I am obese with back & knee pain. What can you suggest?

Our suggestion first and foremost is to ensure you're cleared by your Physician to exercise. A strong focus is weight loss, especially that you're in the obese range. Your weight is a major contributor to your back and knee pain. Small changes go a long way and easier to implement on a daily basis; such as, eating whole foods, vegetables, fruit, drinking water, avoid processed foods and snacking after 7pm. If you incorporate this with a 20-30 minute walk, 4x a week, you will see great results. Remember, to lose weight, it is 70% healthy diet and only 30% exercise. That's how important to change your diet and eating habits in order to achieve a normal and healthier weight.