Why do certain exercises work?

There are many different philosophies for exercise, particularly for low back pain.  When assessing these programs, there are two separate questions- do they work, and why do they work?

As an example, there is an older form of exercise for the low back called Williams Flexion Exercises, that have been around since 1937.  They were developed with the idea that lumbar lordosis (the natural curve in the lower back) is unhealthy, and needs to be reversed, so he developed exercises that flex the spine to protect the back.

So do Williams Flexion exercises work?  They can.  I had a patient of mine who developed back pain, was taught Williams Flexion exercises, and did them for 36 years without having a recurrence of his low back pain.  He did eventually hurt his back again, which is why I saw him, but 36 years of prevention is pretty darn good.

So, summary action points:
1. Exercise
2. Exercises that help improve the range of motion in your hips are especially good- things like Williams flexion exercises, yoga, pilates, tai chi
3. Exercises that make you have explosive contractions of your muscles are good if you fit and healthy already (like P90X)
4. Caloric restriction is helpful for losing weight, particularly by controlling the size of your portions
5. It is often easier to restrict your portions by using a structured diet
6. If you are going to restrict your food options, try to eliminate dead calories first.  Soda and juice are good places to start, since they are essentially sugar water and empty calories.

Do Williams Flexion exercises work for the reason that was claimed?  Is it unhealthy to have a lumbar lordosis?   No, the reasoning is incorrect.   The reason Williams Flexion exercises work is because they improve hip flexibility, so that you are not asking the back to more than it was designed to do, but allowing the hips to improve their range of motion.

This is true for many diet and exercise programs.  Many diets, for example, are designed with food restrictions- just grapefruit, no carb, power fasting, etc.  These diets work, at least in part, because you are reducing your caloric intake.  An all-Twinkie diet would probably help you lose weight too, since it would restrict what else you were eating.

Similarly, there are some popular new exercise programs like P90X.  There are many benefits, but a large part of the benefit of P90X is that it structures diet and exercise.  Anything that makes someone diet and exercise is beneficial, and the specifics are probably less important.