TAMPA — In the military, back pain is considered a "silent killer" and a "lingering pain of war."
While not as immediately disabling as the blast injuries seen in combat in Iraq and Afghanistan, the toll is still huge. After retirement, back pain is a top reason that soldiers leave service, according to researchers at the University of South Florida studying a potential source of relief.
With a grant from the Department of Defense, the USF team aims to see if exercise can prevent back injury. They're examining an intensive regimen using a high-tech machine that allows trainers to target the specific muscles involved in lower back pain.
The study of 600 combat medics in training at the Fort Sam Houston Army base in Texas could have implications for millions of Americans suffering back pain.
Nearly everyone eventually experiences back pain, the second leading neurological ailment after headaches, according to the National Institute of Neurological Disorders and Stroke. Back pain costs Americans $86 billion a year spent on surgeries, injections, pain pills and other treatments.
And once someone has experienced chronic back pain — an episode lasting three months or longer — even if they find relief, the injury is likely to recur, noted Dr. John Mayer, a chiropractor and associate professor at the USF College of Medicine, who is leading the study.
In the military, he added, back pain is especially endemic among field soldiers who routinely carry 50 to 100 pounds of gear as they walk across uneven terrain.
"It causes problems for the individual like severe disability, and problems for society at large if they are there to protect us and can't," he said.
"Once they have back pain," he added, "a large majority don't go back" to combat duty.
To try and break the cycle, USF researchers are looking into the effectiveness of high-intensity exercise on a machine designed to strengthen the lumbar paraspinal muscles, located between the pelvic area and the rib cage. They are atrophied in people with lower back pain.
Beginning this spring, researchers from USF and their co-investigators will randomly assign soldiers to two regimens. Half will train once a week for 12 weeks on a $75,000 machine that isolates the lumbar muscles.
Soldiers in the other group will do low-intensity core exercises, such as floor crunches and plank holds, which conditions back, abdominal and pelvic muscles.
Researchers will measure the strength, stability and endurance of the soldiers and how they liked each approach. The study could become the first phase in a longer-term investigation.
The machine involved, the MedX Lumbar Extension Dynamometer, is at least four times the size of typical gym equipment. It isolates the lumbar spinal muscles, which is the key to working them intensely.
In other back exercises, Mayer noted, people can shift the load onto their hips and abdominal muscles. With the high-tech equipment, users are belted in a seated position, a restraint pulled tightly around their thighs. They work their lower back muscles by slowly moving back and forth, pushing against weights. A typical soldier could be pushing at least 200 pounds.
The soldiers must go until they are too fatigued to continue, typically after 20 repetitions and two or three minutes.
Benefits level off after 12 weeks. After that, strength can be maintained by using the equipment once to twice a month.
"We think this is a perfect fit for (the military)," he said. "They like high intensity and they don't have extra time in the day."
The approach may have applications for others at high risk of back injury. The machine has been studied on coal miners, Mayer said, with early results showing fewer back injuries.
The back pain study is one of two research efforts for which USF has received $1.6 million in defense funding. The other will examine prosthetic feet that might help soldiers who wish to return to active duty.
Letitia Stein can be reached at firstname.lastname@example.org or (813) 226-3322. For more health news, visit www.tampabay.com/health.