In “Strength and Power Goals for Competitive Rowers” (2005), authors McNeely, Sandler, and Bamel make a few relevant observations from earlier rowing literature.

“Muscular endurance, strength, and boat speed are closely related. Rowers maintain an average of 686-882 Newtons (N) or the 210-240 strokes that make up a 2,000m race. It has been found that to maintain this level of muscular endurance a rower works at approximately 40% of peak rowing strength for the duration of the race.”

Research with Danish Olympic, national, and club-level heavyweight rowers of similar stature and age found that, in isometric rowing simulation, Olympic rowers generated 204 kilograms of force (kgf) on average. National-level rowers generated 183kgf and club rowers generated 162kgf. Using other non-specific rowing tests–isometric arm pull, back extension, trunk flexion, and leg extension–on the same groups of athletes, it was found that the higher the competition level of the rower, the greater the strength in all tests.

At this point, people often say, “Well, I pull 100% on every stroke, so how does increasing my strength increase my endurance?”

The truth is, you do not pull 100% on every stroke in a race. A 2,000-meter race is between 77 and 88% aerobic. Energy system use is determined by intensity AND duration of the activity. Powerlifters can exert absolute maximal force into a 1-rep max squat, bench, or deadlift lift because they are doing one repetition lasting under ten seconds, using energy almost exclusively from the ATP-PC system. THEY are exerting 100% against the external load of the barbell because the duration is very short.

Rowers cannot exert their absolute maximum strength against the resistance of the water beyond the initial starting strokes. The surface area of the blade, the momentum of the system, and the density of the water all reduce the absolute maximum force that the rower can apply.

In all other rowing circumstances, increasing peak force decreases the amount of effort required to move the system. Increasing your peak rowing strength decreases the amount of effort required for submaximal rowing. Rowing at a lesser intensity increases the duration that you can hold that intensity. This is how increasing strength decreases per-stroke effort and improves endurance.

If you are interested in further rowing research, a great resource is https://rowingstronger.com