2,000 m row
Row 2,000 meters on the erg, for time. Use the same damper setting every test.
The 2k is the standard test of aerobic capacity under load: long enough that you can't muscle through it, short enough that you can't hide. Your pace over seven-plus minutes is a direct read on the engine the Friday conditioning builds.
Most people land between 7 and 9 minutes. Go out at a pace you believe, hold it through the middle thousand — that's where the test is decided — and empty what's left over the final 500. If the last minute isn't ugly, you paced too soft.