June 2019

“Capstone” Research Has Great Value to Orthotics and Prosthetics

By Geza F. Kogler, PHD

Georgia Institute of Technology initiated its Masters of Science in Prosthetics and Orthotics (MSPO) program in 2002, knowing that considerable advances in the profession would be possible if research was an emphasis in clinical education. Students entering the program came with added bases of knowledge, dominated by undergraduate degrees in engineering (eg, mechanical, biomedical), followed by kinesiology and exercise science.

From the beginning, the program required a relatively rigorous research component to complete the degree, commonly referred to as a “Capstone research project.” A Capstone is the culmination of foundational clinical and biomechanical sciences used to formulate clinically relevant questions that are then solved using scientific methodology. Three main deliverables are required: a scientific abstract, a poster, and, eventually, a culminating oral presentation in a public forum (eg, an annual research symposium). [Two abstracts presented at the 2019 symposium can be found at the end of this article.]

Exposure to Research Yields Results and Awards

Research exposures can vary greatly among the different Capstone student teams, ranging from exploratory pilot studies and test apparatus development to comprehensive data collections leading to peer-reviewed manuscript publication. Actual participation in research activities allows students to understand and appreciate the merits of scientific inquiry and its relevance to evidence-based medicine as graduates enter clinical practice.

This year marked the Ninth Annual Prosthetic Orthotic Research Symposium at Georgia Tech. Although the Symposium is in its ninth year, formal Capstone research presentations began with the first MSPO class (2004), which carried on until they were formalized at the first symposium, held in 2011. The quality of student research would continue to improve with recognition realized by an impressive record of award-winning student research at professional national meetings, dominated by Georgia Tech MSPO students: namely, the American Orthotic & Prosthetic Association (AOPA) awards for Best Orthotic and Prosthetic Student/Resident Poster awards (the Otto and Lucille Becker Award for Orthotics and the Edwin and Kathryn Arbogast Award for Prosthetics).

Furthermore, Capstone research by MSPO students contributes considerably to the research efforts of their faculty mentors, who feature MSPO student research as pilot studies that have led to major grant funding from the National Institutes of Health, the National Science Foundation, and the US Department of Defense. In addition, several scientific publications from the Capstone projects further grace the research output of the program.

Despite the success and accolades that the Georgia Tech MSPO program has experienced, it could not endure administrative decisions to eliminate small graduate programs. Academia has always been plagued with faculty retention problems,1 but administration turnover2 is even more prevalent; with each change in administration comes new visions and loss of program champions. All prosthetic and orthotic masters’ programs are vulnerable because they cannot compete against the high return of online graduate programs that are trending in higher education. The end of an era at Georgia Tech will therefore result in a “diminished research-culture infusion” that its graduates provided to the profession.

If the field of O & P is to continue to grow, to preserve and expand research activities, existing educational programs need to provide more exposure to scientific study and its importance to evidence-based practice.

Geza F. Kogler, PhD, is Director of the Masters of Science in Prosthetics and Orthotics program and Principal Investigator of the Clinical Biomechanics Laboratory in the School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia.


  1. Kaminski D, Geisler C: Survival analysis of faculty retention in science and engineering by gender. Science. 2012;335(6070):864-866.
  2. College administrator data/turnover rates: 2016-present. Press release. April 12, 2018. Higher Education Publications, Inc. https://hepinc.com/newsroom/college-administrator-data-turnover-rates-2016-present/. Accessed July 9, 2019.

Editor’s Note: Georgia Institute of Technology deactivated its Masters of Science in Prosthetics and Orthotics program in May 2018; it has 2 years to decide whether to reactivate or terminate the program. Although the program has not been officially shuttered, the contract for its director, Geza Kogler, terminates December 2019. Discussions about the program’s future are ongoing at various levels in Georgia. LER will be reporting on its future in an upcoming issue—stay tuned.


From Georgia Institute of Technology School of Biological Sciences 9th Annual Prosthetic & Orthotic Research Symposium April 18, 2019

The Influence of AFO Strut Stiffness on Ankle Joint Angle During Treadmill Walking

By Ryan Sharry, BS, Robert Hinks, BS, Young-Hui Chang, PhD
Comparative Neuromechanics Laboratory

Recent developments in orthotic technology include the emergence of passive-dynamic ankle foot orthoses (PD AFOs) which utilize deformable carbon fiber springs, or struts, to emulate the action of the plantar flexor muscles during the stance phase of gait. From heel strike through midstance, the strut is designed to deform from its original shape as it absorbs energy, much like the eccentric muscle action typically performed by the plantar flexors. During third rocker, the strut then returns to its original shape, providing useful energy return for patients through toe-off. While current research has demonstrated that these devices may effectively lower cost of transport and increase gait velocity for patients exhibiting plantar flexor weakness, there is currently no research-based method for selecting appropriate stiffness for prefabricated AFO struts. The purpose of our research was to develop a method for selecting PD AFO strut stiffnesses that will yield more predictable outcomes.

Our study evaluated custom composite PD AFOs (n=3) with eight different strut stiffness conditions during treadmill walking at three different walking speeds, 0.8 m/s, 1.1 m/s, and 1.4 m/s. Subjects walked on split belt treadmill while kinematic and kinetic data was collected via a Vicon motion analysis system to evaluate the influence of strut stiffness on ankle range of motion (ROM). Additionally, the eight struts (five carbon composite and three thermoplastic composite struts) were subjected to cantilever style mechanical testing to provide comparative data for analysis with the walking trials.

Our results showed that increased strut stiffness decreases ankle ROM across the range of walking speeds, suggesting that there is a relationship between PD AFO strut stiffness and ankle ROM which clinicians could use to achieve desired outcomes. A linear relationship appears to exist between stiffness of the strut and ROM with R2 scores over 0.8, which showed that speed has less of an effect than stiffness when walking. Similar trends were noted between subjects, indicating that height and weight ranges of patients may be grouped into similar categories like those used for prosthetic feet. The structural stiffness properties of strut type AFOs directly influences a user’s response when walking. Therefore, strut stiffness properties should be determined as part of the clinical assessment to formulate orthosis prescription. The results of our pilot study point to the significance of mechanical properties of struts for orthosis prescription.

A Test Apparatus to Quantify Ankle Joint Torque to Determine AFO Stiffness Parameters

By Samantha Dansby, BS, Bennett Lemmon, BS, Nick Bolus, BS, Geza Kogler, PhD, CO
Clinical Biomechanics Laboratory

The determination of AFO stiffness parameters is still widely reliant on subjective estimates based on experiential practice rather than clinical stiffness measures taken of a user’s foot ankle complex (Bolus et al., 2017). Orthotic fundamental principles stipulate that the least amount of orthotic joint motion control be employed to achieve the desired functional outcome with minimal impedance to normal beneficial movements. Excessive AFO stiffness can limit ankle joint range of motion (ROM) and mobility during gait while inadequate AFO stiffness can lead to user safety issues if ankle foot control cannot insure toe clearance. The purpose of this study is to develop a test apparatus that will reliably and accurately quantify ankle joint torque to determine mechanical stiffness parameters for AFO’s. This pilot study serves as the foundation for a larger data collection with healthy individuals as well as patients with functional limitations to their ankle foot complex (eg, drop foot).

Subjects (n=11) for this study were seated with their hips and knees at 90° while also allowing mild internal or externally rotation on the seat for comfort. Ankle joint torque (Nm) and ankle joint angle (°) were quantified with the foot passively moved from a relaxed position (ie, plantar flexed) and raised to 10° of dorsiflexion. The results showed that ankle joint torque increased as the subject’s foot was moved from PF position to a DF position which was comparable to previously reports. To achieve toe clearance during walking, the ankle joint should be positioned at neutral (90°) and thus the ankle joint torque measure at 90° was of clinical interest. The findings from this study showed that ankle joint torque to achieve neutral ankle foot positioning (90°) ranged from 2.5 to 4.5 Nm (n=11).

Our study showed that reliable and repeatable ankle joint torque measurements can be acquired with the test apparatus developed. We propose that ankle joint torque stiffness is a critical clinical measure to determine the mechanical joint properties for an AFO and should be used as a principle value in establishing the desired orthotic motion control characteristics (ie, ankle joint stiffness). Ideally, clinical practice should evolve to more accurately match joint stiffness parameters of the individual user to the mechanical joint stiffness properties of the orthosis.

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