Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 107
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
PLoS One ; 14(9): e0221761, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31479492

RESUMO

OBJECTIVE: The aims of this study were to analyze the shoulder functional profile of young male and female tennis players and to establish the relationship among physical variables and serve speed. METHODS: A total of 128 Spanish tennis players (Under-13 (n = 32/32 males/females) and Under-15 (n = 36/28 males/females), were tested during National training camps. Tests included passive shoulder range of motion (ROM) for both internal (IR) and external rotation (ER) and isometric strength (i.e., IR and ER) of the dominant/non-dominant shoulders, medicine ball throws (MBT), and serve speed. Age and sex pairwise comparisons were carried using the Hedges' g index (dg). RESULTS: Results showed age and sex effects on serve speed and all MBT, with males showing greater changes (1.51≤dg≤1.98) with age than females (0.92≤dg≤1.35; p<0.05). U15 males showed higher (p<0.05) absolute shoulder IR and ER strength than U13, with only significant differences between males and females in the U15. Regarding ROM, U15 males showed a decreased IR ROM compared to U13 (dg = -0.84; p<0.05) and higher significant IR bilateral deficit (dg = 0.51; p<0.05). The distances obtained in the different MBT were the variables more correlated to serve speed. CONCLUSION: The present results suggest that shoulder strength, medicine ball throws and serve speed increased along with age in young elite tennis players of both sexes. However, a decreased range of motion and bilateral deficit for glenohumeral internal rotation is evident in male under-15 tennis players. Muscle strength, power and shoulder range of motion are key factors for serve speed in young tennis players.

2.
Res Sports Med ; : 1-14, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31516016

RESUMO

The aim of the study was to assess the use of different positioning systems and sampling frequencies to measure spatial-positioning variables in team sports. Articles were selected when the sampling frequency was detailed. 2,194 articles were identified and 59 works were selected for the systematic review. The sampling frequency used to measure tactical behaviour differed considerably among studies. For Global Navigation Satellite System, the sampling frequency ranged from 5- to 15 Hz for raw data, the most commonly used sampling frequency being 5 Hz. For Optic-based tracking systems, the sampling frequency ranged from 10- to 30 Hz. For Local Position System, the sampling frequency ranged from 45- to 100 Hz, the most commonly used sampling frequency being 42 Hz and 57.7 Hz. There is no common criterion in the sampling frequency used to measure each tactical variable. Further studies should investigate the impact of the sampling frequency on the measurement of the tactical variables.

4.
Biol Trace Elem Res ; 2019 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-30924068

RESUMO

The aim of this study was to monitor the circulating and salivary ion concentrations by total reflection X-ray fluorescence (TXRF) in futsal players submitted to the futsal-specific intermittent shuttle protocol (FISP). TXRF may allow identification of changes in ion concentrations induced by physical efforts. Saliva and blood samples of 13 male futsal players were collected before (Pre) and after (Post) the FISP. Salivary and plasma ion levels were detected by TXRF, and differences from Pre to Post (paired t test or Wilcoxon test) and correlations between both biological fluids were determined (P < 0.05). All saliva samples presented phosphorus (P), sulfur (S), chlorine (Cl), potassium (K), calcium (Ca), iron (Fe), zinc (Zn), bromine (Br), and rubidium (Rb). S, Cl, Ca, Fe, Cu, Zn, Br, and Rb were detected in all blood samples. K, Cu, Br, and Rb presented reduced secretion rate from Pre to Post samples (P < 0.05). The salivary concentrations of K (r = - 0.53) and Zn (r = 0.54) were correlated with plasmatic concentrations. After FISP, salivary secretion of S (r = - 0.76), Cl (r = - 0.64), P (r = - 0.67), Mn (r = - 0.74), and Zn (r = 0.69) were correlated with plasma levels. We concluded that TXRF may be used to monitor salivary (P, S, Cl, K, Ca, Fe, Zn, Br, and Rb) and circulating (S, Cl, Ca, Fe, Cu, Zn, Br, and Rb) levels of several elements in futsal athletes. However, an acute bout of futsal-specific physical effort did not significantly imbalance ion concentrations in saliva or plasma.

5.
J Strength Cond Res ; 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30908372

RESUMO

Castillo, D, Rodríguez-Fernández, A, Nakamura, FY, Sanchez-Sanchez, J, Ramirez-Campillo, R, Yanci, J, Zubillaga, A, and Raya-González, J. Influence of different small-sided game formats on physical and physiological demands and physical performance in young soccer players. J Strength Cond Res XX(X): 000-000, 2019-The aim of this study was to quantify the acute impact of bout duration and individual interaction space on physical and physiological demands and on physical performance. Ten young male soccer players (age: 14.8 ± 0.6 years) from the same team playing in the National U-16 Division participated. Physical (total distance [TD]; distance covered at different speeds; and maximum velocity [Velmax]) and physiological (peak [HRpeak] and mean [HRmean] heart rate) parameters were collected for every bout during each small-sided game (SSG) format. Moreover, the effects of SSGs on horizontal jump (HJ) and 30-m sprint performances were evaluated. The SSG formats were composed of 6 players a side (including goalkeepers) and included 4 repetitions of 6 minutes in a space of 100 m (SSG1) or 200 m (SSG2) and 6 repetitions of 4 minutes in 100 m (SSG3) or 200 m (SSG4). The TD, the distance covered at different speeds, and Velmax were greater (p < 0.01, effect size [ES] = 1.25-5.95, large) in SSG2 and SSG4 than SSG1 and SSG3, respectively. Furthermore, the HRmean and HRpeak were lower (p < 0.05, ES = 1.53-2.23, large) during SSG3 than other SSGs. In addition, while a significant (p < 0.05, ES = 0.70-2.04, moderate to large) increase in SPR30 time in SSG1 and SSG3 was observed, HJ performance was not affected (p > 0.05, ES = 0.03-0.54, trivial to moderate) by any SSG format. These findings suggest increasing pitch size to induce greater physical demands and to use SSGs with smaller pitch size, and independently of the bout duration, to induce neuromuscular fatigue.

6.
PLoS One ; 14(2): e0211700, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30730959

RESUMO

Flywheel iso-inertial training has been shown to positively affect muscular strength and sports performance (e.g. agility). However, implementing such eccentrically-biased training during a microcycle needs to be carefully planned due to its purported effects on the neuromuscular system that can last for hours/days post-exercise. This study aimed at using tensiomyography to verify the effects of different inertias during the hip extension exercise on the contractile function of biceps femoris and semitendinosus muscles of the dominant leg for up to 72 hours post-exercise. Thirty participants (24.4 ± 3.4 years) were divided into 0.075 or 0.1 kg·m2 inertia groups and a control group. Magnitude-based analysis was used for the comparisons. Several tensiomyography parameters were changed after both intensities of flywheel exercise (in most cases indicating a decrement in muscle stiffness), whereas most between-group differences suggested that in the semitendinosus muscle, the higher inertia (0.1 kg·m2) influenced the muscle stiffness parameters more (e.g. Dm = maximal radial displacement) while in the biceps femoris, the greater effect was caused by the lower inertia (0.075 kg·m2) (e.g. Tc = contraction time). Most changes in contractile properties of the investigated muscles occur within 24 hours post-exercise, but can persist for up to 72 hours. However, higher inertia (0.1 kg·m2) influenced the stiffness of the semitendinosus muscle more, while in the biceps femoris, the greater effect was caused by the lower inertia (0.075 kg·m2). These findings should be considered by practitioners when prescribing flywheel iso-inertial training.

7.
J Hum Kinet ; 64: 275-285, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30429918

RESUMO

The purpose of the present study was to describe performance in acceleration capacity, change of direction ability, vertical jump, horizontal jump, repeated sprint ability, and endurance (Yo-Yo Intermittent Recovery Test Level 1) in futsal players, and analyze the differences according to competitive categories or levels. The total sample (n = 40) was divided into three groups depending on the category in which the participants competed: Second Division B (n = 15), Third Division (n = 12) and juniors (n = 13). All the tests were performed with participants' regular competition shoes and on the usual playing surface, in an indoor pavilion with a floating wood floor. The results of the study did not show significant differences in acceleration capacity (5 and 15 m) or change of direction ability among the different categories. In contrast, significant differences were found among the categories with regard to horizontal jump and vertical jump capacity (p < 0.05); but not in all the variables analyzed. Performance in repeat sprint ability varied significantly among the different categories in 30 m (p < 0.01) but not in 5 m (p > 0.05). The distance covered in the Yo-Yo Intermittent Recovery Test Level 1 by the Second Division B and the Third Division groups was greater than that covered by the junior group. In the light of these results repeated sprint ability and aerobic endurance could be two discriminating qualities of the competitive level among different futsal categories.

8.
Lasers Med Sci ; 2018 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-30456534

RESUMO

Cryotherapy and phototherapy have been suggested as recovery methods due to their anti-inflammatory effects. They may also induce mitochondrial biogenesis, thus favoring endurance training adaptation. The aim of this study was to evaluate the anti-inflammatory and ergogenic effects of phototherapy or cold water immersion (CWI) applied daily after exercise in rats. Thirty-five rats were divided into five groups: control (CO), non-exercised (CE), passive recovery (PR), cold water immersion (CWI), and LED therapy (LED). The CO and CE groups were not submitted to training; however, the CE were submitted to an exhaustion test after the training period. Low-intensity swimming training (21 sessions, 45 min) was performed followed by passive recovery (PR), CWI (10 °C, 5 min), or infrared irradiation (940 nm, 4 J/cm2). Forty-eight hours after the final training session, the CE, PR, CWI, and LED animals were submitted to an exhaustion test. The animals were euthanized 24 h later and submitted to hematological, creatine kinase (CK), and C-reactive protein (PCR) analysis. Gastrocnemius and soleus muscles were submitted to histological analysis. No differences in blood cell counts, CK, and PCR were detected between groups. The CE group presented an increased number of areas with necrosis in the gastrocnemius and soleus muscles. The PR group presented the highest frequency of areas with edema and inflammation followed by CWI and LED groups. None of the recovery methods improved the performance in the exhaustion test. Successive applications of recovery methods do not improve exercise performance, but downmodulate the inflammation and prevent muscle necrosis.

9.
Artigo em Inglês | MEDLINE | ID: mdl-30321486

RESUMO

We investigated the effect of post-match cold-water immersion (CWI) on markers of muscle damage, neuromuscular fatigue and perceptual responses within 72 h after a Rugby match. Twenty-two professional male Rugby players were randomized into CWI (10°C/10min; n=11) or Control (CON:30min seated; n=11) groups. Activity profile from Global Positioning Satellite systems and post-match rating of perceived exertion were measured to determined match load. Biochemical (tumor necrosis factor alpha [TNF-α], interleukin-6 [IL-6]), neuromuscular performance (squat and countermovement jump [SJ; CMJ], peak power output [PPO], rate of force development [RFD], stiffness, 10- and 30-m sprint time and perceptual markers (soreness, perceived recovery) were obtained at pre, post, 30 min, 24, 48 and 72 h post-match. Magnitude-based inference and Cohen's effect size (ES) were used to analyze change over time and between-groups. Changes were unclear for the match loads, sprint times and perceptual markers between-groups. Higher %∆SJ at 24 h (very-likely[ES=0.75]) and in %∆PPO_SJ at 48 h (likely[ES=0.51]) were observed in CWI than in CON. Values in %∆RDF_CMJ were higher at post (likely[ES=0.83]), 30 min (very-likely[ES=0.97]) and 24 h (likely[ES=0.93]) in CWI than in CON. Furthermore, %∆LogTNF-α were lower in CWI than in CON group at post (almost-certainly[ES:-0.76]), 24 h (very-likely[ES:-1.09]) and 72 h (likely[ES:-0.51]) and in ∆stiffness_SJ at 30 min (likely[ES=-0.67]) and 48 h (very-likely[ES=-0.97]), as well as, different within-groups effects throughout post-match were reported. Implementing post-match CWI-based strategies improved the recovery of markers of inflammation and fatigue in Rugby players, despite no change in markers of speed or perceptual recovery.

10.
Int J Sports Physiol Perform ; : 1-19, 2018 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-30204512

RESUMO

PURPOSE: To examine the association and predictive ability of internal load markers with regards to non-contact injuries in young elite soccer players. METHODS: Twenty-two soccer players (18.6 ± .6 years) who competed in the Spanish U19 League participated in the study. During a full season, non-contact injuries were recorded and, using session rating of perceived exertion (s-RPE), internal weekly load (sum of load of all training sessions and matches for each week) and acute:chronic workload ratio (typically, acute = current week and chronic = rolling 4 week average) were calculated. A Generalized Estimating Equation analysis was used to examine association of weekly and acute:chronic load ratio markers with a non-contact injury in the subsequent week. Load variables were also analyzed for predictive ability with Receiver Operating Characteristic (ROC) curve and area under the curve (AUC). RESULTS: No association was found for weekly load (CI 1.00, .99 to 1.00) and acute:chronic load ratio (CI .16, .01 to 1.84) with respect to injury occurrence. In addition, the analyzed load markers showed poor ability to predict injury occurrence (AUC<.50). CONCLUSIONS: The results of this study suggest that internal load markers are not associated with non-contact injuries in young soccer players and present poor predictive capacity with regards to the latter.

11.
Rev. bras. med. esporte ; 24(5): 347-351, Sept.-Oct. 2018. graf
Artigo em Inglês | LILACS-Express | ID: biblio-977835

RESUMO

ABSTRACT Introduction: This study involved an analysis of the impact of mental fatigue on heart rate recovery (HRR), subjective measures of fatigue and intermittent running performance in handball players. Objective: This study was aimed at (1) examining the effects of an induced state of mental fatigue on the aerobic performance of handball players, as measured by the Yo-Yo IR1 test, and (2) exploring possible changes in heart rate regulation through HRR analysis. Methods: Twelve handball players (age: 17.50 ± 3.63 years; 5 ± 2.2 years of practice) undertook a Yo-Yo IR1 test on two occasions, separated by an interval of at least 72 hours. The Yo-Yo IR1 test was preceded by a 30-min treatment, consisting of the Stroop Color-Word Test, to induce mental fatigue. Participants in the control condition watched an emotionally neutral video. Results: Higher ratings of mental fatigue and mental effort following the Stroop Test were observed for the experimental group. No differences in motivation were observed between conditions. Moreover, the induction of mental fatigue impaired running performance and led to a higher RPE during the Yo-Yo IR1 test. Notwithstanding, no changes in HRR or blood lactate levels were observed across conditions. Conclusion: Altogether, these results suggest that mental fatigue impairs intermittent running performance, without affecting HRR values. Level of Evidence III; Case-Control study.


RESUMO Introdução: Este estudo envolveu uma análise do impacto da fadiga mental sobre a recuperação da frequência cardíaca (RFC), medidas subjetivas de fadiga e desempenho de corrida intermitente em jogadores de handebol. Objetivo: Este estudo visou (1) examinar os efeitos de um estado induzido de fadiga mental no desempenho aeróbico de jogadores de handebol, medido pelo teste Yo-Yo IR1 e (2) explorar possíveis alterações na regulação da frequência cardíaca através da análise da RFC. Métodos: Doze jogadores de handebol (idade: 17,50 ± 3,63 anos, 5 ± 2,2 anos de prática) realizaram um teste Yo-Yo IR1 em duas ocasiões, com pelo menos 72 horas de intervalo. O teste Yo-Yo IR1 foi precedido por tratamento de 30 minutos que consistiu no teste Stroop Color-Word para induzir estado de fadiga mental. Os participantes na condição de controle assistiram a um vídeo emocionalmente neutro. Resultados: Foram observadas taxas mais elevadas de fadiga mental e esforço mental após o teste Stroop para o grupo experimental. Não foram observadas diferenças na motivação entre as condições. Além disso, a indução de fadiga mental prejudicou o desempenho de corrida e levou a maior PSE durante o teste Yo-Yo IR1. Não obstante, não foram observadas alterações na RFC nem nas concentrações de lactato sanguíneo entre as condições. Conclusão: Em conjunto, esses resultados sugerem que a fadiga mental afeta o desempenho de corrida intermitente, sem alterar os valores de RFC. Nível de Evidência III; Estudo de caso-controle.


RESUMEN Introducción: En el presente estudio se analizó el impacto de la fatiga mental en la recuperación de la frecuencia cardíaca (RFC), las medidas subjetivas de fatiga y el rendimiento intermitente en atletas de handball. Objetivo: los objetivos de este estudio fueron (1) examinar los efectos de un estado inducido de fatiga mental en el rendimiento aeróbico de atletas de handball, medida por el Yo-Yo IR1, y (2) explorar las posibles alteraciones en la regulación de la frecuencia cardíaca a través del análisis RFC. Métodos: Doce atletas (edad: 17,50 ± 3,63 años, 5 ± 2,2 años de práctica) realizaron un test Yo-Yo IR1 en dos ocasiones, separados por un intervalo de al menos 72 horas. El test Yo-Yo IR1 fue precedido por un tratamiento de 30 minutos, consistente en el Stroop Color-Word Test, para inducir un estado de fatiga mental. Los participantes en la condición de control asistieron un video emocionalmente neutro. Resultados: Se observaron altas percepciones de fatiga y esfuerzo mental después del test de Stroop para el grupo experimental. No se observaron diferencias de motivación entre las condiciones. Además, la inducción de fatiga mental perjudicó el desempeño de carrera y llevó a un mayor PSE durante el test Yo-Yo IR1. No obstante, no se observaron alteraciones en la RFC y en las concentraciones de lactato sanguíneo entre las condiciones. Conclusión: En conjunto, estos resultados sugieren que la fatiga mental afecta el rendimiento intermitente de la carrera, sin alterar los valores de FCR. Nivel de Evidencia III; Estudio de caso-control.

12.
PLoS One ; 13(8): e0201111, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30110374

RESUMO

To better understand the detraining effects in soccer, the purpose of the study was to analyse if performance level of soccer players modulate repeated-sprint ability (RSA) and intermittent endurance changes during 2-weeks of detraining (i.e., in-season break). Seventeen professional and sixteen young elite soccer players of two different teams performed, before and after 2-weeks of detraining, the RSA test and the Yo-Yo Intermittent Recovery Test, level 1 (YYIR1). Before detraining, professional players perform better (p < 0.05) RSA best time (RSAbest) than young players. A decrease (p < 0.05) in RSAbest, RSA total time (RSAtotal) and mean time (RSAmean) performance was observed in both teams, without changes in RSA fatigue index (Sdec). No significant changes in distance covered during YYIR1 was observed in any team. Before detraining, faster players from both teams (FG) (following the median split technique, soccer players with RSAbest ≤ 3.95 s) performed better (p < 0.01) in RSAtotal, RSAmean and RSAbest, but worse (p < 0.01) in Sdec. Although FG and the slower players (SG, RSAbest > 3.95 s) showed a worse (p < 0.05) RSAtotal, RSAbest and RSAmean performance after detraining (ES = 1.5, 1.4 and 2.9; ES = 0.6, 1.2 and 0.6; for FG and SG, respectively), the deterioration was greater in the FG for RSAbest (p < 0.05) and RSAtotal (ES = 1.46). After detraining, FG improved (p < 0.05) Sdec performance. In conclusion, a 2-week in-season break (detraining) period induced a worse RSA, with no effect on intermittent endurance in professional and elite young soccer players, with greater detrimental effects on RSAtotal and RSAbest in FG. In addition, Sdec does not seem to be sensitive to changes in RSA after a 2-week in-season break.

13.
Int J Sports Med ; 39(11): 813-821, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30025419

RESUMO

The present study aimed to examine the reliability, usefulness, responsiveness, age-related differences and construct validity of a novel decision-making RSA test (RSA-RANDOM test) in young soccer players. Twenty-five young male soccer players performed the RSA-RANDOM test on 2 occasions separated by 5-7 days to assess test-retest reliability and determine a priori usefulness. Furthermore, the same players executed the RSA-RANDOM test 4 times throughout the season to analyse responsiveness. Forty-five players (U-13 to U-17) were evaluated in such test to examine age-related differences. Finally, 9 players were used to determine the construct validity of the test. Reliability scores showed a high intraclass correlation coefficient (ICC=0.88 to 0.90) and low coefficient of variation (CV=1.0-1.2%). The responsiveness of the RSA-RANDOM test was good, as the typical short- (1.2-1.9%), mid- (1.4-2.4%) and long-term (2.3-3.2%) changes in RSA-RANDOM performance were higher than the CV. Age-related differences analysis showed better RSA-RANDOM performance as age increased in young soccer players. Low (r=-0.50) to moderate (r=-0.75) relationships were found between the RSA-RANDOM test variables (RSA best and mean times) with high-intensity and total distance covered, respectively. A novel decision-making RSA test (RSA-RANDOM) has shown to be reliable and valid in young soccer players.


Assuntos
Desempenho Atlético/fisiologia , Tomada de Decisões , Teste de Esforço/métodos , Destreza Motora/fisiologia , Futebol/fisiologia , Adolescente , Fatores Etários , Criança , Humanos , Masculino , Reprodutibilidade dos Testes , Corrida/fisiologia , Futebol/psicologia
14.
Sports Biomech ; : 1-12, 2018 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-29578379

RESUMO

Knee peak torque (PT) is associated to jump performance in volleyball players. It is not clear whether muscle strength imbalances of the knee joint can influence jump performance. The purpose of study was to analyse the association between PT and knee muscular imbalances with jump performance in professional volleyball players. Eleven elite male volleyball players (90.3 ± 9.7 kg body mass and 1.94 ± 0.06 m height) were evaluated in an isokinetic dynamometer at speeds of 60, 180 and 300 deg/s. Muscle strength imbalances were obtained through calculation of contralateral deficit between limbs and the conventional ratio (hamstrings/quadriceps). Countermovement jump (CMJ) was performed on a force plate to calculate mechanical power and height. Association was found between knee extensor PT at 180 deg/s with CMJ power (r = 0.610, p = 0.046). Conventional ratio at 300 deg/s showed negative association with CMJ (r = -0.656, p = 0.029). The optimal ratio between knee extensors PT in relation to the flexors PT is associated with the greater mechanical power in CMJ. Contralateral deficit does not seem to be associated with the CMJ performance. Considering the knee extensor PT is associated with CMJ power, our findings suggest that strength-based training in volleyball athletes should not omit the conventional muscle ratio.

15.
Res Sports Med ; 26(2): 230-243, 2018 Apr-Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29384020

RESUMO

The purpose of the study was to analyse the effect of two warm-up protocols of different duration on physical performance, perceived load and perception of being ready for a match in handball players. Eighteen handball players were randomly divided into two groups (Wup34min, warm-up protocol of 34 min, Wup17min, warm-up protocol of 17 min). Before and after the warm-up protocols, they performed a battery of physical tests and recorded their perception of feeling ready for a match. At the end of the warm-up protocols, all the players evaluated their differentiated perceived effort (dRPE). The results showed that neither of the protocols significantly modified (p > 0.05) the players' physical performance. However, the Wup34min group showed higher values in the differentiated warm-up perceived load (dRPE-WL) (p < 0.01, TE = 0.97-1.27, high) than the Wup17min group. The players with a greater perceived muscular load (RPEMUSC) experienced a greater decrease in their acceleration capacity (r = 0.48-0.49, p < 0.05). In spite of the fact that neither of the warm-up protocols significantly modified the players' physical performance, a greater perceived muscular load may cause a greater decrease in acceleration capacity.


Assuntos
Desempenho Atlético/fisiologia , Desempenho Atlético/psicologia , Esportes/fisiologia , Esportes/psicologia , Exercício de Aquecimento , Fadiga , Humanos , Masculino , Mialgia , Percepção , Esforço Físico , Sono , Estresse Fisiológico , Adulto Jovem
16.
Int J Sports Med ; 39(3): 189-197, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29284166

RESUMO

There are several methods used in sports science to identify asymmetries in athletes, given their purported relevance to injury prevention and performance optimization. We aimed to verify whether asymmetries provided by isokinetic assessments, jump tests, and tensiomyography (TMG) are associated with each other, and whether their respective functional indices are related to jumping ability. TMG parameters, unilateral and bilateral squat-jump (SJ) and countermovement-jump (CMJ) performances, and peak torque in knee-extension and flexion with angular velocities of 60o/s and 300o/s for twenty-four soccer players were retained for analyses. Asymmetry was detected by examining the percentage difference between dominant and non-dominant legs. The median-split technique was used to identify the best and worst performers in SJ and CMJ tests. Results revealed that the asymmetries detected in the three different methods were not interrelated. Curiously, better performances in SJ and CMJ tests were associated with higher asymmetry levels. Furthermore, only the knee-extension peak torque at both angular velocities was correlated moderately to largely (r=0.48-0.66) with jump performance. Despite their recognized ability to predict the risk of injury, the absence of interrelationships between TMG, isokinetic tests, and unilateral jumps precludes their single use as a unique functional screening diagnostic. Finally, and very importantly, lower-limb asymmetry is not necessarily related to impaired vertical jump performance in soccer players.


Assuntos
Teste de Esforço/métodos , Extremidade Inferior/fisiologia , Força Muscular/fisiologia , Exercício Pliométrico , Traumatismos em Atletas/diagnóstico , Desempenho Atlético/fisiologia , Fenômenos Biomecânicos , Humanos , Joelho/fisiologia , Masculino , Miografia/métodos , Fatores de Risco , Torque , Adulto Jovem
17.
Rev. bras. cineantropom. desempenho hum ; 19(6): 652-662, Nov.-Dec. 2017. graf
Artigo em Inglês | LILACS | ID: biblio-897883

RESUMO

Abstract Aerobic energy transference is highly required and accounts for more than 90% of total energy consumption during a soccer match. In addition high aerobic fitness contributes to recovery from high-intensity intermittent exercise, specific to performance in soccer. The aim of the present study was to examine whether the peak velocity in the Carminatti's test (PVT-CAR) for prescribing interval-training drills is effective in eliciting aerobic-fitness development intensities in male soccer-players. Fifteen Brazilian male elite soccer-players (U20) were tested for T-CAR and monitored for heart rate (HR) during PVT-CAR prescribed interval-training drills (i.e., 4x4min with 3min passive recovery). Drills were performed with a 1:1 work-to-rest ratio with either straight-line (6/6s) or 180° shuttle running (12/12s). The interval training performed at PVT-CAR elicited HR above 90% of HRmax and lactate above 4m.mol.l-1. In the shuttle-running drills, HR and lactate (93.3±2.1% HRmax; 7.7±1.4 m.mol.l-1) were significantly higher than in the straight line drills (vs 90.3±2.6 %HRmax; 4.5±0.9 m.mol.l-1). The coefficient of variations showed low inter-subject variability in HR (CV 2.3 and 3.0% for 12/12 and 6/6 respectively). The results of this study demonstrated that PVT-CAR can be successfully used to individualize high-intensity interval running training in players with different aerobic profiles, while shuttle-running drills presented higher values at intern load than straight line. The physiological and time-motion profiles resemble the most demanding phases of the match, especially for the fittest players.


Resumo A transferência de energia aeróbia é altamente necessária e representa mais de 90% do consumo total de energia durante um jogo no futebol. Ademais, a alta aptidão aeróbia contribui para a recuperação durante exercício intermitente de alta intensidade, específico do desempenho do futebol. O objetivo deste estudo foi examinar se o pico de velocidade no teste de Carminatti (PVT-CAR) para a prescrição de treino intervalado é funcional na obtenção de desenvolvimento de aptidão aeróbia em jogadores de futebol. Quinze jogadores de futebol brasileiros (Sub-20) foram testados no T-CAR e monitorados por freqüência cardíaca (FC) durante o treinamento intervalado prescrito por PVT-CAR (ou seja, 4x4min com recuperação passiva de 3min). Os treinos foram realizados com uma relação de trabalho e repouso de 1:1 com corrida em linha reta (6/6s) e corrida de 180° com mudança de direção em vai-e-vem (12/12s). O treinamento intervalado prescrito com PVT-CAR induziu respostas de FC acima de 90% de FCmax, lactato superior a 4m.mol.l-1. uOs resultados de FC e lactato no treinamento de corrida com mudança de direção (93,3±2,1% FCmax; 7,7±1,4 m.mol.l-1) foram significativamente maiores que no treino de corrida em linha (vs 90,3±2,6 %FCmax; 4,5±0,9 m.mol.l-1). O coeficiente de variação mostrou baixa variabilidade inter-sujeitos na frequência cardíaca (CV 2,3 e 3,0% para 12/12 e 6/6, respectivamente). Os resultados do estudo mostraram que o PVT-CAR pode ser utilizado com sucesso para individualizar o treinamento de corrida intervalado de alta intensidade em jogadores com diferentes perfis aeróbicos. Os perfis fisiológicos e momentos de demandas se assemelham às fases mais exigentes da partida, especialmente para os jogadores melhor condicionados.


Assuntos
Humanos , Masculino , Adolescente , Futebol/fisiologia , Teste de Esforço/métodos , Consumo de Oxigênio
18.
Biol Sport ; 34(3): 273-278, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29158621

RESUMO

The aim of this study was to investigate the differences in loaded and unloaded jump performances between different age categories of top-level volleyball players from the same club. Forty-three volleyball players were divided into four age groups: under-17, under-19, under-21 and professional. Vertical jumping height for squat jump (SJ), countermovement jump (CMJ) and CMJ with arm swing (CMJa) and mean propulsive velocity (MPV) in the loaded jump squat exercise with 40% of the athlete's body mass were compared among the different age categories, considering body mass as a covariate. SJ and CMJ jump height values were higher for professional and under-21 players than under-17 players (p<0.05). CMJa height was higher for under-21 players than under-19 and under-17 players (p<0.05). MPV in the loaded jump squat was higher for under-21 players than under-17 players (p<0.05). From a general perspective, these results suggest that aging per se is not capable of substantially improving loaded and unloaded vertical jump performances across different age categories of top-level volleyball players. Therefore, to increase the vertical jumping ability of these team sport athletes throughout their long-term development, coaches and strength and conditioning professionals are encouraged to implement consistent neuromuscular training strategies, in accordance with the specific needs and physiological characteristics of each age group.

19.
Int J Sports Phys Ther ; 12(6): 977-985, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29158958

RESUMO

Background: The Functional Movement Screen (FMS™) is a widely used seven-test battery used by practitioners working in sport medicine. The FMS™ composite score (sum of seven tests) in soccer athletes from different competitive levels has been well explored in literature, but the specific movement deficits presented by young high competitive level players remains unclear. Purpose: The aim of the present study was to provide a detailed description of the performance of elite young soccer players (age 14-20 years) on the FMS™ testing battery. Study design: Cross-sectional observational study. Methods: One-hundred and three young soccer players (14-20 years) from a premier league club were assessed by two experienced raters using the FMS™ testing battery. FMS™ composite score, individual-test scores and asymmetries were considered for analysis, and comparisons between age categories were performed. Results: FMS™ composite scores ranged from 9 to 16 points (median=13 points). 82% of the athletes had a composite score ≤14 points, and 91% were classified into the "Fail" group (score 0 or 1 in at least one test). Almost half of athletes (48%) had poor performance (i.e., individual score < 2) in "deep squat" test. Most of athletes in the younger categories (under-15 and under-16) had poor performance in the "trunk stability push-up" test (70%) and in the "rotary stability" test (74%). Asymmetry in at least one of five unilateral FMS™ tests was found in 65% of athletes. Conclusion: High-performance young soccer players have important functional deficits, especially in tasks involving deep squat and trunk stability, as well as high prevalence of asymmetry between right and left body side. Level of evidence: 3a.

20.
J Strength Cond Res ; 2017 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-28902113

RESUMO

The purpose of the present study was to analyze the effects of two shuttle-run interval training (SRIT) models with one and three directional changes per running bout on the aerobic and anaerobic performances of elite female futsal players. Sixteen players competing in the Brazilian National Division League took part in the study. The training protocols consisted of shuttle-run intervals organized in four sets of 4-min bouts with 3- min of rest intervals between the sets. The SRIT models were composed of one (7.5 s running and 7.5 s pause [SRIT7.5x7.5]; n=7) or three (15 s running and 15 s pause [SRIT15x15]; n=9) directional changes. The athletes performed the following tests before and after a 5-week training period: incremental treadmill test (ITT), Futsal Intermittent Endurance Test (FIET) [with respective peak speeds (PS)] and a repeated sprint ability (RSA) test. After the training period, PSFIET and speed at the second lactate turnpoint were very likely and almost certainly increased in both training regimens, respectively. SRIT15x15 induced possibly greater improvements in PSITT (+3.28%, 90%CL -0.16 to 6.82) and RSAmean (+1.17%, 90% CL -0.68 to 3.05) than SRIT7.5x7.5. In addition, SRIT15x15 resulted in a likely greater improvement in running economy (+4.33%, 90% CL -0.35 to 9.23) compared with SRIT7.5x7.5. In elite female futsal players, SRIT15x15 is a promising strategy to enhance performance-related physical fitness attributes in a shortterm period (5 weeks) during the preseason, due to its superior effects on these important aerobic and anaerobic qualities than a protocol with fewer directional changes.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA