PT Faculty Research
Stuart Binder-Macleod, PhD, PT
Selected Publications

     Dr. Binder-Macleod's research focuses on the neural control of skeletal muscle force output.  He currently is attempting to identify stimulation patterns that minimize fatigue by most efficiently activating skeletal muscle.  The loss of motor control due to central nervous system (CNS) trauma can be both a psychologically and physically devastating injury.  A number of recent studies have reported the feasibility of using electrical stimulation to help patients walk following spinal cord injury (SCI).  One limiting factor in the clinical application of electrical stimulation is the rapid skeletal muscle fatigue that accompanies its use.  Identifying stimulation patterns that minimize fatigue should increase the clinical usefulness of functional electrical stimulation.
 Traditional neurophysiological techniques, where animal and human skeletal muscle are stimulated electrically and the electromyographic and force responses are recorded, are used in Dr. Binder-Macleod's laboratory.  In addition, simulation experiments in collaboration with Dr. Wexler from Mechanical Engineering, where the contractile characteristics of whole muscles are mathematically modeled, are being used to provide insights into the mechanisms operating and to predict the optimal pattern of stimulation. 
     Results to date have been encouraging.  Recent findings have suggested that the stimulation patterns presently used with patients are not optimal.  All published clinical studies that have used electrical stimulation to activate the muscles of individuals with damaged central nervous systems have used constant-frequency trains (ie, all pulses within a train are separated by regular intervals).  In contrast, Dr. Binder-Macleod's work has shown that varying the stimulation frequency within a brief train of pulses can produce greater forces from the muscle than the traditionally used constant-frequency trains. Current work is exploring how the optimal pattern of activation varies under a variety of physiological conditions including: fatigue state of the muscle, muscle length, and velocity of muscle shortening and lengthening.
      Dr. Binder-Macleod’s  areas of clinical interest include EMG biofeedback and electrical stimulation of skeletal muscle and he is a consultant to the University of Delaware Physical Therapy Clinic.


James C. (Cole) Galloway, PhD, PT
Selected Publications

     Dr. Galloway’s research focuses on the neuromotor control of infant and adult behavior.  He is  especially interested in learning how very young infants coordinate 'non functional' limb movements such as flapping and kicking for behaviors such as reaching and walking. Dr. Galloway uses standard biomechanical tools and techniques (high speed motion analysis, surface EMG and multijoint equations of motion) to address how coordinated motor behavior emerges from the interaction of the nervous system, the body's mechanics, and the environment. In addition to developmental psychology, his work draws from and has implications for neurophysiology, biomechanics, developmental and evolutionary biology and neurorehabilitation.
 Current infant projects include the development of object exploration with the arms and legs, coordination between the shoulder, elbow and wrist during the development of reaching, and comparisons of the hip, knee and ankle muscle torque during locomotion under different contexts.  Current adult projects include coordination of shoulder, elbow and wrist during reaching, and bimanual coordination in cellists of various skill levels.  Future projects will focus on extending Dr. Galloway’s infant work to pediatric populations such as pre term infants at high risk for developing motor delay.
      Dr. Galloway’s clinical interests are in the physical rehabilitation of adults following stroke and in the treatment of children with motor developmental delays due to central nervous system dysfunction.  Dr. Galloway is a consultant to the University of Delaware Physical Therapy Clinic.


Irene McClay, PhD, PT 
Selected Publications

      The Healthy People 2000 and 2010 Initiative of the national Public Health Service has the broad goal of increasing the quality and years of healthy life.  This initiative has identified regular physical fitness as being an important factor in overall health, longevity, productivity and reduction of health care costs.  Running has become one of the most popular forms of physical fitness in the past few decades.  However, this has been associated with an increase in the number of running-related injuries.  The etiology of these injuries is still not well-understood, however it is believed that the factors of structure, biomechanics and intensity play strong roles in the development of running injuries.  Once these injuries develop, they can progress to chronic conditions such as osteoarthritis and interfere with activities of daily living.  Therefore, the focus of Dr. McClay's research is to further understand the relationship between lower extremity structure, mechanics and injuries in runners.
      A recently completed study was aimed at comparing lower extremity running mechanics and injury patterns between high arched and low arched runners.  Results of this study suggest significant differences in both mechanics and injury patterns between these two groups of runners. Dr. McClay is also engaged in a study comparing lower extremity mechanics between runners who strike the ground with their rearfoot first and those who strike on the ball of their foot.  Results of this study suggest significantly different mechanics, and likely different injury risks, between these two types of runners.  An investigation of the effect of foot orthotics on lower extremity mechanics of forefoot strikers is currently underway. 
     Dr. McClay is currently beginning a 5 year prospective study of the biomechanical factors associated with tibial stress fractures in runners.  400 runners (at 2 collaborating sites) will undergo a structural and biomechanical analysis of their lower extremities.  They will be followed for 2 years to monitor the mileage they run and the injuries they sustain.  Runners with documented tibial stress reactions or fractures will return to the lab, once healed, and have their mechanics assessed once again to also determine whether mechanics are altered as a result of the stress fracture. 
      The overarching goal of the research program is to develop optimal treatment and intervention strategies to minimize the occurrence of running-related injuries.  For example, once the biomechanical factors associated with particular running injuries are identified, Dr. McClay hopes to retrain these abnormal gait patterns in order to decrease the likelihood of sustaining further injuries and allow runners to continue participating in their fitness program.
     Dr. McClay’s clinical interests are in foot, ankle and lower quarter problems, particularly related to overuse injuries.   Dr. McClay is the director of the University of Delaware Running Injury Clinic and is a regular consultant to the University of Delaware Physical Therapy Clinic.


Katherine S. Rudolph, PhD, PT
Selected Publications

Reflex Activation of Muscles in People with Medial Compartment Osteoarthritis.  This project investigates muscle reactions in people with medial compartment osteoarthritis of the knee after rapid perturbations at the knee produce a varus stress at the knee.  A reflex arc between the lateral knee ligaments and muscles in the lower extremity has been demonstrated with electrical stimulation of the medial and lateral collateral ligaments.  Reflexive muscle activation has also been shown in response to varus and valgus stresses at the knee in a non-weight bearing position.  Reflexive muscle activation could provide stability to the knee under stress, but it is unclear to what extent muscles respond to stresses when the limb is in a weight bearing position.  The purpose of this study is to examine reflex muscle activation in young and older people without knee impairment, and in people with OA in response to rapid varus perturbations with the limb in a loaded position.  We also intend to investigate how the laxity associated with medial compartment arthritis affects muscle activity patterns in the knee.

The Effect of Quadriceps Strengthening on Adduction Moments in People with Medial Compartment Osteoarthritis.  Researchers have shown that people with medial compartment osteoarthritis (OA) have increased adduction moments during the stance phase of gait.  An excessive external adduction moment during walking could lead to a cycle of medial joint destruction, varus angulation, increased adduction moments and further medial joint destruction. Rehabilitation techniques should focus on methods to reduce the adduction moment during walking to slow down the progression of OA in the knee.  Some investigators have suggested that quadriceps femoris weakness, pervasive in people with OA, may not only be the result of OA but may contribute to the development of OA.  Researchers have studied the effect of quadriceps femoris muscle weakness on the development of OA and found that individuals with radiographic evidence of OA and no pain had significant quadriceps strength deficits.  They argued quadriceps weakness may precede the development of OA in the knee and that even relatively small increases in quadriceps femoris strength would  predict a 20-30% decrease in the odds for having OA.  The question remains, what affect does the strengthening have on the biomechanical factors involved in the development of OA?  Will quadriceps femoris strengthening reduce the adduction moment in people with medial compartment arthritis?  The purpose of this study is to investigate changes in the adduction moment in people with medial compartment OA in response to a quadriceps femoris strengthening program.  Subjects will be evaluated for the degree of angulation in the knee as well as severity of arthritic changes in the knee in an effort to delineate if patients with fewer arthritic changes would benefit more from strengthening than those with severely involved knees.

Effect of Neuromuscular Electrical Stimulation of the Pretibial Muscles on Gait Patterns in People with Hemiplegia.  Patients with hemiplegia following cerebral vascular accident (CVA) often have diminished control of the muscles of the lower extremity.  A common gait deviation associated with hemiplegia is excessive ankle plantarflexion during the swing phase of gait due to weak  pretibial muscles.  The purpose of this study is to determine the affect of neuromuscular electrical stimulation (NMES) for strengthening of the pretibial muscles on the ankle kinematics during the swing phase of gait.
     Dr. Rudolph’s clinical interests are the evaluation and treatment of gait disorders in elderly patients who are neurologically or orthopedically challenged and is a consultant to the University of Delaware Physical Therapy Clinic.


John P. Scholz, PhD, PT
Selected Publications

      The goal of Dr. Scholz’s research is to understand motor control processes in healthy individuals and patients who have neurological dysfunction, particularly stroke.  His current work combines mathematical modeling with experiments to determine how the nervous system solves the problem of motor redundancy.  This work has focused, to date, on the control structure underlying the stability of postural states of important task variables.  He is currently extending this approach to identify how the coordination of underlying joint motions lead to stable temporal sequences of these postural states.  In addition, a collaborative proposal with Dr. Thomas Buchanan has recently been submitted to extend this work to the neuromuscular level by incorporating muscle modeling.  This work studies patients with mild to moderate arm dysfunction following a stroke.  The goal is to determine how their motor control system is altered compared to healthy, age- and gender matched subjects as well as to explore differences in control in right and left brain lesions. 
      Collaborative projects have also been proposed with Dr. Sunil Agrawal, of Mechanical Engineering, to develop robotic devices that can be used to explore new methods of treating stroke and other neurological deficits. 
      Dr. Scholz’s area of clinic interest is the treatment of adult and pediatric patients with motor dysfunction due to central nervous system damage (e.g., stroke, cerebral palsy).  Dr. Scholz and is a consultant to the University of Delaware Physical Therapy Clinic.


Lynn Snyder-Mackler, ScD, PT
Selected Publications

      Dr. Snyder-Mackler's research efforts focus on dynamic stability of knee and the responses of the quadriceps  muscle after anterior cruciate ligament (ACL) injury.  Studies of the mechanisms by which and the way neuromuscular  electrical stimulation (NMES) and perturbation training can be used to augment muscle strength and  affect function in patients after this injury as well as randomized controlled clinical trials of these interventions comprise the majority of her research. This research reflects an overarching  clinical interest in the effectiveness of therapeutic interventions, particularly  NMES as well as an interest in the relationships between impairments (eg.  quadriceps strength) and dysfunction (eg. gait abnormalities) after ACL injury. Dr. Snyder-Mackler's most recent work has proceeded on several levels, first  characterization of the quadriceps in patients with anterior cruciate ligament  injury, second, the relationship between quadriceps impairments and function, and third, controlled clinical trials of interventions. The  laboratory has attempted to characterize the quadriceps impairment that occurs  after ACL injury by examining their strength and fatigue properties, as well as morphology. The role of failure of central activation in the weakness and fatigue properties of the  quadriceps have been investigated. In a large, multicenter trial, the effectiveness  of NMES was compared with volitional quadriceps exercise in restoring  quadriceps strength and normal gait after ACL reconstruction. Dr. Snyder-Mackler is also investigating the relationship between instability,  laxity and dysfunction after ACL injury. She has studies  the small sub-population of ACL deficient patients who can return to all  activities without episodes of instability or swelling and without  reconstructive surgery to determine if the characteristics identified in those  patients who do not compensate well are different than the population who do compensate. A training program has been developed based on these characteristic and has been tested in a randomized clinical trial. Most recently, Dr. Snyder-Mackler has begun to study some of these same problems in the elderly and those with total knee replacement.  This work has already result in two papers with Dr. Binder-Macleod.  A trial of the use of NMES in elderly patients following total knee replacements is now being undertaken.
      Dr. Snyder-Mackler also regularly collaborates with colleagues in the department and in the  Department of Mechanical Engineering.  She and Dr. Michael Santare have collaborated on orthopedic biomechanics projects  and have two published articles. They have collectively supervised two  students, one in Mechanical Engineering and one in BIOMS. Similarly, Dr. Snyder- Mackler and Dr. Thomas Buchanan collaborate on two projects and two succesful grant applications. First, a new approach to in vivo analysis of musculoskeletal dynamics uses Cine-phase contrast (Cine-PC) magnetic resonance imaging (MRI) to image and track the moving knee. Cine-PC MRI, a non-invasive technique, is capable of measuring 3D muscle fiber and skeletal velocity, in vivo, during dynamic tasks. Through integration, 3D  musculoskeletal movement can be tracked. A combination of the use of this new technology and conventional MRI, electromyography, and musculoskeletal modeling provide a unique opportunity to elucidate the compensation strategies  employed by patients with anterior cruciate ligament (ACL) injuries. Finally, they are examining what makes "copers" and "non-copers"--those who do well with ACL deficiencies and those who don't and will require treatment. This is being done by studying the subjects' kinematics (i.e., gait analysis) and muscle activation patterns (EMGs) during a variety of tasks
      Dr. Snyder-Mackler serves as the Academic Director of the University of  Delaware Physical Therapy Clinic and regularly provides consultative and  clinical services in the areas of knee, shoulder and back rehabilitation. Dr.  Snyder-Mackler provides similar consultation through the clinic to the  University of Delaware’s Athletic Program and several area professional sports  teams. In addition, Dr. Snyder-Mackler, with local Sports Orthopedic surgeons  conducts a monthly teaching clinic for clinic staff, graduate students, residents  and fellows where patients with unique problems are presented, examined and discussed. 

301 McKinly Lab| University of Delaware | Newark, DE 19716 | phone 302-831-8910| fax 302-831-4234
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last edited: 5/2000