Decreases in the number of repetitions between sets is indicative of concentric failure in strength training with trained men

Abstract

The practice of strength training (ST) promotes several benefits such as increased strength, endurance, muscle strength, hypertrophy, as well as changes in body composition. Concentric failure (CF)Several studies show that exercise until CF may be more efficient in promoting positive adaptations about hypertrophy and muscle strength, however, it is still unclear at which time of the exercise CF is achieved. The number of repetitions (NR) performed in each set may be influenced by fatigue caused by CF training. The objective was to analyze the response of the NR between sets as indicative of CF within a session of ST. The study included fourteen trained men (25.0 ± 3.5 years old) (5 ± 4 years) who performed three sets with 75% of 1(repetition maximum) (RM) until CF with fixed rest interval between sets. Statistical analysis: Data normality was tested according to the Shapiro-Wilk test. Subsequently the one-way ANOVA of repeated measures was used to compare the variance of the means between the moments and, when necessary, the post hoc test was used for multiple comparisons using Bonferroni correction. Percentage variations of decreasing NR between sets were found, being from the 1st vs. 2nd set (45,3 ± 14,6 %;), 2nd vs. 3rd set (41,4 ± 19,5%), and 1st vs. 3rd set (67,8 ± 15,1%). The NR can be used to identify if the exercise is being performed up to the CF, considering that the NR between sets decreases substantially due to acute metabolic changes.