Many people who exercise get problems in their knees, hips, or ankles. This is because these joints can sometimes get the full force of your body on them, and sometimes a little bit of rest can cure this, but over a long period, this can lead to more severe consequences, so be aware of how you exercise.
Swimming
Swimming can be a great cardio exercise for you to do, and the best part is that it is low impact, so your knees will not have any problems if you swim. Your glutes, abs, chest muscle, and shoulders, everything will get a workout when you swim. You will also burn many calories when you swim, and there are many different types of strokes that you can do to change things up and keep them interesting. You can burn up to a hundred calories if you do the freestyle stroke for about ten minutes, so it can effectively burn calories.
Elliptical
All exercise causes stress on the body, which can cause old wounds to flare up and inflammation to add up. You can use an elliptical instead of a treadmill as this will not be as forceful on your knees and joints. Since your feet will always be on the pedal, no force or impact is being applied to it by you, so you are mostly safe.
An elliptical can be a good and more stable form of cardio, and it is recommended to people with bad knees to do. You will burn a lot of calories too, and you will have more endurance and fitness. A treadmill will burn more calories in the time that you do it, but for people with knee problems, an elliptical is a great exercise machine.
Rowing
If you can bend your knees without any problems, but you just do not want any extra impact, then rowing can be one of the best exercises that you do. There will be no strain on your knee joints. Rowing is a full-body workout, and this is why it burns off so many calories. Your core strength improves as well every time you use a rowing machine.
Rowing, in general, is a great exercise to strengthen the back muscles. Everyone does a rowing exercise because you can add intensity to it and do it the way you want. Over time you can keep on increasing the intensity of the activity so that you can always feel challenged.