Tom Kernozek's Teaching/Research Interests
Motion Analysis

Tom Kernozek, PhD (Department of Health Professions) has expertise in the areas of biomechanics, research methods and instrumentation.  His main research interests are associated with human movement and injury prevention.  Most of Dr. Kernozek's publications relate to pressure distribution measurements and motion analysis of sports skills like landing and cutting.

We analyze movement patterns with motion analysis using high speed cameras using "reflective markers" or with electromagnetic sensors.  The position of these markers or sensors are tracked automatically as the movement is performed.  The result is a stick figure or skeletal representation of the person performing the movement.  From the markers or sensors, joint position can be calculated as well as the velocity and acceleration of joints or body segments. 

The pictures to the right depict a figure based on motion capture data during a single legged landing.  Motion capture data can be collected via reflective markers (below left) or active sensors (below right).  Reflective markers are tracked by computer at up to 480 samples per second.  Active sensors can be acquired at 100 samples per second.  These data can be used to create rigid bodies representing the various segments of the body.  Data such as joint angles can then be calculated.

By incorporating this motion capture data with force platform measurements, the joint moments and reaction forces can be estimated by link segment modeling.  We currently are using this approach to study anterior cruciate ligament injuries in female athletes.  Subtle differences in performance can be reliably detected and documented that cannot be seen with the naked eye using our laboratory instrumentation.

Dr. Kernozek and Dr. Robert Ragan are currently involved in modeling the loading stresses on the Anterior Cruciate Ligament (ACL) during landing and other high risk movements in female athletes.  Data during landing and cutting movements these data are collected at up to 360 samples per second and synchronized with impact forces.  This data is then processed through a custom model of the knee to estimate internal loads on the knee.  Biomedical physics students and physical therapy graduate students have been involved in this on-going research effort.  See a list of published research at Recent Publications.


 
Pressure Distribution Measurements

The figure on  right is a maximum pressure "mountain" gathered from the stance phase of a barefoot walking trial.  This computerized depiction is an artificial picture that is generated from the maximum pressures during walking.  Data were collected from a pressure platform (figure to the right below) that captures the instantaneous plantar loading throughout the walking cycle.  Note that the "hotter" colors reflect the higher pressures while the lower pressures are displayed with the "cooler" colors.  The biomechanics lab has capabilities to measure in shoe pressures, barefoot pressures and the pressures with seating.

This pressure mountain on the right is from an individual with diabetes measured in the lab.  As the disease progresses an individual begins to lose sensation (called neuropathy) in their extremities. The result is that they are unable to "feel" the high plantar loading as they walk.

High plantar pressures coupled with neuropathy contribute to the development of plantar ulcers or open wounds.  Measuring plantar pressures helps identify individuals with high plantar loads.  The data on the right displays a peak pressure of 91 N/cm2.  This patient may be in danger of developing a plantar ulceration if footwear modifications are not made.

With Robert Ragan, PhD of the Physics Department, we have developed finite element models of the buttocks and pelvis for the prevention of pressure sores using pressure data obtained from seated measurements.  Physics students in the Biomedical Concentration work on joint research efforts between Dr. Ragan (Physics Department) and Dr. Kernozek (Department of Health Professions).  See undergraduate research opportunities.

Current lab projects include the gender differences in landing, stresses on the spine during lifting, joint kinetics during walking with different speeds and cadence, and the plantar loading outcomes after forefoot correction via fore foot surgery.  Click here if you are interested in working in the lab or to find out more information.  We are always looking for participants as subjects or as research assistants!