Walking and hiking are the most natural forms of aerobic exercise. It places little pressure on the joints and lower back, so there's rearely a risk of injury. Its beneefits match those of running, you just have to do it for longer. Every mile walked, for instance, burns essentially the same number of calories as every mile run--about 110. Going further and for a longer period of time, rather than speeding up, is what counts from an aerobic standpoint. Walking is perhaps the most underated of all physical activities, it can make you fit and healthy. Walking any old way won't do it for you if it's fitness you're after. Here are a few basic tips.

• Walk briskly 4 or 5 miles an hour is a realistic goal.
  
  
• Walk with weight slightly forward. The feet should point as straight ahead as possible and legs should be aligned with your hips.
  
  
• Take long stretching strides, working your legs and buttocks to their maximum.
  
  
• Think tall, chest lifted, back flat, and head up - erect but not rigid.



• Swing your arms vigorously.
  
  
• Walk relaxed.
  
  

Always set goals for yourself. Start off with small goals that are attainable. For instance, walk around the block for the first week, then add an extra street the following week and so on. If you start out by walking an hour a day you may find that you can do it but after a few days you might feel very tired and your walking becomes hard work instead of a pleasure. If you push yourself too hard and too fast you will start to miss a day here and a day there and before you realise it you have stopped walking altogether. I always like to finish my walks or any kind of exercise feeling I could do more.

Eventually, if you want to increase the aerobic challenge of walking, you can add weights to your wrists or waist. You can add as much as 20 percent of your body weight, but be sure to do it gradually. I don't recommend using ankle weights when you walk. They put too much stress on the knees and other joints.

To prevent injury from both walking and running, make a habit of doing 5 to 10 minutes of slow stretching before you start and after you finish, especially afterward. Emphasize stretching the backs of the legs--the calves and the backs of the thighs or hamstrings.