Author(s): FUJITA, K., ADACHI, T., YOKOYAMA, T., MARUTANI, Y., Institution: THE UNIVERSITY OF OSAKA, Country: JAPAN, Abstract-ID: 2171

INTRODUCTION:
The UKK Walk Test (UKKWT) is a cardiorespiratory endurance test developed in Finland in the 1990s that can accurately predict maximal oxygen uptake (VO2max) by walking 2 km at full effort and even pace. However, the predictive ability of VO2max by the UKKWT has not been fully examined in Japanese subjects. This study aimed to improve the prediction equation of VO2max by the UKKWT for Japanese subjects (UKKWT_J) and to compare its predictive ability with the original version of Oja et al. (UKKWT_O).
METHODS:
The subjects were 40 healthy Japanese men and 42 women aged 20–65 years. The VO2max was measured during uphill walking on a treadmill. The test protocol followed the method of Laukkanen et al. Respiratory gases were analyzed using the Aero Monitor AE-310S (Minato Medical Science Co., Ltd., Japan). The UKKWT was conducted according to the UKK Walk Test Testers Guide. In the UKKWT, VO2max was predicted from the time taken to walk 2 km at 80% HRR, the heart rate at the end of the walk, BMI, and age. To develop a prediction equation for VO2max in Japanese individuals, multiple regression analysis was conducted using the above four parameters of the UKKWT as independent variables, with measured VO2max as the dependent variable. A paired-t test was used to compare the measured and predicted VO2max and the predictive ability of VO2max by the UKKWT_O vs UKKWT_J were compared using the root mean square error (RMSE) and the coefficient of variation (C.V.).
RESULTS:
The measured VO2max was 43.3 ± 6.7 ml/kg/min in men and 33.5 ± 5.8 ml/kg/min in women. The VO2max predicted by the UKKWT_O was 40.3 ± 7.7 ml/kg/min in men and 30.3 ± 5.0 ml/kg/min in women. A significant difference was observed between the measured VO2max and predicted VO2max by the UKKWT_O (p<0.001). In contrast, the VO2max predicted by the UKKWT_J was 43.4 ± 5.4 ml/kg/min in men and 33.3 ± 4.1 ml/kg/min in women, showing no difference from the measured VO2max. The RMSE and C.V. of the VO2max predicted by the UKKWT_O were 5.2 ml/kg/min and 12.0% in men and 5.4 ml/kg/min and 16.0% in women, respectively. In contrast, they were 3.8 ml/kg/min and 8.8% in men and 4.0 ml/kg/min and 12.1% in women, respectively, in the UKKWT_J. The predictive ability of VO2max was better in the UKKWT_J than in the UKKWT_O.
CONCLUSION:
In the present study, the VO2max prediction equation by the UKKWT was improved for Japanese subjects. As a result, we were able to construct a model that could predict VO2max more accurately than the original test, in both men and women. However, there was still a problem of an error of approximately 10% for the average of the measured VO2max. Further improvement of the prediction accuracy of VO2max is needed for the social implementation of the UKKWT_J in the future.

References:
Oja P et al. (1991). Int J Sports Med, 12(4), 356-362.
Laukkanen RMT, et al. (1999). Int J Sports Med, 20, 113-116.