EL PASO, Texas -

We all know at least one person who's tried the popular exercise routines CrossFit and Zumba. But what many of us don't realize, these fitness trends are behind serious injuries.

The CrossFit fitness trend is taking El Paso by force. But the Olympic-style weightlifting, sided by high intensity squats, kettle bell lifts and cardio --may be hurting exercise enthusiasts, just as much as they think it's helping. 

"If you're not careful, you're going to get hurt, pretty fast," said Lluvia Martinez, a CrossFit competitor. "I had stepped wrong on one of the movements. I wasn't really ready for it. So I picked up the weight and my knee and that's when I got hurt."

Physical therapists say "CrossFitters" can easily injure their lower backs and pull muscles in their legs and shoulders by pushing to hard, too fast.

Although, Martinez has managed to avoid the worst CrossFit-caused injury rhabdomyolsis, a condition caused by tearing the skeletal muscle tissue. The tissue breaks down into the body's system, toxins flow through your body, which not only damages the liver and kidneys, but can lead to death.

"Whenever you workout, your muscle breaks down a little bit," said Arthur A. Tony Islas, a sports medicine physician. "And that's the soreness that you feel afterwards and your muscle rebuilds. Your body has an ability to remove those broken down pieces in your body. But when you break down your muscles quite a bit, you can get to a point where you actually overwhelm the body."

"I think CrossFit is one of those things that, as a therapist, I actually advocate for it because it actually gets people off their couches to exercise, and it motivates them," said Steve Sanchez, physical therapist. "However that motivation can lead to people doing things above their limitations."

Some El Paso's physical therapists said they see CrossFitters come in for rehab nearly every month. Also pushing up patients' injuries: Zumba. 

Attractive to women, Zumba's Latin-inspired aerobics allow you to twist, shake and jump your way into fitness. But many aren't prepared for it's fast-paced routine, twisting ankles, pulling muscles and injuring their knees.

"In my class it's a little higher energy, so I tell them, even though you see me intensifying it, keep it modified to your level," said Araceli Granillo, a local Zumba trainer. 

Granillo recommends starting out slow, building your strength to ensure your muscles and joints are ready for the impact. The same applies to CrossFit.

"I think the key is to have good supervision, a proper warm up and ease your way into it," Sanchez said.

Martinez has learned her lesson, and stays in the gym and out of pain.

"It's very fun," Martinez said. "I enjoy it a lot."

The key to CrossFit, says trainer Daniel Alvarado is finding a good trainer. Getting an initial CrossFit training certification only takes two days and many trainers aren't ready to monitor their clients.