Grant: Travel Awards - Institute Community Support

Simple human movements are far more complex than we typically perceive them to be. The brain must send the appropriate signals to over 600 muscles in order to move 200 bones with precision in order to complete a movement such as a one-legged hop. Our lab uses a special analysis technique called muscle synergies that allows us to group the brain signals into different clusters so that we can compare brain signals between groups such as males and females. Since the incidence of knee injuries has been recorded to be as high as 4.6 times greater in females than in males, it is plausible that the underlying mechanism of these injuries is caused by different signals from the brain to the muscles that are supposed to be protecting the knee. Nine healthy (23.8 ± 1.5y; 5 male) participants were collected for this study and after informed consent, they all completed three one-legged hops. During these hops, we recorded the electrical activity that comes from the brain to the leg muscles using a method called electromyography. Through the use of our muscle synergies, we were able to identify many sex-related differences in how the muscles were firing during the one-legged hop. What we believe to be the most important difference is that at the time of impact, males had their muscles that protect the knee fire to a greater extent than the females. These same muscles were activated slightly later in the females once the large forces that are capable of causing injury have dissipated. Therefore, these altered muscle firing patterns have the potential to be the root cause of the increased incidence of knee injuries in females.