Role of the monocarboxylate transporter MCT1 in the uptake of lactate during active recovery.

PURPOSE: We assessed the role of monocarboxylate transporter 1 (MCT1) on lactate clearance during an active recovery after high-intensity exercise, by comparing genetic groups based on the T1470A (rs1049434) MCT1 polymorphism, whose influence on lactate transport has been proven. METHODS: Sixteen young male elite field hockey players participated in this study. All of them completed two 400 m maximal run tests performed on different days, followed by 40 min of active or passive recovery. Lactate samples were measured immediately after the tests, and at min 10, 20, 30 and 40 of the recoveries. Blood lactate decreases were calculated for each 10-min period. Participants were distributed into three groups according to the T1470A polymorphism (TT, TA and AA). RESULTS: TT group had a lower blood lactate decrease than AA group during the 10-20 min period of the active recovery (p = 0.018). This period had the highest blood lactate for the whole sample, significantly differing from the other periods (p ≤ 0.003). During the passive recovery, lactate declines were constant except for the 0-10-min period (p ≤ 0.003), suggesting that liver uptake is similar in all the genetic groups, and that the difference seen during the active recovery is mainly due to muscle lactate uptake. CONCLUSIONS: These differences according to the polymorphic variant T1470A suggest that MCT1 affects the plasma lactate decrease during a crucial period of active recovery, where the maximal lactate amount is cleared (i.e. 10-20 min period).

Harmonization of anthropometric measurements for a multicenter nutrition survey in Spanish adolescents.

OBJECTIVE: Although the need for accurate anthropometric measurement has been repeatedly stressed, reports on growth and physical measurements in human populations rarely include estimates of measurement error. We describe the standardization process and reliability of anthropometric measurements carried out in a pilot study. METHODS: For the intraobserver assessment of anthropometric measurements, we studied 101 adolescents (58 boys and 43 girls) from five cities. For interobserver assessment, we studied 10 adolescents from the same class in Zaragoza and different from those in the intraobserver sample. RESULTS: For skinfold thickness, intraobserver technical errors of measurement (TEMs) in general were smaller than 1 mm; for circumferences, TEMs in general were smaller than 1 cm. Intraobserver reliability for skinfold thickness was greater than 95% for almost all cases; for circumferences, intraobserver reliability generally was greater than 95%. Interobserver TEMs ranged from 1 to 2 mm for the six skinfold thicknesses measured; for circumferences, TEMs were smaller than 1 cm for the arm, biceps, and waist and between 1 and 2 cm for the hip and thigh. Interobserver reliabilities for skinfold thickness and circumference were always greater than 90%, except for biceps skinfold. CONCLUSIONS: Our results are in agreement with those recommended in the literature. Therefore, these anthropometric measures seem to be adequate to assess body composition in a multicenter survey in adolescents.

La influencia del uso del protector bucal sobre el VO2 máx. Y la frecuencia cardiaca en jugadores de hockey sobre hierba / The influence of mouth protector on max. VO2 and on heart rate in field hockey players

Con frecuencia se observa el uso de protectores bucales en determinadas disciplinas deportivas con el objeto de prevenir las lesiones dentales. El propósito del presente estudio está en determinar la influencia que puede tener el uso de estos protectores sobre el rendimiento aeróbico del jugador de Hockey sobre Hierba, así como comprobar si existen variaciones en los registros de la frecuencia cardiaca. Diez jugadores de Primera División Nacional de Hockey sobre Hierba tomaron parte en el estudio, a todos ellos se les determinó de manera indirecta mediante el protocolo de Bruce y col. (1973) en tapiz rodante el consumo máximo de oxígeno con y sin el uso del protector bucal. Se les realizó igualmente el registro de la frecuencia cardiaca en cada estadio del protocolo. El análisis de los datos obtenidos entre los sujetos con relación al consumo máximo de oxígeno con y sin el uso del protector bucal, muestra diferencias significativas favorables en el consumo máximo de oxígeno con el uso del protector bucal (r = 0,93) (IC - 95 por ciento = 0,73 - 0,98) (F= 52,3112) (p < 0,001). Los resultados obtenidos en el análisis de correlación de los valores medios de la frecuencia cardiaca en los diferentes estadios muestran diferencias significativas con el empleo del protector bucal, provocando una reducción de la frecuencia cardiaca en esfuerzos submáximos. Con los datos que aporta este estudio podemos llegar a la conclusión de que el uso del protector bucal no sólo no disminuye la potencia aeróbica máxima del jugador de Hockey sobre Hierba, sino que observamos una mejoría significativa del mismo; igualmente el empleo del protector bucal reduce la frecuencia cardiaca en esfuerzos submáximos. Teniendo en cuenta este estudio podemos afirmar la importancia que puede tener el uso del protector bucal, en el rendimiento aeróbico del jugador de Hockey sobre Hierba durante la competición (AU)