Reference equation for the incremental shuttle walk test in Japanese adults

The incremental shuttle walk test (ISWT) is widely used in clinical and research settings. However, there are no reference equations to predict the walk distance achieved in the ISWT (ISWD) for healthy Japanese adults. We aimed to establish a reference equation for the ISWD prediction in Japanese adults.

The sample comprised 590 healthy Japanese subjects (237 male). All subjects performed the ISWT twice, and their anthropometric and demographic data were collected, including gender, age, height, weight, and body mass index (BMI).

Subjects walked 640 [490-793] m in the ISWT. The ISWD correlated (p < 0.001 for all) with age (r = - 0.51), gender (r = 0.56), weight (r = 0.39), and height (r = 0.62), but not with BMI (r = - 0.01, p = 0.74). The stepwise multiple regression model showed that age, gender, and height were independent contributors to the ISWT in healthy subjects, explaining 50% of the variability. The reference equation for the ISWD was: ISWD(m) = - 4.894 - 4.107 × Age (years) + 131.115 × Gender + 4.895 × Height (cm), where male gender = 1.

We have established a reference equation for the ISWD prediction in Japanese adults. The prediction accuracy was high (R² = 50%), and a reference equation was established using anthropometric and demographic variables that can be easily assessed in clinical settings. The reference equation developed in this study will be useful for evaluating the magnitude of exercise intolerance in Japanese adults.