Purpose The purpose of this study was to develop the new indirect method assessing maximal oxygen uptake (VO2max) using heart rate (HR) and accelerometer during walk exercise. Methods One hundred seven participants (55 male, 52 female) performed a graded exercise test to determine VO2max and two types of 1,600 m walk exercises (fast walk and pace controlled walk). The equations for estimating VO2max was developed by stepwise multiple regression. The validity of developed equations tested through the correlation between measured VO2max and estimated VO2max, was assessed by predicted residual sum of squares, and Bland-Altman plotting. Results VO2maxwas correlated with time, and HR/activity count per minute (ACM) measured in pace controlled walk exercise at all distance (400 m, 800 m, 1,200 m, 1,600 m). The equations were valid significantly and their multiple correlation coefficients or standard estimated error were similar to that Åstrand-Rhyming cycle ergometer test or Rockport 1 mile walk test. Using HR/ACM in pace controlled walk (400 m), it was possible to estimate VO2max(R2: 0.675, %SEE: 10.7). The equation was: VO2max=121.659+6.656×Gender-0.865×Age-9.540×Time-2460.952×HR/ACM (Gender, 0=female, 1=male: Time, hundredth of a minute: HR, heart rate: ACM, activity count per minute). Conclusion Estimation equations developed in this study are considered to estimate VO2max through a shorter distance, or a lower intensity of walk exercise. It is required studies to target a wide range of ages or to develop walk test on a lower bpm.
