From Solid Mechanics to Biomechanics
– Musings of Dr. Jamie Hsu, 10.16.2019
As I age and begin to pay more attention to my aching body, my interest is changing from my Ph.D. in Solid Mechanics to the biomechanics of how my body works.
During my doctoral program, my thesis was on “Stress Wave Propagation in Solids” and “Material Properties and Behavior in High Rate Impact.” The research findings were relevant to missile firing, rocket launching, and seismic wave propagation during earthquakes. I conducted experiments, solved equations, proposed hypotheses, and validated new findings. It was an interesting and rewarding experience, but it never directly touched my personal or professional life.
After retiring from GM and my professional career, I had more time to pursue other interests like golf and body strengthening exercises. It was fun for a while until my age caught up with me. I began to experience muscle strains, knee pain, and back injuries. This prompted me to begin my novice’s journey into the field of biomechanics. It was an eye-opener for me.
I began to realize the kinematics and differences in walking, jogging, and running. There are different muscles involved in the way we push, pull, and lift our legs, and how we move from heel to toe when walking. The impact and load on our bodies will vary depending on our stride and speed, and the way we engage our muscles. I have finally learned why my back feels sore due to improper postures.
A golf swing is a lot more complex. The coiling, bending, twisting, and turning requires a lot of muscles to move in sync. No wonder I had such a tough time hitting the ball straight. I also learned from my therapist that my back pain is due to “the big muscles overpowering the small muscles” in my body. That understanding has prompted me to do more core strengthening and small muscle exercises. It seems to help quite a bit. I hope it will last.
That is my journey from solid mechanics to biomechanics. Learning is indeed endless and everywhere. Do you have similar journeys in your professional and personal lives?
從固體力學，到人體力學
-作者 許俊宸博士
-中譯 薛乃綺
隨著年紀增加、開始注意到身體一些老毛病，我的興趣逐漸從博士學位念的固體力學，轉變成身體如何運作的人體力學。
過去念博士班時，我的論文題目是”固體應力傳遞” 以及”高速衝擊下的材料特性與行為”。研究結果與導彈發射、火箭發射以及地震時的振波有相關聯。我進行了實驗、解出了方程式、提出了假設、並驗證了新的發現。那是個有趣且有意義的經驗，但卻從未對我個人或工作發生什麼直接的影響。
從GM退休後，我有更多的時間去追求自己其他的興趣嗜好，像是打小白球以及鍛鍊體能。有好一陣子都還蠻有趣的，直到我開始有上了年紀的退化感覺。我經歷過肌肉拉傷、膝蓋疼痛、背部還受了傷。這驅使我進入了生物力學的領域，開始去多了解人体，也讓我大開眼界。
於是我了解到步行、慢跑和跑步的學問與差別。當我們在推、拉及抬腿時，從腳跟，腳趾頭，到背部和肩膀，都用到了不同的肌肉。對我們身體的衝擊與負荷，也會因為我們踩的步伐與速度，以及肌肉鍛鍊的方式而有所變化。我終於了解為什麼姿勢不正確，會導致背部和腰的痠痛。
高爾夫球揮桿可就更複雜多了。重心擺放、彎曲、扭轉、摔臂都需要许多的肌肉同步運動，才能做到顺而有力的揮桿。難怪我很難打到直球。我也從治療師那邊知道，我的背痛是由於大肌壓迫拉动到小肌所造成的。這樣的理解也促使我做更多核心訓練和小肌肉的鍛鍊。效果似乎還不錯，希望能持續下去。
以上是我從固體力學一路到人体力學的心歷路程。深深体会到每件事裡都有許多的學問，真是活到老學到老。你是否在生活中或職場中也有類似的經歷呢？
