Biomechanics Commons^™

Response To Chastin Et Al.: Analysis Of Nonlinear Patterns Of Activity, James T. Cavanaugh, Nicholas Stergiou

Journal Articles

We appreciate the thoughtful commentary by Chastin and colleagues regarding our recent article entitled “Nonlinear Analysis of Ambulatory Activity Patterns in Community-dwelling Older Adults.” (1) We fully agree with their observation that the application of nonlinear analytical tools to accelerometry data is an emerging area of research that shows potential for illuminating the complex nature of physical activity profiles. We also welcome the opportunity to discuss their concerns regarding (a) our application of detrended fluctuation analysis (DFA), entropy rate, and approximate entropy to natural activity data and (b) our narrow focus on stepping activity.

Pre-Swing Deficits In Forward Propulsion, Swing Initiation And Power Generation By Individual Muscles In Hemiparetic Walking, Carrie L. Peterson, Allison Kinney, Steven A. Kautz, Richard R. Neptune

Mechanical and Aerospace Engineering Faculty Publications

Clinical studies of hemiparetic walking have shown pre-swing abnormalities in the paretic leg suggesting that paretic muscle contributions to important biomechanical walking subtasks are different than those of non-disabled individuals. Three-dimensional forward dynamics simulations of two representative hemiparetic subjects with different levels of walking function classified by self-selected walking speed (i.e., limited community=0.4–0.8 m/s and community walkers=>0.8 m/s) and a speed-matched control were generated to quantify individual muscle contributions to forward propulsion, swing initiation and power generation during the pre-swing phase (i.e., double support phase proceeding toe-off). Simulation analyses identified decreased paretic soleus and gastrocnemius contributions to forward propulsion …

Effect Of Tilted Surfaces On Ankle Kinematics And Emg Activities In Landing, Divya Bhaskaran

Masters Theses

The purpose of this study was to examine the effects of landing on a combined inverted and plantarflexed surface on the ankle kinematics and electromyographic (EMG) activities of the medial gastrocnemius (MG), peroneal longus (PL) and anterior tibialis muscles (TA). Twelve recreational athletes performed five drop landings from an overhead bar of 30 cm height on to each of these surfaces: a flat surface, a 25° inversion surface (inverted), and a combined surface (combined) of 25° inversion and 25° plantarflexion. The three dimensional kinematic variables and integrated EMG (IEMG) of the three muscles were assessed using one-way repeated measures analysis …

Differences In Muscle Activation In The Lower Extremities While Performing Traditional Squats And Non-Traditional Squats, Christopher M. Scotten

Boise State University Theses and Dissertations

Purpose: To determine if muscle activation in the lower back and lower extremities differ when performing traditional squats compared to non-traditional (forward center of pressure on foot) squats. The erector spinae, hamstrings, quadriceps, adductor longus, gastrocnemius, and gluteus maximus muscles were monitored for differences in this study. There are several variations of the back squat and each variation may possibly target muscles differently. Determining if non-traditional squats leads to larger erector spinae muscle activation, which in turn may lead to more lower back fatigue and possible lower back injury is a major aim of this study. Participants: Thirteen healthy males …

Kinematic Evidence For Superfast Locomotory Muscle In Two Species Of Teneriffiid Mites, Grace C. Wu, Jonathan C. Wright, Dwight L. Whitaker, Anna N. Ahn

All HMC Faculty Publications and Research

Locomotory muscles typically operate over a narrow range of contraction frequencies, characterized by the predominant fiber types and functional roles. The highest documented frequencies in the synchronous sound-producing muscles of insects (550 Hz) and toadfish (200 Hz) far exceed the contraction frequencies observed in weight-bearing locomotory muscles, which have maximum documented frequencies below 15-30 Hz. Laws of scaling, however, predict that smaller arthropods may employ stride frequencies exceeding this range. In this study we measured running speed and stride frequency in two undescribed species of teneriffiid mites from the coastal sage scrub of southern California. Relative speeds of both species …

Treatment With Pharmacological Agents In Peripheral Arterial Disease Patients Does Not Result In Biomechanical Gait Changes, Jessie M. Huisinga, Iraklis Pipinos, Nikolaos Stergiou, Jason Johanning

Journal Articles

Pharmacological treatment has been used to alleviate the claudication symptoms and improve walking performance in peripheral arterial disease (PAD) patients. However, the effects of claudication treatments on gait mechanics have not been objectively indentified with biomechanical techniques. For this study, 20 PAD patients were assigned to take either pentoxifylline (n = 11) or cilostazol (n = 9), the two FDA-approved pharmacological therapies used to treat intermittent claudication symptoms. All patients completed a gait evaluation protocol that involved the acquisition of kinematic and kinetic gait data before use of the medication and after 12 weeks of treatment. Results showed that treatment …

Head And Shoulder Posture Affect Scapular Mechanics And Muscle Activity In Overhead Tasks, Charles A. Thigpen, Darin A. Padua, Lori A. Michener, Kevin M. Guskiewicz, Carol Guiliani, Jay D. Keener, Nikolaos Stergiou

Journal Articles

Forward head and rounded shoulder posture (FHRSP) is theorized to contribute to alterations in scapular kinematics and muscle activity leading to the development of shoulder pain. However, reported differences in scapular kinematics and muscle activity in those with forward head and rounded shoulder posture are confounded by the presence of shoulder pain. Therefore, the purpose of this study was to compare scapular kinematics and muscle activity in individuals free from shoulder pain, with and without FHRSP. Eighty volunteers were classified as having FHRSP or ideal posture. Scapular kinematics were collected concurrently with muscle activity from the upper and lower trapezius …

Hip Power Asymmetry In Older Adult Fallers And Non-Fallers, Lauren Grace Mcdonald

Boise State University Theses and Dissertations

The purpose of this study was to determine if a difference exists in hip power asymmetry between community-dwelling older adult fallers and non-fallers. Hypothesis: fallers would be more asymmetrical than non-fallers. Participants: 21 non-fallers (10 females, 11 males) and 18 fallers (14 females, 4 males) over the age of 65 (76.5 ± 6.9yrs). Method: Isokinetic peak torque during flexion, extension, abduction, and adduction at four velocities was recorded as measures of leg power. Asymmetry equaled the percent of power difference between each leg. Data analysis: Differences in age, physical activity, height, weight, and BMI were assessed …

Abnormal Joint Powers Before And After The Onset Of Claudication Symptoms, Panagiotis Koutakis, Jason Johanning, Sara A. Myers, Nikolaos Stergiou, G. Matthew Longo, Iraklis Pipinos

Journal Articles

Objective: Claudication is the most common manifestation of peripheral arterial disease, producing significant ambulatory compromise. Our study evaluated patients with bilateral lower limb claudication and characterized their gait abnormality based on advanced biomechanical analysis using joint torques and powers.

Methods: Twenty patients with bilateral claudication (10 with isolated aortoiliac disease and 10 with combined aortoiliac and femoropopliteal disease) and 16 matched controls ambulated on a walkway while 3-dimensional biomechanical data were collected. Patients walked before and after onset of claudication pain. Joint torques and powers at early, mid, and late stance for the hip, knee, and ankle joints were calculated …

Relationships Between Muscle Contributions To Walking Subtasks And Functional Walking Status In Persons With Post-Stroke Hemiparesis, Allison Kinney, Carrie L. Peterson, Steven A. Kautz, Richard R. Neptune

Mechanical and Aerospace Engineering Faculty Publications

Walking speed is commonly used to predict stroke severity and assess functional walking status (i.e., household, limited community and community walking status) post-stroke. The underlying mechanisms that limit walking speed (and functional walking status by extension) need to be understood to improve post-stroke rehabilitation. Previous experimental studies have shown correlations between paretic plantarflexor output during the pre-swing phase and walking speed and suggest that the paretic hip flexors can compensate in some hemiparetic subjects. Modeling and simulation studies of healthy walking have shown that the ankle plantarflexors, soleus (SOL) and gastrocnemius (GAS), and uniarticular hip flexors (IL) are essential contributors …

Joint Moments And Powers In Healthy Young Adults During Stair Negotiation, Mira M. Momcilovic

Student Work

The primary objective of this study was to determine lower limb joint moments and powers of stair negotiation in healthy young individuals. These results will provide baseline information for future studies with elderly and clinical populations designed to prevent falls that occur during stair negotiation. In previous stair negotiation studies, researchers investigated joint moments and powers initiating stair ascent in front of the stairway. Starting farther away from the stairway allows individuals to stabilize gait velocity and thus, exclude the influence of velocity on joint moments and powers generated during stair ascent. Ten young, healthy individuals underwent gait analysis during …

The Effect Of Virtual Reality On Gait Variability, Dimitrios Kastavelis, Mukul Mukherjee, Leslie M. Decker, Nikolaos Stergiou

Journal Articles

Optic Flow (OF) plays an important role in human locomotion and manipulation of OF characteristics can cause changes in locomotion patterns. The purpose of the study was to investigate the effect of the velocity of optic flow on the amount and structure of gait variability. Each subject underwent four conditions of treadmill walking at their self-selected pace. In three conditions the subjects walked in an endless virtual corridor, while a fourth control condition was also included. The three virtual conditions differed in the speed of the optic flow displayed as follows – same speed (OFn), faster (OFf), and slower (OFs) …

Hydrodynamic Fin Function Of Brief Squid, Lolliguncula Brevis, William J. Stewart, Ian K. Bartol, Paul S. Krueger

Biological Sciences Faculty Publications

Although the pulsed jet is often considered the foundation of a squid's locomotive system, the lateral fins also probably play an important role in swimming, potentially providing thrust, lift and dynamic stability as needed. Fin morphology and movement vary greatly among squid species, but the locomotive role of the fins is not well understood. To begin to elucidate the locomotive role of the fins in squids, fin hydrodynamics were studied in the brief squid Lolliguncula brevis, a species that exhibits a wide range of fin movements depending on swimming speed. Individual squid were trained to swim in both the …

The Effect Of Pharmacological Treatment On Gait Biomechanics In Peripheral Arterial Disease Patients, Jessie M. Huisinga, Iraklis Pipinos, Jason Johanning, Nikolaos Stergiou

Journal Articles

Background: Pharmacological treatment has been advocated as a first line therapy for Peripheral Arterial Disease (PAD) patients suffering from intermittent claudication. Previous studies document the ability of pharmacological treatment to increase walking distances. However, the effect of pharmacological treatment on gait biomechanics in PAD patients has not been objectively evaluated as is common with other gait abnormalities. Methods: Sixteen patients were prescribed an FDA approved drug (Pentoxifylline or Cilostazol) for the treatment of symptomatic PAD. Patients underwent baseline gait testing prior to medication use which consisted of acquisition of ground reaction forces and kinematics while walking in a pain free …

Effects Of Varying Amounts Of Pronation On The Mediolateral Ground Reaction Forces During Barefoot Versus Shod Running, Joanna B. Morley, Leslie M. Decker, Tracy Dierks, Daniel Blanke, Jeffrey French, Nikolaos Stergiou

Journal Articles

Despite extensive research on running mechanics, there is still a knowledge gap with respect to the degree of relationship between mediolateral ground reaction forces (ML-GRF) and foot pronation. Our goal was to investigate whether differences exist in ML-GRF among runners that exhibit different degrees of pronation. Seventeen male and 13 female recreational runners ran with and without shoes while ML-GRF and frontal kinematics were collected simultaneously. Subjects were divided into groups based upon their peak eversion (low pronation, middle pronation, high pronation). Discrete parameters from the ML-GRF were peak forces, respective times of occurrence, and impulses. No significant differences were …

Kinetics At Front Foot Contact Of Cricket Bowling During A 10-Over Spell, Jacobus Noël Liebenberg

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to determine what effect bowling a 10 over spell (60 balls) would have on approach velocity, vertical ground reaction forces and shock attenuation during the front foot contact of a delivery stride in cricket.

Ten Amateur cricket players (age 27±4 years, height 1.78±0.3 m, mass 80.6±8.5 kg) participated in the study. Testing was conducted at University of Nevada, Las Vegas in the Biomechanics laboratory. Participants performed a 10-over bowling spell from a 12 meter run-up. These dependent variables were measured and calculated during the bowling protocol: 1) approach velocity 2) vertical ground reaction force …

Effects Of Obesity On The Biomechanics Of Children’S Gait At Different Speeds, Philana-Lee Gouws

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of the study was to investigate the relationship between body mass index (BMI) and spatio-temporal gait characteristics of overweight/obese and non-obese school-aged children (12-14 years) at two different walking speeds. Eighty-four overweight/obese (n=28; age: 13.96 ± 0.79 yrs; mass: 74.8 ± 18.21 kg; height: 159.2 ± 7.1 cm and BMI: 29.28 ± 5.64 kg/m2) and non-obese students (n=56; age: 13.72 ± 0.79 yrs; mass: 51.7 ± 10.2 kg; height: 157.8 ± 8.3 cm and BMI: 20.69 ± 2.74 kg/m2) with no present injuries were recruited. Participants were instructed to walk across an electronic walkway in each of two …

Evaluation Of A 3-Dimensional Inertial Tracking System For Quantifying Human Movement, David T. Delion

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to evaluate an inertial tracking unit (ITU) by comparing it to an optical tracking system. The ITU was attached to a bowling ball along with reflective markers for the optical system. Each trial started with the ball at rest on a pedestal the ball was then hung from a steel cable 10 feet long and set in motion in an elliptical pattern for approximately 25 seconds. The ball was then removed from the cable and returned to the pedestal so as to end each trial at rest. This was repeated 10 times with 5 …

A Biomechanical Analysis Of The Jete Dessus Using Dartfish Motion Analysis Software, Beatrice Turrubiartes

Undergraduate Research Conference

No abstract provided.

Impact Of Resistance Training On Balance And Gait In Multiple Sclerosis, Mary Filipi, M. Patricia Leuschen, Jessie M. Huisinga, Lorene Schmaderer, Jeanna Vogel, Daryl Kucera, Nikolaos Stergiou

Journal Articles

Multiple sclerosis (MS) is an incurable neurodegenerative disease whose symptoms are only partially relieved by pharmaceutical intervention. Disability due to this disease process can impede activities of daily living and decrease quality of life, both for MS patients and for their care partners and families. A nonrandomized, nonblinded prospective cohort study of 45 patients with MS was undertaken to investigate the impact of an exercise program emphasizing resistance training on balance and gait. This article presents data for the first 33 participants to complete the study protocol. The exercise program consisted of twice-weekly 50-minute sessions for 6 months. At 3 …