Professor Steven Lehman

Dr. Steven Lehman

Dr. Lehman studies muscle physiology, from the cellular level to the human scale.

Research

Dr. Lehman is an integrative physiologist whose research starts with questions at the human scale, but often involves experiments at the cellular scale. He uses mathematical models to understand function at a systems level, given more particular data.

His lab is currently working on how muscles store and dissipate energy, and how repetitive motion relates to muscle fatigue.

How Muscles Store and Dissipate Energy

During locomotion stretched muscles store and release energy. During rapid voluntary movements, stretched muscles act as brakes to dissipate energy. Control of energy storage and release is a key problem in motor control. To determine how muscles store and dissipate energy, Dr. Lehman conducts experiments on single muscle fibers in vitro.

He describes the biomechanics of the muscle fibers, builds mathematical models that simulate those mechanics, and conducts tests of the models by changing the physical and chemical environment of the fibers. The goal is to characterize force production, energy storage and dissipation, then extend the fiber model back to the whole animal scale, and compare model predictions to experiments at each stage.

Ergonomics and Muscle Fatigue

Repetitive movements cause musculoskeletal disorders, such as carpal tunnel syndrome and tendonitis. They also cause muscle fatigue.

The Lehman lab has recently characterized the relationship between repetitive work and low-frequency fatigue, a type of muscle fatigue caused by failure of excitation/contraction coupling. By using fatigue to measure repetitive work, Dr. Lehman and collaborators hope to identify and eliminate high-risk tasks in the workplace.

Dr. Lehman: Q&A

Why did you decide to become a scientist ?

I have always been curious about the natural world, and I have always loved mathematics. As a Peace Corps Volunteer, I learned that I also enjoy teaching.

To combine experimental work and mathematical modeling to discover how our bodies work, and to teach this to bright, motivated students is the best of all worlds for me.

What led you to the questions you are now investigating in your research?

While studying the control of rapid voluntary movements, I learned that muscles often act as brakes, but the mechanics of stretched muscles were barely understood -- data were insufficient to describe or predict energy dissipation or storage.

The first class I taught here was about fatigue. I learned that muscle fatigue has many sites and mechanisms, and that the most common kind in today’s workplace is the least investigated.

Collaborations with wonderful colleagues and graduate students also inspire my work.

How does your research affect your classroom and/or lab?

Both of my undergraduate classes have lab components, and some of the lab exercises students do in the physiology and motor control classes originated in my research lab. I also include our research and new research I learn about at meetings in my lectures.

What do you enjoy most about your research?

I enjoy hands-on work in all aspects of my research. I like to design experiments, to build equipment and write programs, to invent and analyze mathematical models, and to work individually with students.

January / February 2007