HANDRAIL SUPPORTED TREADMILL TESTING: PRACTICAL ASSESSMENT AND APPLICATION

Oxygen uptake (VO2) estimates provided by treadmill time during Bruce graded exercise tests (GXT) are used to help physicians prescribe exercise for cardiac patients. These estimates are based on the assumption that patients do not use handrail support (HS) during the GXT. However, it is common for patients to grasp the handrail during these tests. Past research has demonstrated that this practice may alter the patient's energy expenditure during the Bruce test, thus decreasing the accuracy of VO2 estimates and subsequent exercise prescriptions. We found little evidence of studies examining the reliability and validity of standardized GXT protocols, with and without handrail support. PURPOSE: To 1) determine the reliability of Bruce GXTs performed with and without handrail support (HS vs NoHS), 2) determine whether submaximal (stage 2) cardiorespiratory and psychophysiologic responses differ between HS and NoHS conditions, and 3) predict NoHS treadmill time from treadmill time attained with HS. METHODS: Fifteen (age = 33.2 ± 9.4 yr) healthy men (n = 8) and women (n = 7) completed four Bruce GXTs were performed with HS and two with NoHS. Heart rate, blood pressure, respiratory gases, and ratings of perceived exertion (RPE) were measured during all tests. RESULTS: Treadmill time was significantly (p < 0.01) higher with HS (10.9 ± 2.8 min) vs NoHS (8.4 ± 1.7 min). Reliability was high (r = 0.96; CI = 0.88–0.98) for both HS (SEM = 0.6 min), and NoHS (SEM = 0.3 min) conditions. VO2, heart rate, and RPE were significantly higher (p < 0.01) at stage 2 of the GXTs in NoHS conditions. The model for predicting treadmill time (min) for NoHS is: Treadmill time (NoHS) = [Treadmill time (HS) *0.57] + 2.182 (r = 0.96 SEE = 0.50 min). CONCLUSION: Both handrail support and no support conditions were shown to be reliable methods of determining treadmill time at 85% of age predicted heart rate maximum during Bruce GXTs. Although submaximal physiological responses differed between HS and NoHS conditions, treadmill time without handrail support can be predicted accurately from Bruce GXT results obtained when subjects utilize the handrail.