Validity of a newly-designed rectilinear stepping ergometer submaximal exercise test to assess cardiorespiratory fitness

The maximum oxygen uptake (vo2max),determined from graded maximal or submaximal exercise tests,is used to classify the cardiorespiratory fitness level of individuals. the purpose of this study was to examine the validity and reliability of the ymca submaximal exercise test protocol performed on a newly-designed rectilinear stepping ergometer (rse) that used up and down reciprocating vertical motion in place of conventional circular motion and giving precise measurement of workload,to determine vo2max in young healthy male adults. thirty-two young healthy male adults (32 males; age range: 20 - 35 years; height: 1.75 ± 0.05 m; weight: 67.5 ± 8.6 kg) firstly participated in a maximal-effort graded exercise test using a cycle ergometer (ce) to directly obtain measured vo2max. subjects then completed the progressive multistage test on the rse beginning at 50w and including additional stages of 70,90,110,130,and 150w,and the rse ymca submaximal test consisting of a workload increase every 3 minutes until the termination criterion was reached. a metabolic equation was derived from the rse multistage exercise test to predict oxygen consumption (vo2) from power output (w) during the submaximal exercise test (vo2(ml ∙ min-1) = 12.4 x w(watts) + 3.5 ml ∙ kg-1 ∙ min-1 × m + 160ml ∙ min-1,r2 = 0.91,standard error of the estimate (see) = 134.8ml ∙ min-1). a high correlation was observed between the rse ymca estimated vo2max and the ce measured vo2max (r=0.87). the mean difference between estimated and measured vo2max was 2.5 ml ∙ kg-1 ∙ min-1,with an see of 3.55 ml ∙ kg-1 ∙ min-1. the data suggest that the rse ymca submaximal exercise test is valid for predicting vo2max in young healthy male adults. the findings show that the rectilinear stepping exercise is an effective submaximal exercise for predicting vo2max. the newly-designed rse may be potentially further developed as an alternative ergometer for assessing cardiorespiratory fitness and the promotion of personalized health interventions for health care professionals. © journal of sports science and medicine.