( periods when the neurons fire faster f...)When your brain talks, your muscles don't always listen

The results showed lower firing rates among older subjects versus younger subjects--a diminished ability of the muscle fibers to "hear" and respond to the neurons' commands.

"The repeated contraction of muscles is essential to movements such as walking," Knight said. "However, our muscles have a reduced capacity to contract or 'twitch' as we grow older. We lose fast-twitch muscle fibers as we age."

However, there are steps we can take to preserve this critical motor capacity, according to Knight.

"After power training with weights, we see an increase in firing rates," Knight said. "For safety, we're commonly advised to do things slowly when exercising, but it's important to also do some fast exercises. You need a fast movement to prevent a fall. Even in the frail elderly, it is possible to use exercise bands for manual resistance to improve the speed of movement."

Knight has always been interested in how the body adapts to exercise. When he entered college years ago, his goal was to become an elite track-and-field athlete. While he competed well, he realized that his dreams lay elsewhere, and his attention focused full force on academics.

At the University of Connecticut, a class on the biology of the brain introduced him to the nervous system and movement, and he was hooked. His interests were further piqued during a summer research experience, where he had the opportunity to work with wheelchair athletes.

"People with severe spinal cord injuries have limited cooling because they can't perspire below the site of injury," Knight said, "so their core body temperature can reach dangerous levels."

In graduate school, he decided to pursue motor control research, and he's never looked back.

"My early interests were based on sport, but my career in this field now allows me to address a much larger population that
'"/>

Source:University of Delaware