According to a recently published article in ‘Gerontology,’ leg power has a strong correlation to total grey matter in aging adults. Steves, Mehta, Jackson and Spector conducted a study that compared the differences in leg power and cognitive aging in twins. By using sets of twins, biological factors such as genetics could be controlled, and not have an effect on the difference between the two individuals in each set (think: nature versus nurture – genes versus environmental factors). Previous studies using twins had shown that approximately 33% of one’s fitness could be attributed to genetic factors. There has also been a strong correlation between genetics and cognitive aging.

In order to measure cognition, the researchers used seven computerised tests on a total of 324 female twins. There were two variables of fitness, one being leg extension power and the other being a self-reporting physical activity questionnaire. Each of these measures were taken at baseline and again 10 years later. They compared the amount of cognitive decline, or “age-related cognitive change” after the test at ten years, and compared the results between twins. Additionally, 20 pairs of twins were tested using MRI imaging, and grey matter volume was calculated from the medial temporal lobe (MTL) and the middle frontal gyrus (MFG). The MTL is a region of the brain that includes the hippocampus, which is responsible for emotions, memory, as well as functions such as breathing, heartbeat, etc. The MFG is a region of the brain associated with conscious movement.

Results of the study showed that there is a relationship between greater muscular fitness and improved cognitive aging over 10 years in non-impaired women. There was a weak correlation between self-reported fitness and cognitive function compared to that of the discrete leg power test. This means that leg power and cognition could be associated with each other and not associated with factors such as genetics alone. Alternatively, the results of the study could suggest that common pathways exist, meaning that leg power is a marker of the amount of cognitive aging that can be influenced.

For more information, a pdf version of the published article can be found here: http://www.karger.com/Article/Pdf/441029