4 × 4 rowing intervals: four hard pieces, paced as one set.

Concept2 currently publishes a RowErg aerobic-power example of four 4-minute work intervals with 2-minute recovery, starting moderately hard and increasing effort through the set. Its 4-minute test training plan uses 4 × 4 minutes with 3 minutes recovery.

Rowing research has also studied 4 × 4 minutes. In national-level adolescent male rowers, a protocol using four 4-minute bouts around 90% of power at VO₂max with 3 minutes active recovery produced substantial cardiorespiratory and metabolic demand. That study describes one population and one protocol, not a universal prescription for every rower.

If the purpose is repeatable aerobic-power work, opening far above a sustainable set pace can turn the later pieces into survival. A better starting point is a target you expect to hold with manageable decay, then adjust future sessions from the evidence you actually produce.

There is no universal split such as “2k pace plus X seconds” that correctly accounts for every rower, because the tolerable power for four minutes depends on the athlete's power-duration profile and the recovery allowed between bouts.

A shorter recovery leaves more residual strain before the next repetition. A longer recovery generally permits greater restoration of power. If you change the recovery, compare the resulting session as a different prescription rather than assuming the same target should transfer unchanged.