Li Li

• PhD.
• Research Professor at Georgia Southern University

Introduction The purpose of this study was to investigate the relationships between a Power Leg Press test (PLP) with walking capacity and self-reported performance and participation in individuals with Cerebral Palsy (CP), and to compare the strength of the associations between two power tests (PLP and isokinetic (IsoK)) with walking capacity. Me...

This study investigated the validity and sensitivity of a custom-made shoelace tensile testing system. The aim was to analyze the distribution pattern of shoelace tension in different positions and under different tightness levels during running. Mechanical tests were conducted using 16 weights, and various statistical analyses, including linear re...

Background Patients with knee osteoarthritis (KOA) are at high risk for falls, which is attributed to their impaired balance control. Identifying factors associated with balance control facilitates the development of precise KOA rehabilitation programs. This study was to investigate the correlations of balance control with proprioception, plantar t...

Peripheral neuropathy is characterized by decreased foot sole sensitivity and slowed nerve conduction velocity, leading to impaired postural control and functional gait performance. This study assessed the differential effects of reduced foot sole sensitivity and slowed nerve conduction velocity on postural control and functional gait. Thirty-five...

Conclusion: We observed biased recruitment of the left BF and right GMAX despite no differences in pre-experimental active knee ROM or isokinetic, isometric strength measurements. Future Direction: Further investigation is warranted to decipher whether this intra-exercise bias predicts side of hamstring injury or is a compensatory motor strategy (...

Introduction: Electromyography (EMG) normalization often relies on maximum voluntary isometric contraction (MVIC), which may not be suitable for knee osteoarthritis (KOA) patients due to difficulties in generating maximum joint torques caused by pain. This study aims to assess the reliability of standard isometric contraction (SIC) for EMG normaliz...

Objective To investigate the effect of a 16-week Tai Chi practice on strength, tactile sensation, kinesthesia, and static postural control among older adults of different age groups. Methods This is a quasi-experimental study. Thirteen participants aged 60–69 years (60–69yr), 11 aged 70–79 years (70–79yr), and 13 aged 80–89 years (80–89yr) complet...

Background The development of computer vision technology has enabled the use of markerless movement tracking for biomechanical analysis. Recent research has reported the feasibility of markerless systems in motion analysis but has yet to fully explore their utility for capturing faster movements, such as running. Applied studies using markerless sy...

Background: Effects of Tai Chi on people with peripheral neuropathy (PN) are not yet apparent. This systematic review was conducted to evaluate the effects of Tai Chi on postural control in people with PN. Methods: Literature was screened in seven databases for relevant randomized controlled trials. The reports and methodological quality were ev...

The development of computer vision technology has enabled the use of Markerless (ML) movement tracking for biomechanical analysis. Recent research has reported the reliability of ML in motion analysis but has not yet further explored the clinical potential and limitations. The purpose of this study was to investigate the effects of speed on the com...

Objective The purpose of this study was to investigate the effects of an 8-week proprioceptive neuromuscular facilitation (PNF) stretching in relieving pain and balancing knee loading during stepping over obstacles among older people with knee osteoarthritis, and further explore the improvements in gait patterns. Design Thirty-two older adults (66...

Background: Lower extremity muscle power influences walking ability in individuals with Cerebral Palsy (CP). Aim: Determine the reliability, validity, and minimal detectable change (MDC) of a novel power leg press (PLP) test to measure muscle power in individuals with CP. Methods: Individuals with spastic CP (n = 26 (10 adults, 16 children); m...

Objective: To investigate the effects of foot sole insensitivity on the outcomes of the triceps surae muscle H-reflex and functional gait. Material and Methods: People with peripheral neuropathy were recruited and divided into two groups: people with more (n = 13, 73.3 ± 4.3 years old) or less (n = 10, 73.5 ± 5.3) sensitive tactile sensation. Their...

In people with peripheral neuropathy (PN), impaired plantar sensation can cause adaptive changes in the central nervous system (CNS), resulting in changes in the standing postural control, which is reflected in the variability of standing output signals. Standard deviation (SD) and entropy are reliable indicators of system variability, especially s...

Electromyography (EMG) measures muscle activity by an electrical signal and is useful in studying motor control, postural control, and physical therapy. A current research topic is creating an algorithm that can use the EMG signal to reliably classify a muscle as active or inactive. This thesis presents a classification algorithm for leg muscles wi...

Hamstring injury has been considered one of the most common exercise-induced injuries in sports. Hamstring injuries mostly occur proximal to the biceps femoris. However, the reasons and mechanisms remain unclear. To summarize hamstring morphological structure features and what the relationship is between their structure and risk of injury from the...

Background: Markerless (ML) motion capture systems have recently become available for biomechanics applications. Evidence has indicated the potential feasibility of using an ML system to analyze lower extremity kinematics. However, no research has examined ML systems’ estimation of the lower extremity joint moments and powers. This study aimed to c...

Elderly loss of the ability to maintain postural control during manual manipulation is a risk factor for falls. The straightness of the trunk trajectory (STT) can be used to assess trunk motion during a precision fitting task. The ability to maintain postural control can also be evaluated by the temporal coordination between the wrist movements and...

Purpose The relationships of postural stability with its three potential contributing factors, namely, muscle strength, tactile sensation, and proprioception, have not been clarified at different ages among older adults. Differences in the relationships may explain the increased incidence of falls among older adults 75 and older. This study compare...

Background Falls are directly related to visuospatial ability and postural stability. Perturbations of upper body movements pose a challenge to older adults and may cause falls. This study investigated visuospatial ability and postural stability during goal-directed upper body movements between the Tai Chi and control groups and tried to connect th...

Purpose: The project was to examine the influence of peripheral neuropathy (PN) severity on the relationship between Hoffmann-reflex (H-reflex) and postures. Methods: A total of 34 participants were recruited. H-reflex (H/M ratio and H-index) during prone, standing, and the heel-contact phase of walking was tested, along with foot sole sensitivity....

Introduction Peripheral neuropathy (PN) affects up to 20% of the population over the age of 60. Hoffmann reflex (H-reflex) may assess PN adaptation by measuring the function of the peripheral neural system and central nervous system (CNS) modulation. This project aimed to find a reliable muscle among triceps surae muscles during standing and walkin...

Past studies have investigated the association between the built environment and active lifestyle, but the environmental exposure in most of these studies was measured in residential settings with predefined boundaries. In this study, we investigated the relationship between destinations in cities and walking behaviors in national and provincial ca...

Objective: This study aimed to investigate the effects of a 6-week proprioceptive neuromuscular facilitation (PNF) stretching on pain, proprioception, joint range of motion (ROM), and joint moments during stair ascending among older adults with knee osteoarthritis (KOA). Design: This study is a randomized, controlled, and assessor-blinded trial....

Purpose: To evaluate the relationship between specific aspects of core stability and knee injury risk factors during drop-jump (DJ) landing. Methods: Eighteen college-aged male amateur basketball players participated in the project. Kinetic and kinematic data for DJ tasks were collected with force plates and infrared cameras. Raw data were processe...

PURPOSE: To assess the severity of peripheral neuropathy (PN) on lateral gastrocnemius Hoffman reflex (H-reflex, both H/M ratio and H-index) modulation during walking stance phases (heel-contact, mid-stance, and toe-off). METHODS: Thirty-two participants were recruited in this study. Nine of them were in the Control group (healthy population) with...

PURPOSE: To examine the effects of Hoffman-reflex (H-reflex) and foot sole sensitivity on low extremity kinematics in people with peripheral neuropathy (PN). METHODS: People who are more (MST group, N = 13) and less (LST group, N = 10) sensitive to touch with physician-diagnosed PN were recruited for the experiment. Key outcome variables were H-ref...

The running footwear literature reports a conceptual disconnect between shoe cushioning and external impact loading: footwear or surfaces with greater cushioning tend to result in greater impact force characteristics during running. Increased impact loading with maximalist footwear may reflect an altered lower-extremity gait strategy to adjust for...

Purpose: Balance impairment is one of the strongest risk factors for falls. Proprioception, cutaneous sensitivity, and muscle strength are 3 important contributors to balance control in older adults. The relationship that dynamic and static balance control has to proprioception, cutaneous sensitivity, and muscle strength is still unclear. This stu...

This cross-sectional study examines the association between pain and activities requiring motor skill performance among a nationally representative sample of US children with cerebral palsy.

The initial contact and midstance angles may influence injury risk. Previous literature has not assessed these angles under the influence of new footwear for a non-exhaustive prolonged run or the relationship between the angles. To assess lower extremity kinematic changes and the relationship between kinematic parameters at initial contact and mids...

This study investigated the effects of a 16-week Tai Chi (TC) intervention on cutaneous sensitivity and proprioception among older adults with and without sensory loss. Thirty-six older adults were divided into sensory loss and control groups, and they underwent a 16-week TC intervention. Significant interactions were detected in heel cutaneous sen...

A novel device has been developed to assess eccentric hamstring strength during the Nordic hamstring exercise (NHE) by measuring the contact force at the ankle hook (brace). The purpose of this study was to determine the correlation between the force measured at the ankle hook and the hamstring force estimated by a low extremity model. Thirteen mal...

Stairs are among the most hazardous locations, and stair descending contributes to a high risk of falls among the elderly under dual-task (DT) conditions. The purpose of this study was to determine whether the practitioners of Tai Chi (TC), one type of mind-body exercise, have lower fall risks under DT conditions during stair descending, compared w...

This study investigated the lower extremity torque's active and passive features during the walk-to-run gait transition with continuously increased walking speed. Fourteen volunteers participated in the experiment. Kinematic and kinetic data were collected synchronously. Five strides leading up the gait transition were examined. Peaks of the passiv...

Featured Application Our results showed that the structure of kinematic and kinetic core training is essential to improve CMJ performance and dynamic core flexion strength played a more critical role in improving CMJ with arm-swing. For all movements where arm-swing is used to increase jump height, athletes can benefit from enhanced dynamic core fl...

Background : A fall would impact elderly population’s quality of life, which associate with diminished physical and psychological function, and can even be life-threatening. Tai Chi has been used to improve age-related postural instability in locomotion. However, it does not fully explain the mechanism of a lower risk of falling among the Tai Chi p...

Background: Patellofemoral pain (PFP) is a common overuse injury that has been suggested to cause abnormal gait kinematics and variability in runners with PFP. Conflicting results have been presented as to the variability of joint kinematics and joint coordination. Objective: The purpose of this study was to examine the variability of lower extremi...

PURPOSE: To determine if muscle excitation amplitudes differed from beginning, middle, and end of a prolonged run in runners with and without patellofemoral pain. METHODS: Five recreationally active female runners with history of running with patellofemoral pain (PFP) were matched to five female runners without lower extremity pain (CON) (PFP: age...

Purpose Knee osteoarthritis (KOA) is a common disease that causes pain and limits functionality in the elderly during daily activities, especially during stair descent. Proprioceptive neuromuscular facilitation (PNF) practices promote multiple‐plane joint movements, which relieve pain and increase joint range of motion (ROM). This study aims to exa...

INTRODUCTION: Peripheral neuropathy is characterized by a loss of foot sole sensitivity and slowed nerve conduction velocity. Individuals with peripheral neuropathy have decreased postural control ability and functional gait performance. No research was found that differentiated the effects of the main symptoms of peripheral neuropathy on postural...

Featured Application The authors concluded that the influence of gait velocity should be considered when assessing the effects of dual-tasks. Understanding the effects of the interaction between the dual-task paradigm and gait velocity on dynamic gait stability may provide new insights into a dynamic postural control mechanism. Abstract Falls duri...

Background: Lower extremity muscle power is critical for daily activities and athletic performance in clinical populations. Objective: The purpose of this study was to determine the reliability and validity of 3 clinically feasible methods to measure lower extremity muscle power during a leg press. Methods: Ten of 26 subjects performed 2 sessions o...

Aim: To examine the effects of an upper-extremity, community-based, and power-training intervention. Methods: Twelve participants with cerebral palsy (CP) [8 males, 4 females; mean age 14 years 6 months (SD 5 years 4 months), range 7–24] were randomly assigned to a rest-training (RT; n = 6) or training-rest (n = 6) group in this randomized, cross-...

Bicycle saddle height configurations have been shown to affect knee joint biomechanics. Research suggests that an excessively low saddle height may lead to Patellofemoral Pain Syndrome, which is thought to be caused by the knee adduction moment during cycling. However, how saddle heights affect frontal plane knee biomechanics was not clear. We aime...