Prediction of aerobic capacity in firefighters using submaximal treadmill and stairmill protocols

Accurate assessments of aerobic capacity are essential to ensuring the health and well-being of firefighters, given their arduous and stressful working conditions. The use of a submaximal protocol, if proven accurate, addresses concerns such as administrative cost, time, and ease of test performance. The purposes of this study were to develop and validate graded submaximal and maximal stairmill protocols and to develop accurate maximal and submaximal equations to predict peak VO2 using both the stairmill and Gerkin treadmill protocols. Fifty-four subjects, men (36.3 +/- 5.6 years) and women (36.4 +/- 6.3 years), performed maximal graded exercise tests using both the stairmill and Gerkin treadmill protocols. Significant predictors of peak VO2 included body mass index, time to completion for maximal protocols, and time to 85% of predicted maximal heart rate for submaximal protocols. Maximal prediction equations were more accurate on both the treadmill (R = 0.654, standard error of the estimate [SEE] = 3.73 ml x kg(-1) x min(-1)) and stairmill (R = 0.816, SEE = 2.89 ml x kg(-1) x min(-1)) than developed submaximal prediction equations for both the treadmill (R = 0.325, SEE = 5.20 ml x kg(-1) x min(-1)) and stairmill (R = 0.480, SEE = 4.85 ml x kg(-1) x min(-1)). Both of the newly developed submaximal prediction equations more accurately predict peak VO2 than the current Gerkin equation. In summary, we support the use of both the stairmill and treadmill as a means for aerobic assessment in this population. The use of the developed submaximal prediction equations should lead to a reduced cost and time of assessment; however, direct measurement of maximal oxygen consumption remains the better alternative.