I first started rowing as a warm up with a friend - but it's rapidly becoming a staple in my pilgrimage back into race shape. So far my rowing sessions have all been 5 minutes or less. But they're growing. A learning point for me has been that I don't ALWAYS have to row 35 strokes per minute.
Here are some benefits I've found from rowing:
1. It's a killer warm up
Rowing can get my heart rate through the roof and tell my body "it's time to work" before I even get on the bike. It uses so many muscles not just one area is targeted. This is a great lead-in for stretching. (if I stretch cold; I feel like I don't get anywhere, but while warm, I'm like Gumby - okay not true but closer)
2. Total Body
As eluded to in 1. the fact that it works the whole body is good for many other things.
Weightloss - I have friends who are 250lbs+, ride 5 hours per week and can crank out 345 watts on the flats, which is great, but you always have to wait for them at the top of hills, or even overpasses. Rowing seems to burn calories 'everywhere'
Definition/Muscle Building - In cycling we need strong arms and backs to help us go fast. It may be cheating as I don't enjoy free weights that much; but I can row and have already felt it start to make a difference. (Zabel's a ripped little dude, and it seems like a lot of OCup races are crit and sprint finished based so this will be important).
Is it REALLY total body?
As you catch the handles of the rowing machine and begin to pull forward, you are engaging your pelvis and thighs. As you pull, your arms, shoulders, back, and abdomen get involved. As you slide back, your legs, hips, and torso do the brunt of the work. The backs of your upper arms, shoulders, and butt also get a good workout with proper rowing form.
3. It's not a bike.
There are times when it's good to just not be on the bike. Here you can get your anaerobic work out in. Build your lung capactiy, work your body, and not be sitting on your saddle. Had I not lived in Toronto; I likely wouldn't have discovered rowing machines, but since you can't be outside all year round - you gotta rock what you got.
People may make fun of me for using a 'machine'- but at least it's not an elliptical :P