Figure 1. Overview of the within-subject design. Participants underwent two training periods, starting with either high-intensity interval training (HIIT) or moderate-intensity continuous training (MICT) and switched groups for the second period. This results in two sequences: MICT–HIIT (dotted line) and HIIT–MICT (dashed line). Comprehensive assessments were conducted at baseline, follow-up I, and follow-up II, including an incremental step test, paper-pencil questionnaires, and in-situ assessments via smartphone during a standardized vigorous-intensity continuous exercise (VICE) session.