Psychometric properties of the stage of change scales for walking and cycling to school among Spanish children and adolescents

Introduction Active commuting to school (ACS) is a feasible and sustainable way to increase daily physical activity among youth. However, validated and context-specific measures of behavioural readiness remain limited. This study examined the reliability and predictive validity of two single-item scales assessing stage-based behavioural readiness for walking and cycling to school in Spanish youth: the Stage of Change for Walking to and from School (SC-W) and the Stage of Change for Cycling to and from School (SC-C). A secondary aim was to describe the distribution of participants across stages of change for walking and cycling by age group and gender. Methods A total of 372 students (13.1 ± 2.4 years, 52% girls) participated in this study. Of these, 333 provided valid SC-W data and 322 valid SC-C data. Both scales were administered twice over a 14 day interval. Test-retest reliability was evaluated using weighted kappa, and predictive validity for walking was tested using logistic regression models using the Stage of Change score as a predictor of usual walking to school. Results Reliability was moderate to substantial for both scales (SC-W: κ = 0.558, 95% CI [0.441,0.668]; SC-C: κ = 0.552, 95% CI [0.436,0.670]). Predictive validity was supported for walking among adolescents (B = 0.997, OR = 2.71, R 2 = 0.331, p < 0.001), with higher stages associated with a greater likelihood of walking to school. Among children, the association was weaker and not statistically significant (B = 0.237, OR = 1.27, R 2 = 0.045, p = 0.060). Walking was common among adolescents, whereas cycling was rarely reported. Conclusion The SC-W and SC-C scales showed acceptable reliability. Predictive validity was supported for walking, especially among adolescents, while cycling could not be tested due to low prevalence. These brief scales may provide low-burden tools to assess stage-based behavioural readiness toward ACS, particularly for walking among adolescents, although further validation is needed, especially for cycling behaviours and younger populations.