Biomechanics Commons^™

Effects Of Footstrike Pattern On Low Back Posture, Shock Attenuation, And Comfort During Running, Traci L. Delgado, Emilia Kubera-Shelton, Robert R. Robb

UNLV Theses, Dissertations, Professional Papers, and Capstones

Purpose: Barefoot running (BF) is popular in the running community. Biomechanical changes occur with BF, especially when initial contact changes from rearfoot strike (RFS) to forefoot strike (FFS). In addition, changes in lumbar spine range of motion (ROM), particularly involving lumbar lordosis, have been associated with increased low back pain (LBP). However it is not known how changing from RFS to FFS affects lumbar lordosis or LBP. Thus, the purpose of this study was to determine if a change from RFS to FFS would change lumbar lordosis, and/or decrease shock attenuation, and/or change comfort levels in healthy recreational/experienced runners.

Methods: …

Investigations Toward Tunability Of Mechanical, Thermal, And Impact Properties Of Thiol-Ene Networks For Novel High Energy Absorbing Materials, Olivia Devon Mcnair

Dissertations

The UV polymerization of thiols with electron rich alkenes is a highly resourceful reaction that has been utilized by scientists within various disciplines to produce an even more versatile display of applications. This dissertation focuses on a newer application, thiol-ene network (TEN) materials for energy absorption devices. TEN networks display a host of positive polymer properties such as low stress, high optical clarity and uniformity, but they also suffer from unfavorable mechanical properties such as low toughness and elongation at break. The poor mechanical properties demonstrated by TENs prohibit them as choice materials for applications requiring thicker material forms, including …

Examination Of Lower Extremity Muscle Activity During An Overhand Lacrosse Shot In Females, Brianna Millard

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study intends to provide a basic biomechanical understanding of a specific movement within the sport of lacrosse, an overhand goal shot. Its purpose is to identify the different muscles of the lower extremity and the roles they perform during each phase of the lacrosse shot. Specifically, the study will compare how active muscles are between phases as well as between two different shot speeds. This research provides insight into the importance of timing muscle contractions that lead to a more accurate and faster shot.

Subjects (n=5 females, age: 21.8 ± 2 years, height: 162.56 ± 15.24cm, mass: 63.68 ± …

Temporal Structure Of Variability Reveals Similar Control Mechanisms During Lateral Stepping And Forward Walking, Shane R. Wurdeman, Nikolaos Stergiou

Journal Articles

Previous research exploring a lateral stepping gait utilized amount of variability (i.e. coefficient of variation) in the medial-lateral (ML) and anterior-posterior (AP) direction to propose that the central nervous system’s active control over gait in any direction is dependent on the direction of progression. This study sought to further explore this notion through the study of the temporal structure of variability which is reflective of the neuromuscular system’s organization of the movement over time. The largest Lyapunov exponent (LyE) of the reconstructed attractors for the foot’s movement in the AP and ML was calculated. Results revealed that despite the obvious …

Humeral Torsion And Shoulder Biomechanics: Comparison Of A Novel Ultrasonographic Technique With The Computed Tomography Benchmark, Bryan Thurston

All Theses

The rotation angle between the proximal and distal axes of long bones is known as torsion, and it is thought to be indicative of the forces applied to the bone during growth. The humerus, for example, develops an internal twist or antetorsion, as daily activities are anterior to the body. However, the strong posterior stress induced by an overhead throwing motion may counteract this internal twist in young athletes and cause prominent bilateral dimorphism.
To measure torsion in these young athletes, a new technique using ultrasound has been developed and implemented in clinical practice. However, before widespread use in diverse …

The Effects Of Arch Taping On Shock Attenuation During Landing, Shun Jinnouchi

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to investigate the effects of two different arch taping techniques on shock attenuation during landing. Each subject (n=12, age 25.5 ± 3.37 years, height 1.73 ± 0.04 m, mass 82.06 ± 16.23) was instrumented with accelerometers at the leg and forehead (sample rate = 1000 Hz). Subjects performed landings from a 30 cm box under three taping conditions: no tape, Low Dye, and Weave. For each condition, subjects completed 5 landing trials. Rest was provided between each trial and order of conditions was counterbalanced. During each landing, accelerations were recorded at 1000 Hz for …

Biomechanical Comparison Of A Rounded Outsole Shoe And Traditional Outsole Shoe, Sarah Horsch

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of the study was to determine the effects of shoe outsole design on maximum vertical acceleration and select kinematic parameters during level and uphill walking across phases of stance. Twelve participants, 7 males (75.1±9.3 kg, 173.6±3.6 cm, 22.9±3.5 yrs) and 5 females (56.5±5.1 kg, 158.3±4.5 cm, 25.4±11.1 yrs) granted written consent and preferred walking speed was determined. An accelerometer (480 Hz) was attached to the distal leg to measure maximum leg acceleration (Aleg) and an electrogoniometer (480 Hz) was placed on the back to measure sagittal lumbar motion (LumbarROM). Sagittal video capture (60 Hz) included thigh range of …

Effect Of Racing Flats On Running Economy In Male Adolescent Runners, Paul Hafen

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to investigate whether running economy differs in racing flats versus standard running shoes in high school cross-country runners. In order to measure running economy the oxygen cost of running (mL O₂∙kg^-1∙min^-1) was measured in 20 male adolescent runners (mean age = 16.25 ± 0.97 years, 5 km best time = 17.52 ± 0.78 min) when running two separate trials at a controlled speed. The speed was determined by estimating treadmill running speed at 85% of each runner's VO_2max. Each trial required the participants to run while …

A Home-Based Exercise Program For The Foot And Ankle To Improve Balance, Muscle Performance And Flexibility In Community Dwelling Older Adults: A Pilot Study, Laurel Long, Kurt Jackson, Lloyd L. Laubach

Physical Therapy Faculty Publications

Background and purpose: Strength and range of motion of the foot and ankle have been shown to be related to measures of balance and fall risk in older adults. The primary purpose of this pilot investigation was to evaluate the feasibility of a 6-week home-based exercise program focusing on the foot and ankle and any associated changes in balance, muscle performance and range of motion in older adults. Methods: This single-group repeated measures study involved a convenience sample of 21 healthy communitydwelling older adults age 60-90. Nineteen participants completed all phases of the testing and training. The intervention was a …

Kinematic Effects Of Stride Length Perturbations On System Com Horizontal Velocity During Locomotion, Josh Bailey, Andrew Nordin, Janet Dufek, D. Lee

Interdisciplinary Research Scholarship Day

PURPOSE: To investigate the kinematic effect on the systems’ center of mass horizontal velocity in response to stride length perturbations. METHODS: Twelve healthy adults (23.1±7.71 yrs; 1.69±0.1 m; 66.82±12.6 kg; leg length 894.7±66.1 mm) performed 5 trials of preferred speed walking (PW) and running (PR)followed by 5 stride length perturbations based on percentages of leg length (60%, 80%, 100%, 120% and 140%). 3D kinematic analysis was completed using a 12-camera infrared motion capture system (Vicon, 200hz). Dependent variables computer for each condition included: center of mass horizontal velocity at the highest vertical position (COMHVhi) and at the lowest vertical position …

Step Length Perturbations Alter Variations In Center Of Mass Horizontal Velocity, Josh Bailey, Andrew Nordin, D. Lee, Janet Dufek

Interdisciplinary Research Scholarship Day

PURPOSE: The purpose of the study was to investigate the effects of SL perturbations on system COM forward velocity (vx) during walking gait. METHODS: Eight healthy adults (23.5±3.6 yrs; 1.72±0.18 m; 73.11±15.29 kg) performed 5 trials of preferred speed walking (PW) and running (PR) followed by 5 stride length perturbations based on percentages of leg length (LL: 60%, 80%, 100%, 120% and 140%). 3D kinematic analysis was completed using a 12-camera infrared motion capture system (Vicon MX T40-S, 200Hz). Data filtering and interpolation included a low pass, 4th order Butterworth filter (cutoff frequency 15Hz) and cubic (3rd order spline). Maximum …

Effects Of Footstrike On Low Back Posture, Shock Attenuation, And Comfort In Running, Traci L. Delgado, Emilia Kubera-Shelton, Robert R. Robb, Robbin Hickman, Harvey Wallmann, Janet Dufek

Interdisciplinary Research Scholarship Day

To determine if a change from rearfoot strike (RFS) to forefoot strike (FFS) would change lumbar lordosis, influence shock attenuation, or change comfort levels in healthy recreational/experienced runners.

Effects Of Shoe Outsole Design And Incline On Walking Biomechanics, Sarah Horsch, Janet Dufek

Interdisciplinary Research Scholarship Day

The purpose of the study was to examine the effects of incline at foot contact of treadmill walking between rounded outsole (ROS) and traditional outsole (TOS) shoes. A rounded outsole shoe (ROS) is specifically designed with a fulcrum under the sole so that when the mass of the body is over it, the foot is forced to roll anteriorly. Traditional ROS studies have included analyses on bipedal stance single leg standing, muscle
activity during treadmill walking, kinetics during over ground walking, and kinematics after a 6-week accommodation period. Presently, there is no research comparing a ROS and a TOS at …

Sitting Postural Control In Infants With Typical Development, Motor Delay, Or Cerebral Palsy, Anastasia Kyvelidou, Regina T. Harbourne, Sandra L. Willett, Nikolaos Stergiou

Journal Articles

Purpose: To determine whether infants born full-term, infants born preterm with motor delays, and infants born preterm who have a diagnosis of cerebral palsy (CP) differed in postural control at the emergence of early sitting.

Methods: Thirty infants born at term who were developing typically, 6 infants born preterm who were later diagnosed with CP, and 5 infants born preterm who were delayed in motor development participated in this study. Center-of-pressure data from unsupported sitting were recorded and analyzed using measures of both amount and temporal organization of center-of-pressure variability.

Results: Infants born full-term, infants born preterm …

Transtibial Amputee Joint Motion Has Increased Attractor Divergence During Walking Compared To Non-Amputee Gait, Shane R. Wurdeman, Sara A. Myers, Nikolaos Stergiou

Journal Articles

The amputation and subsequent prosthetic rehabilitation of a lower leg affects gait. Dynamical systems theory would predict the use of a prosthetic device should alter the functional attractor dynamics to which the system self-organizes. Therefore, the purpose of this study was to compare the largest Lyapunov exponent (a nonlinear tool for assessing attractor dynamics) for amputee gait compared to healthy non-amputee individuals. Fourteen unilateral, transtibial amputees and fourteen healthy, non-amputee individuals ambulated on a treadmill at preferred, self-selected walking speed. Our results showed that the sound hip (p = 0.013), sound knee (p = 0.05), and prosthetic ankle …

Enhancing Fundamental Robot-Assisted Surgical Proficiency By Using A Portable Virtual Simulator, Jung Hung Chien, I. H. Suh, Shi-Huyn Park, Mukul Mukherjee, D. Oleynikov, Ka-Chun Siu

Journal Articles

Background. The development of a virtual reality (VR) training platform provides an affordable interface. The learning effect of VR and the capability of skill transfer from the VR environment to clinical tasks require more investigation.

Methods. Here, 14 medical students performed 2 fundamental surgical tasks—bimanual carrying (BC) and peg transfer (PT)—in actual and virtual environments. Participants in the VR group received VR training, whereas participants in the control group played a 3D game. The learning effect was examined by comparing kinematics between pretraining and posttraining in the da Vinci Surgical System. Differences between VR and playing the 3D game were …

Motor Control Of The Lower Extremity Musculature In Children With Cerebral Palsy, David J. Arpin, Wayne A. Stuberg, Nick Stergiou, Max J. Kurz

Journal Articles

The aim of this investigation was to quantify the differences in torque steadiness and variability of the muscular control in children with cerebral palsy (CP) and typically developing (TD) children. Fifteen children with CP (age = 14.2 ± 0.7 years) that had a Gross Motor Function Classification System (GMFCS) score of I-III and 15 age and gender matched TD children (age = 14.1 ± 0.7 years) participated in this investigation. The participants performed submaximal steady-state isometric contractions with the ankle, knee, and hip while surface electromyography (sEMG) was recorded. An isokinetic dynamometer was used to measure the steady-state isometric torques …

New Perspectives In Human Movement Variability, Thurmon Lockhart, Nikolaos Stergiou

Journal Articles

Movement variability is defined as the normal variations that occur in motor performance across multiple repetitions of a task.2 Bernstein1 described movement variability quite eloquently as ‘‘repetition without repetition.’’ Traditionally, movement variability has been linked to noise and error, being considered to be random and independent. This theoretical approach blends well with traditional statistical and assessment methods of movement variability that assume randomness and independence of observations. However, numerous studies have indicated that when movement is observed over time variations are closely related with each other neither being random nor independent. Practically, traditional methods can mask the temporal structure of …

Lower Extremity Biomechanics During Single Leg Drop Landings In Individuals With Patellofemoral Pain, Stacey L. Gaven

Human Movement Studies & Special Education Theses & Dissertations

Patellofemoral joint pain (PFP) is one of the most common afflictions of the active population. While etiological factors encompassing the entire lower extremity have been associated with PFP, participation in athletic activities while fatigued may further influence abnormal biomechanics in individuals with this condition. The aim of Project I was to investigate the lower extremity (LE) biomechanics during a single leg(SL) drop landing in individuals with and without PFP. Project II aimed to investigate the LE biomechanics of individuals with PFP during a SL drop landing pre and post an aerobic exercise protocol. Project 111 investigated the LE biomechanics of …

An Informational Algorithm As The Basis For Perception-Action Control Of The Instantaneous Axes Of The Knee, Wangdo Kim, Margarida M. Espanha, António P. Veloso, Duarte Araújo, Filipa João, Luis Carrão, Sean S. Kohles

Mechanical and Materials Engineering Faculty Publications and Presentations

Traditional locomotion studies emphasize an optimization of the desired movement trajectories while ignoring sensory feedback. We propose an information based theory that locomotion is neither triggered nor commanded but controlled. The basis for this control is the information derived from perceiving oneself in the world. Control therefore lies in the human-environment system. In order to test this hypothesis, we derived a mathematical foundation characterizing the energy that is required to perform a rotational twist, with small amplitude, of the instantaneous axes of the knee (IAK). We have found that the joint’s perception of the ground reaction force may be replaced …