This article, along with various others that cite the same study, has been making the rounds. It first appeared in my email inbox a few days back, and now I see that it has made the "front page" of Google News' health news section.
The study was very complete. Subjects were divided into three groups: Only-cardio, only-strength training, and a combination of the two. The only-cardio group lost the most weight. The combination group lost a little bit of weight and reduced a little bit of fat mass. The only-strength training group gained weight and lost no fat mass.
So it looks like cardiovascular exercise has finally and conclusively been proven to be "the one best form of exercise, period."
...but wait a minute here. What is this study really telling us?
Recall what I wrote some time ago, in my "Two-Penny Science Lesson" on exercise physiology. The fact of the matter is that aerobic (i.e. cardiovascular) exercise is the only kind of exercise that burns fat, period. Anaerobic exercise involves anaerobic cellular respiration, i.e. using the body's cells' existing stored energy to engage in short-term bursts of physical activity. Never, at any point, is fat metabolization involved in anaerobic exercise. This isn't true as a matter of circumstance, nor is it true "on average." It is true by definition and by the laws of physics.
That is to say, if you are burning fat while you are exercising, then there is no chance whatsoever that the activity you are performing can be classified as "anaerobic exercise." That means: You're not jumping, you're not lifting, you're not sprinting. If you're burning fat during exercise, then you're engaging in cardiovascular, aerobic exercise. That is the one and only possibility.
So Duke University researchers engaged in an expensive, rigorous study on exercise in order to prove that aerobic exercise does what the laws of physics say it does, whereas anaerobic exercise does not.
Gee, thanks, Duke University researchers! You cracked the case!
Next item on Duke's list of studies to perform is a double-blind study that will answer once and for all the question as to whether there is more energy contained in a ball of plasma or an empty vacuum. We await their results with baited breath...