Body mass to predict 4-6 rm of pectoral and leg muscles exercises in bodybuilders / Predicción de 4-6 rm de ejercicios de piernas y pectorales por masa corporal / Predição de 4-6 rm de exercicios de perna e peitoral pela massa corporal

ABSTRACT Introduction: Submaximal strength testing appears to be valid to prescribe the intensity for strength training protocols that reduce the risk of injuries and testing time. Objective: This study aimed to assess the predictive ability of body mass parameters to estimate 4-6 repetitions maximum (4-6 RM) of Leg press 45°, Chest press, and Pull-down exercises. Methods: Eleven male bodybuilders (age 38.27 ± 10.48 years) participated in this study. Participants completed an incremental external load up to find the load allowing them to perform 4 to 6 maximal repetitions for each exercise in random order. The starting load was 50% of body mass for chest press and pull-down exercises and 100% for leg press. The load increment after each set was 20 kg for lower limb exercises and 10 kg for upper body exercises. Results: Results revealed that body mass had good to optimal relationships with 4-6 RM for all three exercises. Results showed that body mass had a good prediction ability for all three criterion measures. Conclusion: The prediction equations suggested in this study may allow coaches to estimate the 4-6 RM of leg press 45°, chest press, and pull-down performances. Evidence Level IV; Case series.

RESUMEN Introducción: El test de fuerza submáxima parece ser válido para prescribir la intensidad en protocolos de entrenamiento de fuerza, reduciendo el riesgo de lesiones y la duración del test. Objetivo: Evaluar la capacidad predictiva de los parámetros de masa corporal para estimar 4-6 repeticiones máximas (4-6 RM) de ejercicios de Leg press 45°, Chest press y Pull-down realizados por fisicoculturistas. Métodos: Once fisicoculturistas masculinos (38,27 ± 10,48 años) participaron en el estudio. Completaron la carga externa incremental hasta encontrar la carga que les permitiera realizar de 4 a 6 repeticiones máximas para cada ejercicio, en orden aleatorio. La carga inicial se fijó en el 50% de la masa corporal para los ejercicios Chest press y Pull-down, y en el 100% para los ejercicios Leg press. El incremento de carga después de cada ronda fue de 20 kg para los miembros inferiores y 10 kg para los miembros superiores. Resultados: Los resultados revelaron que la masa corporal tiene relaciones satisfactorias con 4-6 RM para los tres ejercicios. Los resultados mostraron que la masa corporal tiene una buena capacidad predictiva en las tres medidas. Conclusión: Las ecuaciones de predicción sugeridas en este estudio pueden permitir a los entrenadores utilizar estos ejercicios para medir el rendimiento a 4-6 RM en ejercicios de Leg press 45°, Chest press y Pull-down. Nivel de Evidencia IV; serie de casos.

RESUMO Introdução: O teste de força submáxima parece ser válido para prescrever a intensidade nos protocolos de treinamento de força, reduzindo o risco de lesões e duração dos testes. Objetivo: Avaliar a capacidade preditiva dos parâmetros de massa corporal para estimar o exercício de 4-6 repetições máximas (4-6 RM) nos exercícios de Leg press 45°, Chest press e Pull-down efetuados por fisiculturistas. Métodos: Onze fisiculturistas masculinos (38,27 ± 10,48 anos) participaram do estudo. Eles completaram a carga externa incremental até encontrar a carga que lhes permitia realizar de 4 a 6 repetições máximas para cada exercício, em ordem aleatória. A carga inicial foi fixada em 50% da massa corporal para os exercícios de Chest press e Pull-down, e 100% para o de Leg press. O incremento de carga após cada rodada foi de 20 kg para o exercício de membros inferiores e 10 kg em membros superiores. Resultados: Os resultados revelaram que a massa corporal apresenta relações satisfatórias com 4-6 RM para todos os três exercícios. Os resultados mostraram que a massa corporal possui boa capacidade preditiva em todas as três medidas. Conclusão: As equações de previsão sugeridas nesse estudo podem permitir o uso desses exercícios pelos técnicos para medir a performance a 4-6 RM nos exercícios de Leg press 45°, Chest press, e Pull-down. Nível de evidência IV; série de casos.

Electromyographic analysis of riding posture during the bicycling start moment

Abstract Professional cyclists often adopt a competition-start standing posture, which has been shown to improve performance. The biomechanical basis of this is unclear, and might be due to a greater mechanical advantage or increased key muscle activity. Previous observations in steady state cycling showed greater activation of the tibialis anterior, erector spinae, and biceps brachii when adopting a standing vs. seated-riding posture. Little is known regarding the effect of riding posture on activation during a standing start. Eleven cyclists performed standing starts in seated and standing-postures using stationary-cycle and on the track. Electromyography of the gastrocnemius medialis, tibialis anterior, erector spinae, and biceps brachii was recorded during first and subsequent pedal strokes. Results showed that the gastrocnemius medialis did not modify activity. The tibialis anterior, erector spinae, and biceps brachii activity was increased during the standing posture compared to seated, only during the first pedal stroke. These increased activation intensities were accompanied by a corresponding 10% increase in bike speed during the first 5 meters following a standing start in the standing posture compared to the seated one. Adopting a standing posture during a standing start improves performance through greater initial acceleration.