Effect of unilateral and bilateral resistance exercise on maximal voluntary strength, total volume of load lifted, and perceptual and metabolic responses.

The present study investigated the effect of unilateral and bilateral resistance exercise (RE) on maximal voluntary strength, total volume of load lifted (TVLL), rating of perceived exertion (RPE) and blood lactate concentration of resistance-trained males. Twelve healthy men were assessed for the leg extension one-repetition maximum (1RM) strength using bilateral and unilateral contractions. Following this assessment, an RE session (3 sets of repetitions to failure) was conducted with bilateral and unilateral (both limbs) contractions using a load of 50% 1RM. The TVLL was calculated by the product of the number of repetitions and the load lifted per repetition. RPE and blood lactate were measured before, during and after each set. Session RPE was measured 30 minutes after RE sessions. There was a significant difference in the bilateral (120.0±11.9) and unilateral (135.0±20.2 kg) 1RM strength (p < 0.05). The TVLL was similar between both RE sessions. Although the repetitions decreased with each successive set, the total number of repetitions completed in the bilateral protocol (48) was superior to the unilateral (40) protocol (p < 0.05). In both bouts, RPE increased with each subsequent set whilst blood lactate increased after set 1 and thereafter remained stable (p < 0.05). The RPE and lactate responses were not significantly different between both sessions. In conclusion, a bilateral deficit in leg extension strength was confirmed, but the TVLL was similar between both RE sessions when exercising to voluntary fatigue. This outcome could be attributed to the number of repetitions completed in the unilateral RE bout. The equal TVLL would also explain the similar perceptual and metabolic responses across each RE session.

Validade e reprodutibilidade de receptores para o GPS em relação à distância percorrida / Validez y reproducibilidad de receptores GPS en relación de la distancia recorrida

Objetivo. El presente estudio evaluó la validez y reproducibilidad de dos modelos de receptores para el Global Positioning System (GPS). La validez fue evaluada comparando la distancia registrada por los receptores con la distancia conocida de estos trayectos. Método. Seis jóvenes tenistas (177,6 ± 6,2 cm; 76,6 ± 3,2 kg) recorrieron tres trayectos: 1) 100 m en la pista de atletismo (número de "disparos" = 120); 2) 400 m en la pista de atletismo (número de "disparos" = 60) y 3) 100 m con cambios de dirección (número de "disparos" = 120), utilizando los equipos Garmin© Forerunner 405 y Polar© RS800. Resultados. En los trayectos sin cambios de dirección (100 y 400 m), a través de la ANOVA two way (distancia y velocidad) no se detectaron diferencias entre la distancia conocida y las distancias registradas por los receptores analizados (p > 0,05). En el trayecto de 100 m con cambios de dirección, se observaron diferencias entre la distancia conocida y las registradas tanto por el Polar© RS800 como por el Garmin© Forerunner 405 (p < 0,05). También se verificó la diferencia en las distancias registradas por el Polar® RS800 y por el Garmin© Forerunner 405 para el trayecto realizado con cambios de dirección (p < 0,05). Conclusión. A través de los datos, se puede afirmar que los receptores para GPS evaluados presentaron un nivel aceptable de precisión para distancias recorridas sin cambios de dirección, sin embargo, la precisión de estos equipos en trayectos con cambios de dirección fue limitada (AU)

Objective. The present study evaluated the reproducibility and validity of two models of receivers for the Global Positioning System (GPS). Validity was assessed by comparing the distance recorded by the GPS receivers with the known distance. Method. Six young players (177.6 ± 6.2 cm; 76.6 ± 3.2 kg) performed three routes with different characteristics: 1) 100 m in the athletics track (number of "sprints" = 120); 2) 400 m in the athletics track (number of "sprints" = 60) and 3) 100 m with changes of direction (number of "sprints" = 120), using equipment Garmin© Forerunner 405 and Polar© RS800. Results. Regarding linear routes (100 and 400 m), no differences were detected using ANOVA two-way (distance and speed) between the known distance and distance recorded by GPS receivers analyzed (p > 0.05). Regarding non-linear route of, significant differences were observed between the known distance and recorded distance by the GPS receivers (p < 0.05). There was also a significant difference between the distance recorded by Polar© RS800 and Garmin© Forerunner 405 for the non-linear route (p < 0.05). Analysis of the limits of agreement reinforces the limitation of equipment in relation to accuracy for the non-linear route. Conclusion. These data suggest that the GPS receivers evaluated showed acceptable level of accuracy for linear routes, however, the accuracy of such devices on non-linear routes was limited (AU)

Planejamento e monitoramento da carga de treinamento durante o período competitivo no basquetebol / Planning and monitoring training loads during an in-season basketball period

El estudio tuvo como objetivo examinar las correlaciones entre la dificultad de partidos (dificultad prevista al principio de la temporada [DP] y la dificultad actualizada a cada partido [DA]) y la carga interna de entrenamiento en microciclo anterior al partido (CIT-A) de 12 jugadores profesionales de baloncesto (25,3 ± 4,8, masa corporal 97,6 ± 14,9 kg, altura de 195,8 ± 10,2 cm) durante una temporada de competición. CIT-A se determinó por el método de la PSE del sesión. La relación entre DP, DA y CIT-A se analizó mediante el coeficiente de correlación de Pearson. Se encontró fuerte correlación (r = 0,86) entre DA y PD (p <0,05), así como entre la DP y CIT-A (r = -0,59) y DA y CIT-A (r = -0.65). El coeficiente más alto de correlación entre DA y CIT-A sugiere que la dificultad prevista al comienzo de la temporada (DP) debe actualizarse durante la temporada de competición, y por lo tanto puede proporcionar información valiosa para la planificación y control de las cargas de entrenamiento en microciclos que preceden a los partidos oficiales(AU)

This study aimed to examine the relationships between the difficulty of the matches (difficulty scheduled at the beginning of the season [DBS] and the in-season match difficulty [DIS]) and the weekly internal training load (ITL) in twelve professional male basketball players (25.3 ± 4.8 years, 97.6 ± 14.9 kg, and 195.8 ± 10.2 cm) during a in-season period. DBS was determined before the commencement of the competitive season, and DIS due to reassessing DBS on a weekly basis. ITL was determined by means of session-RPE method. Significant correlations (p < 0.05) were verified between DBS and DIS (r = 0.86), DBS and ITL (- 0.59), and DIS and ITL (- 0.65). The greater coefficient of relationship between DIS and ITL suggest a key role of reassessing the difficulty of the matches on a weekly basis to provide appropriate information to coaches regard planning and monitoring in-season training loads(AU)

The acute effects of strength, endurance and concurrent exercises on the Akt/mTOR/p70S6K1 and AMPK signaling pathway responses in rat skeletal muscle

The activation of competing intracellular pathways has been proposed to explain the reduced training adaptations after concurrent strength and endurance exercises (CE). The present study investigated the acute effects of CE, strength exercises (SE), and endurance exercises (EE) on phosphorylated/total ratios of selected AMPK and Akt/mTOR/p70S6K1 pathway proteins in rats. Six animals per exercise group were killed immediately (0 h) and 2 h after each exercise mode. In addition, 6 animals in a non-exercised condition (NE) were killed on the same day and under the same conditions. The levels of AMPK, phospho-Thr172AMPK (p-AMPK), Akt, phospho-Ser473Akt (p-Akt), p70S6K1, phospho-Thr389-p70S6K1 (p-p70S6K1), mTOR, phospho-Ser2448mTOR (p-mTOR), and phospho-Thr1462-TSC2 (p-TSC2) expression were evaluated by immunoblotting in total plantaris muscle extracts. The only significant difference detected was an increase (i.e., 87%) in Akt phosphorylated/total ratio in the CE group 2 h after exercise compared to the NE group (P = 0.002). There were no changes in AMPK, TSC2, mTOR, or p70S6K1 ratios when the exercise modes were compared to the NE condition (P ≥ 0.05). In conclusion, our data suggest that low-intensity and low-volume CE might not blunt the training-induced adaptations, since it did not activate competing intracellular pathways in an acute bout of strength and endurance exercises in rat skeletal muscle.