(Context: 61 y/o male, 162 pounds, 5'7")
I can row 500 m and stay focused and keep the pace in the range of 2:05-2:15.
I can go to 1000m and perform in a pretty similar range (say 2:10-2:20).
But when we do these assessments that involve rowing for 15 or 20 minutes, I just fall apart...