West Virginia University · School of Medicine

YuJen (Eugene) Chang
張祐仁

PT, PhD  ·  Associate Professor
Division of Physical Therapy

"Understanding how musculoskeletal disorders shape human movement — from tendon collagen architecture to whole-body neuromechanics."

538
Citations
9
h-index
10+
Years at WVU

Bridging tissue mechanics
and movement science

I am an Associate Professor in the Division of Physical Therapy at West Virginia University School of Medicine, where I have been on faculty since 2015. My research explores how localized musculoskeletal pathology — particularly tendon degeneration — cascades across multiple levels of the neuromechanical system: from tissue mechanics and collagen microarchitecture to muscle activation, central nervous system modulation, and whole-body movement dynamics.

A central focus of my work is non-invasive ultrasound-based quantification of tendon microstructure using Spatial Frequency Analysis (SFA), a method that estimates collagen bundle organization from standard B-mode sonograms. My research has established SFA-derived peak spatial frequency radius (PSFR) as a meaningful predictor of tendon mechanical properties in degenerated Achilles tendons, and I continue to extend this approach to the supraspinatus, patellar, and other clinically relevant tendons.

In addition to my research program, I am a member of the orthopedic physical therapy teaching team at WVU, where I teach in the musculoskeletal track, coordinate student research projects, and instruct in prosthetics and orthotics. I also serve the profession as a member of the Education Committee and Research Committee for the American Physical Therapy Association - West Virginia Chapter (APTA-WV).

Education

2015
PhD, Biokinesiology
University of Southern California
Los Angeles, CA, USA
2003
MS, Physical Therapy
National Taiwan University
Taipei, Taiwan
1995
BS, Physical Therapy
National Taiwan University
Taipei, Taiwan

Academic Positions

2023 – Present
Associate Professor
West Virginia University
Division of Physical Therapy, School of Medicine
2015 – 2023
Assistant Professor
West Virginia University
Division of Physical Therapy, School of Medicine
2005 – 2007
Physical Therapist
Buddhist Tzu Chi General Hospital
Taipei Branch, Taiwan

Areas of Investigation

My laboratory investigates multi-level consequences of tendon degeneration — from collagen microarchitecture quantified by ultrasound to altered neuromechanical control of movement. A unifying theme is developing non-invasive imaging biomarkers that guide clinical decision-making in orthopedic rehabilitation.

Tendon Micromorphology & SFA

We use Spatial Frequency Analysis (SFA) of B-mode ultrasound images to quantify collagen bundle organization within tendons. Peak spatial frequency radius (PSFR) serves as a non-invasive index of tendon microstructural integrity, correlating with mechanical stiffness and elastic modulus in degenerated Achilles tendons.

Neuromechanical Adaptations to Tendinosis

Achilles tendinosis induces system-wide adaptations: increased electromechanical delay, altered pre-activation timing of triceps surae, and compensatory changes in hopping and gait mechanics. We study the reversibility of these multi-level adaptations through targeted rehabilitation protocols.

Tendon Health Across Clinical Populations

We examine patellar tendon morphology in volleyball athletes and trans-tibial amputees, Achilles tendon microstructure in runners and dancers, and supraspinatus tendon changes in manual wheelchair users — bridging imaging science with clinical orthopedic management across diverse populations.

Movement Biomechanics & Injury Prevention

Landing mechanics, cutting maneuvers, fatigue-induced changes in muscle activation and tibial acceleration — our biomechanical work informs injury risk assessment and rehabilitation design for both athletic and clinical populations, including dancers, volleyball athletes, and individuals with lower-limb pathology.

Selected Publications

Peer-reviewed journal articles, book chapters, and conference proceedings. View full list on Google Scholar →

538
Total Citations
9
h-index
8
i10-index
11+
Journal Articles
2020
A Perspective on Reversibility of Tendinosis-Induced Multi-Level Adaptations
Kulig K, Chang YJ, Ortiz-Weissberg D.
Frontiers in Physiology, 11:651
View
2019
Patellar Tendon Morphology in Trans-Tibial Amputees Utilizing a Prosthesis with a Patellar-Tendon-Bearing Feature
Ho KY, Harty M, Kellogg J, Teter K, Lee SP, Chang YJ, Bashford G.
Scientific Reports, 9:16392
View
2019
Factors Related to Intra-Tendinous Morphology of Achilles Tendon in Runners
Ho KY, Baquet A, Chang YJ, Chien LC, Harty M, Bashford G, Kulig K.
PLoS ONE, 14(8):e0221183
View
2016
Ultrasound-Based Tendon Micromorphology Predicts Mechanical Characteristics of Degenerated Tendons
Kulig K, Chang YJ, Winiarski S, Bashford GR.
Ultrasound in Medicine and Biology, 42(3):664–673
View
2015
The Neuromechanical Adaptations to Achilles Tendinosis
Chang YJ, Kulig K.
Journal of Physiology, 593(15):3373–3387  ·  100 citations
View
2015
Landing Limb Posture in Volleyball Athletes with Patellar Tendinopathy: A Pilot Study
Kulig K, Joiner DG, Chang YJ.
International Journal of Sports Medicine, 36(5):400–406
View
2013
Patellar Tendon Morphology in Volleyball Athletes With and Without Patellar Tendinopathy
Kulig K, Landel R, Chang YJ, Hannanvash N, Reischl S, Song P, Bashford G.
Scandinavian Journal of Medicine & Science in Sports, 23(2):e81–e88  ·  116 citations
View
2012
Dancers with Patellar Tendinopathy Exhibit Higher Vertical and Braking Ground Reaction Forces During Landing
Fietzer AL, Chang YJ, Kulig K.
Journal of Sports Sciences, 30(11):1157–1163  ·  70 citations
View all publications on Google Scholar

Courses & Mentorship

I am a member of the orthopedic physical therapy teaching team in the Doctor of Physical Therapy (DPT) program at WVU, committed to preparing clinician-scientists who integrate evidence with patient-centered care.

DPT Program

Musculoskeletal Physical Therapy

Lower extremity orthopedic examination and management, with emphasis on foot, ankle, and tendon pathology. Integrates current evidence with clinical reasoning frameworks.

DPT Program

Prosthetics & Orthotics

Clinical management of patients requiring prosthetic and orthotic devices; lower and upper extremity device selection, fitting, and rehabilitation across the lifespan.

DPT Program

Evidence-Based Practice

Research methodology, critical appraisal of the literature, and integration of scientific evidence into clinical decision-making in physical therapy practice.

Research Mentorship

Student Research Coordination

Mentorship of DPT students on independent research projects and scholarly inquiry, fostering development of the next generation of physical therapist-researchers.

Education Committee, Research Committee — American Physical Therapy Association - West Virginia Chapter (APTA-WV)

Leading Reserach and continuing education initiatives for physical therapy professionals across West Virginia. 2021 – Present

Peer Reviewer — Journal of Physiology, Ultrasound in Medicine and Biology, JOSPT

Providing scholarly peer review for leading physical therapy and biomechanics journals.

Faculty Advisor — WVU DPT Student Research Projects

Guiding students through the research process from question development to dissemination.

AI-Assisted Web Applications

Interactive tools and educational apps built at the intersection of physical therapy, AI, and web technology — designed to support students, clinicians, and researchers.