Novak Djokovic's rapid launch to tennis stardom and number one ranking this summer has left many of his fans and competitors asking, "What's his secret?"
A special training routine? A lucky jock-strap? No -- just a spaceship-like pressurized pod that gives him super-human healing powers, according to comments made by the athlete last week.
At first, the 24-year-old Serb credited his recent sharpness on the courts to his new gluten-free diet, but last week he revealed something even more unorthodox in his arsenal to obtain athletic edge: the CVAC Pod.
"I think it really helps -- not with muscle but more with recovery after an exhausting set," he said at a sponsor event last week according to the Wall Street Journal. "It's like a spaceship. It's very interesting technology."
The pod may look like the bizarre synthetic egg that hatched Lady Gaga at this year's Video Music Awards, but the CVAC is being taken seriously by a number of professional athletes looking for the next big thing in performance enhancement, including Olympic cyclist John Howard and martial artist Rampage Jackson.
CVAC, short for Cyclic Variations in Adaptive Conditioning, simulates rapid changes in altitude, which reportedly stimulates the body on a cellular level, increasing oxygen absorption, promoting muscle recovery, and boosting the lymphatic system.
The concept of using altitude and pressure changes to promote better athletic performance is nothing new -- the fact that high altitudes increase the number of oxygen- transporting red blood cells in your system has been studied for years. This is why many athletes will spend time at high altitudes during training season to increase their body's oxygen absorption, and by extension their stamina and athletic performance.
The shocking -- and controversial -- claim of the CVAC system, however, is that it accomplishes these bodily changes in just a couple 20 minute sessions a week.
"It does between 100 and 200 pressure changes in 20 minutes," says Allen Ruszkowski, president/CEO of CVAC Systems, which makes the device. "Typically the body requires several weeks before it adapts to altitude, but by changing the pressure in very specific patterns, we can reduce the amount of time that someone has to spend at altitude," he says.
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Studies done at the University of Hawaii and Stanford University have offered support for these claims and more clinical trials are underway, according to Ruszkowski.
Dr. Benjamin Levine, a professor of medicine at University of Texas Southwestern Medical Center and a long-time expert in using altitude changes to enhance athletic performance, is dubious that the CVAC chamber can really do all it promises.
Levine, who directs the Institute for Exercise and Environmental Medicine at Texas Health Presbyterian, developed the concept of "live high, train low" almost 20 years ago. The basic idea was that living at high altitudes causes the body to adapt and produce more red blood cells, but training at that altitude is more difficult and hence limits how hard an athlete can work out -- hence the "train low," meaning that athletes would come down from high altitudes once a day to train in locations closer to sea level.
With "live high, train low" however, it takes athletes at least 12 hours of high altitude exposure each day over three to four weeks to really see the effects.
"My personal opinion is that there's absolutely no evidence that the CVAC system works. The duration of the stimulus is way too short for your biological systems to become activated," Levine says.
Levine is also concerned that the rapid changes in altitude could harm those using the CVAC pod. When you intermittently get low levels of oxygen, as opposed to adapting to a static high altitude, low oxygen state, it mimics the effects of sleep apnea, where sufferers periodically stop breathing while asleep. This oscillation between oxygen levels can cause high blood pressure, insulin resistance, and other negative side effects that Levine worries might also be a byproduct of using the CVAC chamber.
"Everyone is looking for Djokovic's secret, but his secret is he has a stupendous backhand, great intensity on the court and is just a great tennis player in general," Levine says. "I think every athlete is looking for an edge, but I don't think you'll find it with CVAC."
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Others are slightly less skeptical: Dr. Laith Jazrawi, chief of sports medicine division at NYU Langone Medical Center, says that while the CVAC's effects need further study to really support its use, the logic of it fits into research on altitude training.
"While 20 minutes seems like a short time frame, any stress will allow for some changes. More studies need to be done to confirm some of the red blood cell changes, but there also other adaptive enzymatic changes that may not be so easily measured," he says.
The pod also might be having a placebo effect, as is the case with many athletes' secret training tips -- offering athletes with that extra boost of confidence they need to excel during competitions.
"Ultimately, the pod may be more of a psychological edge with mild improvement in stamina. However, at the professional level -- with extremely talented individuals -- any minor edge might make a big difference," says Jazrawi.