You can burn upward of 1,000 calories an hour while running, making this the most energy-consuming of aerobic exercises. As a result, running is a useful mode of exercise for people trying to lose weight. However, if you're overweight, the stress on your joints and other tissues when you run is considerably greater than it would be were you at your idea weight. Back and stomach trouble in overweight runners stems from a number of causes.
Back Pain in the Overweight
Being overweight or obese is a predisposing factor to back pain, according to Christopher Silveri, M.D. If you are overweight, chances are good that you have not been exercising much or at all. This means that your back muscles may be weak, which leads to poor posture and pain in the lumbar spine, or middle to lower back. Poor posture is a special detriment in overweight people because the back in these cases has to support a load greater than it is structured to support.
Poor Form
If you're determined to lose weight by running and want to eliminate back pain, you may need to focus on your running form. According to Dana Williamson of "Running Times," you should try to maintain as upright a posture as possible and should resist the temptation to lean forward. Keep your lower abdominal muscles tight and pulled in, and consciously relax your shoulders. Work on expanding your chest up and out as you breathe, as this takes strain off your shoulder blades.
Lack of Flexibility
Williamson points out that back pain in runners can result from a lack of flexibility in other parts of the body, in particular the hamstrings, which work together with some of the muscles of the spine responsible for holding the torso erect. If it has been a while since you've regularly exercised, you are probably not yet very flexible. In addition to stretching your hamstrings, strengthening your quadriceps and abdominal muscles may be in order.
Side Stitch and Cramping
If your stomach or abdomen in general are bothering you during running, it is most likely the result of either a side stitch -- pain in an abdominal muscle along the side of your belly -- or issues inside your gastrointestinal tract itself. According to the Sports Med Web, a side stitch is probably caused by insufficient oxygen supply to the muscle in question; side stitches tend to wane with improved conditioning as you lose weight. If you're having pain in your stomach itself, dehydration is the usual culprit, so be sure to take in water or a dilute carbohydrate beverage both before and during your run.
