It's Thursday at 5:30 p.m. at the YMCA, and Zumba instructor Laura Van Fleet dims the room and flips on the disco lights. Latin music blasts from the speakers as Van Fleet starts the warm-up.
Her workout is intense, mixing salsa moves with jumping, arm movements and hip-hop style moves, like an M.C. Hammer-esque ankle-pump from the '80s.
There are about 30 women in the class following her lead.
Exercise fans and fitness novices alike are flocking to Zumba classes. Touted as energetic and fun, these instructor-led workouts combine Latin dancing, hip-hop and other moves with feel-good music you can't help but move to.
But organizations like the American Academy of Orthopaedic Surgeons are warning about an uptick in injuries that appear to be related to Zumba. Doctors are seeing an increase in knee injuries (especially torn meniscus), ankle sprains, overuse injuries and more.
In an interview with "Today," Dr. Orly Avitzur, a neurologist and Consumer Reports medical adviser noted, "There's so much side-to-side movement that you really need to synchronize your hips, your knees, your feet and your ankles so they're going in the same direction.
"If you move in one direction and the joint doesn't go with you in that direction, it's a setup for injury."
It doesn't help that many newcomers to Zumba are middle-aged, overweight women who aren't in the habit of exercising. They also may not be familiar with the proper way to do common exercises like squatting or lunging.
While Zumba-related injuries may make the news, Van Fleet said that in the two and a half years of teaching the popular workout style, she's only seen one injury.
Because her class takes place on carpet, Van Fleet encourages students to pick up their feet more to avoid knee injury. She also recommends a shoe with very little tread, like a dance shoe or non-running, non-crosstrainer shoe.
Mary Cox, 66, a snowbird from Illinois, did it in her socks.
"It was fun. I knew it'd be fun," said Cox, who was trying Zumba for the first time and described it as "vigorous." "I was going by the seat of my pants. I'll be back a couple times a week."
Courtney Lenhart, 35, has been taking Van Fleet's class since she started offering it. "I like the music. It's a good workout for my legs. It keeps me from getting bored."
Lenhart has never experienced an injury from Zumba.
While Cox had a hard time keeping up with the moves, Lenhart encouraged new Zumba students to stay with it. After a while that awkward feeling goes away, she said. "Have fun with it. It's a really good workout."
Van Fleet recommended stretching after the workout to help avoid injury, and she includes that in her class. Five to seven minutes of deep stretching encourages lengthening and strengthening of the muscles and strengthens the knees, she stated.
She also encouraged Zumba students to work out at their own level. Newbies can focus on the footwork first before incorporating their arms. Someone with physical limitations can do the opposite — do the arm work while leaving the feet stationary. She emphasized that you can still get a great aerobic workout.
"The longer the arms are away from your body, the higher your heart rate will be," said Van Fleet.
As with any exercise regimen, Consumerreports.org recommends that you consult your doctor before you begin Zumba, especially if you have heart disease, high blood pressure, kidney disease, asthma, emphysema, osteoporosis, arthritis or disk herniations.