Rowing machine or Treadmill… help!

Yeah, food intake for the win.

I've been a rower for roughly 20 years. I row on water in season (those skinny boats like in the Olympics, except mine is slower). I row on machines in Winter. I've trained hard and even competed in both (not always unsuccessfully). For around 12.5 of those years, I was class 1 obese. I may've been one of the more fit class 1 obese women you'd be likely to meet, but obese I was. For something around 6.5 of those years - the more recent ones - I've been thin . . . doing pretty much the same amount of rowing the whole time

It was about the food.

Rowing hard actually burns quite a few calories. (It's just super easy to eat that many more, too.) There are a couple of things, though.

I know that walking/running can be hard on your knees. How do I know? I have bad knees - osteoarthritis and at least one torn meniscus, maybe both. Running is a thing I should only do to save a life, because I've learned it always causes me further knee damage, not to mention pain. Would that be true for everyone? No. It matters what's wrong with your knees.

Here's the thing: Rowing also involves major leg work. Most of the power comes from legs. In my case, straight-line hinge motions don't cause further damage to my knees (though they sometimes make them hurt). I can row, and I can cycle, because those are straight-line hinge motions. Would that be true for everyone? No. It matters what's wrong with your knees.

Rowing has a learning curve. It's not intuitively obvious. Most people who assume it's intuitively obvious end up doing it wrong. At worst, they self-injure; but even if that thankfully doesn't happen, they will reach a point where they can't get a decently challenging workout. Why? With a rower like the Concept 2, there is not a setting for resistance to make it harder. (Yes, there's a little lever thingie on the side with numbers that people think is supposed to be resistance, but that's not actually what it is.)

Even most general-practice trainers I see do or demonstrate rowing in gyms don't do it correctly, unfortunately.

You make a rowing workout more intense by putting more energy into the flywheel. Eventually, you reach a point where the only way to make progress - to put more energy into the flywheel - is if you have reasonable technique. If you didn't learn reasonable technique right up front, you would have bad technique grooved into muscle memory, and it's hard to fix at that point.

What does that mean? It means that if you want to be a longtime rower, get fit and strong rowing, you want to go slowly and patiently at first, using solid videos and mirrors and self-filming and things like that, or ideally learning from a qualified coach. That limits the calorie burn in the early weeks (because you're going slowly to get the technique right), but opens up a nearly infinite potential to increase the challenge in the long run.

Me, obviously I'd encourage you to get a rower, and the Concept 2 is the gold standard. They're not cheap, but they're excellent. I've had mine since 2004 (or was it 2005?), have put millions of meters on it, and have just given it a little chain oil, kept the slide clean, and put in a change of batteries (maybe 2?). Super high quality piece of equipment.

If you have questions about the Concept 2 specifically or rowing generally, ask. I could talk about rowing all day, and I've been lucky to have some top-notch coaches along the way, even though I'm a mere duffer.

Rower vs. treadmill? Rower, but that's just my opinion. Weight loss? Manage your eating. Fitness feels great, but - maybe surprisingly - being fit and being thin aren't synonymous. The routes to reach them are different, even they're both worth pursuing, big time.

Best wishes!