Research Focus

Control and dynamics of movement under physically demanding and contextually relevant conditions.

 

Research Approach

  • Basic science to translation of solutions into practice

  • Involvement of end users throughout the process

  • Integration of experimental and dynamic modeling

A diagram with four arrows pointing in a circle. The arrows are labeled: "what?" "how?" "why?" "modify"
Participatory Action Research shows our research process. Each question relates to a set of research publications.

Research Questions Specific to Control and Dynamics

Participatory Action Research

    What?

    Our research process focuses on real world tasks performed under stressful conditions. Our aim here is to understand what the performer does in order to accomplish a task.

     

    Diagram labeled Tasks featuring three quadrants split by arrows "Accuracy" and "Load Distribution" and "Power"

    Figure: When we study goal directed movements, we think about the accuracy, speed, and mechanical loading consequences of each task when performed in a particular context.

    Currently the Biomechanics Research Lab is focusing its research on the following areas:

    Golf
    Soccer
    Volleyball (Jump, Land, Quick first step)
    Gymnastics/Diving(Tumbling, Vaulting, Landing)
    Sprinting, Prosthetic
    Long Jump, Hurdles
    Shot Put, Javelin
    Parachute Landings
    Wheelchair Propulsion
    Sit-to Stand (Osteoarthritis)
    Music Performance(Cello, Trumpet)
    Dance
    Dental Hygiene
    Assistive Interactive Robotics

    How?

    This phase of our biomechanics research, Model, involves concentrating on how the performer interacts with the environment to perform the task:

     
    A depiction of gymnast in motion

    Figure: Human movement reflects the ongoing interaction between the control system (neuromuscular system), the dynamic system (musculoskeletal system), and the environment.

    Why?

    The Model leading to Solutions phase of our biomechanics research involves the following steps:

    – Integrate Experimental Results into Models of the Control System and Musculoskeletal Dynamics to Understand Why and ask What if?
    – Simulation Studies to Identify Feasible Solutions for Individuals

    A computer graphic of a female figure sitting next to a graphic of a skeleton of the same sitting female figure.

    Figures Above: We use kinematic data to animate 3D movements and visually represent the musculoskeletal system as segments or bones (Poser, Visual3D). Experimentally validated dynamic models (ADAMS) are used to analyze the interrelationship between control and dynamics.

     
    A line graph. The X axis is labeled

    STS Figure: We use experimental electromyographic and kinematic data as well as subject specific musculoskeletal models (SIMMS) to determine which muscles contribute to the net joint moments required to perform the task.
    We also use models of muscle tendon units and dynamic models of the musucloskeletal system (ADAMS) to assess internal loading consequences of subject specific muscle activation patterns.

    Modify?

    Our main goal in this stage of the biomechanics research process is to modify performance using feedback during skill acquisition to facilitate learning.

    A photo of a diver jumping onto crash pads and being monitored by a computer.

    Figure: We use real time feedback to help the performer and the trainer understand the external forces (reaction forces) and internal forces (muscle forces) that are needed to perform complex goal directed tasks.

    A diagram with four colorful arrows pointing in a circle. The arrows are labeled:
    A diagram with four colorful arrows pointing in a circle. The arrows are labeled:
    A diagram with four colorful arrows pointing in a circle. The arrows are labeled:
    A diagram with four colorful arrows pointing in a circle. The arrows are labeled:

    Areas of application:

    Closeup of someone playing cello A photo depicting the phases of a diver diving into a pool
A series of photos of legs landing after a jump.
    A series of two photos depicting someone walking. A photo of a surgeon working A series of photos depicting a person in a wheelchair and the computer rendering of their skeleton in a wheelchair.
    A gymnast landing after jumping off a vault A group of people dancing in a dark room A group of people playing volleyball

    Research  Opportunities

    Graduate

    • PhD Biomedical Engineering (with Dr. McNitt-Gray)
    • PhD Aerospace and Mechanical Engineering (with Dr. Flashner)
    • PhD Biological Sciences (with Dr. McNitt-Gray)

    Undergraduate

    • Women in Science and Engineering (WiSE) Program
    • Student Opportunities for Academic Research (SOAR)
    • Summer Undergraduate Research Fund (SURF)

    Contact

    Jill L. McNitt-Gray  Ph.D

    Gabilan Distinguished Professor in Science and Engineering

    Dept. of Biological Sciences- HEB
    3616 Trousdale Pky AHF 252, University of Southern California, Los Angeles, CA 90089-0372