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Department of Orthopedics

Department of Orthopedics

Center for Gait and Movement Analysis

CU Orthopedics

James Carollo and Frank Chang
James Carollo, PhD, PE | Frank Chang, MD

Director: James Carollo​, PhD, PE
Co-Director: Frank Chang, MD

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. We then use this knowledge to improve quality of life for individuals with neurological and skeletal disorders.

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 Department of Orthopedics. CGMA now occupies a 4800 sq. ft. space on the lower level of Children's Hospital Colorado's on the Anschutz Medical Campus.

The updated and expanded facility—also the first and only clinical movement analysis lab in Colorado—was designed specifically to increase capacity so that multi-center projects and expanded clinical service in sports performance, hip, spine, 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 multidisciplinary 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.

Sagittal plane coordination dynamics of typically developing gait. Worster K, Valvano J, Carollo JJ. Clin Biomech (Bristol, Avon). 2015 Feb 24. pii: S0268-0033(15)00051-0. doi: 10.1016/j.clinbiomech.2015.02.013. [Epub ahead of print]

Are our expectations bigger than the results we achieve? A comparative study analysing potential advantages of ankle arthroplasty over arthrodesis. Braito M, Dammerer D, Kaufmann G, Fischler S, Carollo J, Reinthaler A, Huber D, Biedermann R. Int Orthop. 2014 Aug;38(8):1647-53. doi: 10.1007/s00264-014-2428-5. Epub 2014 Jul 2.

The role of gait analysis in treating gait abnormalities in cerebral palsy. Chang FM, Rhodes JT, Flynn KM, Carollo JJ. Orthop Clin North Am. 2010 Oct;41(4):489-506. doi: 10.1016/j.ocl.2010.06.009. Review.

Rectus femoris transfer in children with cerebral palsy: evaluation of transfer site and preoperative indicators. Muthusamy K, Seidl AJ, Friesen RM, Carollo JJ, Pan Z, Chang FM. J Pediatr Orthop. 2008 Sep;28(6):674-8. doi: 10.1097/BPO.0b013e3181804c04.

Effectiveness of instrumented gait analysis in children with cerebral palsy--comparison of outcomes. Chang FM, Seidl AJ, Muthusamy K, Meininger AK, Carollo JJ. J Pediatr Orthop. 2006 Sep-Oct;26(5):612-6.

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.

In 2014, CGMA's research projects addressed five areas of study. Each area had many  projects, but a few stood out. Here are some of the highlights:

Surgical outcomes in cerebral palsy

One study focused on understanding how the foot and ankle change over time following surgical intervention for flatfoot and ankle valgus. Through this study we were able to predict the rate of correction and recurrence of ankle valgus in children when using a transphyseal medial malleolar screw.

Nonsurgical interventions in cerebral palsy

One project developed a novel method of upper extremity assessment involving motion capture that has been adopted to examine the outcomes of wrist tendon transfers in children with hemiplegic cerebral palsy.

Quality of life in individuals with cerebral palsy

Our research methods have expanded beyond motion analysis techniques to include measures of physical well-being, self-perception, and endurance while promoting participation in society and encouraging a lifelong commitment to physical exercise. We believe there is a critical and unrecognized link between walking and secondary health conditions that explain the symptoms of premature aging observed in individuals growing older with cerebral palsy. This ongoing study has led us to conduct more patient education and outreach.

Methodological advances in cerebral palsy 

One project combines standard modeling techniques with novel nonlinear mathematical methods to describe the dynamics of typical and pathological gait. These quantitative methods are interpreted through a motor control perspective to make this work clinically applicable. Specifically, the research applies sophisticated mathematical models to describe the pendulum-like properties of leg segments' behavior during the swing period of gait.

Applications of motion capture beyond cerebral palsy and collaborations

In collaboration with the spine program, we developed a novel method of characterizing clinical scoliosis deformity using motion capture. These clinical measurements have historically been unreliable and thus underutilized in surgical planning. In our second year, we are studying this method's ability to detect change after a spinal fusion procedure and correlating with surgical outcomes. This work validates this new technique that may reduce the frequency of radiographs used to track curve progression in adolescent idiopathic scoliosis.

Surgical outcomes in cerebral palsy

1. Determining the Natural History of the Femoral Physeal Angle in Normal Children During Development

Collaborators: Chang FM, Miller NH, Kolnik A, Carry P, Merritt C, Pan Z & Davis J

2. Outcomes of Varus Derotational Osteotomies for Hip Dysplasia in Children with Cerebral Palsy and Predictors for Re-subluxation

Collaborators: May A, Chang FM, Novais E, Faulk LW, Miller NH, Pan Z, Davies K, Kark J, Ma J

3. Acetabular Remodeling After a Varus Derotational Osteotomy (VDRO) in Children with Cerebral Palsy

Collaborators: Chang FM, Novais E, Pan Z, Ma J, Ingram JD

4. The Relationship Between Hip Disease and Scoliosis in Children with Cerebral Palsy

Collaborators: Garg S, Chang FM, Miller NH

5. Results of Patellar Advancement Procedures for the Treatment of Crouch Gait in Patients with Cerebral Palsy (Collaboration with MRC)  

Collaborators: Chen Q, Rhodes J, Hotchkiss M, Robertson D, Pritchard B, Frickman A

6. Effective of Age at Surgery on Distal Femoral Remodeling Following Extension Osteotomies in Children with Cerebral Palsy

Collaborators: Rhodes J, Roy D, Pan Z, Chang F, Pritchard B, Frickman A

7. Retrospective Comparison of Allograft versus Bovine Xenograft in Evan’s Calcaneal Osteotomy for Planovalgus Foot Deformity in Cerebral Palsy

Collaborators: Chang FM, Mansour A, Davies K, Pritchard B, Miller N

8. Comparison of Graft Materials Used in the Evans Calcaneal Lengthening in Children with Cerebral Palsy

Collaborators: Chang FM, Rhodes J, Miller N, Davies K, Pritchard B, Autruong P

9. Rectus Femoris Manuscript

Collaborators: Rhodes J, Carollo JJ, Chang FM, Friesen R, Pritchard B

10. Correction of Ankle Valgus in Children Using a Transphyseal Medial Malleolar Screw

Collaborators: Chang FM, Hoversten L, Ma J, Novais E

11. Clinical Outcomes and Biomechanical Assessment of Pes Planovalgus in Children with Cerebral Palsy 

Collaborators: Chang FM, Look N, Carollo J, Ma J, Autruong P

12. A Comparison of Treatment Methods for Femur Fractures in Patients Affected by Cerebral Palsy

Collaborators: Chang FM, Tulk K, Autruong P

13. Timing of intensive strengthening and immobilization following Strayer, Percutaneous TAL and Open TAL procedures in patients with hemiplegic cerebral palsy

Collaborators: Rhodes JT, Harris N, Hutchinson B, Frickman A

14. Biomechanical Assessment of Three Patellar Advancement Procedures

Collaborators: Carollo J, Seidl A, Rhodes J, Baldini T

15. Upper extremity kinematics in hemiplegic cerebral palsy before and after wrist tendon transfer

Collaborators: Mayo M, Scott F, Faussett M, Carollo J


Nonsurgical interventions in cerebral palsy

16. Evaluation of Upper Limb Motor Control in Children with Hemiplegic Cerebral Palsy after Combined Botulinum Toxin – A Injections and Constraint-Induced Movement Therapy: A Pilot Study 

Collaborators: Oleszek J, Valvano J, Kenyon P, Denniston N.

17. Effect of Adapted Skiing and Snowboarding on the Motor Function and Endurance of Children with Physical Disabilities

Collaborators: Chang FM, Davies K, Valvano J, Kanai S, Faulk W, Pritchard B, Carry P Carollo JJ, Ma J

18. Musculoskeletal Simulation Guided Therapy for Children with Cerebral Palsy

Collaborators: Carollo J, Silverman A, UNMC, Omaha, NE


Quality of life and health outcomes

19. Walking and its Effect on Health and Function in Inpiduals with Cerebral Palsy as they Transition to Adulthood: A Health Outcomes Study

Collaborators: Carollo JJ, Hein P, Valvano J, Bodkin A

20. Cerebral Palsy Transition to Adulthood: Systematic Review

Collaborators: Robertson DM, Heyn P, Carollo JJ, Valvano J

21. Effects of Adapted Skiing and Snowboarding On Quality Of Life of Children With Physical Disabilities

Collaborators: Chang FM, Davies K, Hotchkiss M, Prichard B, Ma J, Autruong P

Methodological advances in cerebral palsy

22. Changes in Coordination and Functional Outcomes after the Rectus Femoris Transfer Procedure in Children with Spastic Cerebral Palsy

Collaborators: Valvano J, Worster K, Carollo JJ, Pan Z, Davies K, Ma J

23. Apparent Equinus Gait in Children with Cerebral Palsy, A Quantitative Analysis

Collaborators: Rhodes J, Halgrimson W, Davies K, Sinha, Carollo JJ, Pritchard B, Frickman A

24. An Analysis of Leg Length Discrepancies in Children with Hemiplegic Cerebral Palsy      

Collaborators: Rhodes J, Chang FM, Pritchard B, Dudevoir M, Frickman A

25. Inter-Segmental Coordination and Ankle-foot Orthoses during Gait by Children with Spastic Cerebral Palsy     

Collaborators: Carollo JJ, Valvano, J, Worster K, Robertson D

26. The Effect of Pelvic Positioning on Radiographic Measurements Used in Treating Hip Dysplasia in Children with Cerebral Palsy

Collaborators: Carollo JJ, Chang FM, Novais E, Robertson DM, Ma J, Ingram JD, Autruong P

27. Data Base Setup For Developing Gait-Cycle Indexed Gait Performance Score

Collaborators: Pan Z, Carollo JJ, Denniston N, Worster K

28. Coordination Dynamics of Walking – Dissertation    

Collaborators: Worster K, Carollo J, Valvano J

29. IMove: Instrumented Movement Analysis to Quanitfy Gait in Cerebral Palsy

Collaborators: Carollo J, Bodkin A, Robertson D, Frickman A

30. Gait Deviation Index Representative Gait Cycle Selection in Cerebral Palsy

Collaborators: Sauer C, Carollo J

Applications of motion capture beyond cerebral palsy and collaborations

31. Impact of Spinal Fusion Construct with Sacropelvic Fixation on Gait Dynamics  

Collaborators: Carollo JJ, Erikson MA, Miller NH, Nicklas T, Hotchkiss M, Hogy S, Robertson DM

32. Impact of VEPTR (Vertical Expandable Prosthetic Titanium Rib) Surgery on Chest Wall Dynamics 

Collaborators: Erickson MA, Carollo JJ, Nicklas T, Miller NH, Nguyen T, Hotchkiss M, Robertson D

33. Is There a Correlation Between Clinical and Radiographic Measures in Scoliosis?

Collaborators: Garg S, Carollo JJ, Robertson DM, Niswander C

34. Manual Task Analysis Discerns Limitations in Motor Control in Children with Down Syndrome    

Collaborators: Valvano J, Worster K, Denniston N, Winders P, Hogy S, Carollo JJ, Ma J

35. An Investigation in Validating a Six Degree of Freedom Knee Model with Applications in Total Knee Replacement Stability in Downhill Walking 

Collaborators: Cucuel C, Carollo JJ

36. Stability as an Assessment Tool for ACL Repair Comparison

Collaborators: Burnim K, Carollo JJ, Albright J, Terhune E, Sochanska A

37. Anterior Knee Pain in Adolescents (Collaboration with MRC)

Collaborators: Provance A, Carry P, James D, Kanai S, Coel R, Mooney R

38. Evaluating the Functional Muscle Units in Van Ness Rotationplasties

Collaborators: Heare T, Silverman A, Donaldson N, Mooney R, Carollo JJ, Kanai S, Hogy S, Wylie E, Beebe C

39. Lower limb Alignment and Biomechanics after Derotational Femoral Osteotomy

Collaborators: Rhodes JT, Mei-dan O, Kanai S, Frickman A

40.Validity and Reliability of 2D versus 3D gait analysis for kinematic measures during running gait

Collaborators: Nagle K, Rhodes J, Kanai S, Sremba M, Frickman A