio time (RRT) 1.5 vs. 4.2), HSD (RRT: 1.6 vs. 4.6), and SPD (RRT: 1.7 vs. 7.7) compared to weeks of high-load. The findings highlight an increased risk of non-contact injuries during high weekly sprint workloads. Possibly, TD, HSD, and SPD measured via a wearable inertial measurement unit could be modeled to track training and to reduce non-contact injuries. Finally, the interval time between the last injury and the new injury at the high-load is shorter than the low-load.

Association Between Endocrine Markers, Accumulated Workload, and Fitness Parameters During a Season in Elite Young Soccer Players.

The purpose of this study was to analyze differences between endocrine markers in soccer players, based on playing positions, and correlations between endocrine markers (testosterone, cortisol, growth hormone, and insulin-like growth factor-1), with accumulated workload training and fitness parameters [maximal oxygen uptake (VO2max), countermovement jump (CMJ), and isometric maximal strength (1-RM) of the knee for hamstring (ISH) and quadriceps (ISQ) muscles] during early-, mid-, and end-seasons. Twenty-four elite soccer players under 17 participated in this study. The results showed that there was no difference between levels of the endocrine markers among the different positions of the players. Significant correlations were observed between endocrines parameters and fitness performance (ISQ, ISH, VO2max, and CMJ). Regression analysis showed that 1-RM and VO2max were the best predictors of endocrine markers. These findings demonstrated that the activity profiles of youth soccer players were not influenced by endocrine markers. Also, it may be assumed that endocrines levels can be used to better explain the physical capacities of this population. Finally, endocrines markers may help to predict changes in 1-RM and VO2max.