Occasionally, clients with lumbar spinal stenosis ask me about rowing machines. Are they good? Are they bad? What muscles do they work?
Rowing provides a work out for several large muscle groups (gluteals, quads, abs, lats), some that directly attach to the spine. Working muscles that attach to the spine improves circulation to the spine, which can be very advantageous for someone with spinal stenosis. Rowing also allows you to get a low impact aerobic workout, without having to be on your feet for long periods. Still, as with any new exercise, you'll want to proceed with caution. It's best to try out a rowing machine for a few minutes first, see how you feel the next day, and progress from there. Also, you'll want to start with small arcs of movement and low low resistance.
Advantages: 1) rowing specifically targets back muscles 2) it can be tailored quite easily to fit your fitness and strength level 3) is excellent for more fit individuals 3) involves exercising in a sitting position, which is often more comfortable when you have stenosis
Disadvantages: 1) May involve large movements of knees, hips and spine that will aggravate severe cases of arthritis (if you're not mindful of limiting your range of movement proactively) 2) May not be comfortable for people with arthritic hips or knees.
For tips on proper form while rowing: http://dailyburn.com/life/fitness/rowing-machine-mistakes/