The effect of Two-equal Volume Training Protocols upon strength, body composition and salivary hormones in strength trained males
Resistance training has been used extensively for improving muscle strength and athletic performance. Researchers have reported that training volume was one of the most important variables for improving strength and performance. This has been highlighted by greater performance improvements when performing three sets per exercise compared to a single set. Two commonly used training protocols are the full body (FB) and split body (SB) protocols, both of which have been used by athletes to improve training adaptations. However, very little research has directly compared the effects of FB and SB protocols. Muscle tissue growth is one important aspect of the adaptive process with testosterone (T), the main anabolic hormone, and cortisol (C), the primary catabolic hormone, being key contributors. Although many training studies have compared the effects of different protocols upon performance and hormones, none have been equated for training volume. Therefore, this study sought to examine the effects of two equi-volume training protocols (FB and SB) upon strength, body composition and hormones (resting T and C) in strength-trained males. Using a crossover study design, twenty four strength-trained males (mean 29.8 ± 6.8 years; mean 92.9 ± 12.2 kg) with a minimum of two years resistance training experience were randomly allocated into either a FB or SB training protocol. All subjects performed each protocol for four weeks separated by an eight-week wash-out period. Each training protocol involved three weekly workouts with the same number of sets and repetitions performed across each week. Rest periods were 60 seconds between sets and 90 seconds between exercises. Saliva samples were collected to assess the T and C responses to training. Body composition was assessed by skinfold assessments and maximal strength was determined by one repetition maximum (1RM) assessments. Dependent t-tests were used to analyse within-group changes in the outcome variables, while independent t-tests were used to analyse the between-group differences in these variables. Statistical significance was set at an alpha level of p < 0.05. There were a number of significant within-group changes, in particular, both protocols showed significant increases in strength (p < 0.01) and decreases in fat mass (p < 0.05) and percent body fat (p < 0.05). The resting hormonal responses were less consistent with SB producing significant increases in Sal-T (p < 0.05), while there were no significant changes in Sal-C (p > 0.05) after both training protocol. There was also a significant difference (p < 0.05) between training protocols observed for the Sal-T/C ratio. Both the FB and SB training protocols appeared to be effective during a four week training period with similar strength and body composition changes observed. There were differences in our hormonal data but these results may have been due to differences in baseline levels. Future research should address the possible effects of longer training periods using the same training protocols examined in this study. This analysis would provide a better understanding of the underlying stimulus for subsequent training adaptations. It also appears that using a high weekly training volume and training frequency (three or more training sessions per week) may provide a greater stimulus for muscle hypertrophy and strength improvements compared to performing one or two training sessions per week.