Figure 2. Correlation analysis between Feeling scale (FS) and heart rate (A), exercise enjoyment scale (B) and rating of perceived exertion (C) during 70%HIIE (•), 85%HIIE (■) and 100%HIIE (♢) work intervals. Abbreviations: Ventilatory threshold (VT), which is denoted by the vertical dotted line. * Significantly negative correlations. # Significantly positive correlations. See text for details.