The purpose of this paper is to estimate the effect of interdisciplinary teaching in physical
education (PE) on the interest of upper secondary students by considering the extent to which
different disciplines are integrated. Three interdisciplinary projects are studied and compared to their
discipline-based counterparts. Depending on the extent to which the disciplines are integrated, some
sequences are considered interdisciplinary (project 1), while others are considered multidisciplinary
(projects 2 and 3). The experimental design includes a total of 90 students and six teachers. Student
interest is measured using a situational interest (SI) scale and an individual interest (II) scale. Paired
t-tests show significant differences for Maintained-SI Feelings in PE (p = 0.008) in favor of the
interdisciplinary sequence for project 1 (PE and art), as well as for Maintained-SI Feelings (p = 0.004)
and Maintained-SI Value (p = 0.002) in art (project 1). However, when integration is limited (projects
2 and 3), higher Maintained-SI Feelings (p < 0.001) are measured in the disciplinary sequence during
the PE lessons. These results show that interdisciplinary sequences have positive effects on students’
interest when the disciplines are sufficiently integrated, indicating that training must be initially
developed and maintained accordingly.