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The purposes were to evaluate kinetics in lower limbs using single leg countermovement jump (SLCMJ) and to identify the differences in SLCMJ kinetics between sprinting fast players and sprinting slow players in elite university female soccer players. Seventeen participants at the national tournament level completed the survey. SLCMJ and 30 m sprinting tests were performed. A force-plate was used to collect the data of the SLCMJ test. Significant differences of concentric maximum rate of force development (RFD), concentric RFD, concentric RFD/body weight (BW), peak net takeoff force/BW, peak power, and peak power/BW existed between both legs during the SLCMJ among all the participants. For further analysis, the participants were divided into fast group and slow group based on sprinting performance. Significant differences existed between the two groups in concentric peak velocity (nondominant, p = 0.028) and vertical velocity at takeoff (nondominant, p = 0.021). Concentric maximum RFD (p = 0.036) was significantly different between both legs in the slow group. Among elite university female soccer players, the players who presented more increased asymmetry of kinetic characteristics of jumping, also showed weak sprinting performance. Moreover, the players presented the best performance in velocity of the jumping variables and also had the best sprinting performance. Coaches and players should focus on keeping inter-limb balance and developing jumping velocity to improve sports performance. In future, the cause-and-effect relationship between jumping and sprinting should be identified.
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BACKGROUND: Dietary practices of the University of Limpopo soccer team athletes have been reported. However, the practices of those engaging in soccer for general fitness from different non-competitive teams remain unknown. To respond to this gap, the researchers investigated the energy, macronutrient intake, and BMI status and further correlated the two variables of the fitness non-competitive soccer athletes registered at the University of Limpopo in South Africa. METHOD: A quantitative study design was undertaken to conveniently sample 60 out of 90 fitness soccer athletes from the four non-competitive soccer teams at the University of Limpopo sports grounds. Ethics approval was obtained from the University of Limpopo Research and Ethics Committee, and permission was given by the university sports management and team coaches. Athletes signed the informed consent form before participating in the study. Data were collected at the soccer fields during the afternoons before the start of training. Macronutrient intake data were collected using multiple (two) 24-h recall questionnaires on different days, which were validated by the food frequency questionnaire. Weight and height were measured using a digital scale (Seca 813 electronic flat scale) and stadiometer (Seca 213 portable stadiometer) for BMI calculations, respectively. The average energy and macronutrient intakes were calculated through the SAMRC FoodFinder software (3.0). The nutrient averages, together with the BMI results, were loaded into SPSS (26.0) for further analysis. Descriptive statistics were used to report the energy, macronutrient intake, and BMI statuses of athletes using percentages, means, and standard deviations (±SD). A one-way ANOVA test was used to determine the association between the latter variables. A p-value of ≤ 0.05 was the criterion used to correlate the variables. RESULTS: All (100%) athletes were males, most of whom played soccer for 2-3 years while at the university. Almost half (48%) of athletes consumed energy (39.6 kcal/kg) below the recommendations. About 92% and 53% of athletes consumed carbohydrates (5.0 g/kg) and fat (1.2 g/kg) below the recommended values; while 43% consumed protein (1.4 g/kg) optimally. The majority (>80%) had a normal BMI (21.6 ± 2.6 kg/m2) status. However, there were no relationships between the energy (p = 0.383), CHO (p = 0.261), protein (p = 0.543), and fat (p = 0179) intake and the BMI status of athletes. CONCLUSION: The macronutrient intake of fitness soccer athletes at the University of Limpopo is, on the whole, suboptimal. However, the athletes had normal body weights. There was no association between both the energy and macronutrient intake and the anthropometric (BMI) status of soccer athletes.
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Futebol , Atletas , Carboidratos , Dieta , Carboidratos da Dieta , Ingestão de Alimentos , Ingestão de Energia , Feminino , Humanos , Masculino , Nutrientes , África do SulRESUMO
Anterior cruciate ligament (ACL) injury frequently occurs in female soccer athletes during deceleration movements such as landings. In soccer, landings mostly occur following jumping headers. Little research has been done to determine the mechanics that follow and how they compare to standard drop vertical jumps (DVJ). The purpose of this study was to analyze differences in kinematics between the DVJ and the soccer-specific vertical jump (SSVJ) in female soccer athletes to better assess the sport-specific risk for ACL injury. A secondary aim was to compare second landings (L2) to first landings (L1). Eight female recreational soccer athletes performed DVJs and SSVJs initiated from a 31 âcm height. Motion capture was performed during landings and data were analyzed using repeated-measures ANOVA. SSVJs produced less peak hip flexion (p â= â0.03) and less peak knee flexion (p â= â0.002) than DVJs. SSVJs also demonstrated increased ankle plantarflexion at initial contact (IC) than DVJs (p â= â0.005). L2s produced less peak hip (p â= â0.007) and knee flexion (p â= â0.002) than L1s. SSVJs and L2s displayed a more erect landing posture than the DVJs and L1s at the hip and knee, a known ACL risk factor. The significant results between jump styles show that the SSVJ displays mechanics that are different from the DVJ. The SSVJ may be a better sport-specific screening tool for ACL injury mechanisms than the DVJ in soccer athletes as it has a more direct translation to the sport.
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BACKGROUND: Chronic ankle instability (CAI) is a common peripheral joint injury and there is still no consensus on the mechanisms. It is necessary to investigate electrocortical parameters to provide clinical insight into the functional alterations of brain activity after an ankle sprain, which would greatly affect the implementation of rehabilitation plans. The purpose of this study was to assess cortical activation characteristics during drop-jump landing among soccer athletes with CAI. METHODS: A total of 24 participants performed the drop-jump landing task on a force platform while wearing a 64-channel EEG system. The differences of power spectral density (PSD) in theta and alpha (alpha-1 and alpha-2) bands were analyzed between two groups (CAI vs. CON) and between two limbs (injured vs. healthy). RESULTS: CAI participants demonstrated significantly higher theta power at the frontal electrode than that in healthy control individuals (F(1,22) = 7.726, p = 0.011, η2p = 0.260). No difference in parietal alpha-1 and alpha-2 power was found between groups (alpha-1: F(1,22) = 0.297, p = 0.591, η2p = 0.013; alpha-2: F(1,22) = 0.118, p = 0.734, η2p = 0.005). No limb differences were presented for any frequency band in selected cortical areas (alpha-1: F(1,22) = 0.149, p = 0.703, η2p = 0.007; alpha-2: F(1,22) = 0.166, p = 0.688, η2p = 0.007; theta: F(1,22) = 2.256, p = 0.147, η2p = 0.093). CONCLUSIONS: Theta power at the frontal cortex was higher in soccer athletes with CAI during drop-jump landing. Differences in cortical activation provided evidence for an altered neural mechanism of postural control among soccer athletes with CAI.
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Background: Sleep disruption (SD) increases sympathetic activity and cortisol secretion, and delays cognitive functions such as reaction-time (RT). Sympathetic activity of disturbed sleepers, is similar to those of so-called decision-reinvesters. Decision-reinvestment refers to traits in individuals with greater tendency to ruminate and reinvest in their decisions, with significant decrease in both motor-control and cognitive performance. Decision-making quality is a crucial attribute to athletic performance which relies on RT. Consequently, SD affects pitch-performance negatively, particularly in decision-reinvesters. This observational pilot-study examined the relationship between SD and cognitive function, perceived health, as well as reinvestment strategies. The hypothesis was that athletes with lower SD perceive their health better, report lower stress levels, perform better in cognitive tasks, and show lower tendency for decision-reinvestment. Methods: Twenty-one football player recorded their sleep with fit-trackers for 7 nights. Participants self-reported their mental and physical health, decision-reinvestment strategy, sleep behaviour, and perceived stress levels. Athletes then performed a set of cognitive tests to examine memory function (Backwards Corsi), selective attention (STROOP), and cognitive flexibility (Wisconsin Card Sorting Test, WCST). Normality was tested with a Shapiro-Wilk test, and analysed with a Pearson's or Spearman's correlation test. Results: Significant correlation appeared between extended sleep-interruptions and Backwards Corsi RT, r = 0.66, p = 0.010, as further in total sleep time and wellbeing r = 0.50, p = 0.029. A negative correlation exist in regard of pain scores and Backwards Corsi scores r = -0.57, p = 0.110. Physical health correlated with error-rates in the WCST, r = 0.69, p ≤ 0.001. Also, reinvestment negatively correlated with physical health, r = -0.80, p ≤ 0.001. Conclusion: Wellbeing relies on total sleep-time. Athletes with extended sleep-interruptions are slower in recalling memory, and those with greater reported pain have lower memory scores. Participants who rate physical health greater, have more error-rates in the WCST; indicating that cognitive flexibility is enhanced in individuals with inferior perceived health. However, individuals with lower physical health scores also have greater tendency to ruminate and reinvest in decisions, suggesting interrelation between reinvestment and physical health.
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PURPOSE: The purpose of this study was to investigate the influence of the soccer pitch area during small-sided games (SSG) in prepubertal children on physiological and technical demands, and to compare them, for the physiological demands, to high-intensity interval training (HIIT). METHODS: Ten young soccer players (13.0 [0.3] y) performed a HIIT and 3 SSG of various field sizes (30 × 20 m, 42 × 38 m, and 51 × 34 m). Each SSG was performed with 5 players per team, during 4 × 4-minutes interspaced with 1 minute of passive recovery in between. HIIT also followed a 4 × 4-minute protocol with running speed set on an individual basis. Heart rate (HR) was continuously monitored during training sessions. For each exercise modality, time spent above 90% of HRmax (T≥90%,HRmax) was calculated, and technical actions were quantified during SSG by video analysis. RESULTS: T≥90%,HRmax was similar between the 3 SSG (â¼587 [276] s; P > .2) but 24% to 37% lower than during HIIT (826 [140] s, P < .05). Coefficients of variations in T≥90%,HRmax were 2.3 to 3.5 times larger in SSG compared with HIIT. For technical actions, greater number of possessions (21 [6] vs â¼14 [4]), and lower ball touches per possession (2.4 [0.6] vs â¼2.9 [0.6]) were found in the small SSG compared with larger SSG, respectively (P < .05). CONCLUSION: The 3 SSG led to lower acute stimulation of the aerobic metabolism, suggesting a lower potential for chronic aerobic adaptations, compared with HIIT. Moreover, interindividual variability in the physiological response was substantially greater in SSG compared with HIIT, indicating increased heterogeneity among players performing the same training protocol.
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Frequência Cardíaca , Treinamento Intervalado de Alta Intensidade , Corrida , Futebol , Adaptação Fisiológica , Adolescente , Exercício Físico , HumanosRESUMO
We recently observed a high prevalence of low pelvic bone mineral density (BMD) in female professional ballet performers. Because this population is susceptible to musculoskeletal overuse injuries, we aimed to determine which regions of the pelvis may be at greatest risk compared to general population females (GENPOP) as well as professional female soccer players (SOCCER, a comparison to other elite athletes regularly subjected to high degrees of loading). Three groups of age-matched females [(GENPOP; n = 38, 27±1yrs), (BALLET; single company, n = 36, 26±3yrs), (SOCCER; single NWSL® club, n = 34, 25±1yrs)] consented to have their BMD and body composition assessed (DEXA, GE®). In addition to soft tissue and total and regional BMD analyses, a segmental analysis of the pelvis was performed to determine site-specific BMD for the iliac fossa, iliac fossa/iliac crest/ilium combined, pubic bone, ischium, and sacrum. A mixed-model ANOVA followed by a Tukey's post-hoc test was used to compare the groups (Type-I error; α = 0.05). The BALLET group had lower pelvic BMD for all measures (Avg.%Diff. = 15%-27%, p<0.001) compared to the SOCCER group and for the ischium (Avg.%Diff.= 8%; p=0.007) and sacrum (Avg.%Diff. â= â7%; p = 0.028) compared to the GENPOP group. The BALLET group had lower lean mass for all measures compared to the other groups (Avg.%Diff. = 12%-18%; p < 0.01). Professional ballet performers exhibit reduced pelvic region soft tissue and site-specific BMD not previously detected using standard DEXA analyses. These findings highlight which pelvic regions may benefit from preventative strength training and/or nutritional interventions.
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Female athletes are at a greater risk for anterior cruciate ligament (ACL) injuries than males. Current training programs for ACL injury reduction focus on muscle strengthening, appropriate movement patterns, and balance training. However, there is limited research on effective strategies to teach youth female soccer athletes how to properly perform desired movements associated with a decreased risk of ACL injuries. Behavioral skills training (BST) programs have been shown to be effective in teaching a wide variety of skills, but research on applications to sports is limited. This study evaluated a BST package for teaching a stepwise agility program to 3 youth female soccer athletes that consisted of verbal instructions, modeling, rehearsal, and feedback, which included video replay. Results showed a significant improvement in the number of steps the participants performed correctly relative to baseline, as well as maintenance of skills at follow-up. Implications for coaches and athletes, as well as limitations and directions for future research, are discussed.
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(1) Background: Limited information exists on the prevalence of low energy availability (LEA) in collegiate team sports. The purpose of this study was to examine the prevalence of LEA in collegiate women soccer players. (2) Methods: Collegiate women soccer athletes (n = 18, height: 1.67 ± 0.05 m; body mass: 65.3 ± 7.9 kg; body fat %: 24.9 ± 5.6%) had their body composition and sport nutrition knowledge assessed in the pre-season. Energy availability was assessed mid-season using a 4-day dietary log and activity energy expenditure values from a team-based monitoring system. A validated screening tool was used to screen for LEA. (3) Results: The screening tool classified 56.3% of athletes as at risk of LEA (<30 kcal/kg of FFM); however, the actual dietary intake identified 67% as LEA. Athletes identified as non-LEA consumed significantly more absolute (p = 0.040) and relative (p = 0.004) energy than LEA athletes. (4) Conclusions: There was a high prevalence of LEA among collegiate women soccer athletes. Although previously validated in women endurance athletes, the LEA screening tool was not effective in identifying those at risk of LEA in this sample of athletes.
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BACKGROUND:: Tendon overuse injuries are an issue in elite footballers (soccer players) and may affect tendon function. Achilles and patellar tendinopathy are the most frequent pathologies. Tendon stiffness, the relationship between the force applied to a tendon and the displacement exerted, may help represent tendon function. Stiffness is affected by training and pathology. Nevertheless, information regarding this mechanical property is lacking for elite soccer athletes. HYPOTHESIS:: Achilles and patellar tendon stiffness assessed using myotonometric measurements will be greater in elite soccer athletes than in control participants. STUDY DESIGN:: Cross-sectional study. LEVEL OF EVIDENCE:: Level 4. METHODS:: Forty-nine elite soccer athletes and 49 control participants were evaluated during the 2017 preseason. A handheld device was used to measure Achilles and patellar tendon stiffness. Dominant and nondominant limbs were assessed for both groups. RESULTS:: A significantly stiffer patellar tendon was found for both the dominant and the nondominant limb in the elite soccer athletes compared with the control group. Nevertheless, no differences were found in Achilles tendon stiffness between groups. When comparing between playing positions in soccer athletes, no significant differences were found for both tendons. CONCLUSION:: Greater patellar tendon stiffness may be related to an improvement in force transmission during muscle contraction. On the other hand, it seems that after years of professional training, Achilles tendon stiffness does not change, conserving the storing-releasing function of elastic energy. The nonsignificant differences between positions may be attributable to the years of homogeneous training that the players underwent. CLINICAL RELEVANCE:: The present study shows another technique for measuring mechanical properties of tendons in soccer athletes that could be used in clinical settings. In the future, this technique may help clinicians choose the best exercise protocol to address impairments in tendon stiffness.
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Tendão do Calcâneo/fisiologia , Biometria/métodos , Ligamento Patelar/fisiologia , Futebol/fisiologia , Tendão do Calcâneo/lesões , Adulto , Fenômenos Biomecânicos , Estudos Transversais , Transtornos Traumáticos Cumulativos/fisiopatologia , Humanos , Contração Muscular , Ligamento Patelar/lesões , Futebol/lesões , Tendinopatia/fisiopatologia , Adulto JovemRESUMO
Recent neuroimaging studies have suggested that repetitive subconcussive head impacts, even after only one sport season, may lead to pre- to post-season structural and functional alterations in male high school football athletes. However, data on female athletes are limited. In the current investigation, we aimed to (1) assess the longitudinal pre- to post-season changes in functional MRI (fMRI) of working memory and working memory performance, (2) quantify the association between the pre- to post-season change in fMRI of working memory and the exposure to head impact and working memory performance, and (3) assess whether wearing a neck collar designed to reduce intracranial slosh via mild compression of the jugular veins can ameliorate the changes in fMRI brain activation observed in the female high school athletes who did not wear collars after a full soccer season. A total of 48 female high school soccer athletes (age range: 14.00-17.97 years) were included in the study. These athletes were assigned to the non-collar group (n = 21) or to the collar group (n = 27). All athletes undewent MRI at both pre-season and post-season. In each session, a fMRI verbal N-Back task was used to engage working memory. A significant pre- to post-season increase in fMRI blood oxygen level dependent (BOLD) signal was demonstrated when performing the N-back working memory task in the non-collar group but not in the collar group, despite the comparable exposure to head impacts during the season between the two groups. The collar group demonstrated significantly smaller pre- to post-season change in fMRI BOLD signal than the non-collar group, suggesting a potential protective effect from the collar device. Significant correlations were also found between the pre- to post-season increase in fMRI brain activation and the decrease in task accuracy in the non-collar group, indicating an association between the compensatory mechanism in underlying neurophysiology and the alteration in the behavioral outcomes.
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Traumatismos em Atletas/prevenção & controle , Lesões Encefálicas Traumáticas/prevenção & controle , Memória de Curto Prazo , Equipamento de Proteção Individual , Futebol/lesões , Adolescente , Feminino , Humanos , Veias Jugulares , Estudos Longitudinais , Imageamento por Ressonância Magnética , Estudos ProspectivosRESUMO
This study investigated whether ACTN3 R577X, AMPD1 C34T, I/D ACE, and M235T AGT polymorphisms can affect performance tests such as jumping, sprinting, and endurance in 220 young male athletes from professional minor league soccer team from São Paulo Futebol Clube, Brazil. I/D ACE and M235T AGT polymorphisms were also analyzed according to cardiac and hemodynamic parameters. Athletes were grouped or not by age. DNA from saliva and Taqman assays were used for genotyping 220 athletes and the results were associated with performance tests. Ventricle mass, ventricle end-diastolic diameter, end-diastolic volume, and ejection fraction were assessed by echocardiogram. Arterial pressure, heart rate, and oximetry were assessed by a cardioscope. The main results of this study were that athletes who carried RR/RX (ACTN3) and DD (ACE) genotypes presented better performance during jump and sprint tests. On the other hand, athletes with ID/II genotype presented better results during endurance test, while AGT genotypes did not seem to favor the athletes during the evaluated physical tests. CC genotype (AMPD1) only favored the athletes during 10-m sprint test. Although there are environmental interactions influencing performance, the present results suggest that RR/RX ACTN3 and ACE DD genotypes may benefit athletes in activities that require strength and speed, while II ACE genotype may benefit athletes in endurance activities. This information could help coaches to plan the training session to improve the athletes' performance.
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Desempenho Atlético , Hemodinâmica , Polimorfismo Genético , Futebol , AMP Desaminase/genética , Actinina/genética , Adolescente , Adulto , Angiotensinogênio/genética , Atletas , Brasil , Técnicas de Genotipagem , Humanos , Estilo de Vida , Masculino , Peptidil Dipeptidase A/genética , Análise de Sequência de DNA , Adulto JovemRESUMO
BACKGROUND: The fifth metatarsal bone is a common site of stress fractures in soccer athletes. Although several endocrine risk factors for stress fractures have been proposed, the endocrine risks for fifth metatarsal (5-MT) stress fractures have not been evaluated. METHODS: To evaluate the endocrine risks of fifth metatarsal stress fractures, we conducted a cumulative case-control study. The present study included 37 athletes, of which 18 had a history of a zone 2 or zone 3 fifth metatarsal stress fracture and 19 controls. We analyzed serum 25-hydroxyvitamin D (25-OHD), serum parathyroid hormone (PTH), as well as biochemical markers of bone turnover by univariate or multivariate analyses. RESULTS: Logistic regression analyses adjusted for multiple confounders revealed that insufficient serum 25-OHD levels less than 30 ng/mL (odds ratio [OR], 23.3), higher serum PTH levels (OR, 1.01), or higher serum bone-specific isoform of alkaline phosphatase levels (OR, 1.10) rather than serum tartrate-resistant acid phosphatase 5b were associated with statistically significantly increased odds of 5-MT stress fractures. A postestimation calculation demonstrated that 25-OHD levels of 10 and 20 ng/mL were associated with 5.1 and 2.9 times greater odds for 5-MT stress fractures, respectively. CONCLUSION: 25-OHD insufficiency was associated with an increased incidence of 5-MT stress fractures. This insight may be useful for intervening to prevent 5-MT stress fractures. LEVEL OF EVIDENCE: Level III, case-control study.
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Fraturas de Estresse/sangue , Fraturas de Estresse/etiologia , Ossos do Metatarso/lesões , Vitamina D/análogos & derivados , Fosfatase Alcalina/sangue , Atletas , Biomarcadores/sangue , Estudos de Casos e Controles , Humanos , Isoenzimas/sangue , Masculino , Hormônio Paratireóideo/sangue , Medição de Risco , Fosfatase Ácida Resistente a Tartarato/sangue , Vitamina D/sangue , Adulto JovemRESUMO
A variável força muscular (FM) na prática esportiva, sobretudo no futebol, é de extrema importância em atividades como chutes, disputas de bola, arrancadas e saltos. Além disso, permite identificar indivíduos que estão em grupos de risco para lesões. Assim, técnicas, como a auto liberação miofascial (ALM), vêm sendo utilizadas para o aprimoramento do desempenho esportivo e para prevenir lesões. OBJETIVO: Verificar o efeito crônico da ALM na FM em atletas de futebol feminino. METODOLOGIA: Este estudo trata-se de um ensaio clínico randomizado. Participaram do estudo 14 atletas de futebol feminino. Inicialmente foram realizadas avaliações no aparelho dinamômetro isocinético dos extensores e flexores de joelho. As participantes foram divididas em dois grupos, um grupo intervenção (GI) e um grupo controle (GC). As participantes do GI realizaram um aquecimento associado à ALM com um foam roller. Já as participantes do GC, realizaram o mesmo aquecimento, porém sem a associação da ALM. Após 48 horas da última intervenção, foi realizada uma reavaliação no aparelho dinamômetro isocinético. RESULTADOS: Não foram verificados efeitos significativos entre os grupos no pós-teste. Na comparação pré e pós-teste entre os grupos, houve uma piora significativa na variável pico de torque de extensão do membro inferior dominante no grupo que não fez a ALM (p = 0,013). CONCLUSÃO: Conclui-se que uma abordagem crônica de ALM não foi capaz de gerar mudanças significativas na FM dos extensores e flexores de joelho. Mais estudos são necessários para apoiar esses achados. Registro ReBEC: RBR-7qnxty.
The variable muscle strength (MS) in sports practice, especially in football, is extremely important in activities such as kicks, ball disputes, sprints and jumps. In addition, it allows identifying individuals who are at risk groups for injuries. Thus, techniques, such as selfmyofascial release (SMF), have been used to improve sports performance and to prevent injuries. OBJECTIVE: To verify the chronic effect of SMF on MS in female soccer athletes. METHODOLOGY: This study is a randomized clinical trial. 14 female soccer athletes participated in the study. Initially, evaluations were performed on the isokinetic dynamometer device of knee extensors and flexors. The participants were divided into two groups, an intervention group (IG) and a control group (CG). IG participants performed a warm-up associated with SMF with a foam roller. CG participants, on the other hand, performed the same warm-up, but without the association of SMF. 48 hours after the last intervention, a reassessment was performed on the isokinetic dynamometer device. RESULTS: There were no significant effects between groups in the post-test. In the pre- and post-test comparison between the groups, there was a significant worsening in the peak torque variable of the dominant lower limb extension in the group that did not perform SMF (p = 0.013). CONCLUSION: It is concluded that a chronic SMF approach was not able to generate significant changes in the MS of knee extensors and flexors. Further studies are needed to support these findings. ReBEC Registration: RBR-7qnxty.
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Força Muscular , Futebol , FásciaRESUMO
Brazilian soccer championships involve a large number of teams and are known to cause stress and loss of muscle mass besides other negative physical consequences. This study was designed to compare the effects produced by three types of protein supplements on body composition, biochemical parameters and performance of a top Brazilian professional soccer team during an actual tournament. Twenty-four athletes assessed as having a normal nutrient intake were divided into three groups according to supplementation. Immediately after each daily training, the athletes received 1 g × kg(-1) of body weight × day(-1) of either whey protein (WP), hydrolyzed whey protein (HWP) or casein (CAS) for eight weeks. Before and after the experimental period, anthropometric characteristics, physical performance by the yo-yo and 3000m tests, and several biochemical variables in blood (uric acid, total cholesterol, HDL-cholesterol, creatinine, glucose) were measured. While no improvement in physical performance was observed with regard to the applied treatments, casein supplementation resulted in muscle mass increase (p<0.039), while WP and HWP favoured the maintenance of the initial muscle mass. Moreover, the eight-week intervention was found to cause no abnormalities in biochemical and anthropometric variables monitored, but instead, the intervention showed to be positive in comparison to the adverse anthropometric changes, when no supplementation was made. It was concluded that supplementation immediately after training sessions with any of the three sources of protein during the competitive period is beneficial and safe, as well as capable of sustaining or even increasing muscle mass.