Life Lines: Biomechanics — The science of body motions
By Elof Axel Carlson
Nedra had her right knee replaced on Sept. 13, 2017, and our daughter Christina and I waited in Indiana University’s General Hospital in Bloomington. She was groggy after some of the anesthesia wore off, and I was surprised that during the same day she was shown how to get out of bed and use a walker to get to the bathroom.
The next day she learned from an occupational therapist how to dress and undress. Also that second day she learned about 10 different exercises in bed to move her right leg. This included sliding her foot along the bed back and forth with her knee elevated and doing a half snow angel movement with her right leg.
I vaguely knew that the mechanics of body motion were first worked out by Giovanni Borelli (1608-1679). Borelli was taught by one of Galileo’s students and was skilled in mathematics, physics and medicine. He also used a microscope for his studies and discovered the stomata of plant leaves and the corpuscles in blood. He did experiments and claimed all body motion is caused by muscle contractions and he worked out the mathematics of animal motion, identifying where the limbs were in relation to the body’s center of gravity.
One of the marvels of being a conscious organism is our capacity to interpret the things we do. Many of those things — like walking, running, holding things or grooming our bodies — we do without a knowledge of the science that is involved in making them possible. We also assign other functions to body motions besides their pragmatic uses. Nedra and I both take Tai Chi for Arthritis at our local YMCA and the slow graceful motions provide exercise of all our joints. The “chi,” or vital energy, I equate in my mind with the same sensation as phantom limbs for amputees, which is neurologically based and not a psychiatric lament for the slow withdrawal of that feeling.
Body motion is paramount for those who dance, relating motion to music and the bonding and unbonding of partners as they go through a dance routine. Judo and tae kwan do are martial arts and can be used for aggressive or defensive activities among combatants. Yoga provides a spiritual aspect to body motion accompanied by meditation for those who practice it. Virtually all of us enjoy spectator sports whether watching baseball, football, basketball, tennis or the myriad of activities in winter or summer Olympic Games.
Anatomists today are well acquainted with the way muscles and bones and their tendons interact for any motion of our limbs, neck, head, hands, feet or other parts of our body. The one activity I did not include in this list is one that I find particularly appealing. The name given to it was by Thoreau who tells us in his Walden diaries that he enjoyed sauntering. It is walking with no direction or goal in mind, just wandering about in the woods or along a stream to take in the delights of nature and to stimulate thoughts for his writing.
When I was in high school and as an undergraduate, I loved solitary walks through Central Park in Manhattan, and my favorite discovery was a spot where I could sit and there were no buildings from Central Park West or Fifth Avenue visible to my eye. I thought of myself as an urban nature boy.
Nedra spent three days in the hospital and she then moved to a rehabilitation facility in a retirement community called Bell Trace. It is nice to see Nedra doing her exercises, converting pain into progress, and we look forward to her returning to our home which will be safety checked before she arrives to prevent slips and falls. For those coming days and weeks our daughter Erica, followed by two of our granddaughters and their husbands, will be out to enjoy Nedra’s progress to experience the confident walking by those with successful knee surgery enjoy.
Elof Axel Carlson is a distinguished teaching professor emeritus in the Department of Biochemistry and Cell Biology at Stony Brook University.