Sustained attention
Staying with a chosen target over time instead of drifting after the first minutes.
Sustained attention is less about intensity and more about continuity — returning after a lapse instead of abandoning the session.
Larger Schulte grids and timed focus sessions lean on this skill. Short, frequent runs usually beat rare marathon sessions.
If your times worsen mid-session, you have likely left training and entered grinding; stop, rest, and resume tomorrow.