They're inexpensive. They're portable. They're safe. And, experts say, they provide a better muscle building workout than do weight machines. So it's no wonder resistance bands are growing in popularity.
Resistance bands (also known as Thera-Bands, after a leading manufacturer) have long been used in rehabilitation.
"Every one of our patients has a Thera-Band tied to the back of their wheelchair," said Barbara Swan, the medical director for the Acute Rehabilitation Unit at West Penn Hospital. "I also use them in the office. I call them a poor man's Soloflex [a popular home exercise machine]. They're easy to use. They have different densities. They're cheap."
"I use bands for shoulder and ankle strengthening," said Sean Karr, a physical therapist for Panther Physical Therapy in Hampton. "They work better than weights because they are able to isolate the foot and ankle movements better.
"We give them to our patients to take home with them, so they can supplement what we do in rehab and they can recover more quickly," Dr. Karr said. "They're small, they're not cumbersome, they're less expensive than weights."
Elite athletes such as Pittsburgh Steelers safety Troy Polamalu have largely replaced weights with resistance bands in their off-season conditioning programs.
"Research demonstrates that elastic resistance training provides as much benefit in strength gains as the use of more expensive and cumbersome weight training equipment," said strength and conditioning expert Phil Page, who has worked with football players for the New Orleans Saints and Seattle Seahawks.
And working with bands provides benefits that can't be obtained from workouts with weights.
"Specific movement patterns relating to a sport. That's when bands are really beneficial," said Ron DeAngelo, director of sports performance training at UPMC's Center for Sports Medicine. "We use them for lateral movements. If we really want to strengthen a person doing side-to-side movements, we'll use the bands a lot."
"If you are comparing bands with machines, bands are a lot more superior, because they allow you to deal with gravity, balance and ground reaction," Mr. DeAngelo said. "Your body is always going to adapt better when it is in a position of function."
A primary benefit of bands over weight machines is that bands "allow you to work groups of muscles rather than isolating muscles," Mr. DeAngelo said.
"Elastic resistance allows you to exercise multiple joints and planes in a standing position [rather than seated on machines], thus bringing more core training into the same machine-based exercise," said Mr. Page, who has written a book on resistance bands, "Strength Band Training" (Human Kinetics, 2011).
Resistance bands are making their way into local health clubs. At Club One in Shadyside, managing partner Chris Labishak has installed on the main exercise floor a rack to which to tie resistance bands, and instruction in their benefits, and use is offered in introductory sessions for new members.
Mr. Labishak said he put in the rack because "before I built this, the [personal] trainers were tying the bands to everything."
A studio upstairs is also devoted chiefly to resistance bands.
The chief evangelist for resistance bands at Club One is Shawn Horwat, 29, who has been a personal trainer for 10 years.
"I can't think of anything you can't do with them," he said.
All of his clients -- he works with about 50 people a week, on average -- use resistance bands, Mr. Horwat said. Some use only resistance bands for strength training.
"I like the bands for young athletes, and for the elderly," he said. "They're more complex, more dynamic, they hit more muscles."
A major advantage of bands over barbells and dumbbells is safety.
"You don't have to worry about dropping them on your toe," West Penn Hospital's Dr. Swan said.
And bands are more flexible, figuratively as well as literally. Bands enhance stretching exercises, and even can be used for cardiovascular exercises. In the upstairs studio, Mr. Labishak has a band anchored where sprinters can practice more explosive starts.
"By simply varying the level of resistance, the number of repetitions and the speed of the exercise, you can tailor a program for weight loss, body toning, general strength and conditioning, or you can improve speed, power and agility for sports," Mr. Page said.
Although bands can substitute for free weights in resistance training, experts say they work well together.
"We use bands in conjunction with barbells and dumbbells," Mr. DeAngelo said. "For instance, bands enhance the squat a little bit more."
Dr. Swan said she discourages the use of barbells in rehabilitation "because you can hurt yourself." But West Penn uses hand weights in addition to bands.
"We don't use machines at all," Mr. DeAngelo said. "They're not functional. They're one-dimensional, and we're not one-dimensional. We're three-dimensional. You have to train that way."
Despite the attention his trainers give to bands, the weight machines at Club One remain as popular as ever, especially with newcomers, Mr. Labishak said.
"It's the convenience," he said. "You just move the pin [to change the weight]."
Another reason for the popularity of weight machines despite what experts say are their inferiority to both bands and free weights is that with weight machines, a person knows how much weight he or she is lifting, Mr. Labishak said.
"The downside of bands is they are not calibrated," Mr. DeAngelo said. "You don't know whether you are working against 100 pounds, 300 pounds, whatever."
But bands have had an impact on the strength training habits of Club One members, Mr. Labishak said.
"We used to see people transitioning to free weights," he said. "Now, not so much."
Thera-Bands come in eight color-coded levels of resistance. They can be purchased through Amazon.com for less than $10. Packages with accessories are more.
Correction/Clarification: (Published December 18, 2010) In a Dec. 6 story, "Resistance Bands Growing in Popularity," the name of an expert at Panther Physical Therapy was misspelled. He is Sean Karr.
Jack Kelly: email@example.com or 412-263-1476.