I play ultimate frisbee. I don't play competitively per se, but many of us who play play to win. Given the nature of the sport, it helps to have endurance to keep one's speed up all game but it also helps to have fast 5-10 second sprinting ability as well as a good vertical. It wouldn't be too helpful to be an awesome sprinter and jumper in the first ten minutes of the game and then get tired, nor would it be good to last the whole game at the same mediocre speed.
I imagine that it's the same sort of fitness that would best suit a soccer player.
Well, I have more personal experience with another ' stop & go ' sport - hockey. But, I'd say that the energy system demands for both sports ( hockey and soccer ) are pretty similar. I also happen to own a Concept 2 rower btw........so I speak from experience.
In terms of working on your improving the overall efficiency of your energy systems I've found that doing different forms of interval training on the rower can be of help.
For example, to work the energy system you need for those 10 +/- sprints you could do sprint intervals of 10 - 20 seconds going as hard as you can - ' flat out ' - followed by rest interval about 3 - 4 times as long in duration ( i.e 20 seconds of work.....60+ seconds of rest ). You want to make sure get all your breath back before you start your next work interval. So, you could try a a 5 minute warm-up, 15 - 20 minutes of work/rest intervals and a 5 minute cool down.
Another workout you could do is along the same 5 minute warm-up, 15 - 20 minutes of work/rest intervals and a 5 minute cool down model ( longer if you can handle it
), except you can make your intervals last about 1+ ( 1 - 2 ) minutes long and your rest intervals a bit shorter at 2 x as long ( i.e 2+ minutes ). Again, go hard for those 1-2 work interval minutes. Also, there is no need to get your all of your breath back during these rest intervals.
And to work on some endurance, you can do an interval session where you go hard on work intervals of 5 minutes or so and then do a recover interval for a period of about half that time of 2-3 minutes. You could easily do a 45 - 60 minute workout using this approach...I've done variations of this one many times.
And, it goes without saying, that you'd want to supplement this cardio training with some resistance, quickness, speed and agility training in the gym.