Rowing involves many more forces than just that applied by the athletes' legs. The buoyant force, and minute forces applied to the boat by the athletes by their movement in the shell all contribute (since boats need to be balanced, the resultant of these small movements must equate to zero). Additionally, air resistance opposes the movement of the crew, which explains why the British did not continually accelerate throughout the race. This cursory consideration of rowing hints at how comprehensive a lesson in physics rowing can be. Click the link to watch the race from earlier this month!