Wei Liu

VCOM, Auburn · Osteopathic Rehabilitation and Biomechanics

After stroke, movement patterns of the upper limb (UL) during functional arm reaching change to accommodate altered constraints. These compensatory movement control strategies do not, however, have a one-to-one mapping with posttraining outcomes. In this study, we quantify arm movement control strategies in unilateral and bilateral reaching tasks u...

Introduction: T'ai chi chuan is a beneficial exercise of improving health and function. Biomechanical insights of t'ai chi chuan are less understood. Objectives: To study t'ai chi gait (TCG), a common form of t'ai chi chuan in order to quantify external knee adduction moment (EKAM) as a key indicator of mechanical loading of the medial compartment...

Tai-Chi (TC) practice has been increasingly used to prevent falls in older adults. However, the biomechanical mechanisms underlying the effects of TC practice on fall risk among older adults remain unanswered. The objective of this pilot study was to examine how TC gait biomechanically impacts the human body in terms of dynamic gait stability and l...

Background Tai Chi (TC) training has been increasingly used to prevent falls. However, the underlying biomechanical mechanisms of TC training which influence fall risk remain unknown. As a result, the selection of TC forms differs among studies, leading to inconsistent results. Research question Is dynamic stability different between the simplifie...

Objectives Tai Chi (TC) is a multi-beneficial exercise for improving health and function in knee osteoarthritis (OA). Biomechanical insights of 24 TC forms at the knee joint are not well understood. We aimed to examine knee joint biomechanics of TC actions form by form and their interactions with pain in individuals with knee OA. Methods Ten knee...

Objectives Tai Chi (TC) shows some beneficial effects in reducing pain in knee osteoarthritis (OA). However, the selection of criteria TC forms in previous studies were unclear and inconsistent, possibly accounting for the varying outcomes and rendering the training effects suboptimal. We have selected four optimal TC (OTC) forms based on the knee...

Objective Knee osteoarthritis increases the risk of falls among older adults. Tai Chi (TC) has been increasingly utilized to prevent falls in older adults. However, findings from previous studies are inconclusive, possibly due to a lack of scientifically sound methodologies to identify targeted TC forms, which likely maximize the training effects i...

Objectives Tai Chi (TC) has shown beneficial effects on joint function in knee osteoarthritis (OA). Biomechanical mechanisms of knee joint contact load (JCL) and muscle activations during TC are less understood. The purpose of this biomechanical simulation study was to examine JCL of TC gait, the most common used TC from and its causal interactions...

The increase in the use of flexible electronics in wearable applications has resulted in an increased focus on the study of movement characteristics of the human body and its impact on electronics under various day-to-day actions. The flexible electronics that are attached to the human body are tested for reliability under various conditions of hum...

The use of flexible electronics in assisting daily human activities has prompted to characterize the failure of the prior for different operating conditions of human movements. The failure analysis and acceleration factors during various operating conditions of human motion were estimated using experimental flexing of the flexible electronic substr...

Falls are a serious health threat also for people with multiple sclerosis (MS). Dynamic gait stability has been identified as a key risk factor of falls. The development of effective interventions for preventing falls requires a sound understanding of how MS affects dynamic gait stability. The purpose of the study was to compare dynamic gait stabil...

Knee Osteoarthritis (OA) is a degenerative joint disease, specifically degeneration of the cartilage leading to pain, stiffness, swelling, and tenderness. It is clinically understood that knee joint instability correlates to the onset of OA. The majority of current research on knee laxity is limited to subjective, self-reported questionnaires based...

Knee Osteoarthritis (OA) is a degenerative joint disease, specifically degeneration of the cartilage leading to pain, stiffness, swelling, and tenderness. It is clinically understood that knee joint instability correlates to the onset of OA. The majority of current research on knee laxity is limited to subjective, self-reported questionnaires based...

The increase in use of flexible electronics in wearable applications has prompted in analyzing the movement characteristics of human body under various day to day actions. The flexible electronics that are attached on the human body were tested for reliability under various conditions of human activity such as walking, jumping, squats, lunges and b...

Constraint-induced movement therapy (CI therapy) has been shown to reduce disability for individuals with upper extremity (UE) hemiparesis following different neurologic injuries. This article describes the study design and methodological considerations of the Bringing Rehabilitation to American Veterans Everywhere (BRAVE) Project, a randomized con...

Ankle sprain is the most commonly diagnosed injury experienced by ballet dancers with few studies investigating preventive support measures such as Kinesio taping. The need exists to examine the mechanical support characteristics of Kinesio taping and effect of application on ankle motion and performance. This may be important to understanding the...

Research Objectives To determine the efficacy of CI Therapy compared to LEFT, a holistic fitness program (meditative and physical excercises) for improving upper extremity (UE) motor deficit and PTSD symptomatology in veterans and civilians with TBI. Design Single-blinded RCT with 1-year follow-up Setting Academic medical center Participan...

Purpose: To evaluate the accuracy of Blumensaat's line (BL) in predicting the tendinous graft length and tibial tunnel length (TTL) in an independent-tunnel anterior cruciate ligament reconstruction (ACLR) using a bone-patellar tendon-bone (BTB) allograft. Methods: Eighteen ACLRs were performed on cadaveric specimens using an anteromedial portal...

Background: Shoulder and elbow injuries are common in young athletes, especially high school baseball players. Understanding the risk factors associated with baseball injuries is an essential first step in the development of injury prevention strategies. Purpose: To provide a comprehensive understanding of the epidemiology of shoulder and elbow...

Background and purpose: This case study reports patterns of muscle inhibition and techniques for therapeutic intervention in a well-trained cyclist with chronic low back pain (CLBP) following a discectomy at L5-S1. It has been shown that repeated or prolonged flexion can lead to inhibition of the spine stabilizing muscles. Competitive cyclists exer...

The purpose of this study was to provide a comprehensive understanding of the epidemiology of shoulder and elbow injuries among high school baseball players in the United States.

To investigate the relationships between postural stability and outcomes of physical health and functional performance, among adults with symptomatic knee OA. [Acknowledgements: This study was funded by the National Center for Complementary and Integrative Health (NCCIH) (#R01AT005521-01A1, NCT01258985, PI - Dr. Chenchen Wang ). The views expressed...

Purpose: To compare the displacement, stiffness, and ultimate failure load of a fixed-loop cortical suspensory device with 2 adjustable-loop devices when positioned on metaphyseal bone. Methods: Thirty devices (10 of each device) were positioned on the metaphyseal cortex of 30 porcine femora simulating anatomic anterior cruciate ligament femoral...

Purpose: To report a large number of highly active patients who underwent arthroscopic Bankart repair at our institution over the last decade. Methods: A retrospective analysis of patients who underwent primary and revision arthroscopic Bankart repairs using bioabsorbable anchors was performed. Outcome measures included recurrence of dislocation...

Figure 1: Global and local coordinate system set up Figure 2: Mean joint moments of shoulder, elbow and wrist of non-disabled subjects (n=3). Positive direction (+): E (Extension), Ad (Adduction), ER (External Rotation); Negative direction (-): F (Flexion), Ab (Abduction), IR (internal Rotation). Profiles are the average of three trials for the thr...

Robotic assisted rehabilitation, taking advantage of neuroplasticity, has been shown to be helpful in regaining some degree of gait performance. Robot-applied movement along with voluntary efferent motor commands coordinated with the robot allows optimization of motion training. We present the design and characteristics of a novel foot-based 6-degr...

Background Ankle sprain is the most commonly diagnosed injury experienced by ballet dancers. Traditional taping and bracing affect function by restricting range of motion but are aesthetically unappealing as practical modes of injury prevention for ballet dancers. Few studies have investigated alternative support measures such as Kinesio® taping. O...

[Purpose] Medial knee osteoarthritis, a degenerative joint disease, affects adults. The external knee adduction moment, a surrogate knee-loading measure, has clinical implications for knee osteoarthritis patients. Tai Chi is a promising intervention for pain alleviation in knee osteoarthritis; however, the characteristics of external knee adduction...

Radial tears of the meniscus represent a challenging clinical scenario because benign neglect and partial meniscectomy have both been shown to have negative biomechanical and long-term clinical consequences. Complex suture repair constructs have higher failure loads and stiffness values compared with simple constructs. Controlled laboratory study....

Background: Many types of screws, plates, and strut grafts have been utilized for ankle arthrodesis. Biomechanical testing has shown that these constructs can have variable stiffness. More recently, headless compression screws have emerged as an evolving method of achieving compression in various applications but there is limited literature regard...

This study shows that perceived geographical slant affects postural stability. In 2 experimental conditions participants stood on a force platform that measured center of pressure (COP) during quiet stance while looking at a rigid, flat ramp surface of varying geographical slants. Using an otherwise identical procedure, participants in the second c...

Context This is part II of a 2-part series discussing stability characteristics of the ankle complex. In part I, we used a cadaver model to examine the effects of sectioning the lateral ankle ligaments on anterior and inversion motion and stiffness of the ankle complex. In part II, we wanted to build on and apply these findings to the clinical asse...

Context The mechanical property of stiffness may be important to investigating how lateral ankle ligament injury affects the behavior of the viscoelastic properties of the ankle complex. A better understanding of injury effects on tissue elastic characteristics in relation to joint laxity could be obtained from cadaveric study. Objective To biomec...

Functional arm reaching involves multilinked joints: shoulder, elbow, and wrist. We propose that induced position analysis is a useful analytical tool for multijoint coordination of arm reaching. This method was used to compute the contributions of the net joint moment to the hand position when reaching forward. We describe the method and give exam...

Hemiparesis is the most common impairment after stroke, the leading cause of adult disability in the United States. The initial severity of hemiparesis had been the strongest predictor of neuromotor functional recovery level. However, the intervention response of stroke survivors does not always correlate with their initial level of impairment. Thi...

Hemiparesis is the most common impairment after stroke, and the initial severity of hemiparesis had been the strongest predictor of neuromotor functional recovery level. However, the intervention response of stroke survivors does not always correlate with their initial level of impairment, which implies the existence of other factors that may signi...

Principles of motor control and learning such as bilateral coordination and task-specificity, are increasingly incorporated in the design of upper extremity rehabilitation protocols for stroke survivors. Yet most studies investigating the efficacy of new protocols report composite scores of standardized tests, such as the Fugl-Meyer Upper Extremity...

The purpose of this study was to investigate knee muscle activity patterns in experienced Tai-Chi (TC) practitioners during normal walking and TC stepping. The electromyographic (EMG) activity of vastus lateralis (VL), vastus medialis (VM), bicep femoris (BF), and gastrocnemius (GS) muscles of 11 subjects (five females and six males) during the sta...

Finger tapping involves 3 important features: time, spatial amplitude, and frequency. In classical analysis, investigators examine timing parameters; in spectral analysis, they examine frequency parameters. Both types of analysis are based on stationary tap information. The authors propose that time-frequency analysis is a useful tool for analyzing...

Upper extremity (UE) hemiparesis results in decreased movement speed and impaired coordination leading to functional limitations and disability. The effects of UE hemiparesis on bilateral functional reaching have not been studied even though most activities of daily living are bilateral tasks. We examined the characteristics of bilateral simultaneo...

This study was to quantitatively characterize the spatial, temporal, and neuromuscular activation patterns of Tai Chi gait (TCG). Ten healthy young subjects were tested. The kinematics of TCG and normal gait (NG) were measured using a marker-based motion analysis system and two biomechanical force plates. Surface electromyography (EMG) was recorded...

To compare isokinetic strength of leg muscles and foot center of pressure (COP) as a measure of sway between long-term Tai Chi practitioners and controls. Cross-sectional study. Community setting. Twenty subjects in the Tai Chi group and 19 subjects in the control group (age, >55 y). Subjects in Tai Chi group had practiced Tai Chi for a minimum of...

Osteoporosis increases with age. It is a major cause of mortality, morbidity, and medical expense worldwide [1]. It has been shown that increased activity level is associated with decreased osteoporosis [1–4]. These activities include walking, running, weight lifting, or Tai Chi [2–5]. However, it is not clearly known yet what characteristics of th...

The purpose of this study was to examine the normal walking pattern of 21 older adults who had practiced Tai Chi for more than 5 years (TC group) and 20 older adults who often performed other kinds of physical activity (CTRL group). The results of the study indicated that there were significant differences in kinematic parameters of the hip joint a...