Groundbreaking UAB Clinical Trial to Identify Exercise Prescription for Older Adults

As the number of older adults in the U.S. steadily increases to an expected 70 million by 2030, health experts predict that sarcopenia — age-related muscle atrophy — has the potential to become an epidemic public health threat that could cause devastating functional limitations in older adults. Because resistance training has proven the most effective intervention against sarcopenia, UAB is conducting a groundbreaking, five-year clinical trial called the STRIVE II Project funded by the National Institute on Aging (grant 5R01 AGO17896). The focus of the study is to determine the most effective strength training program for improving muscle mass, bone density, and physical function in men and women aged 60 to 75.

Exercise — a Dose-dependent Prescription

“When healthcare providers give older patients instructions regarding exercise, their recommendations are often based on what is effective for younger adults,” explains Marcas Bamman, PhD, FACSM, STRIVE II Principal Investigator, Director, the Muscle Research Program of the Birmingham/Atlanta VA Geriatric Research, Education, and Clinical Center (GRECC) and the Clinical Exercise Facility, and UAB Center for Aging Associate Director. He says he is hopeful that the results of STRIVE II will help physicians view exercise recommendations as prescriptions – in a dose-dependent manner, just as pharmaceuticals are. “Also, if you’re going to ask patients to engage in an activity for one hour three times a week, you want to make certain it’s the right activity in the correct quantity that will achieve optimal results.”

Currently in its third year, the STRIVE II Project (Strength Training to Renew Independence, Vigor, and Efficacy) is a follow-up study to an earlier five-year clinical trial (STRIVE I) that compared the relative effectiveness of a standardized strength training prescription in young and older adult subjects. As part of STRIVE II, 88 subjects (44 men and 44 women) who have been pre-screened for serious health or physical limitations, including frailty, are randomly assigned to one of four exercise prescriptions for 30 weeks. All training sessions are private for the STRIVE II group and are conducted by certified trainers in the UAB Clinical Exercise Facility in the heart of the UAB medical school campus. Dr. Bamman says that initially, all participants engage in four weeks of the same training during an early adaptation and pre-training period. “This period is very important, as all subjects typically achieve rapid strength gains during this initial phase. Completing this phase before random assignment (to one of the four prescriptions) will enable us to better evaluate the four prescriptions being tested.”

Distinct Prescriptions, Routine Measurements

Upon completion of the initial pre-training period, participants are randomly assigned to one of four distinct exercise prescriptions: (1) high-intensity training on Monday, Wednesday, and Friday; (2) high-intensity training Monday and Friday, and low-intensity training on Wednesday; (3) high-intensity training Monday and Friday, and no training on Wednesday; and (4) high-intensity training on Monday and low-intensity training on Friday. “In the earlier STRIVE I study, muscle adaptations seen in young adults (20-35 yrs.) were superior to those found among older adults,” observes Dr. Bamman. “This may not be surprising to many, but we are not convinced that older muscles have a lesser ability to adapt; rather, it is a matter of manipulating the prescription to optimize gains. We hypothesize that the standard prescription we utilized for both young and old in STRIVE I did not allow the older adults sufficient time for recovery between exercise bouts. This is primarily based on our findings regarding differences in muscle stem cell recruitment between young and old. We’re testing this hypothesis in the STRIVE II study by building extended recovery periods into three of the four prescriptions.”

Every few weeks, STRIVE II participants undergo specific tests designed to measure the effects of the various strength training regimens. These include: MRIs to determine muscle size; DEXA scans to measure bone density; body fat percentage measurements; muscle fatigue, strength, and power measurements; EMGs to determine how well muscle can be activated voluntarily; muscle tissue and serum assays to study cellular and molecular processes involved in muscle growth; walking speed tests; and balance and coordination tests. “Our goal is to help older adults become stronger and better able to conduct routine activities,” says Dr. Bamman.

“Increased muscle strength achieved with resistance training will help prevent falls, for example. But if falls occur, the hip and spine will not be as susceptible to debilitating fractures as a result of increased bone density achieved through consistent strength training.” Another benefit to strength training, says Dr. Bamman, is that it may reduce the need for certain medications. “If the exercise prescription is optimal, polypharmacy — common among older adults — can be reduced.”

The Future of Dose-dependent Exercise Research at UAB

Dr. Bamman says that beyond the current STRIVE II trial, he and his colleagues have plans to conduct additional dose-response research aimed at identifying the most efficacious exercise prescriptions to improve specific conditions. “We want to carve a niche for UAB as a leader in dose-response exercise research,” he adds. Moreover, he says that a growing body of research has led to an increased understanding in the medical community that exercise and physical activity can be effective in preventing and treating many chronic diseases, paving the way for future research efforts.

“The American College of Sports Medicine (ACSM) and the American Medical Association (AMA) have formed a joint national education initiative called Exercise is Medicine™,” he explains. “The initiative recognizes the important role of exercise in preventing and treating disease and states that more should be done to address physical activity and exercise in healthcare settings. This initiative underscores the important future role of dose-dependent research in helping healthcare providers identify the most effective exercise prescriptions for their patients. ”