Locomotion Laboratory Clare 106 and 111 phone: 303-492-0926 fax: 303-492-4009

Research Interests

• The biomechanics, energetics, and neural control of walking and running.

Personnel

• Co-Directors: Claire T. Farley, Ph.D. and Rodger Kram, Ph.D.


• Graduate Student:



• Collaborators: Alain Belli, Ph.D., University of St. Etienne, France; Chris Hurt, M.S., University of Illinois at Chicago; Jinger Gottschall, Ph.D., Penn State University; Justus Ortega, Ph.D., California State University at Humboldt; Max Donelan, Ph.D., Simon Fraser University, Canada; Nitin Moholkar, Ph.D., Kessler Rehab Insitute, New Jersey; Ray Browning, Ph.D., Colorado State University; Rick Neptune, Ph.D., University of Texas at Austin; Craig McGowan, Ph.D. University of Texas at Austin; Todd Gleeson, Ph.D., University of Colorado at Boulder; William Byrnes, Ph.D., University of Colorado at Boulder; Peter Zani, Ph.D., Lafayette College, Easton, Pennsylvania.

(L to R): Back row -- Kenny Mensch, Rodger Kram, Matt Ashley, Jon Priebe; Front row -- Alena Grabowski, Erin Waddrip, Jamie Bartlett, Joss Talbot, Craig McGowan

Current Research Projects

• Control of Leg Stiffness in Running (Moholkar, Farley). To identify the mechanisms used to modulate leg stiffness when runners vary their stride frequency.


• Effect of aging on biomechanics and metabolic cost of walking (Ortega, Farley). To determine the mechanisms underlying the high metabolic cost of walking in older adults.


• Biomechanical Basis for the Energetic Cost of Human Walking (Kram, Grabowski, Browning, Bartlett, Priebe). Muscles must perform at least four functions during walking: (1) Generate muscular force to support body weight; (2) Perform mechanical work to redirect and restore the center of mass velocity during the step-to-step transition; (3) Swing the legs; and (4) Maintain stability. We are performing a series of experiments that manipulate one or more of these functions so as to quantify the cost of each function in normal healthy adults. In addition, we are investigating the greater energetic cost of walking by obese persons and the underlying mechanisms for the greater cost.


• Biomechanical Basis for the Energetic Cost of Human Running (Kram, Grabowski, Warddrip). In running, our research shows that generating force to support body weight is the major biomechanical factor determining metabolic cost. However, we have found that generating forward propulsive forces comprises about 30% of the cost of running and leg swing appears to consume about 10%. We continue to refine these ideas as to how the cost changes with speed and grade.


• Comparative Locomotion Biomechanics and Energetics (Kram, Zani, Gleeson, Hutchinson, Donelan). We continue to study different animal species that exhibit exceptional locomotion. For example, we are studying elephant and crocodile locomotion to understand the extreme of gravitational constraints. We are studying giant Galapagos tortises and other turtles to understand if their exceptionally efficient muscles and slow gait result in exceptionally economical locomotion.

Opportunities for Undergraduates

• Prof. Kram is on sabbatical until August 2009 and thus there are no current laboratory opportunities for undergraduates. The following information is for applicants after August 2009.


• The requirements for undergraduate students who want a research experience in our Laboratory are:
• Completed at least one year in college.
• Will be at CU for at least two more semesters.
• Available for 8-10 hours of time per week in blocks of 2-4 hours at a time.
• IPHY, MCDB, PSYCH, Applied Math, and Engineering majors are accepted.


• For more information, contact Prof. Rodger Kram (rodger.kram@colorado.edu)

Recent Publications

• Bartlett JL, Kram R. Changing the demand on specific muscle groups affects the walk-run transition speed. Journal of Experimental Biology 211: 1281-1288, 2008.


• Browning RC, Kram R. Effects of obesity on the biomechanics of walking at different speeds. Medicine and Science in Sports and Exercise 39:1632-1641, 2007.


• Browning RC, Modica JR, Kram R. The effects of adding mass to the legs on the energetics and biomechanics of walking. Medicine and Science in Sports and Exercise 39:515-525, 2007.


• Chang YH, Kram R. Limitations to maximum running speed on flat curves. Journal of Experimental Biology 210:971-982, 2007.


• Ortega JD, Farley CT. Individual limb work does not explain the greater metabolic cost of walking in elderly adults. Journal of Applied Physiology 102:2266-2273, 2007.


• Teunissen LPJ, Grabowski A, Kram R. Effects of independently altering body weight and body mass on the metabolic cost of running. Journal of Experimental Biology 210: 4418-4427, 2007.