Body Composition Is Related to Maximal Effort Treadmill Test Time in Firefighters

Firefighting tasks may require near maximal levels of cardiorespiratory fitness. Previous research has indicated that body fat percentage (BF%) and aerobic capacity (VO2peak) are related to the performance of firefighting tasks. Since a standard submaximal treadmill test for firefighters is terminated at 85% of maximal heart rate (MHR), key performance information relating to maximal cardiorespiratory effort may not be measured in a submaximal test. The purpose of this study was to examine the relationships between body composition and time spent running at intensities greater that 85% MHR. Height, weight, body mass index (BMI; kg/m2), BF%, MHR (bpm), VO2peak (mL/kg/min), predicted VO2peak (P-VO2peak; mL/kg/min), submaximal treadmill test time (WFIsub Test Time; min), and maximal treadmill test time (WFImax Test Time; min) were collected in fifteen active-duty firefighters. The results indicated that significant relationships (p < 0.05) existed between BF% and VO2peak, BF% and WFImax Test Time, BF% and Tdiff, and VO2peak and WFImax Test Time. P-VO2peak was not significantly different than VO2peak, and the WFImax Test Time was significantly longer than the WFIsub Test Time. These results indicate that a submaximal treadmill test may reasonably predict VO2peak, but key information about physiological work at intensities greater than 85% MHR may be missed when using submaximal effort tests.