Tag: Li-Shan Chou

Age-Related Differences in Healthy Male Runners

Presenter: Justine Silberberg

Mentors: JJ Hannigan and Li-Shan Chou, Human Physiology

Poster: 60

Major: Human Physiology

Previous research suggests that older males display less ankle plantar flexion and greater hip flexion during gait compared to younger individuals. Differences in running gait between younger and older individuals, however, are largely unknown. This study investigated differences in strength, flexibility, and range of motion between younger runners (n = 15; age range = 18-21) and older runners (n = 10; age range = 40-51). All subjects were males who ran at least 20 miles per week. For testing, subjects ran continuous laps of approximately 40-meters in the Motion Analysis Laboratory. Running kinematics were collected using a 10-camera motion capture system, strength was measured using a Biodex System 3 dynamometer, and flexibility was measured statically by a trained clinician. Independent sample t-tests were used to examine group differences. Older individuals were found to have increased hamstring flexibility, increased first metatarsal-phalangeal joint range of motion, decreased quadriceps flexibility, and decreased trunk flexion compared to younger runners (p < 0.01). Limitations include the relatively small sample size and cross-sectional nature of this study. Understanding age-related differences in running gait may help clinicians better treat injuries in older runners. Future studies exploring age-related differences in running should recruit a wider age range and follow these individuals over time.

Differences in Functional Recovery Following Concussion between Males and Females

Presenter: Rachel Klas

Mentors: Li-Shan Chou and Quinn Peterson, Human Physiology

Poster: 38

Major: Human Physiology

Concussion, a brain trauma resulted from linear or rotational acceleration to the head, represents a majority of the traumatic brain injuries (TBI) sustained each year. To understand if there are recovery differences between males and females post-concussion, this research examined males and females with matched controls for two months following the injury. In this study, a 3-dimensional motion analysis system was used to observe the trajectory of 29 anatomical locations in order to determine the peak anterior velocity of each subject’s center of mass (COM, the point where the mass is equally distributed) and the medial-lateral COM sway. Symptom severity was assessed based on a 22-symptom inventory and a scale similar to the Likert scale for each symptom (ranking each symptom from 0-6). A three-way analysis of variance, or ANOVA, was performed to analyze the data in order to determine the effect of concussion, sex (male and female), time (72 hour, one week, two week, one month, and two month post-injury), and the interactions between these independent variables. It was revealed that males and females do not objectively differ in terms of the peak anterior COM velocity or COM medial-lateral displacement across the 2-month study, but that females reported more severe symptoms than males. The findings suggest that subjects of both sexes follow the same general gait balance recovery trends and that both sexes report heightened symptoms for at least two months after experiencing a concussion. Across all time points, females reported more symptoms than males, so either males are underreporting their symptoms or females are experiencing more symptoms than males.

Changes in Walking While Using a Smartphone

Presenter: Taylor Kay

Mentor: Li-Shan Chou, Human Physiology

Oral Presentation

Major: Human Physiology 

It is common to see people using a phone while walking on campus. Our research analyzed gait in walking and crossing an obstacle while performing a visual cognitive test on a smartphone. Ten young healthy adults (5 males and 5 females, age: 21.5±2.07 years) randomly accomplished the following five tasks: 1) Gait only: walking at self- selected speed, 2) Gait + Stroop: walking while answering a Stroop test app (EncephalApp) on an iPod touch, 3) OBS only: walking over an obstacle set at a 10% of the subject’s height, 4) OBS + Stroop: crossing an obstacle while answering a Stroop test app, 5) Stroop only: sitting while answering a Stroop test app. A 10-camera motion capture system (Motion Analysis Corp., Santa Rosa, CA) was used for data collection and Cortex software (Motion Analysis Corp., Santa Rosa, CA) was used for processing the data. Our data suggested that individuals walked slower, swayed more, and raised their legs higher while using a smartphone during walking or obstacle crossing. These altered gait behaviors can lead to higher risks to pedestrian safety.

Correlations between Static and Dynamic Asymmetry in Runners

Presenter: Varneet Brar

Mentors: Li-Shan Chou and JJ Hannigan, Human Physiology

Poster: 6

Major: Human Physiology 

Asymmetry between limbs can be assessed statically, as measured by passive flexibility and range of motion (ROM), and dynamically, as measured by joint angle ROM during gait. Both types of asymmetry have been suggested as possible factors in developing a lower limb injury. The purpose of this study was to identify if there is a correlation between static and dynamic asymmetry. Sixty healthy subjects running at least 20 miles per week participated in the study. Dynamic joint angle ROM for the hip and knee was collected as subjects ran continuous laps in the UO Motion Analysis Laboratory using a 10 camera motion capture system. Static flexibility and ROM were measured by a trained clinician using a goniometer. Static and dynamic asymmetry between limbs was then calculated using an established method: the symmetry index (SI). Pearson correlation coefficients were used to test the strength of the relationships between static and dynamic SI. A moderate, significant correlation was found between static hip internal rotation ROM and dynamic hip internal rotation ROM (r = 0.296, p = 0.035). No additional significant correlations were found. As internal hip rotation has been linked to lower limb injury, future studies should investigate whether clinical correction for static asymmetry, especially for hip internal rotation, alters asymmetry during running gait. Correcting these asymmetries may help prevent injury setbacks for both recreational and competitive runners.

Hip Joint Moment during Obstacle Crossing Following Concussion in Adolescents

Presenter: Austin Thompson

Co-Presenters: Quinn Peterson, David Howell, Li-Shan Chou

Faculty Mentor: Li-Shan Chou, Quinn Peterson

Presentation Type: Poster 84

Primary Research Area: Science

Major: Human Physiology

Patients with concussion often complain of instability while walking. Previous studies have shown that subjects with concussion have altered gait under normal conditions, dual-task walking, and obstacle crossing. While other studies have looked at joint moments in healthy adolescents and the geriatric population and found that older adults have increased hip moment compared to young adults, there has not been a study looking at the changes in joint moment during obstacle crossing in subjects with concussion. The purpose of this study was to determine the effect of concussion on hip joint moment during obstacle crossing in adolescents. It was hypothesized that peak
hip joint moment of the leading and trailing limbs would be increased in patients with concussion. Nine patients with concussion diagnosed by health professionals were matched with eight control subjects by age, height, mass, sex, and sport. Subjects were tested five subsequent times: 72hrs, 1wk, 2wks, 1mo, and 2mo. Twenty-nine retro- reflective markers were placed on boney landmarks, and motion analysis was performed using a 10 camera, 60 Hz system. The subjects stepped over an obstacle 10% of body height during steady state gait, and data was analyzed using Orthotrakä. The neurometabolic cascade of concussion causes changes to motor control, which could lead to unnecessary strain and a mechanism of further injury while providing further insight into how concussions affect gait.

Obstacle Crossing Toe Clearance Following Concussion in Adolescents

Presenter: Maisie Rapp

Faculty Mentor: Quinn Peterson, Li-Shan Chou

Presentation Type: Poster 81

Primary Research Area: Science

Major: Human Physiology

Sustaining a mild traumatic brain injury (mTBI) can lead to physical and cognitive deficits; however, it has not been determined how long these deficits last. Previous research concluded that after a month post-concussion young adults still have deficiencies with toe-clearance during split attention obstacle crossing. Another study found that adolescents have greater gait balance control deficits two months post-injury compared to young adults. To determine how these deficiencies affect obstacle crossing during gait after two month, obstacle toe clearance was measured in adolescents following concussion and healthy matched controls. Data was collected using a 10-camera motion capture system which recorded the positions of twenty-nine retroflective markers that were placed on bony landmarks of the each subject. Concussion subjects came to the lab 72 hours, one week, two weeks, one month, and two months after the date of their injury. The purpose of this study is to determine the effect of navigating obstacles during gait in adolescents following concussion.

Symmetry Differences in Clinical and Running Measures between Achilles Tendinopathy and Medial Tibial Stress Syndrome and Controls

Presenter: Varneet Brar

Faculty Mentor: Li-Shan Chou, JJ Hannigan

Presentation Type: Poster 80

Primary Research Area: Science

Major: Human Physiology

Achilles tendinopathy (AT) and medial tibial stress syndrome (MTSS) are two common overuse injuries prevalent in the running population (Gallo et al, 2012). Susceptibility to such injuries may arise from training errors, but biomechanical and structural asymmetries may also be contributing factors (Zifchock, 2008). The purpose of this study was to compare static and dynamic asymmetries between injured (AT and MTSS) and healthy runners. 12 AT and 9 MTSS injured subjects and 21 matched, healthy, uninjured subjects running at least 20 miles per week participated in the study. Dynamic ankle range of motion (ROM) was collected as subjects ran continuous laps in the UO Motion Analysis Laboratory using a 10 camera motion capture system. Static flexibility and ROM measures of the lower extremity were gathered by a trained clinician using a goniometer. Asymmetry between limbs for both running and clinical measures was then calculated using an established method: the symmetry index (SI). An independent samples t-test calculated differences between the symmetry indices of injured and control subjects, p < .05. A significant difference between AT and matched controls was seen for ankle dorsiflexion (p = 0.041). Subtalar eversion (p=0.052) also trended towards significance. In both measures, there was greater asymmetry in the injured population. No additional significant differences were found. Future studies should evaluate the efficacy of corrections to these asymmetries in runners with AT.

The Effects of a Fatiguing Run on Hip Abductor Muscle Strength and Pelvic Kinematics

Presenter(s): Hao Tan − Human Physiology

Co Presenter(s): Colin Lipps

Faculty Mentor(s): Li-Shan Chou, JJ Hannigan

Poster 24

Research Area: Natural/Physical Science

Funding: UROP Mini-Grant, Sue Grigsby Scholarship, William and Marjorie Shearon Memorial Scholarship

Existing literature has identified several risk factors for the development of lower limb pathologies in recreational runners, including hip abductor muscle strength deficits as well as abnormal patterns in pelvic running kinematics. Studies have indicated that hip abductor muscles play a role in stabilizing the hip during running and that hip abductor strength deficits are associated with the development of overuse injuries as well as abnormal pelvic kinematics while performing tasks upright. However, the relationship between hip abductor strength deficits and abnormal pelvic kinematics while running remains unclear. This study intends to clarify the relationship between hip abductor muscle fatigue and associated pelvic kinematic changes in healthy runners by implementing a novel 30-minute lactate threshold treadmill run as a fatigue protocol while investigating pelvic kinematic changes at 7 equidistant time points over the course of the protocol. In terms of analyzing pelvic kinematics, this study implemented a dynamical systems approach, analyzing the variability of Trunk-Pelvis and Pelvis- Thigh segment couplings in the 3 anatomical planes, as well as an analysis of individual pelvic kinematic variables, specifically pelvic drop, hip adduction, trunk lean, and hip internal rotation. 23 subjects, between the ages of 18 – 40 who have not sustained major running related injuries and regularly run at least 20 miles a week, participated in this study. Participants performed a triplet of hip abductor muscle maximal voluntary contractions (MVCs) to establish a baseline and a post-fatigue strength assessment before and after a 30-minute fatiguing run, during which kinematic changes were assessed. Using a significance threshold of 0.05, it was found that hip abductor strength decreased significantly following the fatigue protocol (p < 0.0001) while pelvic drop significantly increased following the fatigue protocol (p < 0.001). No significant changes were observed in trunk lean, hip adduction, or hip internal rotation. The results of a repeated measures one-way ANOVA used on the entire participant pool indicated that there were no significant changes in variability between the 7-time points for both Trunk-Pelvis and Pelvis-Thigh coupled segments in the three anatomical planes. However, paired t-tests indicated that female participants experienced a significant decrease in variability within the sagittal plane of Pelvis-Thigh (p < 0.001) coupled segments and the frontal plane of Trunk-Pelvis (p < 0.01) coupled segments following the fatigue protocol. The experimental results indicate that a 30-minute lactate threshold treadmill run is an effective method of inducing hip abductor fatigue and potential increases in pelvic drop. Additionally, the findings of the dynamical systems approach used implicates that females may be more prone to lower limb overuse pathologies, which is consistent with the experimental findings of past studies.

Fatiguing During Repetitive Sit-To-Stand Movement: How Can We Tell

Presenter(s): Spencer Smith − Human Physiology, Psychology

Faculty Mentor(s): Li-Shan Chou, Teresa Chen

Poster 30

Research Area: Biomechanics

Funding: Undergraduate Research Opportunity Program Mini Grant

The biomechanically challenging sit-to-stand (STS) task, in which subjects repeatedly sit on and stand up from a chair, has been widely used as a functional mobility assessment as well as fatigue protocol. The purpose of this study was to identify the biomechanical measures that could potentially indicate muscle fatigue during repetitive STS movement. Subjects sat on an armless chair with their shanks perpendicular to the floor and were instructed to perform a repetitive STS movement at a self-selected pace, with arms across the chest for 30 minutes. The center of mass (CoM) trajectory on the sagittal plane (plane that divides body into left and right) was plotted and the area enclosed by rising and falling trajectories was calculated (CoMarea). No significant difference of CoMarea from start to finish was found. However, different changing patterns were observed between participants who were able to finish the fatigue protocol (Groupfinish) and those who failed to complete the task (Groupfail). CoMarea in Groupfail was significantly larger than Groupfinish during the first 3 durations (0-60% of STS protocol), indicated by independent t test, p < .05. In Groupfail, CoMarea has a higher value during 20-40% of the STS protocol, while it showed lower values at beginning and end stages.

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Dual-Task Gait Stability Assessment Utilizing a 180° Turn

Presenter(s): Emma Silverman − Human Physiology

Faculty Mentor(s): Will Pitt, Li-Shan Chou

Poster 27

Research Area: Biomechanics

The purpose of this study is to determine if a 180° turn is a useful metric for assessment of dynamic instability. 15 healthy subjects were recruited for this study. Angular velocity around a vertical axis was measured with a sensor over the L5 vertebrae. Utilizing that data, total medial-lateral center of mass deviation during a 180o turn was compared between conditions. All subjects performed a walking task at a self-selected pace, which consisted of an 8m walk, a 180 degree turn, and a return to the starting position. This walking task was performed under three different conditions (single-task walking and two dual-task conditions), in two different environments (laboratory and a hallway stimulating a medical clinic), over two testing days (approximately 7-10 days apart), and by two different raters. Currently, data collection has been completed. Data is currently being processed and thorough statistical analysis will begin shortly. Initial data analysis suggests a trend for significance (p=0.072), indicating that a 180° turn may be an additional useful metric for assessment of dynamic instability.