Validity of the baltimore therapeutic equipment work simulator in the measurement of lifting endurance in healthy men.

OBJECTIVE: To examine the criterion validity of the Baltimore Therapeutic Equipment (BTE) work simulator by comparing endurance time, oxygen uptake (VO2), and heart rate measured during real and simulated lifting tasks and to derive a regression equation for predicting actual lifting endurance from measurements on the work simulator. METHOD: Twenty healthy male volunteers repetitively lifted and lowered a load of 40 lb using the BTE work simulator and actual weights at a laboratory workstation. Postures, location, and frequency of lifts were kept constant. Endurance (defined as the time taken for the rating of perceived exertion to increase 2 units on the Borg scale) was measured under both conditions. VO2 and heart rate were also recorded, using standard physiological procedures. RESULTS: The mean values for endurance time, steady-state VO2, and heart rate were significantly different between the real and simulated tasks (p < .05). Correlation of endurance time between the two tasks was significant (r = .71, p < .05). Step wise regression analysis resulted in the following equation for predicting real endurance from simulated time measurements: predicted real time = .34 simulated time + 3.29; r = .71; SE = 1.00 min. CONCLUSION: The BTE work simulator tends to overestimate real lifting endurance performance in healthy men. The lower physiological stress during the simulated task suggests a significant difference between the real and simulated loads. Occupational therapists should exercise caution when using the results of the BTE work simulator during functional capacity evaluations.