Humans love the feeling of floating free. Astronauts enjoy it in space, and even if the closest you get to a shuttle is the bus on the 16th Street Mall, the earthbound can become airborne via rebounders and trampolines.
And thanks to NASA, we have proof that jumping is good for us. “Rebound exercise is the most efficient, effective form of exercise yet devised by man,” says an oft-quoted study from the Journal of Applied Physiology in 1980. The study found that rebounding helps rebuild bone and muscle lost by astronauts during weightlessness.
Rebounding exercises and strengthens every muscle, organ and cell in the body, says Michael Brook, who just happens to be the 1971 Colorado state trampoline champion, now owner of New Dimensions in Health in Provo, Utah. Exercise puts a positive stress on muscles and cells, forcing them to adapt, which in turn makes them (and us) stronger and healthier.
“All exercise works against the gravitational pull of the Earth,” Brook says. “By accelerating and decelerating in a vertical line while bouncing, the G-force that is created when the feet strike the mat is increased according to the height of the bounce. The G-force can be two to three times more than when standing still, which in turn forces every cell in the body to ‘lift’ more weight.”
NASA found that rebounding was 68 percent more efficient than running on a treadmill. The weight of a 200-pound person bouncing on a trampoline doubles at the point of impact to 400 pounds, while at the top of the bounce the force is zero. The body reacts to this force like an extra “weight,” causing the cells to work harder and absorb more oxygen, which in turn improves overall organ function.
Bouncing on a quality rebounder, for just 10 minutes a day is all it takes to get your body headed in a healthier direction. Start with a simple “health bounce,” just standing on the rebounder and gently moving up and down with the feet remaining on the mat. As fitness improves, add more time and, finally, more action: jumping jacks, the twist and other fun dance moves.
“Rebounding is the closest thing to the fountain of youth that science has found,” writes James R. White in “Jump for Joy: The Rebounding Exercise Book.”
Small rebounders are low-impact and easy on the knees. They are “designed for the downward push of the legs rather than for achieving height,” says Jessica Matthews, continuing education coordinator for the American Council on Exercise. “This makes a rebounder not only good for cardiovascular conditioning but also very joint-friendly.”
For those who want to jump on a large trampoline, gymnastics schools offer classes that start with how to bounce. J.A. Dominguez, of Jet Kids in Jefferson County, says the most important skill is learning how to stop. “We call it ‘killing your bounce.’ You have to bend your knees,” he says.
Gymnastics instructors spot students as they learn to be aware of their bodies as they move through space, starting with a simple seat bounce before moving on to more complicated flips. Dominguez suggests looking for classes through the “Find a gymnastics club” link at usa-gymnastics.org.
Getting the most bounce for your buck.
“If you buy a rebounder made from quality materials, the surface will have more stability and will not stretch,” says Matthews. She encourages shoppers to read reviews and look closely at the warranty details and refund policy. Also, some have weight limits on rebounders designed for home use and have time limits on replacement parts.
A $30 rebounder will be made from inexpensive materials that may allow the feet to pronate with each contact on the mat, and will likely stretch out in a year or two. Repeated pronation of the feet — especially with the added G-force of bouncing — can create or exacerbate back, ankle and knee problems.
Quality materials will make the difference between a good, safe experience that will keep you jumping and one that will send your rebounder to a garage sale and you to the doctor.
What to look for in a quality rebounder.
Chassis integrity: A one-piece steel frame will provide the rigidity and support for 20 or more years of use, which makes the $300-$500 price range affordable in the long run. Avoid hand-welded frames. Computerized welding is the best and safest.
Springs: Should be made of top-quality USA grade steel. One of the best-reviewed rebounders, for example, is the “Cellerciser,” which offers a unique triple-tiered spring made of high-carbon steel wire that adjusts to body weight.
Mat: Should be made of quality polypropylene fiber that is tested under many tons of pressure. When bouncing, the user should feel balanced and supported no matter how or where he or she lands on the mat. The stitching should be four-ply polyester thread.
Legs: Avoid the screw-in variety. Best is a pop-in design secured with piano wire. More information: .
Linda J. Buch is a certified fitness trainer in Denver; linda@ljbalance.com.
Bouncing’s benefits
Health benefits from bouncing on a trampoline or mini- trampoline/rebounder include improvements in:
Yard “tramps” risky, prof warns
About those backyard jumpers and trampolines that roll out of the garage and onto the lawn every summer: Denver sports professor Marc Rabinoff warns that consumers should think twice about buying a backyard “tramp.”
Consumer Reports anaylzed Consumer Product Safety Commission data and found that more than 105,000 hospital-treated injuries in the U.S. in 2007 were linked to trampolines.
“Ninety percent of injuries on trampolines are from backyard trampolines and 60 percent of those injuries are from falling off. Many of those people are now paraplegics,” warns Rabinoff, a professor in the human performance and sport department at Metropolitan State College of Denver. “Parents are being led to believe that if they put up an enclosure that they are installing a safety net. Unfortunately, this is just a false sense of security.”
While enclosures have dramatically reduced fall-off injuries, closed-head injuries from people crashing into each other as they bounce on the mat together have increased dramatically, says Rabinoff, who invokes the following three rules for those who still want a trampoline:
1. No double jumping — only one person jumping at a time.
2. No flips or somersaults.
3. Supervision at all times. “This equipment, even with the enclosure, is not a playpen,” he says.
Anyone who wants to learn how to trampoline or who wants to experience the joy of jumping, should contact a gymnastics school where there is proper equipment, instruction and supervision. Linda J. Buch
