calf stretches and brain function

Recently, I came across the following written by Cecilia Koester, one of your practitioners:

"If you were to do some lengthening activities with your child, the brain will respond and he/she will become more able to focus. For example, in Brain Gym we have a movement called the “calf pump.” It is similar to the “runners’ stretch.” Extend your right leg behind you and as the heel is touching the floor, hold it down for approximately 8 seconds and release. Repeat 7-8 times and then repeat with the other leg. This should take about one minute on each leg. This movement stimulates the brain by using the body and subsequently the neurological flow increases and we are able to comprehend our task with greater ease."

Please tell me what actual evidence there is that stretching one's calf muscles stimulates the brain, increases neurological flow, and helps us comprehend tasks with greater ease. By "evidence" I'm referring to any supportive opinions or research from neurologists, psychologists, physical therapists or other professionals not affiliated with Brain Gym.