Perceived exertion in different strength exercise loads in sedentary, active, and trained adults.

The aim was to analyze the relationship between the perceived exertion (PE) and different loads in strength exercises (SEs), in sedentary, active, and trained adult subjects. Thirty young men (18-34 years) were divided into 3 groups (experimental group [EG]): sedentary EG (SEG), physically active group (PAG), and the strength trained group (STG). Maximum strength was established using the 1 repetition maximum test (1RM). Using series of 12 repetitions, different loads were applied until the 4 ratings of PE (RPEs) (11, 13, 15, and 17) from 15 category Borg Perceived Exertion Scale (RPE 6-20). The pace of the repetitions and the intervals between the sets were controlled, the loads were blind, the order of the RPE randomized, whereas the PE was localized and determined after completion of the series. Strength correlations between the RPE and the %1RM, according to the EGs and SEs (0.826-0.922, p < 0.001), were observed. Similar behavior was seen in the SEs. Higher loads are related to higher RPEs and are differentiated between the EGs. The STG used higher %1RM when compared to the SEG, whereas the PAG, displayed an intermediary behavior in relation to the other groups. The use of PE represents a reliable instrument for the measurement of intensity in strength training.

Salivary hormonal responses to different water-based exercise protocols in young and elderly men.

Although adaptations to water-based resistance exercise and conventional water-based exercise have been investigated, little is known regarding acute anabolic and catabolic hormonal responses to these 2 types of exercise. The purpose of this study was to investigate the acute responses of salivary testosterone and cortisol to 2 water-based exercise protocols in which the different intensities were determined using Borg's perceived exertion scale. Ten young (24 +/- 2.7 yr) and 7 elderly men (65 +/- 5.5 yr) who were familiar with exercise in water were subjects of the study. Salivary samples were collected at rest and 5 minutes after the 2 water-based exercise protocols. One session involved intermittent water resistance training at a Borg-scale intensity of 19 (W19), whereas the other involved continuous water aerobic training at an intensity of 13 (W13). The samples were used to determine salivary levels of free testosterone and cortisol. There was a significant increase on salivary testosterone in both groups after the W19 protocol (p < 0.05), but no such alteration was observed after W13. The testosterone response to the W19 protocol was significantly higher in young than in elderly men (p < 0.05). Although no modification on salivary cortisol was observed after either protocol, in young men, the cortisol response to W19 was higher than in elderly men (p < 0.05). Water-based exercise with emphasis on strength development was found to stimulate a more acute increase on salivary testosterone than water-based aerobic exercise, probably as a result of the higher intensity used in that training protocol. Given the known relationship between acute hormonal responses and chronic neuromuscular adaptations, the testosterone response after W19 should be considered when prescribing water-based exercise, especially to older populations.