Subjects vs Instructor Perceived Training Load in TRX Fitness Activity

Introduction The use of suspension straps (TRX) has recently become a popular form of exercise in fitness centers as a form of resistance training, designed to train stable body positions (McGill et al 2014). Rating of perceived exertion (RPE) and muscular pain (RMP) are widely used as estimate of exercise intensity and to quantify training load in sport activities. Few studies have investigated their applicability in fitness activities (Cortis et al 2013). Moreover, a lack of correspondence between the training load as designed by coaches and as executed by athletes has been demonstrated (Foster et al 2001), although comparable information has not-been reported on fitness activities. Therefore, the aim of this study was to compare instructor’s and subjects’ perceptions of training load in TRX. Methods Following informed consent, 58 volunteers (M=21; F=37) regularly (3 weekly sessions) practicing TRX, participated in the study. RPE, upper (RMPU) and lower (RMPL) limb values were recorded for each subject (RPEs, RMPUs, RMPLs) 30-min following the exercise session (Foster et al 1995). Instructors filled in the rating of intended exertion (RPEi) and muscle pain (RMPUi, RMPLi) for each participant based on class observation. Differences (p<0.05) between subjects’ and instructor’s values (RPEs vs RPEi; RMPUs vs RMPUi; RMPLs vs RMPLi) were tested by means of repeated measures and Pearson correlations. Results There were no differences between subjects’ and instructor’s values for RPE and RMPL, while RMPUi (6.2±1.5) was higher (p=0.02) than RMPUs (5.4±2.3). Correlations were weak to moderate between subjects’ and instructor’s (RPE: r=0.5, R2=0.3, p<0.0001; RMPU: r=0.6, R2=0.3, p<0.0001; RMPL: r=0.4, R2=0.1, p<0.004), with subjects (RPEs: 6.5±1; RMPLs: 5.5±1.8) perceiving training less intense than the instructors (RPEi: 6.8±1.6; RMPLi: 6.2±1.8). Discussion The present findings indicate reasonable correspondence between subjects’ and instructor’s RPE and RMPU, although weak correlation was found with respect to RMPL. RPEi and RMPUi could be a useful and practical method to monitor training load during TRX. RMPLi should be used cautiously, although it has to be considered that RMPU and RMPL strongly depend on the specific exercises and muscle involved during the session. References Cortis C et al (2013) Ital J Anat Embryol, 118: 64. Foster C et al (1995) Eur J Appl Physiol, 70: 367-372. Foster C et al (2001) S Afr J Sports Med, 8: 3-7. McGill SM et al (2014) J Strength Cond Res, 28: 105-116.