The researchers say their findings show the importance of encouraging people of all abilities to be active through life.
Previous research suggests the better our physical performance in middle age, the more likely we are to retain our independence and cope with everyday activities in old age, such as carrying our shopping and getting dressed.
Researchers who study this area usually employ a number of tests - such as handgrip strength, balance, chair rises, jumping height (a measure of leg strength), and back strength - when measuring physical performance.
For their study, researchers at the University of Copenhagen in Denmark examined the relationship between intelligence in early adulthood and subsequent physical performance between the age of 48 and 56 years, in a group of 2,848 Danish men born in 1953 or 1959-61. The data came for the Copenhagen Aging and Midlife Biobank.
They found that every 10-point increase in intelligence score in early adulthood was linked to a 0.5 kg increase in back force, a 1 cm increase in jumping height, a 0.7 kg increase in hand-grip strength, 1.1 more chair rises in 30 seconds and 3.7% improved balance in midlife.
Policies should encourage people of all abilities to be active through life
Rikke Hodal Meincke, first author and doctoral student at Copenhagen University's Center for Healthy Aging and Department of Health, says:
"Our study clearly shows that the higher intelligence score in early adulthood, the stronger the participants' back, legs and hands are in midlife. Their balance is also better."
She and her colleagues conclude their findings could be important for drawing up and implementing initiatives to get people from all walks of life, regardless of ability, to stay physically active throughout life.
However, Hodal Meincke urges more studies be done to find the reasons behind the links they found. Other researchers have, for example, suggested that childhood factors, exercise, health status and socioeconomic background may also affect physical performance in later life.
One explanation, she suggests, could be that more intelligent people find it easier to understand health information - such as advice on lifestyle and exercise - and put it into practice.
Last month, Medical News Today reported the findings of three studies that showed not only is it likely that physical exercise reduces risk of developing Alzheimer's disease and vascular dementia - it may also serve as an effective treatment.
For example, one of the studies found that aerobic exercise reduces levels of tau protein in the brain, one of the hallmarks of Alzheimer's disease. There are currently no approved drugs that rival such an effect, the researchers noted.