Category Ratio Ratings of Perceived Exertion is Not Related to the Stress of a Squat Resistance Exercise Workout as Reflected By Heart Rate and Load Intensity

INTRODUCTION: Perception of effort is a key factor in understanding the strain and stress of an exercise bout. The purpose of this study is to examine the relationships among ratings of perceived exertion (RPE), heart rate (HR), load used, among each set and with a total resistance exercise workout. METHODS: 137 untrained healthy subjects (consisting of 81 men [(mean ± standard deviation) age 22 ± 4.1, weight 81 ± 13.9kg, and height 180 ± 6.7cm] and 56 women [age 23 ± 3.7, weight 65 ± 11.4kg, and height 163 ± 7.1cm]) volunteered for the study and completed a 1 repetition maximum (1 RM) strength test and acute resistance exercise test (ARET). The ARET consisted of 6 sets of 1 0 repetitions using a Smith-squat within a computerized ballistic power system (Lismore, Australia) at 60% of their 1 RM, with 2 minutes of rest between each set. HR and RPE were obtained after each set. The load was adjusted to complete each 1 0 repetition set. Subjects gave RPE ratings using the Borg CR-10 with magnitude estimation scale. Significance was set at P ^ 0.05. RESULTS: Heart rate and RPE significantly increased for every set of the ARET in both men and women. For the total workout no apparent sex-related differences occurred. For the whole workout there were significant (P < 0.05) correlations between: set & HR (a = .000, r = .331), set & RPE (a = .000, r = .662), HR & Load (a = .040, r = -.073), HR & RPE (ex = .000, r = .291), and Load & RPE (a = .000, r = -.131). For individual sets a different pattern was observed. Set 1 : No significant relationships found among HR, load, or RPE. Set 2: No significant relationships found among HR, load, or RPE. Set 3: HR & RPE (a = .041 , r = .1 77) and Intensity & RPE (a = .037, r = -.1 79) were significant. Set 4: HR & RPE (a = .028, r = .190) were significant. Set 5: HR & Load (a = .021, r=-.201) were significant. Set 6: Load & RPE (a = .009, r = -.228) were significant. CONCLUSIONS: In a squat resistance exercise protocol, a low degree of the shared variance is explained with any of the variables measured in this study. This relationship is even worse when one examines individual sets. Thus, the use of RPE in untrained individuals during a resistance exercise protocol only explains the actual stress they are experiencing during the workout. This may be due to the intermittent nature of the exercise stress and differences in the recovery capability in untrained individuals. PRACTICAL APPLICATIONS: Surprisingly in a large group of u