Manjunath

Hi Madhu, Both aerobic(cardio) & weight training are equally important when it comes to weight loss. Most people often do the same mistake thinking that doing only cardio exercises like cycling, treadmill will help in weight loss. But doing only cardio exercises can lead to muscle weakness as you are not strengthening the muscles,  Hence weight training is really important inorder to maintain the muscle mass, higher the muscle mass higher the calories that you burn. Hence both cardio & strength training are really important for a healthy weight loss.

The common site of injuries include knee & ankle joints as the aerobic activities fast & continuous & high impact  movements, it add strain on the knees & ankles. It's better to follow a low to moderate impact activities that doesn't add much strain on the joints, especially if you are a beginner or if you have high BMI.