- Retirement-age people who underwent a 12-month weight lifting training regimen had noticeably stronger leg muscles three years after finishing the program than those who did more moderate strengthening exercises or none at all, the study found.
- The weight lifting training group visited a commercial gym three times a week for a year and repeatedly lifted what was considered a heavy load: 70 to 85 percent of the maximum weight a person can physically lift at one time.
- Although the supervised program lasted only a year, scientists followed up three years later. Individuals in the “heavy” weight lifting cohort were the only participants to have maintained, on average, the leg strength they had before they began the training program.
Notably, leg strength is a critical indicator of wider health and mobility among older people. The findings add to a growing body of evidence suggesting that weightlifting can help older people stave off frailty and stay healthy as they age.
“Leg strength is really important,” Mads Bloch-Ibenfeldt, a medical researcher at the University of Copenhagen who co-wrote the study, said in a phone interview Wednesday. “We use the legs in a lot of everyday tasks, like getting up and down from a chair. So it’s important for reducing the risk of falls, and for a lot of everyday tasks we do.”
The weight lifting workout
As part of the study, scientists at a university hospital in Copenhagen divided 451 people at retirement age into three randomized groups, each tasked with completing a different one-year exercise regimen.
- The “heavy” weight lifting training group visited a commercial gym three times a week for a supervised program of full-body strength training.
- Participants determined the most weight they could lift at one time using typical weight machines found in gyms. Then they calculated 70 to 85 percent of their one-rep maximum and used that weight in their training. So if the most they could lift at one time was 100 pounds, they used 70- to 85-pound weights in their training.
- They trained 3 times a week, doing three sets of every exercise. Each set included 6 to 12 repetitions.
- The routine included a mixture of nine upper and lower body exercises: leg press, knee extension, leg curl, ankle plantar flexion exercises, hip abduction, low rowing, chest press, abdominal crunches and lower back exercises.
- Although the scientists described the regimen as “heavy” weight lifting compared to two other groups in the study, the weight training program may be similar to many standard weight training routines.
Heavy weight training vs. moderate resistance
The second group underwent a year-long moderate intensity training regimen using body weight and resistance bands three times a week. The resistance bands were less challenging than the heavy group’s weights — about 50 to 60 percent of the maximum weight a person can lift at one time.
The third cohort was a control group who did less than one hour of strenuous exercise a week.
Over four years, scientists observed participants’ physical strength, including leg strength, handgrip strength and lean leg mass. Researchers measured participants’ strength at the beginning of the supervised 12-month training regimen, then again after it ended. They followed up again one year after it finished, and three years after it ended.
After three years, researchers noted that a small minority of exercise participants had continued with the same program of their own accord, yet the benefits of the heavy training workout were maintained.
“We found that if you did one year of resistance training with heavy weights, you were able to maintain the strength in your legs that you had when you began the study,” Bloch-Ibenfeldt said.
The other groups were found to have lost strength from their baselines. Four years after the start of the study, leg strength performance decreased on average among those in the moderate intensity training cohort and the non-exercising control group — although more significantly among the latter. Those who did the moderate program initially benefited from increased leg strength at the end of the one-year regimen, but those benefits did not endure: After four years, their strength was less than it had been at baseline.
The scientists observed that all three groups, including those lifting the heaviest weights, exhibited diminished handgrip strength and a lower lean leg mass after four years.
But the fact that the heavy lifting group had maintained their baseline leg strength while losing lean leg mass was notable, the authors observed, underscoring some of the potential neuromuscular benefits of weight training beyond building muscle.
“Neural adaptations influence the response to resistance training,” they wrote. “In conclusion, we showed that in a group of well-functioning older adults around retirement age, one year of (heavy resistance training) may induce long-lasting beneficial effects by preserving muscle function.”
At the end of the study, the average age of the 369 remaining participants was 71 years old and included 61 percent women.
The researchers noted that the participants were likely to be healthier and more active than the average aging population, given that they averaged almost 10,000 daily steps as a sample group. They noted that this group was not necessarily a representative sample of the wider population.
Also, the one-year training regimen, was supervised, with people’s technique and load monitored and adjusted, meaning it might be difficult for people to replicate on their own.
Why leg strength matters as we age
According to research by the National Institute on Aging, age-related loss of muscle mass and strength — known as sarcopenia — is a significant contributor to limited mobility in older age, which in turn can threaten a person’s physical independence. Older people with limited mobility can have difficulty walking, ascending stairs, and getting out of chairs.
Leg strength in particular — which is crucial for balance and mobility — is associated with better health outcomes for older adults. Research suggests that people older than 50 with lower levels of leg power are more likely to also experience chronic health conditions, although more research is needed.
Federal guidelines suggest adults older than 65 should do muscle-strengthening activities every week, as well as regular aerobic activity and exercises to improve balance.
“In addition to aerobic activity, older adults need to do things to strengthen muscles at least 2 days a week. Do muscle-strengthening activities to the point where it’s hard to do another repetition without help,” the Centers for Disease Control guidance states. According to the CDC, this could include lifting weights, working with resistance bands, or doing body-weight activities like sit-ups.
