Rowing!

I'm assuming you're going to be starting on an indoor rower.

If you're visiting a gym - the make is probably a Concept2.

See: http://www.concept2.co.uk/indoor-rowers/training/technique-videos

Things you should remember - do not put the intensity on really high. I used to practice with the men's uni rowing team - and the highest they used was 4 (out of 10). Anywhere between 4 and 6 is like rowing in a small size boat in the water. Rowing at a 10 is like being in a galley of a large ship. A resistance of 1 is like being on a paddleboard (something that weighs next to nothing).

It's not impressive to put it on the highest resistance and then be a seat shooter - though most people tend to do just that. So, if you want - start below 4 and watch your technique very carefully. Watch your posture, watch that you pull back with your legs... then hinge your hips... then pull your arms back (back muscles and arms)... then release arms... release hips... release hips. Repeat. It's very easy to release your legs as you pull your arms back - which means you don't really row - you shoot your seat.
It's easy to increase the intensity without increasing the resistance.

Take it slow. You have bad knees and ankles - those joints get a good workout during the row. The majority of the row is from the legs... so watch the position of your feet (the height they are on the board).

Youtube videos - there are a few.

I prefer to do a steady row for anywhere between 6-10 km. I started by rowing by doing 2km at an easy pace. After that was comfortable I just increased length. You can do all sorts of workouts - check out the Concept2 website for ideas. Or - if it can be done with running - it can be done on the rower (1km slow pace - 500m fast, fartlek etc).

The people who I've seen do the HIIT on the rower at the gym do not have good form at all. So, keep the resistance low, watch your form, put on some good music, and go for it.

Hi OP,

Bad knees here too. I started in at rowing without a clue. Now I'm trying to think my way through fixing bad habits. Need to call a local row/spin gym and see if maybe I can get some coaching. There is a local rowing club, but they only do indoor training for members and I'm just trying this out, not that committed yet.

So, yes, figure out the form from the start and save yourself some hassle.

I second cycling/spinning too. Try it for awhile before deciding if you like it or not. Music and quality of coaching varies quite a bit, as does the focus of the sessions (resistance vs. speed).

One of the best decisions I made was to buy a rowing machine (Concept2 - the gold standard but, surprisingly, not the most expensive). I'm primarily a runner but row at least 3 times weekly as cross training.

Rowing is a great, low-impact workout.

I'll second the advice of building slowly and focusing on form (ignore the advice re HIIT sessions.....those can come later after you've got your form down and have improved your aerobic base) Lots of great videos on youtube and visit concept2's website, they have lots of great training tips too.

I'll also second the advice re: cycling........

I love my new row machine. Ive put about 55 miles on it so far at 2 miles a session. I go for about 40 minutes a workout and keep the 3 mile an hour pace. I have not done HIIT on it yet but my machine the resistance is so god damn hard i do not see it being possible. Any ways it is low impact and i constantly sweat throughout the 40 minutes. Im starting to see some changes on my body because of it and i have only done like 26 sessions, cant wait to hit 100 sessions!