Biomechanics Commons^™

Visual And Somatosensory Contributions To Infant Sitting Postural Control, Anastasia Kyvelidou, Nicholas Stergiou

Journal Articles

There are a limited number of studies that have investigated sitting posture during infancy and the contribution of the sensory systems. The goal of this study was to examine the effects of altered visual and somatosensory signals on infant sitting postural control. Thirteen infants (mean age ± SD, 259.69 ± 16.88 days) participated in the study. Initially, a single physical therapist performed the Peabody Developmental Motor Scale to determine typical motor development. Then the child was placed onto a force platform under four randomized conditions: (a) Control (C) – sat independently on the force plate, (b) Somatosensory (SS) – Sat …

Comparison Of Cervical Angle During Different Equipment Removal Techniques Used In Ice Hockey For Suspected Cervical Injuries, Kendell Sarah Galor

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of the study was to compare cervical movement between two different methods of removal of the helmet and shoulder pads. Seven college age male subjects (height: 172.54 ± 7.98 cm; weight: 85.70 ± 15.75 kg) with hockey experience volunteered to participate in the study. Each subject agreed to and signed the institutional review board approved informed consent before articipation. Subjects used their own game fit hockey helmet and were fitted with a pair of shoulder pads (CCM Tacks 1052 Sr Shoulder Pads). Cervical spine motion was measured using 3D kinematics (Vicon Motion Systems Ltd., UK). Reflective markers affixed …

Lower Limb Joint Angle Variability And Dimensionality Are Different In Stairmill Climbing And Treadmill Walking, Peter C. Raffalt, Srikant Vallabhajosula, Jessica Renz, Mukul Mukherjee, Nicholas Stergiou

Journal Articles

The present study tested if the quadratic relationship which exists between stepping frequency and gait dynamics in walking can be generalized to stairmill climbing. To accomplish this, we investigated the joint angle dynamics and variability during continuous stairmill climbing at stepping frequencies both above and below the preferred stepping frequency (PSF). Nine subjects performed stairmill climbing at 80, 90, 100, 110 and 120% PSF and treadmill walking at preferred walking speed during which sagittal hip, knee and ankle angles were extracted. Joint angle dynamics were quantified by the largest Lyapunov exponent (LyE) and correlation dimension (CoD). Joint angle variability was …

Optimizing Beat Synchronized Running To Music, Jeska Buhmann, Edith Van Dyck, Dobromir Dotov, Marc Leman, Bart Moens

Journal Articles

The use of music and specifically tempo-matched music has been shown to affect running performance. But can we maximize the synchronization of movements to music and does maximum synchronization influence kinematics and motivation? In this study, we explore the effect of different types of music-to-movement alignment strategies on phase coherence, cadence and motivation. These strategies were compared to a control condition where the music tempo was deliberately not aligned to the running cadence. Results show that without relative phase alignment, a negative mean asynchrony (NMA) of footfall timings with respect to the beats is obtained. This means that footfalls occurred …

Development And Validation Of Hybrid Continuum/Structural Finite Element Model For Evaluating Foot And Ankle Biomechanics, Saif Alrafeek

Dissertations

Bone is composed of two structures: compact bone and spongy bone. Spongy bone porosity highly affects the strength and the physical endurance of bone to carry loads. Most studies use continuum finite element (FE) approaches to model spongy bone and neglect porosity. Neglecting porosity may not efficiently assist orthopaedic surgeons to treat patients who experience bone physical disability. The purpose of this study is to demonstrate an inexpensive approach that simulates spongy bone with more accurate capturing of porosity and less requirements of bone information. The approach is developed through investigating the mechanical characteristics of spongy bone; that is, by …

Human Body Motions Optimization For Able-Bodied Individuals And Prosthesis Users During Activities Of Daily Living Using A Personalized Robot-Human Model, Dimitrios Menychtas

USF Tampa Graduate Theses and Dissertations

Current clinical practice regarding upper body prosthesis prescription and training is lacking a standarized, quantitative method to evaluate the impact of the prosthetic device. The amputee care team typically uses prior experiences to provide prescription and training customized for each individual. As a result, it is quite challenging to determine the right type and fit of a prosthesis and provide appropriate training to properly utilize it early in the process. It is also very difficult to anticipate expected and undesired compensatory motions due to reduced degrees of freedom of a prosthesis user. In an effort to address this, a tool …

When Coordinating Finger Tapping To A Variable Beat The Variability Scaling Structure Of The Movement And The Cortical Bold Signal Are Both Entrained To The Auditory Stimuli, Steven Harrison, Michael Hough, Kendra K. Schmid, Boman Groff, Nicholas Stergiou

Journal Articles

Rhythmic actions are characterizable as a repeating invariant pattern of movement together with variability taking the form of cycle-to-cycle fluctuations. Variability in behavioral measures is atypically random, and often exhibits serial temporal dependencies and statistical self-similarity in the scaling of variability magnitudes across timescales. Self-similar (i.e. fractal) variability scaling is evident in measures of both brain and behavior. Variability scaling structure can be quantified via the scaling exponent (α) from detrended fluctuation analysis (DFA). Here we study the task of coordinating thumb-finger tapping to the beats of constructed auditory stimuli. We test the hypothesis that variability scaling evident …

Sampling Frequency Influences Sample Entropy Of Kinematics During Walking, Peter C. Raffalt, John D. Mccamley, William Denton, Jennifer M. Yentes

Journal Articles

Sample entropy (SaEn) has been used to assess the regularity of lower limb joint angles during walking. However, changing sampling frequency and the number of included strides can potentially affect the sample entropy. The present study investigated the effect of sample frequency and the number of included strides on the calculations of SaEn in joint angle signals recorded during treadmill walking. Eleven subjects walked at their preferred walking speed for 10 minutes, and SaEn was calculated on sagittal plane hip, knee and ankle angle signals extracted from 50, 100, 200, 300 and 400 strides at sampling frequencies of 60, 120, …

Optic Flow Improves Step Width And Length In Older Adults While Performing Dual Task, Taylor Leeder, Farah Fallahtafti, Molly Schieber, Sara A. Myers, Julie Blaskewicz Boron, Jennifer M. Yentes

Journal Articles

Background

Dual-task paradigms are used to investigate gait and cognitive declines in older adults (OA). Optic-flow is a virtual reality environment where the scene flows past the subject while walking on a treadmill, mimicking real-life locomotion.

Aims

To investigate cost of environment (no optic-flow v. optic-flow) while completing single- and dual-task walking and dual-task costs (DTC; single- v. dual-task) in optic-flow and no optic-flow environments.

Methods

Twenty OA and seven younger adults (YA) walked on a self-paced treadmill in 3-min segments per task and both environments. Five task conditions included: no task, semantic fluency (category), phonemic fluency (letters), word reading, …

Altering Gait Variability With An Ankle Exoskeleton, Prokopios Antonellis, Samuel Galle, Dirk De Clercq, Philippe Malcolm

Journal Articles

Exoskeletons can influence human gait. A healthy gait is characterized by a certain amount of variability compared to a non-healthy gait that has more inherent variability; however which exoskeleton assistance parameters are necessary to avoid increasing gait variability or to potentially lower gait variability below that of unassisted walking are unknown. This study investigated the interaction effects of exoskeleton timing and power on gait variability. Ten healthy participants walked on a treadmill with bilateral ankle-foot exoskeletons under ten conditions with different timing (varied from 36% to 54% of the stride) and power (varied from 0.2 to 0.5 W∙kg-1) combinations. We …

Linking Gait Dynamics To Mechanical Cost Of Legged Locomotion, David V. Lee, Sarah L. Harris

Life Sciences Faculty Research

For millenia, legged locomotion has been of central importance to humans for hunting, agriculture, transportation, sport, and warfare. Today, the same principal considerations of locomotor performance and economy apply to legged systems designed to serve, assist, or be worn by humans in urban and natural environments. Energy comes at a premium not only for animals, wherein suitably fast and economical gaits are selected through organic evolution, but also for legged robots that must carry sufficient energy in their batteries. Although a robot's energy is spent at many levels, from control systems to actuators, we suggest that the mechanical cost of …

Orderliness Of Visual Stimulus Motion Mediates Sensorimotor Coordination, Joshua L. Haworth, Nicholas Stergiou

Journal Articles

We explored the coupling of gaze and postural sway to the motion of a visual stimulus, to further understand sensorimotor coordination. Visual stimuli consisted of a horizontally oscillating red dot, moving with periodic (sine), chaotic, or aperiodic (brown noise) temporal structure. Cross Recurrence Quantification Analysis (cRQA) was used to investigate the coupling between each measured signal with the time series of the visual stimulus position. The cRQA parameter of percent determinism indicated similar strength of coupling of gaze with either periodic or chaotic motion structures, yet weaker coupling to aperiodic stimulus motion. The cRQA parameter of Maxline indicated a particular …

On The Choice Of Multiscale Entropy Algorithm For Quantification Of Complexity In Gait Data, Peter C. Raffalt, William Denton, Jennifer M. Yentes

Journal Articles

The present study aimed at identifying a suitable multiscale entropy (MSE) algorithm for assessment of complexity in a stride-to-stride time interval time series. Five different algorithms were included (the original MSE, refine composite multiscale entropy (RCMSE), multiscale fuzzy entropy, generalized multiscale entropy and intrinsic mode entropy) and applied to twenty iterations of white noise, pink noise, or a sine wave with added white noise. Based on their ability to differentiate the level of complexity in the three different generated signal types, and their sensitivity and parameter consistency, MSE and RCMSE were deemed most appropriate. These two algorithms were applied to …

On The Calculation Of Sample Entropy Using Continuous And Discrete Human Gait Data, John D. Mccamley, William Denton, Peter C. Raffalt, Jennifer M. Yentes

Journal Articles

Sample entropy (SE) has relative consistency using biologically-derived, discrete data >500 data points. For certain populations, collecting this quantity is not feasible and continuous data has been used. The effect of using continuous versus discrete data on SE is unknown, nor are the relative effects of sampling rate and input parameters m (comparison vector length) and r(tolerance). Eleven subjects walked for 10-minutes and continuous joint angles (480 Hz) were calculated for each lower-extremity joint. Data were downsampled (240, 120, 60 Hz) and discrete range-of-motion was calculated. SE was quantified for angles and range-of-motion at all sampling rates and multiple combinations …

Stride-To-Stride Fluctuations In Transtibial Amputees Are Not Affected By Changes In Push-Off Mechanics From Using Different Prostheses, Chase G. Rock, Shane R. Wurdeman, Nikolas Stergiou, Kota Z. Takahashi

Journal Articles

Stride-to-stride fluctuations of joint kinematics during walking reflect a highly structured organization that is characteristic of healthy gait. The organization of stride-to-stride fluctuations is disturbed in lower-limb prosthesis users, yet the factors contributing to this difference are unclear. One potential contributor to the changes in stride-to-stride fluctuations is the altered push-off mechanics experienced by passive prosthesis users. The purpose of our study was to determine if changes in push-off mechanics affect stride-to-stride fluctuations in transtibial amputees. Twenty-two unilateral transtibial amputees were enrolled in the 6- week cross-over study, where High and Low Activity (based on the Medicare Functional Classification System) …

Effects Of Variable Resistance Training On Kinetic And Kinematic Outcomes During A Heavy Conventional Deadlift, Timothy J. Gerking

Masters Theses & Specialist Projects

Variable Resistance Training (VRT), loading elastic band tension on a barbell, has shown improvements in force, power, and velocity. Studied extensively in the squat and bench press, VRT is less researched in the context of the deadlift. Additionally, while no acute VRT deadlift studies exist where intensity was ≥ 90% 1- RM, some heavy VRT studies suggest that at approximately 90% 1-RM, less band tension (BT) is required to enhance force and power than seen at lower intensities in existing research. Therefore, the purpose of this study was to determine the effects of VRT on peak relative vertical ground reaction …

Pertinacity Volume 4, Issue 2, Courteney L. Benjamin

Pertinacity

Pertinacity is a biannual magazine that features stories and reports on recent Korey Stringer Institute's initiatives.

Effects Of Stretching Vs. Self-Myofascial Release On Ankle, Hip, And Shoulder Flexion, Trent S. Edwards

Student Theses and Dissertations

Deficits in range of motion can hinder performance, lead to more issues and prohibit some individuals from doing basic, everyday tasks. Stretching is one way people attempt to increase their range of motion. Self- myofascial release is a newer way of achieving increases in range of motion. Self-Myofascial Release (SMR) has been shown to increase ROM (Blandpied & Dorfman, 2014). However, use of a foam roller produced suboptimal SMR due to inadequate pressure on the roller (Evans, 2014). One solution to this problem would be to create additional pressure using a smaller, more targeted device of denser material. The current …

Effects Of Compex As A Warm Up For Glenohumeral Range Of Motion, Melissa Ericson, Elizabeth R. Neil, Kenneth E. Games

Journal of Sports Medicine and Allied Health Sciences: Official Journal of the Ohio Athletic Trainers Association

Purpose: Research regarding proper upper extremity warm-up protocols remains inconclusive, especially for electrical stimulation methods like the Compex Sport Elite^® unit. The purpose of this study is to evaluate the acute effects of a single treatment of the Compex^® using the pre-warm-up protocol on glenohumeral range of motion compared to a standardized upper body ergometer (UBE) warm-up protocol. Methods: Thirty-five healthy, young adults completed the study (19 men, 16 women; age=22±2y; height=172.1±9.4cm; mass=71.3±16.1kg; right-hand dominant=28; left-hand dominant=7). Participants came to the research laboratory on two occasions, at least 48 hours apart. Participants were randomly assigned the order to …

Effect Of Ankle Taping On Dynamic Balance And Perception Of Stability, William S. Gear, Megan J. Lundstrom

Journal of Sports Medicine and Allied Health Sciences: Official Journal of the Ohio Athletic Trainers Association

Purpose: The purpose of this study was to examine the actual and perceived effect of taping on dynamic stability. Methods: 21 physically active subjects [12 females (age = 20.33 ± 1.44 years, height = 165 ± 0.05 cm, mass = 68.76 ± 12.69 kg), and 9 males (age = 21.33 ± 1.66 years, height = 180 ± 0.10 cm, mass = 86.54 ± 9.46 kg)] participated in this study. Dynamic stability and perception of stability were assessed barefoot and with the ankle taped. The taped ankle condition used a standard preventive tape application including two anchors, three stirrups, close …

Terrestrial Locomotion Of The Northern Elephant Seal (Mirounga Angustirostris): Limitation Of Large Aquatically Adapted Seals On Land?, Kelsey A. Tennett, Daniel P. Costa, Anthony J. Nicastro, Frank E. Fish

Biology Student Work

The aquatic specializations of phocid seals have restricted their ability to locomote on land. The amphibious northern elephant seal, Mirounga angustirostris, is the second largest phocid seal in the world, with males reaching 2700 kg. Although elephant seals are proficient swimmers and deep divers, their extreme size and aquatic specializations limit terrestrial movement. The kinematics of terrestrial locomotion in northern elephant seals were analyzed from video recordings of animals observed on the beach of Añ o Nuevo State Reserve, CA, USA. The seals moved using a series of rhythmic undulations produced by dorsoventral spinal flexion. The traveling spinal wave moved …

Quantification Of Daily Physical Activity And Sedentary Behavior Of Claudicating Patients, Hernan Hernandez, Sara A. Myers, Molly Schieber, Duy M. Ha, Sarah Baker, Panagiotis Koutakis, Kyung-Soo Kim, Constance Mietus, George P. Casale, Iraklis Pipinos

Journal Articles

Background

Methods

A Novel And Safe Approach To Simulate Cutting Movements Using Ground Reaction Forces, Amelia Lanier, Brian Knarr, Nicholas Stergiou, Thomas S. Buchanan

Journal Articles

Control of shear ground reaction forces (sGRF) is important in performing running and cutting tasks as poor sGRF control has implications for those with knee injuries, such as anterior cruciate ligament (ACL) ruptures. The goal of this study was to develop a novel and safe task to evaluate control or accurate modulation of shear ground reaction forces related to those generated during cutting. Our approach utilized a force control task using real-time visual feedback of a subject’s force production and evaluated control capabilities through accuracy and divergence measurements. Ten healthy recreational athletes completed the force control task while force control …

Exoskeleton Assistance Symmetry Matters: Unilateral Assistance Reduces Metabolic Cost, But Relatively Less Than Bilateral Assistance, Philippe Malcolm, Samuel Galle, Pieter Van Den Berghe, Dirk De Clercq

Journal Articles

Background: Many gait impairments are characterized by asymmetry and result in reduced mobility. Exoskeletons could be useful for restoring gait symmetry by assisting only one leg. However, we still have limited understanding of the effects of unilateral exoskeleton assistance. Our aim was to compare the effects of unilateral and bilateral assistance using a within-subject study design.

Methods: Eleven participants walked in different exoskeleton conditions. In the Unilateral conditions, only one leg was assisted. In Bilateral Matched Total Work, half of the assistance from the Unilateral conditions was applied to both legs such that the bilateral sum was equal …

An Electromyography Study Of Muscular Endurance During The Posterior Shoulder Endurance Test, Neil A. Evans, Emily Dressler, Timothy L. Uhl

Physical Therapy Faculty Publications

The primary purpose was to determine if there is a difference between the median frequency slopes of 5 posterior shoulder muscles during the initial portion of the Posterior Shoulder Endurance Test (PSET) at the 90° and 135° shoulder abduction positions. Fifty-five healthy volunteers (31 females) participated. The median frequency of the posterior deltoid (PD), upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and infraspinatus (INF) was measured during the PSET at 90° and 135° of shoulder abduction. External torque of 13 ± 1 Nm was used for females and 21 ± 1 Nm for males. A fixed effect multi-variable …

Entraining Chaotic Dynamics: A Novel Movement Sonification Paradigm Could Promote Generalization, Dobromir Dotov, Tom Froese

Journal Articles

Tasks encountered in daily living may have instabilities and more dimensions than are sampled by the senses such as when carrying a cup of coffee and only the surface motion and overall momentum are sensed, not the fluid dynamics. Anticipating non-periodic dynamics is difficult but not impossible because mutual coordination allows for chaotic processes to synchronize to each other and become periodic. A chaotic oscillator with random period and amplitude affords being stabilized onto a periodic trajectory by a weak input if the driver incorporates information about the oscillator. We studied synchronization with predictable and unpredictable stimuli where the unpredictable …

Mutual Synchronization And Control Between Artificial Chaotic System And Human, Dobromir Dotov, Tom Froese

Journal Articles

Dexterous assistive devices constitute one of the frontiers for hybrid human-machine systems. Manipulating unstable systems requires task-specific anticipatory dynamics. Learning this dynamics is more difficult when tasks, such as carrying liquid or riding a horse, produce unpredictable, irregular patterns of feedback and have hidden dimensions not projected as sensory feedback. We addressed the issue of coordination with complex systems producing irregular behaviour, with the assumption that mutual coordination allows for non-periodic processes to synchronize and in doing so to become regular. Chaos control gives formal expression to this: chaos can be stabilized onto periodic trajectories provided that the structure of …

Compensatory Hip And Knee Mechanics In Transtibial Amputees During Stair Descent And Directional Task, Mindie Clark

All NMU Master's Theses

This study compared lower limb mechanics in unilateral transtibial amputees and able bodied controls during strenuous activities of daily living (ADL). Seven unilateral transtibial amputee and five matched-abled bodied control participants executed stair descent on a four-step rehabilitation staircase followed by one of two anticipated directional tasks. Force, kinematics and gait parameters were chosen to compare mechanics and stride characteristics between the residual limb, intact limb and able-bodied dominant limb between a straight walking condition and a non linear directional movement (wide-step cutting task). Results indicated that significant compensatory mechanisms occurred in the intact limb, perhaps from decreased load tolerance …

Design And Testing Of A Passive Prosthetic Ankle Foot Optimized To Mimic An Able-Bodied Gait, Millicent Schlafly

USF Tampa Graduate Theses and Dissertations

Currently there are nearly 2 million people living with limb loss in the United States [1]. Many of these individuals are either transtibial (below knee) or transfemoral (above knee) amputees and require an ankle-foot prosthesis for basic mobility. While there are an abundance of options available for individuals who require an ankle-foot prosthesis, these options fail to mimic an intact ankle when it comes to key evaluation criteria such as range of motion, push-off force, and roll over shape. The roll over shape is created by plotting the center of pressure during a step in a shank-based coordinate system. To …

Control Of Redundant Pointing Movements Involving The Wrist And Forearm, Garrett R. Dorman, Kevin C. Davis, Allan W. Peaden, Steven K. Charles

Faculty Publications

The musculoskeletal system can move in more ways than are strictly necessary, allowing many tasks to be accomplished with a variety of limb configurations. Why some configurations are preferred has been a focus of motor control research, but most studies have focused on shoulder-elbow or whole-arm movements. This study focuses on movements involving forearm pronation-supination (PS), wrist flexion-extension (FE), and wrist radial-ulnar deviation (RUD), and elucidates how these three degrees of freedom (DOF) combine to perform the common task of pointing, which only requires two DOF. Although pointing is more sensitive to FE and RUD than to PS and could …