In the treatment of back strain, bed rest should be limited in duration, and regarded as only part of a program of recuperation, according to a physician at New York University Medical Center.

"Prolonging bed rest beyond a week or 10 days may perpetuate stiffness and weakness," said Dr. Joseph F. Fetto, clinical assistant professor of orthopedic surgery.

"Although a degree of inactivity may be required to allow injured tissues to heal, too much immobility will lead to weakening and atrophy of the muscles," Fetto maintained. "The longer the rest, the more time it takes to restore muscle function."

An article in an upcoming issue of the center's Health Letter explains that back strain is a general term for injury due to the tearing of muscles in the back. There are three grades of strain, ranging from microscopic damage to muscle fibers, resulting in soreness without bruising or swelling (grade 1), to severe tearing with tissue damage, resulting in hemorrhage - visible as black-and-blue areas - and swelling (grade 3). Grade 2 falls between.

"Since back pain may indicate a serious problem, evaluation is advised to determine the exact cause and its severity," Fetto stated.

He outlined a treatment program for back strain that includes medication to relieve pain, swelling, and muscle spasms: cold packs: and respite from strenuous physical activity, followed by a gradual return to gentle reconditioning exercises. If back muscles are in spasm, muscle relaxants may be prescribed. In some cases, 7 to 10 days of bed rest may be part of treatment. "Bed rest is an appropriate initial phase for grades 2-3 injury," Fetto noted. "If there was much damage, with pain and bleeding into surrounding tissues, bed rest is required." From 24 to 48 hours are needed for bleeding to stop, 3 to 4 days to prevent its restarting.

"Strict bed rest means remaining in bed except for trips to the bathroom with assistance," he said. "Modified bed rest permits the person to get up for meals, baths and modest daily activity, while avoiding any activity accompanied by pain."

When in bed, Fetto recommended lying on the back with a pillow behind the knees to take pressure off back muscles. "Apply ice packs for 15 minutes every few hours. Do not apply heat: while a heating pad or warm compress might feel soothing, it increases swelling and bleeding in injured tissues, which leads to more pain and stiffness."