[Purpose] The aim of this study was to determine the acute effect temporal of a complex training protocol on 30 meter sprint times. A secondary objective was to evaluate the fatigue indexes of military athletes. [Subjects and Methods] Seven military athletes were the subjects of this study. The variables measured were times in 30-meter sprint, and average power and peak power of squats. The intervention session with complex training consisted of 4 sets of 5 repetitions at 30% 1RM + 4 repetitions at 60% 1RM + 3 repetitions of 30 meters with 120-second rests. For the statistical analysis repeated measures of ANOVA was used, and for the post hoc analysis, student’s t-test was used. [Results] Times in 30 meter sprints showed a significant reduction between the control set and the four experimental sets, but the average power and peak power of squats did not show significant changes. [Conclusion] The results of the study show the acute positive effect of complex training, over time, in 30-meter sprint by military athletes. This effect is due to the post activation potentiation of the lower limbs’ muscles in the 30 meters sprint.

Beta-alanine supplementation (BA) has a positive impact on physical performance. However, evidence showing a benefit of this amino acid in aerobic–anaerobic transition zones is scarce and the results controversial. The aim of this systematic review and meta-analysis is to analyze the effects of BA supplementation on physical performance in aerobic–anaerobic transition zones. At the same time, the effect of different dosages and durations of BA supplementation were identified. The search was designed in accordance with the PRISMA® guidelines for systematic reviews and meta-analyses and performed in Web of Science (WOS), Scopus, SPORTDiscus, PubMed, and MEDLINE between 2010 and 2020. The methodological quality and risk of bias were evaluated with the Cochrane Collaboration tool. The main variables were the Time Trial Test (TTT) and Time to Exhaustion (TTE) tests, the latter separated into the Limited Time Test (LTT) and Limited Distance Test (LDT). The analysis was carried out with a pooled standardized mean difference (SMD) through Hedges’ g test (95% CI). Nineteen studies were included in the systematic review and meta-analysis, revealing a small effect for time in the TTT (SMD, −0.36; 95% CI, −0.87–0.16; I2 = 59%; p = 0.010), a small effect for LTT (SMD, 0.25; 95% CI, −0.01–0.51; I2 = 0%; p = 0.53), and a large effect for LDT (SMD, 4.27; 95% CI, −0.25–8.79; I2 = 94%; p = 0.00001). BA supplementation showed small effects on physical performance in aerobic–anaerobic transition zones. Evidence on acute supplementation is scarce (one study); therefore, exploration of acute supplementation with different dosages and formats on physical performance in aerobic–anaerobic transition zones is needed.

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ResumenIntroducción: la nutrición parenteral (NP) en la infancia es un tratamiento cuyas características son muy variables en función de la edad y la patología que presente el paciente. Material y métodos: el grupo de Estandarización y Protocolos de la Sociedad Española de Nutrición Parenteral y Enteral (SENPE) es un grupo interdisciplinar formado por miembros de la SENPE, Sociedad Española de Gastroenterología, Hepatología y Nutrición Pediátrica (SEGHNP) y Sociedad Española de Farmacia Hospitalaria (SEFH) que pretende poner al día este tema. Para ello, se ha realizado una revisión pormenorizada de la literatura buscando las evidencias que nos permiten elaborar una Guía de Práctica Clínica siguiendo los criterios del Oxford Centre for Evidence-Based Medicine. Resultados: este manuscrito expone de forma resumida las recomendaciones en cuanto a indicaciones, vías de acceso, requerimientos, modifi caciones en situaciones especiales, componentes de las mezclas, prescripción y estandarización, preparación, administración, monitorización, complicaciones y NP domiciliaria. El documento completo se publica como número monográfi co. Conclusiones: esta guía pretende servir de apoyo para la prescripción de la NP pediátrica. Constituye la base para tomar decisiones en el contexto de la evidencia existente. Ninguna guía puede tener en cuenta todas las circunstancias clínicas individuales. Abstract

Background: The purpose of this study was to determine the reliability for the strength and movement velocity of the concentric phase from the five Sit-to-Stand (5STS), using three incremental loads measured by a functional electromechanical dynamometer (FEMD) in healthy young adults. Methods: The average and peak strength and velocity values of sixteen healthy adults (mean ± standard deviation (SD): age = 22.81 ± 2.13 years) were recorded at 5, 10 and 15 kg. To evaluate the reliability of FEMD, the intraclass correlation coefficient (ICC), standard error of measurement (SEM) and coefficient of variation (CV) were obtained. Results: Reliability was high for the 10 kg (CV range: 3.70–4.18%, ICC range: 0.95–0.98) and 15 kg conditions (CV range: 1.64–3.02%, ICC: 0.99) at average and peak strength, and reliability was high for the 5 kg (CV range: 1.71–2.84%, ICC range: 0.96–0.99), 10 kg (CV range: 0.74–1.84%, ICC range: 0.99–1.00) and 15 kg conditions (CV range: 0.79–3.11%, ICC range: 0.99–1.00) at average and peak velocity. Conclusions: The findings of this study demonstrate that FEMD is a reliable instrument to measure the average and peak strength and velocity values during the five STS in healthy young adults.

(Rev Med Chile 2017; 145: 972-979)

The purpose of this study was to investigate the acute effect of pre-activation with Variable Intra-Repetition Resistance and isometry on the overhead throwing velocity in handball players. Fourteen female handball players took part in the study (age: 21.2 ± 2.7 years, experience: 10.9 ± 3.5 years). For Post-Activation Potentiation, two pre-activation methods were used: (I) Variable Intra-Repetition Resistance: 1 x 5 maximum repetitions at an initial velocity of 0.6 m·s-1 and a final velocity of 0.9 m·s-1; (II) Isometry: 1 x 5 s of maximum voluntary isometric contraction. Both methods were "standing unilateral bench presses" with the dominant arm, using a functional electromechanical dynamometer. The variable analysed was the mean of the three overhead throws. Ball velocity was measured with a radar (Stalker ATS). The statistical analysis was performed using ANOVA with repeated measures. No significant differences were found for either method (variable resistance intra-repetition: p = 0.194, isometry: p = 0.596). Regarding the individual responses, the analysis showed that 86% of the sample increased throwing velocity with the variable resistance intra-repetition method, while 93% of the sample increased throwing velocity with the isometric method. Both the variable intra-repetition resistance and isometric methods show improvements in ball velocity in female handball players. However, the authors recommend checking individual responses, since the results obtained were influenced by the short rest interval between the pre-activation and the experimental sets.

BACKGROUND: The maintenance of maximal aerobic speed (MAS) until exhaustion is an important parameter for the evaluation of sports performance and prescription and planning of training. OBJECTIVE: To validate a 6-minute race test (6MRT) as a predictor of MAS in university endurance athletes. METHODS: Twenty two university endurance athletes (12 males and 10 females) were part of the study. The design was pre-experimental. The primary variables were the time of maintenance of the MAS on the field through a Time Limit Test (Tlim test), and the VO2 max (laboratory and field). The statistical analysis of the time and ventilatory variables was carried out using descriptive statistics; the comparison between males and females for all variables was carried out through a t-Student test for independent samples (p< 0.05). RESULTS: The performance in the Tlim test was 356.4 ± 52.9 and 327.0 ± 120.2 s in males and females, respectively. CONCLUSION: Based on the time of maintenance of the MAS (Tlim test), the 6MRT is a valid test to determine the MAS in university endurance male athletes. However, the MAS in university endurance female athletes must be evaluated with a shorter test (between 5 and 5.30 minutes long).