Alter-G, a Menlo Park, Ca. company that helps people run on a treadmill with the use of air pressure to reduce their effective weight, has raised $2.5 million in a first round of funding (see VentureWire; sub required).

Red Planet Capital, the venture arm of NASA that has recently come under political pressure, and is likely to be scrapped (quick spend the money while you can!), and buyout firm Hellman & Friedman co-led the round.

The two-year old company’s product is mainly for those people who have trouble supporting themselves with their own legs.
Alter-G’s products allow natural movement, but control the amount of impact experienced by their users — reducing body weight by three to 80 percent.

The company first made a prototype product for Nike in August 2005, based on technology developed by Robert Whalen, a researcher at NASA and the National Institutes of Health.

The products may also be good for injured athletes, or those who simply want to take a break from all the pounding — because they apparently let you keep your natural form, unlike resistance harnesses or practicing in swimming pools, which alter your form. With NASA’s backing, you might think it would be used for astronauts. However, the company doesn’t talk much about this in its materials.

It is still too early to tell whether the product is getting any traction. The company now says it is going after the medical market. This is an odd investment, for both NASA and H&F, which is a buyout firm, and typically likes to make much larger investments.