Ildefonso Alvear-Ordenes

Changes in oxidative stress markers and NF-κB activation induced by sprint exercise

This study was aimed to investigate changes in blood markers of oxidative damage induced by short-term supramaximal anaerobic exercise and to determine whether oxidative stress was associated to activation of the redox-sensitive transcription factor nuclear factor-κB (NF-κB). Both a single Wingate test (WAnT) test and series of four WAnTs separated by 60 min rest intervals were carried out by eight professional cyclists. Leukocyte 8-OH-2-deoxyguanosine levels were significantly elevated 24 h after both exercise protocols. A significant decrease in blood reduced glutathione (GSH) concentration was observed immediately after and at 15, 60 and 120 min of the single WAnT, followed by a return to basal value after 24 h. This decrease was parallel to a significant increase of the oxidised/reduced glutathione (GSSG/GSH) ratio, to an activation of NF-κB and to a significant decrease in the protein level of its inhibitor IκB. GSH concentration and the GSSG/GSH ratio changed significantly for the first three of the WAnTs series and normalised thereafter. A significant activation of NF-κB and a decrease in the IκB protein level were also detected. We conclude that short-term supramaximal anaerobic exercise induces oxidative stress, as evidenced by non cumulative damage to macromolecules and changes in the glutathione status. Our data also indicate that high intensity anaerobic work gives rise to an activation of the transcription factor NF-κB accompanied by a degradation of IκB.

Early explosive force reduction associated with exercise-induced muscle damage.

This study was aimed to analyze the loss of muscle explosive force in the early phase of eccentric exercise-induced damage, and its possible relationships with muscle soreness and blood creatine kinase (CK) levels. Squat jump (SJ) and counter-movement jump (CMJ) heights decreased in response to an eccentric exercise (120 eccentric actions of the knee extensors), with reductions that persisted at least for 24 h. The SJ/CMJ ratio was not significantly modified. Blood CK levels changed significantly over time and CK activity was significantly higher at 6 and at 24 h when compared to values obtained immediately after the eccentric exercise. Muscle soreness perceived at 6 h was slightly higher than that experienced just after finalizing the exercise and reached a clearly upper value at 24 h. A highly significant relationship between SJ and CMJ height loss was observed. CK activity at 24 h was significantly related to the SJ height loss at 6 h and to both the SJ height loss and the CMJ height loss immediately after the exercise. In summary, eccentric exercise induced a reduction in the explosive force generating capacity that affected in a similar way the pure concentric jump (SJ) and the jump eliciting the stretch-shortening cycle (CMJ). Results obtained suggest that CK activity is a better predictor of explosive force reduction than soreness, at least when values close to the peak are used.ResumenEn el presente estudio se analiza la pérdida de fuerza explosiva en la fase temprana del daño inducido por un ejercicio excéntrico, y su posible relación con el dolor muscular y los niveles plasmáticos de creatina quinasa (CK). La altura de salto, tanto estático (SJ) como reactivo (CMJ), disminuyó en respuesta al ejercicio excéntrico (120 contracciones excéntricas de los extensores de la rodilla), con reducciones que persistieron durante al menos 24 h. La relación SJ/CMJ no experimentó modificación alguna. Los niveles plasmáticos de CK cambiaron significativamente a lo largo del tiempo, siendo mayores a las 6 y a las 24 horas que al finalizar el ejercicio excéntrico. El dolor muscular percibido a las 6 horas fue significativamente mayor que el experimentado justo al finalizar el ejercicio y alcanzó un valor claramente superior a las 24 h. Se observó una alta correlación entre la pérdida de altura de SJ y la pérdida de altura CMJ. La concentración plasmática de CK a las 24 h mostró una correlación significativa con la pérdida de altura SJ a las 6 h, así como con la pérdida de altura SJ y CMJ inmediatamente después del ejercicio. En resumen, el ejercicio excéntrico indujo una reducción en la capacidad del músculo de generar fuerza de forma explosiva, que afectó en igual medida al salto concéntrico puro (SJ) y al salto que incluye ciclo, estiramiento-acortamiento (CMJ). Los resultados obtenidos sugieren que la concentración plasmática de CK predice mejor la reducción de fuerza explosiva inducida por el ejercicio excéntrico que el dolor muscular, principalmente cuando se usan valores cercanos al pico.

EFFECTS OF CREATINE SUPPLEMENTATION IN TAEKWONDO PRACTITIONERS

INTRODUCTION Taekwondo (TKD) is a combat sport, which has also been proposed as a fitness program, with a strong anaerobic component. Creatine (Cr) supplementation is used to improve both anaerobic exercise performance and body composition. Therefore, Cr supplementation could be beneficial in TKD. AIMS To determine the effect of Cr supplementation (50 mg/kg body wt) on body composition, anaerobic power and blood chemistry in young male TKD practitioners. METHODS Ten male TKD practitioners (age [20 ± 2 yr], height [1.69 ± 0.06 m], and mass [67 ± 9.8 kg]) participated in a placebo-controlled, double blind, crossover study. Body composition (DEXA), anaerobic power (Wingate Test), blood lactate and blood chemistry were measured before and after supplementation. Differences between data before and after supplementation were calculated for each treatment (Cr and Placebo) and were compared using the Wilcoxon signed-rank test. RESULTS Fat mass (kg) decreased after placebo (Mdn [IqR] = -0.75 [-1.44 to 0.03]) and increased following Cr intake (0.17 [-0.77 to 1.13] kg) (Z = 2.191, p < 0.028, r = 0.49). Serum triglyceride concentration (mg/mL) increased after Cr (45.00 [-7.50 to 75.00]) and decrease with placebo (-7.00 [-10.75 to 12.00]) (Z = 2.090, p < 0.037, r = 0.47). No changes were found in others parameters. CONCLUSION Cr supplementation may increase fat mass and serum triglycerides concentration in young male TKD practitioners without improvement in anaerobic power. Cr supplementation appears to be safe, but athletes should be careful when they want to loss fat.

Maximal strength on different resistance training rowing exercises predicts start phase performance in elite kayakers.

Abstract Ualí, I, Herrero, AJ, Garatachea, N, Marín, PJ, Alvear-Ordenes, I, and García-López, D. Maximal strength on different resistance training rowing exercises predicts start phase performance in elite kayakers. J Strength Cond Res 26(4): 941–946, 2012—This study aimed to examine the relationship existing between maximum strength values in 2 common resistance training row exercises (bilateral bench pull [BBP] and one-arm cable row [OACR]) and short sprint performance in elite kayakers. Ten junior kayakers (5 women and 5 men) were tested on different days for 1 repetition maximum (1RM) and maximal voluntary isometric contraction in both exercises. Moreover, a 12-m sprint kayak was performed in a dew pond to record split times (2, 5, and 10 m), peak velocity, distance completed considering the first 8 strokes, and mean acceleration induced by right blade and left blade strokes. No differences (p > 0.05) were observed when right and left arms were compared in sprint testing or strength testing variables. Maximal strength values in BBP and OACR were significantly correlated with short sprint performance variables, showing the bilateral exercise with slightly stronger correlation coefficients than the unilateral seated row. Moreover, the relationship between strength testing and sprint testing variables is stronger when maximal force is measured through a dynamic approach (1RM) in comparison with an isometric approach. In conclusion, maximal strength in BBP and OACR is a good predictor of the start phase performance in elite sprint kayakers, mainly the 1RM value in BBP.

El B-hidroxi-B-metilbutirato (HMB) como suplemento nutricional (II): mecanismos de acción moleculares y celulares

INTRODUCTION In recent years, several investigations have related -hydroxy--methylbutyrate (HMB) to a reduced muscle proteolysis and to an increase in muscle mass. Therefore, a number of studies focused on the cellular and molecular mechanisms regulating these effects have been carried out. AIMS The objectives of this review are: to know both HMB metabolism and toxicity, and to identify HMB cellular and molecular mechanisms of action when used as a dietary supplement. METHODS A search was performed in the Web of Science, Pubmed and SportDiscus data bases. RESULTS were divided into two parts; this article presents aspects referring to HMB mechanisms of action. RESULTS There is insufficient evidence that HMB intake increases muscle cholesterol synthesis. It probably has positive effects on muscle metabolism through both the mTOR and ubiquitin-proteasome pathways, although the mechanism of action is unknown. HMB may increase blood levels of -hydroxybutyrate and this could explain the main effects of HMB on muscle proteolysis. CONCLUSION According to these results, the possibility of justifying the action of HMB through the beta-hydroxybutyrate pathway opens an interesting line of research for future studies.

Valoración isocinética del hombro en jóvenes nadadores mediante un patrón diagonal

Resumen La evaluacion isocinetica del hombro de la manera mas funcional posible, es mediante la reproduccion de patrones diagonales semejantes a los aplicados durante procedimientos de facilitacion neuro-muscular propioceptiva. El objetivo de nuestro trabajo es el estudio comparativo de la valoracion isocinetica del hombro, segun genero, mediante el patron diagonal D2, en jovenes nadadores promesas. 18 nadadores (9 mujeres y 9 varones), diestros, y entrenados por el mismo entrenador fueron valorados mediante el dispositivo dinamometro Biodex System 3 ® segun modo concentrico a 180°/s y a 60°/s de velocidad, de acuerdo al patron diagonal D2. Se utilizaron los accesorios especificos para evaluacion de diagonales, y el eje de rotacion orientado a traves de la articulacion glenohumeral. En el analisis estadistico de los grupos de datos se aplico el programa informatico Statgraphics Plus 4.0 ® . La magnitud de todas las variables isocineticas estudiadas (peak torque, peak torque/peso corporal, trabajo y potencia) fue mayor durante el movimiento de E/AD/RI, con diferencias estadisticamente significativas con el movimiento de F/AB/RE. Esto se observo en el lado dominante y no dominante, en las dos velocidades estudiadas y en ambos generos. La natacion se presenta como un deporte que logra un desarrollo armonico de ambos segmentos y en ambos generos, a diferencia de otros deportes asimetricos.