Validity of a V·O2maxPrediction Equation of the 2-km Walk Test in Female Seniors

Walking is a useful exercise mode for most adults due to its general ease, acceptability, and safety. Therefore, many field tests based on performance in walking have been developed to predict V.O (2 max). Even if these tests are much easier to perform than laboratory tests, field tests have to be valid. The objective of the paper was to explore the accuracy and bias of a V.O (2 max) prediction equation of the 2-km Walk Test, in an active female senior group (n=18, mean age: 66.1+/-4.4). V.O (2 max) (l . min (-1)) was measured during cycle ergometry by direct gas analysis from a maximal test (step: 30 W, time: 2 min 30). V.O (2 max) related to body mass was then calculated (ml . min (-1) . kg (-1)). Subjects completed also the 2-km Walk Test (UKK Institute). V.O (2 max) (ml . min (-1) . kg (-1)) was then predicted from age, sex, body mass index, heart rate, and walking time measured during the 2-km Walk Test. Predicted V.O (2 max) and measured V.O (2 max) were highly correlated (r=0.63, p<0.01). Predicted V.O (2 max) (20.5+/-6.1 ml . min (-1) . kg (-1)) was not significantly different from measured V.O (2 max) (18.7+/-3.4 ml . min (-1) . kg (-1)). Prediction equation bias with its 95 % limits of agreement was - 1.8+/-4.8 ml . min (-1) . kg (-1) with a coefficient of variation of 24.2 %. In an active female senior population, the 2-km Walk Test offers a fairly accurate V.O (2 max) prediction. The training and learning effects can be neglected because when the test was repeated no significant bias was observed between the two trials.