Research Interests

Karen Steudel’s research focuses on the relationship between structure and performance in mammalian locomotion and in applying the results of those studies to our understanding of the locomotion of fossil hominins.  Much past work in deducing function from structure in fossils has involved making assumptions about the biomechanical consequences of variations in bone structure.  Yet, when performance is directly correlated with aspects of morphology and physiology, these assumptions are not always supported.  A major focus of work in this laboratory involves grounding the assessment of adaptations in fossils in a much more rigorous context than had  been done previously. Other work has included further contributions to the discussion of the role of locomotor energetics in the evolution of bipedal posture and locomotion and in patterns of group movement in non-human primates.  I recently completed a series of experiments  documenting variation in the cost of both walking and running in modern humans related to limb length, stature, mass and % fat.  Relatively longer limbs result in lower locomotor costs in both walking and running speeds. The short limbs of Australopithecus would have been very energetically costly.  The fact that the short limbs were retained for at least a million years suggests that these hominids may have retained an arboreal adaptation.  The relatively short limbed Neanderthals would have had costs of walking approximately 30% larger than the anatomically modern humans that replaced them.  I am also looking at kinematic data to try to understand the basis for the economy of human walking and for why shorter limbs are more energetically costly.

Courses:

Zoology 101 - Animal Biology
Zoology 380 - Honors Proseminar
Zoology 679 - Thesis Progress Seminar
Zoology 680 - Honors Seminar

Graduate students currently supervised:

Michael Tilkens, mctilkens@yahoo.com
   Mike is working with me on determining whether there are gender differences in the energetic cost of human walking, whether leg length is important in maximum running speed or in resting metabolic rate, and methodological issues in measuring the cost of various activities.

Lisa Powers, lpowers2@wisc.edu
   Lisa is investigating pendular interactions between the forelimb and hindlimb in human walking with applications to  fossil hominins.

Postdoctoral associates currently mentored:

Cara Wall Scheffler, cscheffler@wisc.edu

Students supervised who recently earned graduate degrees:

Michelle Harris, MS 1994, Ph.D. 2000.
Now assistant faculty associate in the Biocore Program, University of Wisconsin - Madison

Yishai Wise, MS 1998. MD 2004.

Dean Faber, Ph.D. 1992.
Now Lecturer in Zoology, University of Wisconsin - Platteville.

Marcella Myers, Ph.D.
Now Associate Professor, College of St. Catherine, St. Paul, MN.

Kevin Strang, MS 1988.
Now Assistant Researcher/Lecturer, Department of Physiology, Medical School, University of Wisconsin - Madison

Selected Publications

• Steudel-Numbers, K., T.Weaver and C.M. Wall-Scheffler (2007). The Evolution of Human Running: Effects of Changes in Lower Limb Length on Locomotor Economy.  J. Hum. Evol. 53:191-6.

• Tilkens, M. C., Wall-Scheffler, T.D. Weaver and K. Steudel-Numbers. (in press) The effects of body proportions on thermoregulation: An experimental approach. J. Hum. Evol.

• Wall-Scheffler, C.M., Geiger, K., and Steudel-Numbers, K. (2007). Infant
  Carrying:  The role of increased locomotory costs in early tool development. American Journal of Physical Anthropology 133(2): 841-846.

• Steudel-Numbers, K. (2006) Energetics in Homo erectus and other early hominins: the consequences of increased lower limb length. J. Hum Evol. 51:445-453.

• Wall-Scheffler, C.M., Myers, M.J. and Steudel-Numbers, K. (2006) The application to bipeds of a geometric model of lower-limb-segment inertial properties.  J. Hum. Evol. 51(3):  320-326.

• Steudel-Numbers, K. and Weaver, T.D.  (2006 ) Froude Number Corrections in Anthropological Studies. Am. J. Phys. Anthrop. 131(1): 27-32.

• Weaver, T. and K. Steudel-Numbers (2005) Does climate or mobility explain the differences in body proportions between Neandertals and their Upper Paleolithic successors? Evol. Anthropol. 14: 218-223.

• Steudel-Numbers, K. and M. Tilkens. 2004. The effect of lower limb length on the energetic cost of locomotion: Implications for fossil hominids.  J. Hum. Evol. 47: 95-109.

• Steudel-Numbers, K. 2003. The energetic cost of locomotion: Human and primates compared to generalized endotherms. J. Hum. Evol. 44: 255-262.

• Harris, M and K Steudel. 2002. The relationship between maximum jumping performance and hindlimb morphology/physiology in domestic cats (Felix silvestris catus). J. Exp. Biol. 205: 3877-3889.

• Steudel-Numbers, K. 2001. The role of locomotor economy in the origin of bipedal posture and gait. Am. J. Phys. Anthrop. 116: 171-173.

• Steudel, K.  2000.  The physiology and energetics of movement: effects on individuals and groups. In: S. Boinski and P. Garber (eds.) Group Movement: Patterns, Processes and Cognitive Implications in Primates and Other Animals. U. Chicago Press. (refereed book chapter)

• Harris, M. and K. Steudel. 1997. The selection of hind limb length in the Carnivora: the influence of daily movement distance, home range area, prey size, latitude, and prey capture method. J. Zool., Lond. 241: 381-408.

• Myers, M.J. and K. Steudel. 1997. Morphological conservation of limb natural pendular period in the domestic dog (Canis familiaris): Implications for locomotor energetics.  J. Morphol. 234:183-196

• Harris, M.A. and K. Steudel. 1998. The relationship between maximal jumping performance and hindlimb morphology in domestic cats (Felis sylvestris catus). Am. Zool. 38: 35A

• Myers, M.J., A.J. Walker and K. Steudel. 1996. Comparison of three methods of determining lower limb natural pendular periods. Med. Sci. Sports Exer. 28: S46.