ISSN 0031-5125 DOI 10.2466/03.06.PMS.118k11w6 © Perceptual & Motor Skills 2014 Perceptual & Motor Skills: Physical Development & Measurement REPETITION DURATION INFLUENCES RATINGS OF PERCEIVED EXERTION 1, 2 RODRIGO C. R. DINIZ, HUGO C. MARTINS-COSTA, SANDRA C. MACHADO, FERNANDO V. LIMA, AND MAURO H. CHAGAS School of Physical Education, Physiotherapy and Occupational Therapy Federal University of Minas Gerais Summary.—This study investigated the effect of different repetition durations on ratings of perceived exertion (RPE) in active muscles (RPE-AM) and the overall body (RPE-O). 19 male volunteers ( M age = 25.4 yr., SD = 3.5) performed strength training protocols with multiple sets matched by the number of sets and repetitions, intensity and rest interval but different repetition durations: 4 sec., 6 sec., or self-paced. Partici- pants were asked to estimate their RPE-AM and RPE-O after each set. Training proto- cols with a 6-sec. repetition duration produced distinct responses on RPE during and after performance compared to 4-sec. and self-paced durations. However, there were no significant differences between 4-sec. and self-paced durations. Ratings of perceived exertion (RPE) have become a topic of interest in strength training research. Gearhart, Goss, Lagally, Jakicic, Gallagher, and Robertson (2001) found a linear RPE response using a Borg 15-Cat- egory Scale and strength training protocols of high and low intensities, with higher RPE observed in training protocols with higher intensities. This response has been found in strength training protocols that use single (Gearhart, Goss, Lagally, Jakicic, Gallagher, Gallagher, et al., 2002; Lagal- ly, Robertson, Gallagher, Goss, Jakicic, Lephart, et al., 2002) and multiple sets (McGuigan, Egan, & Foster, 2004; Focht, 2007), training protocols that include only one exercise (Lagally, McCaw, Young, Medema, & Thomas, 2004), and protocols with more than one exercise (Day, McGuigan, Brice, & Foster, 2004; Sweet, Foster, McGuigan, & Brice, 2004). However, this re- sponse is not consistent between studies. Egan, Winchester, Foster, and McGuigan (2006) evaluated the RPE in different training protocols using the squat exercise in which the number of sets, number of repetitions, and rest intervals were standardized across protocols. The training protocols contained differences in repetition dura- tions (i.e., time spent on performing the concentric and eccentric muscle actions during a repetition). A training protocol with 80% of one repetition maximum (1RM) was performed with the “traditionally” recommended repetition duration for strength training (this value was not reported), but 2014, 118, 1, 1-13. 1 Address correspondence to Mauro Heleno Chagas, Av. Presidente Antônio Carlos, nº 6627 CEP: 31270-901, Belo Horizonte, Brazil or e-mail (mauroufmg@hotmail.com). 2 The authors thank André Gustavo Pereira de Andrade, Ph.D., for assistance in the statistical analysis of this study.