This year, nearly 16 million people will hit the yoga mat. Some will strike a pose in a yoga studio. Others will work out in front of their very own computer...thanks to yoga videos that are popping up all over the internet!

Take Sherri Holman. when she hits the yoga mat…she stretches her body and her soul.

"Practicing yoga allows me to relieve myself of the worldly stress and to just spiritually connect," Holman explains.

Sherri heads to the studio weekly. But now, she also lets go by logging on to a virtual yoga class.

"It's convenient because I can actually tune into a specific yoga class at any given time," Sherri says.

A quick web search turns up thousands of videos. You'll find them on places like You Tube, as well as many yoga and exercise web sites. Some are posted by apparent 'do-it-yourselfers'…others by experienced yogis.

Some show basic breathing and meditation. Others show more advanced positions. But now, doctors and yoga experts say injuries are on the rise, and they're concerned about some of the clips. Dr. Bill Stetson is a member of the American Academy of Orthopedic Surgeons.

"I would say some of the most common injuries that we're seeing secondary to yoga include wrist injuries, shoulder injuries and also low back injuries," Dr. Stetson says.

Dr. Stetson says there are some excellent beginner videos, but he's alarmed by ones that demonstrate advanced moves like headstands.

"If you try to do this at home, alone, you could really suffer a very, very severe sprain of your neck," Dr. Stetson warns.

Terri Kennedy is chair of The Board of the Yoga Alliance, which sets voluntary standards for the industry. She also posts her own videos. She warns, unless you're advanced in your practice, you should never try more difficult positions unsupervised.

"So if you're doing something slightly off, the teacher can adjust you. And your alignment that might be off just a bit if you're watching an online video can cause," Kennedy says.

No certification or specific training is required to teach yoga, although the alliance strongly advocates training, and registers instructors after a minimum of 200 hours of approved schooling.

"Before practicing with a video, find out about the teacher's background and where they trained," Kennedy advises.

Most videos we found link back to personal blogs or teacher biographies. You could also log on to the yoga alliance registry to find members. Finally, know your body.

"If you have a pre-existing injury, I would say stay away from online videos unless you absolutely know what you need to modify," Kennedy says.

Fortunately, Sherri has never been injured and uses 'beginner' videos as a supplement to her practice.

"I might not do it right, or can't hold it as long as maybe they're doing online, but I do generally try to finish," Sherri says.

You can find the yoga alliance registry at: yogaalliance.org. We spoke with three popular web sites that post yoga videos online. All three say that safety is a top priority, and that background info for each of its yoga instructors is posted clearly on the web.