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Department of Orthopedics

Department of Orthopedics

Center for Gait and Movement Analysis

CU Orthopedics

Chang Carollo
James Carollo, Ph.D., P.E. | Frank Chang, MD

Director: James Carollo​, PhD, P.E.
Co-Director: Frank Chang, MD

Visit the CGMA Website on the Children's Hospital Colorado Website

The Center for Gait and Movement Analysis (CGMA) is a facility dedicated to the study of human movement, for the purpose of understanding complex gait and motion abnormalities in children and adults and applying this knowledge in novel ways to prescribe and evaluate mobility related interventions.

CGMA was first developed in 1999 as a collaborative effort between Children’s Hospital Colorado and the University of Colorado Denver Department of Physical Medicine & Rehabilitation and CU Orthopedics. CGMA now occupies a 4800 sq. ft. space on the lower level of Children’s Hospital Colorado’s at the Anschutz Medical Campus, directly below the main outpatient entrance and the clinical departments of Rehabilitation Medicine, Pediatric Orthopedics, and Physical Therapy. The updated and expanded facility was designed specifically to increase clinical and research measurement capacity, so that multi-center projects and expanded clinical service in sports performance, upper extremity assessment, and whole body biomechanics could be undertaken.

With additional faculty support from the Denver Veteran Affairs Medical Center, University of Colorado Department of Bioengineering, and the Colorado School of Mines, CGMA combines a multi-disciplinary team of physicians, physical therapists, kinesiologists, and engineers, with the measurement tools necessary to quantify all aspects of human movement.

CGMA utilizes state-of-the-art instrumentation to characterize the mechanics of human movement, the timing and intensity of muscle activity, and the forces generated by foot/floor contact.  This can be accomplished in either of two measurement environments, the gait lab (1054 sq. ft.) and the training room (320 sq. ft.), which can be run simultaneously from a centrally located control room.  A bodyweight supported treadmill training system, iso-kinetic testing system, and ergo-spirometry unit are also available.

Both environments are equipped with Vicon MX digital optical motion capture systems (Vicon, Inc.)  The 12 camera system in the gait lab and the 8 camera system in the training room are comprised of Vicon F40MX (4.0 megapixel) digital cameras that record images in 10-bit grayscale, use near infrared high intensity LED strobes for illumination, and can operate at up to 1,000 fps. These systems interface with dedicated servers utilizing the latest Vicon Nexus software to track the trajectories of passive retro-reflective markers attached to the subject with sub-millimeter accuracy.  The systems include 128 channel analog to digital converters for measuring, integrating, synchronizing, and visualizing analog force and EMG.  Biomechanical subject models based on the applied marker set and anthropometrics can be viewed in real time overlaid on live observational video in conjunction with 3D ground reaction force vectors, ensuring that all necessary data are being collected for calculation of kinematic and kinetic variables.  Integrated software includes Bodybuilder, Polygon, and PECS (Vicon, Inc.), as well as Visual3D (C-Motion, Inc.) for data processing and visualization.  Quality assurance data analyses, Dionysius, a sports performance analysis package can be performed using customized, in-house  programs created from other software packages such as Matlab, , Labview, etc.

Forces resulting from foot/floor contact are recorded in the gait lab via an array of ten (10) Bertec strain-gaged 6-channel FP 4060-10 (60 cm x 40 cm) force platforms embedded in the main walkway in a 1-2-1 configuration.  This configuration allows forces from foot/floor contact to be recorded for each foot independently, regardless of stride characteristics.  The training room utilizes a Bertec split belt treadmill instrumented with similar strain-gaged 6-channeol force platforms with longer, narrower dimensions under each tread, for the same purpose.  The force platforms are interfaced with the Vicon systems to record force data in 3 orthogonal directions, a moment about a vertical axis, and a point of force application on each platform.  The platforms are synchronized with the motion capture system and have a common laboratory coordinate frame.  These data can be combined with the kinematic model for calculation of inverse dynamics. 

Two systems are available to measure dynamic muscle activity in either the gait lab or training room - a telemetered ZeroWire system (Noraxon U.S.A. Inc.) and a tethered MA-300 Electromyographic Recording System EMG system (Motion Lab Systems, Inc).  Both systems are fully integrated with the Vicon MX data collection hardware/software and the high definition digital video recording system for real time recording.  The ZeroWire consists of 16 miniaturized probes (10 grams each) that perform EMG detection (via a bipolar preamplified surface or fine wire EMG), A/D conversion, and 16 bit digital EMG data transmission (up to 4KHz per channel) across a 2.4 GHz RF band.  The MA-300 Electromyographic Recording System combines 16 bipolar channels of preamplified surface and/or fine wire EMGs, bilateral sets of 4 foot/floor contact switches, and 1 ECG recording channel in a small, subject attached backpack that can be either hardwired to the data recording computer, or connected via radio telemetry.  In either case, EMG, ECG and foot/floor timing data can be recorded while the subject is allowed to move freely within the confines of the laboratory, or at a remote location.  All necessary software to produce standard graphic reports, and time normalized ensemble averages of the raw EMG signals is available.

CGMA also includes a comprehensive, broadcast quality, high definition video system to facilitate observational gait analysis.  Two JVC ProHD GY-HD250U Camcorder systems on pan/tilt units record frontal and sagittal plane video simultaneously at 720P60.  Video streams from the two camcorders are windowed with real time EMG and a character generator, using a Superview 4000 Series windowing system and recorded to a Wafian Direct-to-Disk HD Video Recorder, maintaining native 720P60.  The windowing system can accommodate up to four RGB/DVI/HD signals plus four video signals from sixteen switched inputs, allowing multiple video inputs for additional real time information display/recording.

The gait lab also has the capability to record highly accurate static or dynamic foot pressure measurements at up to 500 Hz.  This is done via an RSscan footscan 3D, 2 m x 0.4 m pressure platform embedded in the main walkway.

The training room has several features specifically for motion related therapy.  In addition to the split-belt treadmill, a Robomedica pneumatically controlled body weight support system was installed.  This provides the ability to remove a percentage of a person’s body weight support, reducing the strength requirement for normal gait during treadmill training.  Manual treadmill training can also be employed.  A HUMAC NORM Testing & Rehabilitation System (CSMI Medical Solutions) is also located in the training room for measuring and improving performance via 22 isolated-joint movement patterns and four resistance modes (isokinetic, isotonic, isometric, and passive).

Energy expenditure during motion can be measured in either environment via Wireless Portable Ergospirometry, including Oxygen Consumption, CO2 Generation, and Pulmonary Function Testing.

When taken together, the systems in both environments provide all the necessary tools to comprehensively evaluate and rehabilitate gait and movement disorders in even the most complex musculoskeletal or neurologic patients.

Related Publications

Chang FM, Seidl AJ, Muthusamy K, Meininger AK, and Carollo JJ. "Effectiveness of Comprehensive Gait Analysis in Children with Cerebral Palsy Part I: Comparison of Outcomes." Journal of Pediatric Orthopaedics, (submitted), July, 2005.

Carollo, J. J. and Matthews, D. "Strategies for Clinical Motion Analysis Based on Functional Decomposition of the Gait Cycle." Physical Medicine and Rehabilitation Clinics of North America, 13: 949-977, 2002.

Martin, M., Shinberg, M., Kuchibhatla, M, Ray, L, Carollo, J., Schenkman, M. "Gait Initiation in Community-Dwelling Adults with Parkinson’s Disease: Comparison with Older and Younger Adults without the Disease." Physical Therapy, 82(6):566-577, June 2002.

Carollo, J. "Predicting overall gait performance from measures of strength, balance, and coordination: a comparison of multiple regression and threshold (NCRA) models." Gait & Posture, 7:187, 1998.

Winchester, P.K., Carollo, J.J., and Wrobbel, J. "Reliability of gait temporal distance measures in normal subjects with and without EMG electrodes." Gait and Posture, 4: 21-25, 1995.

Carollo, J., Winchester, P., and Wrobbel, J. "Intra-subject variability of dynamic EMG using surface and intramuscular electrodes." Gait & Posture, 2(1): 52, 1994.

Winchester, P., Carollo, J., and Habasevich, R. "Physiologic costs of reciprocal gait in FES assisted walking." Paraplegia, 32:680, 1994.

Winchester, P., Carollo, J., and Habasevich, R. "Physiologic costs of reciprocal gait in paraplegic subjects using the Parastep® system." Med. Sci. Sports and Exer., 26(5): S48, 1994.

Winchester, P., Carollo, J., and Wrobbel, J. "The effect of surface and intramuscular EMG electrodes on the temporal distance measures of gait." Gait & Posture, 2(1): 66, 1994.