MONDAY, April 11 (HealthDay News) -- Progressive resistance training helps older adults build muscle and increase their strength to function better in daily life, researchers say.

A team at the University of Michigan Health System conducted a review of available evidence and concluded that an adult can add 2.42 pounds of lean muscle to their body mass and increase their overall strength by 25 percent to 30 percent after doing an average of 18 to 20 weeks of progressive resistance training.

The findings were published recently in the American Journal of Medicine.

In progressive resistance training, the amount of weight used, and the frequency and duration of training sessions, increase as a person's strength capabilities improve.

Sedentary adults over age 50 normally lose up to 0.4 pounds of muscle per year.

"That only worsens as people age. But even earlier in adulthood -- the 30s, 40s and 50s -- you can begin to see declines if you do not engage in any strengthening activities," Mark Peterson, a research fellow in the Physical Activity and Exercise Intervention Research Laboratory at the physical medicine and rehabilitation department, said in a university news release.

"Our analyses of current research show that the most important factor in somebody's function is their strength capacity. No matter what age an individual is, they can experience significant strength improvements with progressive resistance exercise even into the eighth and ninth decades of life," he said.

Anyone over age 50 should give serious thought to doing resistance exercise, Peterson recommended.

More information

The U.S. Centers for Disease Control and Prevention has more about strength training for older adults.