Best cardio exercises for a person with knee injuries?

I love working out and I enjoy cardio of all types..... running, power walking, step classes, boot camp classes, elliptical trainer and treadmill. But I recently hurt my knee and the doctor suggests that I do exercises that do not put my weight on my knee. I enjoy weight lifting but I know that I must mix that with some sort of cardio to maintain balance... Please help, all suggestions are welcomed.

I can share with you some tips based on my some of my PT clients experience. However whatever it is, the most important thing is to listen sttentively to your doctor (ex. if your doctor saya a particular exercise have to be avoided, then listen to his advice). Basically, if you have knee pain, it is best you rest and recover first before attempting any exercise. After that, you can start with some low impact, or non impact type of workouts. Low impact workouts means as long as there is still one ffot in contact with the ground (ex. walking). You may also try non impact workouts (both foot in contact with the floor) like the elliptical trainer, but do limt the angle of knee flexion first.

In addition to that, you may wish to consider water based workout (ex. aqua aerobics, or walking/jogging in the pool). In fact, water based exercises are best for people who have joint injuries or problems; a good way to workout as well.

SEX that is if you are over 18 and you must be an active participant lol