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The aim of this study was to analyze the technical-tactical performance profile of the serve for various age groups and categories of competition in men's volleyball. The sample comprised 13,262 serves performed by 986 players in 299 sets observed in various categories of competition (U-14, U-16, U-19, national senior, and international senior). An observational design was used. The variables studied were category of competition, type of execution, and serve performance. The results showed that for higher age groups (senior categories), there were significantly fewer jump serves and poorer serve performance, regardless of players' maturity and training development. The use of the jump serves increased the serve risk while attempting to hinder the organization of the opponent attack. This paper discusses the serve evolution and the implications on the training process at the different age groups in men's volleyball. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the effects of low-load, high-velocity resistance training (RT) combined with plyometrics on physical performance in pre-peak-height-velocity (PHV) soccer players. Methods: Thirty young soccer players from the same academy were randomly assigned to either a strength training (STG, n = 15) or a control group (CG, n = 15). Strength training consisted of full squat exercise with low load (45-58% 1RM) and low volume (4—8 repetitions/set) combined with jumps and sprints twice a week over 6 wk of preseason. The effect of the training protocol was assessed using sprint performance over 10 and 20 m, countermovement jump, estimated 1-repetition maximum, and average velocity attained against all loads common to pre- and posttests in full squat. Results: STG showed significant improvements (P = .004- 001) and moderate to very large standardized effects (ES = 0.71-2.10) in all variables measured, whereas no significant gains were found in CG (ES = -0.29 to 0.06). Moreover, significant test x group interactions (P < .003-001) and greater between-groups ESs (0.90-1.97) were found for all variables in favor of STG compared with CG. Conclusion: Only 6 wk of preseason low-volume and low-load RT combined with plyometrics can lead to relevant improvements in strength, jump, and sprint performance. Thus, the combination of field soccer training and lightweight strength training could be used for a greater development of the tasks critical to soccer performance in pre-PHV soccer players. [ABSTRACT FROM AUTHOR]

STUDY DESIGN: Clinical measurement study. BACKGROUND: Achilles tendinopathy is a prevalent sport-related injury. The Victorian Institute of Sport Assessment-Achilles (VISA-A) questionnaire is a widely used patient-reported outcome to assess the severity of symptoms for this injury. OBJECTIVE: To adapt the VISA-A questionnaire into Spanish and to assess its psychometric properties. METHODS: Cross-cultural adaptation was conducted according to recommended guidelines. The Spanish VISA-A (VISA-A-Sp) questionnaire was administered to 210 subjects: 70 healthy students, 70 active at-risk subjects (participating in running and jumping), and 70 patients diagnosed with Achilles tendinopathy. Participants were assessed at baseline and after 3 to 5 days. The injured subjects were also evaluated with a quality-oflife questionnaire (Medical Outcomes Study 36-Item Short-Form Health Survey [SF-36]) and at discharge. The final VISA-A-Sp was evaluated for reliability, validity, and responsiveness. RESULTS: Cronbach alpha for the VISA-A-Sp was greater than .8. The intraclass correlation coefficient (model 2,1) was 0.993 (95% confidence interval: 0.991, 0.995; P<.05). In the confirmatory factor analysis, a 1-factor solution obtained a relatively good fit. Subjects with Achilles tendinopathy scored significantly lower than the other 2 groups (P<.001). The VISA-A-Sp score within the Achilles tendinopathy group showed significant correlations with SF-36 physical components (Spearman rho>0.5, P<.001). The standard error of the measurement was 2.53, and the minimal detectable change at the 95% confidence level was 7 points. The responsiveness indicators included an effect size of 2.16 and a standardized response mean of 1.92. CONCLUSION: The VISA-A-Sp showed satisfactory psychometric properties that were comparable to the original English-language version. Therefore, it can be recommended for use in clinical practice and research for assessing the severity of symptoms in Spanish-speaking athletes who suffer from Achilles tendinopathy. [ABSTRACT FROM AUTHOR]

The main purpose of this study was to evaluate running kinematic characteristics and foot strike patterns (FSP) during early and late stages of actual and common high-intensity intermittent training (HIIT): 5 × 2000 m with 120-s recovery between runs. Thirteen healthy, elite, highly trained male endurance runners participated in this study. They each had a personal record in the half-marathon of 70 ± 2.24 min, and each had a minimum experience of 4 years of training and competition. Heart rate (HR) and rate of perceived exertion (RPE) were monitored during HIIT. High levels of exhaustion were reached by the athletes during HIIT (HRpeak: 174.30 bpm; RPE: 17.23). There was a significant increase of HRpeak and RPE during HIIT; nevertheless, time for each run remained unchanged. A within-protocol pairedt-test (first vs. last run) revealed no significant changes (P ≥ 0.05) in kinematics variables and FSP variables during HIIT. There were no substantial changes on kinematics and FSP characteristics in endurance runners after fatigue induced by a HIIT. Only the minimum ankle alignment showed a significant change. The author suggests that these results might be due to both the high athletic level of participants and their experience in HIIT. [ABSTRACT FROM AUTHOR]

This study aimed to compare the effect of 6 weeks of resistance training or combined resistance training and change of direction exercises on physical performance and motor skills in futsal players. Thirty-four futsal players were divided into full squat group (SG, n = 12), combined full squat and change of direction exercises group (S+CDG, n = 12) and control group (CG, n = 10). The resistance training for SG consisted of full squat with low load (∼45-58% 1RM) and low volume (4-6 repetitions), whereas the S+CDG performed the same resistance training program combined with loaded change of direction. Sprint time in 10 and 20 m, change of direction test, countermovement vertical jump (CMJ) height, maximal strength and force-velocity relationship in full squat exercise, kicking speed ball (BSmean ) and repeated sprint ability (RSAmean ) were selected as testing variables. Both experimental groups showed significant improvements for CMJ, BSmean and all strength parameters. Only SG resulted in significant sprint gains, whereas S+CDG also achieved significant improvements in RSAmean.The CG remained unchanged after training period. No significant differences were found between both experimental groups. These findings suggest that only 12 sessions of either lightweight resistance training alone, lifting the load at maximal intended velocity or combined with change of direction exercises is enough to improve several physical and skills capacities critical to futsal performance in adult players. [ABSTRACT FROM AUTHOR]

The effects of exercise on the core musculature have not been investigated in prepubescents. The main purpose of the present study was to determine the volume and degree of asymmetry ofrectus abdominis, obliquesandtransversus abdominis, quadratus lumborum, iliopsoas, gluteusandparavertebralismuscles in prepubescent tennis players and in untrained boys. The muscle volume was determined using magnetic resonance imaging (MRI) in 7 male prepubescent tennis players and 10 untrained controls (mean age 11.0 ± 0.8 years, Tanner 1–2). After accounting for height and body weight as covariates, the tennis players had 14–34% greater volume than the controls in all the muscles analysed (P < 0.05) except inparavertebralis, dominantquadratus lumborumand non-dominantgluteus, which had similar volumes in both groups (P = NS). Compared to controls, the tennis players displayed a greater degree of asymmetry inquadratus lumborumandrectus abdominis(3% vs. 15%,P < 0.01 and 8% vs. 17%,P = 0.06, respectively). The level of asymmetry ofobliquesandtransversus abdominis, iliopsoas, gluteus andparavertebralismuscles was similar in both groups (P = NS). In conclusion, tennis playing at prepubertal ages induces a selective hypertrophy of the core musculature and exaggerates the degree of asymmetry ofquadratus lumborumandrectus abdominiscompared to untrained boys. [ABSTRACT FROM PUBLISHER]

The aim of the present study was to analyse the training load in wheelchair basketball small-sided games and determine the relationship between heart rate (HR)-based training load and perceived exertion (RPE)-based training load methods among small-sided games bouts. HR-based measurements of training load included Edwards’ training load and Stagno’s training impulses (TRIMPMOD) while RPE-based training load measurements included cardiopulmonary (session RPEres) and muscular (session RPEmus) values. Data were collected from 12 wheelchair basketball players during five consecutive weeks. The total load for the small-sided games sessions was 67.5 ± 6.7 and 55.3 ± 12.5 AU in HR-based training load (Edwards’ training load and TRIMPMOD), while the RPE-based training loads were 99.3 ± 26.9 (session RPEres) and 100.8 ± 31.2 AU (session RPEmus). Bout-to-bout analysis identified greater session RPEmus in the third [P < 0.05; effect size (ES) = 0.66, moderate] and fourth bouts (P < 0.05; ES = 0.64, moderate) than in the first bout, but other measures did not differ. Mean correlations indicated a trivial and small relationship among HR-based and RPE-based training loads. It is suggested that HR-based and RPE-based training loads provide different information, but these two methods could be complementary because one method could help us to understand the limitations of the other. [ABSTRACT FROM PUBLISHER]