Prediction of change in maximal aerobic power by the 2-km walk test after walking training in middle-aged adults.

The aim was to study the 2-km walk test's accuracy in predicting maximal aerobic power (VO2max) and its changes during 15-week walking training in 108 healthy middle-aged adults. Training prescription was 65-75% of VO2max 50 min/session, four times weekly. VO2max was measured walking on a treadmill and predicted from the 2-km walk test using gender-specific equations including age, body mass index, performance time and heart rate. The difference in VO2max between the walk test and the maximal exercise test before training was -0.9 ml x min(-1) x kg(-1) (SD 4.4) in men and -2.2 (3.5) in women. The total error was from 4.1 to 4.5 ml x min(-1) x kg(-1). After training the increase in measured VO2max was 2.9 ml x min(-1) x kg(-1) more in the walkers compared to the controls. The difference between the predicted and measured changes in VO2max during training ranged from -1.8 to -1.0 ml x min(-1) x kg(-1) between the study groups except in walking men, for whom the walk test overestimated the difference. The total error was from 3.1 to 4.9 ml x min(-1) x kg(-1). The 2-km walk test can be used as a reasonably accurate field test to predict changes in VO2max due to aerobic training in healthy nonathletic adults.