A Strong Core
Everything comes back to the core. Part of the reason rowing is such a good workout is due to the connectivity of every muscle engaged in the rowing motion, yet the core of the body is doing most of the work.
"The primary load (moving your body weight) is done between your bellybutton and your kneecaps, but the rest of the muscles act as a connective force to that core," Lamb says.
The erg is great at strengthening the core, from the inside out.
More: 5 Reasons to Strengthen Your Core
Cardio Benefits
Depending on how you structure your erg workout, you can get an aerobic workout, an anaerobic workout or an anaerobic threshold workout.
Basically, you can accomplish nearly all of your fitness goals in 30 to 60 minutes on the erg. While training all winter for spring rowing, Bill Lamb puts his athletes through a 40- to 60-minute erg workout, max.
More: Strength Training vs. Cardio: What's Better?
Injury Recovery
The erg is also great for injured athletes who still want or need to get a workout. That's because there's no impact or pounding involved in the controlled rowing motion.
The only real risk of injury on as erg is if you're cross-training or using the erg as a supplemental device. For instance, if you lift weights to fatigue or exhaustion and then get on the rowing machine, you're more likely to sacrifice form and injure yourself, but that's true with any exercise.
However, in order to get the most out of your erg workout, and avoid bad habits that could cause injury, you should consult a coach or take a clinic to learn proper form.
More: How to Test Flexibility to Avoid Injury
Stay in shape in a fitness class.