Northwestern University Feinberg School of Medicine

Northwestern University Prosthetics-Orthotics Center

The Jesse Brown VA Medical Center Motion Analysis Research Laboratory

The Jesse Brown VA Medical Center Motion Analysis Research Laboratory (JBVAMC-MARL) is a state-of-the-art human movement research laboratory designed especially for making measurements necessary for quantifying human movements. One of the primary goals of the JBVAMC-MARL is to provide researchers, and ultimately clinicians, with more complete knowledge and a better understanding of the mechanical interactions that occur between humans and prosthetic/orthotic systems. New knowledge in this area can improve the quality of life for individuals who use prosthetic and orthotic (P&O) devices.

Collecting data at NUPOC in the JBVAMC-MARL

JBVAMC-MARL has a motion measurement system consisting of twelve Eagle and Raptor Digital Real-Time cameras from Motion Analysis Corporation (MAC, Santa Rosa, CA) that is used to measure movement kinematics. The locations of the markers that are placed on the body help to define the particular biomechanical model that is used to analyze the data. As the subject moves around the capture volume, the positions of the markers are recorded by the cameras that are placed on the periphery of the room. Using OrthoTrak gait analysis software (MAC), JBVAMC-MARL researchers can process the data and generate graphs and data files for further analysis. JBVAMC-MARL also has Visual3D software (C-Motion, Germantown, MD) for creating more advanced biomechanical models of various movements.

JBVAMC-MARL has six AMTI (Advanced Mechanical Technology Inc., Watertown, MA) force platforms embedded in the walkway for measuring ground reaction forces as subjects walk across them. A 16-channel wireless EMG system (Trigno, Delsys Inc., Natick, MA) and 8-channel telemetered EMG system (Noraxon, USA Inc., Scottsdale, AZ) enables muscle activity to be recorded during human movement activities. MARL has a pedar pedobarograph system (Novel Electronics Inc., Munich, Germany) that uses insoles for measuring pressures between the foot (anatomical or prosthetic) and the shoe, or the foot and orthosis, during walking. Additionally, JBVAMC-MARL has a pliance pedobarograph system (Novel Electronics, Inc., Munich, Germany) that uses sensor pads to measure pressures between a person’s residual limb and their prosthetic socket.

VAMCMARL

JBVAMC-MARL also uses a Cosmed K4b2 Portable Metabolic Measurement System (Cosmed, Rome, Italy) for collecting energy expenditure data during activity and a Cosmed Sport Treadmill (T170) with a large belt surface, safety harness, incline/decline capabilities, and adjustable handrails. JBVAMC-MARL has a digital video subsystem consisting of two digital camcorders, a digital media recorder (DMR), a monitor, and a video-editing board used for recording split-screen displays of two simultaneous views of research subjects during experiments.

JBVAMC-MARL also has a Biodex Balance System SD used to evaluate dynamic balance and fall risk. The system is used to assess a subject’s neuromuscular control by quantifying their ability to maintain dynamic single or double leg postural stability on either a static or unstable surface. The system allows researchers to measure a subject’s ability to maintain their center of balance, their ability to move and control their body center of mass, and their ability to remain upright and balanced on unstable surfaces.  

JBVAMC-MARL uses a custom-instrumented treadmill (N-Mill, MotekForce Link, Culemborg, the Netherlands) to simulate slips and trips during walking for evaluating locomotor stability. The system allows for quantification of reactive and proactive motor responses to perturbation during walking. An overhead harness ensures safety of research participants as they experience these walking disturbances.

Services Offered

Research studies conducted in the JBVAMC-MARL typically focus on, but are not limited to, persons with amputations, neuromuscular impairments, and musculoskeletal disorders or injuries. We also collect data for healthy, able-bodied individuals.

Quantitative Gait Analysis A gait analysis is an experiment to record data about the way a person walks. Instrumentation included in a basic gait analysis includes a high speed digital motion capture system, force platforms, digital video recordings and digital photos. Cameras track reflective markers that are placed on various anatomical landmarks on the participant. The participant is then asked to walk along a 10 m walkway a minimum of 5 times at varying speeds. Photos and digital recordings are taken. Manual muscle testing using a handheld dynamometer can be performed on the participant’s lower limbs to assess muscle strength. A goniometer is used to measure the flexibility and range of motion of the hip, knee, and ankle joints. Participation for an able-bodied individual takes approximately 2 hours. Participation for a person with a physical impairment usually takes longer.

w/EMG Electromyography (EMG) is a technique used to measure muscle activity. Surface electrodes are attached to the skin over selected muscles using double-sided, non-allergenic tape. EMG is conducted in conjunction with a gait analysis. Preparation time for the subject will increase approximately 45-minutes, in addition to the setup/preparation time required for a gait analysis without EMG.

w/Pressure

There are 2 types of pressure measurements available, either in-sole pressure measurement or in-socket pressure measurement. In-sole pressure analysis involves measuring the pressure applied to the plantar surface of the foot using instrumented insoles placed between the foot and the shoe. Pressure analysis of the plantar surface of the foot can be conducted as a stand-alone procedure or in conjunction with a gait analysis. Participation time for the subject in a stand-alone pressure analysis lasts approximately 1 hour. If conducted in conjunction with gait analysis, preparation time for the subject will increase by approximately 30 minutes, in addition to the setup/preparation time required for a gait analysis without in-sole pressure. 

If the participant wears a prosthesis, instrumented sensors are used to measure the pressure between the residual limb and the socket interface (in-socket pressure measurement). In-socket pressure measurement is conducted only in conjunction with a gait analysis. Preparation time for the subject will increase by approximately 1 hour, in addition to the set/up preparation time required for a gait analysis without pressure.

Motion analysis data are collected for upper limb studies.w/Spine/Upper Extremity 

Conducted in conjunction with a gait analysis, additional reflective markers are placed along the spine and on the head to measure spinal motion while walking or in a static standing position. Preparation time for the subject with the spinal markers will increase by approximately 30 minutes, in addition to the setup/preparation time required for a standard gait analysis. 

w/Energy Expenditure An energy expenditure test is conducted to analyze the air that is exhaled while walking. The test can be done as a stand-alone procedure or in conjunction with a gait analysis. A mask that covers the nose and mouth is fitted to the participant. Additional equipment, including a battery pack and the sampling device, is harnessed to the participant. The test protocol consists of three stages: 1) pre-exercise resting energy expenditure, 2) walking energy expenditure, and 3) post-exercise resting energy expenditure. During the pre- and post-exercise phases, the participant sits quietly for approximately 5 minutes in each phase. During the walking phase, the participant walks for 10 minutes at a self-selected speed on a treadmill. Preparation time for the subject is approximately 30 minutes. Participation time for the subject is approximately 45 minutes.

All of the measurement systems in JBVAMC-MARL are integrated to synchronize the collection of data, providing a comprehensive overview of the particular human movement activity. A primary goal of JBVAMC-MARL is to provide researchers, and ultimately clinicians, with more complete knowledge and a better understanding of the mechanical interactions that occur between humans and P&O systems. Knowledge derived from these systems can contribute to better P&O fitting and improve the quality of life for individuals who use these devices.

JBVAMC-MARL is a Feinberg School of Medicine Research Core

JBVAMC-MARL is a CORE facility for research at Northwestern University.
Inquire about conducting your Motion Analysis research project at NUPOC:

Steven Gard, PhD, Director
312-503-5718

Rebecca Stine, MS, Laboratory Manager
312-503-5726