Biomechanics Commons^™

Multi Segment Finite Element Analysis Of The Lumbar Spine, James J. Doulgeris

USF Tampa Graduate Theses and Dissertations

Finite element analysis of the spine has become popular over the past several decades. However, the current studies often use minimal specimens for modeling. The purpose of this study was to validate and analyze multiple finite element models with data from in vivo experiments and other finite element studies before future investigations. This study developed eight (8) lumbar spine (L2-L5) finite element models followed by finite element analysis of simulated bending in the six (6) basic motions. CT scans were obtained from four (4) males and four (4) females between the ages of forty-four (44) and seventy-three (73) years old. …

Acl Injury And Reconstruction Affect Control Of Ground Reaction Forces Produced During A Novel Task That Simulates Cutting Movements, Amelia Lanier, Brian Knarr, Nicholas Stergiou, Lynn Snyder-Mackler, Thomas S. Buchanan

Journal Articles

After anterior cruciate ligament (ACL) injury and reconstruction, biomechanical and neuromuscular control deficits persist and 25% of those who have experienced an ACL injury will experience a second ACL rupture in the first year after returning to sports. There remains a need for improved rehabilitation and the ability to detect an individual's risk of secondary ACL rupture. Nonlinear analysis metrics, such as the largest Lyapunov exponent (LyE) can provide new biomechanical insight in this population by identifying how movement patterns evolve over time. The purpose of this study was to determine how ACL injury, ACL reconstruction (ACLR), and participation in …

Speed And Rhythm Affect Temporal Structure Of Variability In Reaching Poststroke: A Pilot Study, Amit Sethi, Nicholas Stergiou, Tara Patterson, Carolynn Patten, Lorie G. Richards

Journal Articles

Temporal structure reveals the potential adaptive strategies employed during upper extremity movements. The authors compared the temporal structure of upper extremity joints under 3 different reaching conditions: preferred speed, fast speed, and reaching with rhythmic auditory cues in 10 individuals poststroke. They also investigated the temporal structure of these 3 reaching conditions in 8 healthy controls to aid in the interpretation of the observed patterns in the poststroke cohort. Approximate entropy (ApEn) was used to measure the temporal structure of the upper extremity joints. ApEn was similar between conditions in controls. After stroke, ApEn was significantly higher for shoulder, elbow, …

Mastoid Vibration Affects Dynamic Postural Control During Gait, Jung Chien, Mukul Mukherjee, Nicholas Stergiou

Journal Articles

Our objective was to investigate how manipulating sensory input through mastoid vibration (MV) could affect dynamic postural control during walking, with and without simultaneous manipulation of the visual and the somatosensory systems. We used three levels of MV (none, unilateral, and bilateral) via vibrating elements placed on the mastoid processes. We combined this with the six conditions of the Locomotor Sensory Organization Test (LSOT) paradigm to challenge the visual and somatosensory systems. We hypothesized that MV would affect both amount and temporal structure measures of sway variability during walking and that, in combination with manipulations of the visual and the …

Locomotor Sensory Organization Test: How Sensory Conflict Affects The Temporal Structure Of Sway Variability During Gait, Jung Hung Chien, Mukul Mukherjee, Ka-Chun Siu, Nikolaos Stergiou

Journal Articles

When maintaining postural stability temporally under increased sensory conflict, a more rigid response is used where the available degrees of freedom are essentially frozen. The current study investigated if such a strategy is also utilized during more dynamic situations of postural control as is the case with walking. This study attempted to answer this question by using the Locomotor Sensory Organization Test (LSOT). This apparatus incorporates SOT inspired perturbations of the visual and the somatosensory system. Ten healthy young adults performed the six conditions of the traditional SOT and the corresponding six conditions on the LSOT. The temporal structure of …

Lower Extremity Kinematics During Walking And Elliptical Training In Individuals With And Without Traumatic Brain Injury, Thad Buster, Judith Burnfield, Adam P. Taylor, Nikolaos Stergiou

Journal Articles

Background and Purpose: Elliptical training may be an option for practicing walking-like activity for individuals with traumatic brain injuries (TBI). Understanding similarities and differences between participants with TBI and neurologically healthy individuals during elliptical trainer use and walking may help guide clinical applications incorporating elliptical trainers.

Methods: Ten participants with TBI and a comparison group of 10 neurologically healthy participants underwent 2 familiarization sessions and 1 data collection session. Kinematic data were collected as participants walked on a treadmill or on an elliptical trainer. Gait-related measures, including coefficient of multiple correlations (a measure of similarity between ensemble joint movement profiles; …

A Perspective On Human Movement Variability With Applications In Infancy Motor Development, Nikolaos Stergiou, Yawen Yu, Anastasia Kyvelidou

Journal Articles

Movement variability is considered essential to typical motor development. However, multiple theoretical perspectives and measurement tools have limited interpretation of the importance of movement variability in biological systems. The complementary use of linear and nonlinear measures have recently allowed for the evaluation of not only the magnitude of variability but also the temporal structure of variability. As a result, the theoretical model of optimal movement variability was introduced. The model suggests that the development of healthy and highly adaptable systems relies on the achievement of an optimal state of variability. Alternatively, abnormal development may be characterized by a narrow range …