Biomechanics Commons^™

Reliability Of Gastrocnemius Pennation Angle Using Ultrasound With 15 Degree Adduction And Abduction In Standing Position, Diana J. Tyler

Honors College Theses

A pennate muscle has fascicles that attach obliquely to its tendon. In parallel, more fascicles can be aligned allowing for greater production of force. In previous research, pennation angle has been measured using ultrasound while in a laying supine position. The purpose of this study was to measure pennation angle of the gastrocnemius muscle with ultrasound while standing neutral, in a mechanically loaded position. 16 participants, one two separate days, had their ultrasound imaging taken in three different foot orientations: neutral, fifteen degree adduction / abduction positions. This information was then be analyzed using ImageJ software. This research shows the …

Power Output And Loads On The Lumbar Vertebrae During A Power Clean 2016, Joseph Keleher

Master's Theses

The purpose of the present study was to compare the peak resultant torque, shear, and compressive forces acting at the L3/L4 junction of the lumbar vertebrae and the peak power output during 40% one repetition maximum (1RM) and 80% 1RM attempts of the power clean. It was hypothesized that performance of a power clean at 80% 1RM will result in greater peak resultant compressive force, torque and shear force at the L3/L4 junction of the lumbar spine than that of a 40% 1RM attempt. Power cleans at 80% 1RM will also result in higher maximum instantaneous power outputs than that …

Electromyographic And Mechanomyographic Time And Frequency Responses During Fatiguing, Submaximal, Isokinetic Muscle Actions Of The Biceps Brachii, Ethan C. Hill

College of Education and Human Sciences: Dissertations, Theses, and Student Research

The purpose of the present investigation was to examine the time-course of changes in electromyographic (EMG) and mechanomyographic (MMG), time and frequency domain responses during repeated, submaximal, concentric, isokinetic, forearm flexion muscle actions. Twelve men (mean age ± SD = 22.6 ± 2.2 yrs; body weight = 84.0 ± 8.3 kg; height = 178.6 ± 8.3 cm) performed 50 repeated, submaximal (65% of concentric peak torque), concentric muscle actions of the dominant forearm flexors on an isokinetic dynamometer at 60°·s^-1. Surface EMG and MMG signals were simultaneously recorded from the biceps brachii muscle. Polynomial regression analyses (first, second, …

Identification Of Kinematic And Kinetic Injury Risk Predictors In Division I Football Athletes, Corbin M. Rasmussen, Guilherme M. Cesar, Shinya Takahashi

UCARE: Research Products

biomechanical patterns and insufficiencies that may influence risk of ligamentous injury, such as an anterior cruciate ligament (ACL) tear. One kinematic pattern that has been identified as detrimental to ACL integrity is frontal plane knee collapse (valgus) during jumping and landing tasks.1 Inter-limb differences in force generation have also been connected to the occurrence of lower extremity injury.2 It is not known, however, whether these patterns contribute to the occurrence of lower extremity (LE) non-contact soft-tissue injury. The counter-movement vertical jump (CMVJ) is one way to simultaneously screen for knee collapse and asymmetrical force production patterns. This method was therefore …

Preliminary Results On Organization On The Court, Physical And Technical Performance Of Brazilian Professional Futsal Players: Comparison Between Friendly Pre-Season And Official Match, Luiz Henrique Palucci Vieira, Sera N. Doğramaci, Ricardo Augusto Barbieri, Fabio Milioni, Felipe Arruda Moura, Vitor Luiz De Andrade, Guilherme Manna Cesar, Paulo Roberto Pereira Santiago

Athletic Performance Research

The main aim of this study was to verify possible differences between a friendly pre-season match (FM) and an official in-season match (OM) regarding physical, technical, and organizational performances of a professional Brazilian futsal team. Ten professional futsal athletes participated in this study. The matches were monitored with video cameras (30 Hz) and athlete trajectories obtained with automatic tracking. The values obtained for distance covered per minute, percentage of distance covered at moderate intensity, team coverage area, spread, passes, possessions, ball touches and successful passes per minute were greater for the OM than FM. On the contrary, percentage of distance …

Pertinacity Volume 2 Issue 1, Yuri Hosokawa

Pertinacity

No abstract provided.

Frontal Plane Comparison Between Drop Jump And Vertical Jump: Implications For The Assessment Of Acl Risk Of Injury, Guilherme Manna Cesar, Curtis L. Tomasevicz, Judith M. Burnfield

Athletic Performance Research

The potential to use the vertical jump (VJ) to assess both athletic performance and risk of anterior cruciate ligament (ACL) injury could have widespread clinical implications since VJ is broadly used in high school, university, and professional sport settings. Although drop jump (DJ) and VJ observationally exhibit similar lower extremity mechanics, the extent to which VJ can also be used as screening tool for ACL injury risk has not been assessed. This study evaluated whether individuals exhibit similar knee joint frontal plane kinematic and kinetic patterns when performing VJs compared with DJs. Twenty-eight female collegiate athletes performed DJs and VJs. …

Weight Control Practices Of Division I National Collegiate Athletic Association Athletes, Patrick B. Wilson, Leilani Madrigal, Judith M. Burnfield

Athletic Performance Research

Objectives: Altering body weight can have substantial effects on an athlete’s performance and well-being. Limited information is available describing the weight control practices of Division I National Collegiate Athletic Association (NCAA) athletes.

Methods: Weight control practices data from 188 (138 male and 50 female; 18-23 y) Division I NCAA athletes were analyzed as a part of this cross-sectional, retrospective study. Participants completed questionnaires on weight control practices and weight control nutrition knowledge at the end of their season and were classified into weight-sensitive and less weight-sensitive sports.

Results: A higher proportion of females attempted to lose weight than males among …

Central And Peripheral Weight Gain Affect Trunk Kinematics And Lower-Extremity Muscle Activation Differently During Sit-To-Stand, Michelle Christine Walaszek

Theses and Dissertations--Kinesiology and Health Promotion

Background: Obesity-induced alterations in biomechanics and muscle recruitment during activities of daily living, such as sit-to-stand (STS) are often attributed to increases in adipose tissue (AT) mass. Central or peripheral distribution of AT may differently affect biomechanics and muscle recruitment.

Methods: Fifteen healthy, normal weight (BMI 22.4 ± 1.9 kg/m², 24.1 ± 4.2 years) subjects volunteered. External loads equivalent to a 5 kg/m² BMI increase were applied in three conditions: unloaded (UN), centrally loaded (CL), and peripherally loaded (PL). Subjects completed three successful STS movements in a backless chair under each load condition in random order. Motion …

Examining The Reliability, Validity And Factor Structure Of The Drs-15 With College Athletes, Leilani Madrigal, Diane L. Gill, Kent M. Eskridge

Athletic Performance Research

Hardiness, comprising feelings of commitment, control and challenge, is most frequently measured with the Dispositional Resiliency Scale (DRS), but little work has been done with the brief 15-item version. To examine the factor structure, reliability, validity, and item functioning for gender invariance of the 15-item DRS with 525 collegiate athletes from a wide range of sports. Convergent and divergent validity were examined through relationships with mental toughness, grit and competitive anxiety. Participants completed measures of mental toughness, optimism, grit, competitive anxiety, and the DRS-15. Confirmatory Factor Analysis revealed a poor fit for the three-factor hardiness model, and subsequent exploratory factor …

Glucose-Fructose Likely Improves Gastrointestinal Comfort And Endurance Running Performance Relative To Glucose-Only, P. B. Wilson, S. J, Ingraham

Athletic Performance Research

This study aimed to determine whether glucose-fructose (GF) ingestion, relative to glucose-only, would alter performance, metabolism, gastrointestinal (GI) symptoms, and psychological affect during prolonged running. On two occasions, 20 runners (14 men) completed a 120-min submaximal run followed by a 4-mile time trial (TT). Participants consumed glucose-only (G) or GF (1.2:1 ratio) beverages, which supplied ~1.3 g/min of carbohydrate. Substrate use, blood lactate, psychological affect [Feeling Scale (FS)], and GI distress were measured. Differences between conditions were assessed using magnitude-based inferential statistics. Participants completed the TT 1.9% (−1.9; −4.2, 0.4) faster with GF, representing a likely benefit. FS ratings were …

Misrepresentation Of Carbohydrate For Exercise: ‘It Is Time To Bust The Myth Of Physical Inactivity And Obesity: You Cannot Outrun A Bad Diet’, Patrick B. Wilson

Athletic Performance Research

The contention from Malhotra et al1 regarding the unimportance of carbohydrate for exercise is misguided. First, the reference they provide is an editorial2 that should not be viewed as high-quality evidence. Several oft-cited exercise studies showing benefits with high-fat diets simultaneously utilized carbohydrate restoration strategies,3 which involves “carbohydrate loading” after a high-fat diet. Thus, the evidence provided does not contradict the established belief that carbohydrate is an important fuel for endurance exercise. Second, the authors’ use of the term “carbohydrate loading” is misleading in this context. No public health organizations advocate a diet containing carbohydrate in amounts used in “carbohydrate …

Biomechanical Investigation Of Elite Place-Kicking, Chase M. Pfeifer

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Many studies aim to understand the fundamentals of kicking commonly displayed by soccer players [4,6,10,16,17,18,24,25,28,29,30,34,36,38,40]. Of those studies, most are limited to a two-dimensional (2D) analysis using high-speed cameras for position tracking or utilizing electromyography to observe the activity of select muscles [4,6,18,25,29,36]. The few studies that investigate kicking using a three-dimensional (3D) model are limited in their position tracking capabilities and focus mainly on joint flexion potentials and foot speed.

This dissertation is a comprehensive biomechanical analysis (kinematic and EMG) of the field-goal place-kicking techniques of four elite kickers in American football. Data were compared and contrasted with ball …

Pertinacity Issue 1 Volume 2, Yuri Hosokawa

Pertinacity

No abstract provided.

The Effect Of Various Body Positions On Performance Of The Isometric Mid-Thigh Pull, George K. Beckham

Electronic Theses and Dissertations

The purpose of this dissertation was to evaluate the effects of changing body position on the execution of the isometric mid-thigh pull (IMTP). Furthermore, while there is evidence to suggest that there is an effect of familiarization on performance of maximal strength tests, there has been no known research evaluating the effect of learning on the IMTP. The effect of familiarization was assessed by evaluating changes in variables obtained from the IMTP. Subjects did not statistically improve over the five IMTP testing sessions, regardless of the body position used, or if subjects had previous experience with weightlifting derivatives. This may …

Removable Shoe Spike System, Alex Adams, Nutech Ventures, Inc.,

Athletic Performance Research

The present system, method and apparatus are adapted for the quick and easy exchange of spikes on athletic shoes. More specifically, the system, apparatus and methods comprise a spike having an opening, an aglet adapted for coupling to the shoe, for example by way of a shoelace, and a coupling head affixed to the aglet which is adapted to couple with the opening on the spike so as to allow a user to quickly and easily replace, remove or install spikes in the athletic shoe. The disclosure thus allows the user to have the tool attached to their shoe at …

The Effect Of Posterior Foot Positions On Electromyography, Joint Kinetics And Energetics During A Sit-To-Stand In Young And Older Adults, Eric A. Pitman

Human Movement Studies & Special Education Theses & Dissertations

The sit-to-stand (STS) movement, defined as standing up from a chair to an upright posture, is a common task performed daily. The inability to accomplish this task may lead to dependence, institutionalization and even death in older adults. A common strategy change for the STS is positioning the feet posteriorly by increasing flexion at the knee joint. This reduces the displacement of the center of mass to the base of support while increasing the joint moment of force at the knee while decreasing it at the hip. The aims of this study were to: 1) examine the joint kinetics, joint …

Synergy-Based Two-Level Optimization For Predicting Knee Contact Forces During Walking, Gil Serrancolí, Allison Kinney, Josep M. Font-Llagunes, Benjamin J. Fregly

Mechanical and Aerospace Engineering Faculty Publications

Musculoskeletal models and optimization methods are combined to calculate muscle forces. Some model parameters cannot be experimentally measured due to the invasiveness, such as the muscle moment arms or the muscle and tendon lengths. Moreover, other parameters used in the optimization, such as the muscle synergy components, can be also unknown. The estimation of all these parameters needs to be validated to obtain physiologically consistent results. In this study, a two-step optimization problem was formulated to predict both muscle and knee contact forces of a subject wearing an instrumented knee prosthesis. In the outer level, muscle parameters were calibrated, whereas …

Development Of A Muscle Model Parameter Calibration Method Via Passive Muscle Force Minimization, Allison Kinney, Benjamin J. Fregly

Mechanical and Aerospace Engineering Faculty Publications

Computational predictions of subject-specific muscle and knee joint contact forces during walking may improve individual rehabilitation treatment design. Such predictions depend directly on specified model parameter values. However, model parameters are difficult to measure non-invasively. Methods for muscle model parameter calibration have been developed previously. However, it is currently unknown how the musculoskeletal system chooses muscle model parameter values. Previous studies have hypothesized that muscles avoid injury during walking by generating little passive force and operating in the ascending region of the force-length curve. This hypothesis suggests that muscle model parameter values may be selected by the body to minimize …

Lower Extremity Biomechanics In Individuals With And Without Previous Hamstring Injury, Jessica A. Mutchler

Human Movement Studies & Special Education Theses & Dissertations

Primary risk factors for hamstrings strains such as fatigue, previous injury and strength deficits have been identified in the research, yet re-injury rates remain high among the physically active. Sub-acute analysis of the hip, knee and ankle biomechanics following a hamstrings strain have been largely overlooked and may provide additional insight into re-injury risks. It was the aim of this dissertation to explore long-term adaptations in walking and running tasks following a hamstrings strain, and to develop a hip endurance test that could be used in future studies.

Project one used a cross-sectional study with test-retest design to develop and …

The Influence Of Neuromusculoskeletal Model Calibration Method On Predicted Knee Contact Forces During Walking, Gil Serrancolí, Allison Kinney, Benjamin J. Fregly, Josep M. Font-Llagunes

Mechanical and Aerospace Engineering Faculty Publications

This study explored the influence of three model calibration methods on predicted knee contact and leg muscle forces during walking. Static optimization was used to calculate muscle activations for all three methods. Approach A used muscle-tendon model parameter values (i.e., optimal muscle fiber lengths and tendon slack lengths) taken directly from literature. Approach B used a simple algorithm to calibrate muscle-tendon model parameter values such that each muscle operated within the ascending region of its normalized force-length curve. Approach C used a novel two-level optimization procedure to calibrate muscle-tendon, moment arm, and neural control model parameter values while simultaneously predicting …

Changes In Sprint Kinetics Or Kinematics Following Static Or Dynamic Stretching, Kristyne Bartel

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to determine the effects of static or dynamic stretching on hip kinematics and kinetics during intermittent sprinting. To achieve this aim, intermittent sprint athletes were asked to complete either a static or dynamic stretch, followed by a repeated-sprint protocol. Hip joint kinematics and performance measures were evaluated during the sprint, including changes that occurred in these variables over the course of the sprint protocol. In addition, hip flexion torque was measured with an isokinetic dynamometer. Ten male (age = 25±2.3 years, 175±3.2 cm, 76.2±2.7 kg) and female (age = 20±1 years, 166±1.3 cm, 60±1.1 …

Gait Intervention For Improvements In Human Top Speed Running, Michelle Buechner

Graduate Student Theses, Dissertations, & Professional Papers

Between individuals faster sprinting speeds are achieved by applying greater stance average forces against the running surface. Recent evidence further indicates that elite level performers also strike the ground with leg kinematics that differ from those of non-elites and that these leg movements act to enhance the force transients occurring in the milliseconds following foot-ground impact. I investigated whether sprint performance could be enhanced through a short term gait intervention, consisting of 3 laboratory training sessions wherein subjects (n = 6) completed 5 high-speed runs on an instrumented force treadmill at 90% of their measured top sprint. The subjects received …

A Multi-Directional Treadmill Training Program For Improving Gait, Balance, And Mobility In Individuals With Parkinson’S Disease: A Case Series, Kimberly Smith, Kurt Jackson, Kimberly Edginton Bigelow, Lloyd L. Laubach

Mechanical and Aerospace Engineering Faculty Publications

Treadmill training is a commonly used intervention for improving gait in people with Parkinson’s disease (PD). However, little is known about how treadmill training may also influence balance and other aspects of mobility.

The purpose of this case series was to explore the feasibility and possible benefits of multi-directional treadmill training for individuals with PD. Four participants (62.3 ± 6.5 yrs, Hoehn & Yahr 2-4) performed 8 weeks of treadmill training 3 times per week. Weeks 1-4 included forward walking only, while weeks 5-8 included forward and multi-directional walking. Participants were tested every 4 weeks on 4 separate occasions. Outcome …

A Pilot Study Investigating The Reasons For Playing Through Pain And Injury: Emerging Themes In Men’S And Women’S Collegiate Rugby, Leilani Madrigal, Jamie Robbins, Diane L. Gill, Katherine Wurst

Athletic Performance Research

Collegiate rugby is a competitive, collision sport, yet insufficient empirical evidence exists regarding participants’ perspectives on pain and injury. This study addressed male and female rugby players’ experiences with injury, and their views about playing through pain and injury. Eleven rugby players (five male; six female) competing in USA Rugby’s National College 7’s tournament participated in semi structured interviews, which were recorded, transcribed, and content-analyzed. Two major themes emerged: passion for sport and sport ethic. Passion for sport was composed of (a) love of the sport, (b) meaning of the sport, and (c) desire to be on the field. Sport …

Hip Abductors And Thigh Muscles Strength Ratios And Their Relation To Electromyography Amplitude During Split Squat And Walking Lunge Exercises, Petr Stastny, James J. Tufano, Michal Lehnert, Artur Golas, Amr Zaatar, Zuzana Xaverova, Adam Maszczyk

Research outputs 2014 to 2021

Background: The hip abductors (HAB), quadriceps (Q) and hamstrings (H) reciprocal strength ratios are predictors of electromyography (EMG) amplitude during load carrying walking at moderate intensity. Therefore, these strength ratios might predict also the EMG during the exercises as walking lunge (WL) or split squat (SSq) at submaximal intensity. Objective: To determine whether the EMG amplitude of vastus mediali (VM), vastus laterali (VL), biceps femoris (BF) and gluteus medius (Gmed) is associated with muscle strength ratio during SSqs and WLs. To determine whether the EMG amplitude differs between individuals with HAB/H ratio above and below one and between individuals with …

How Sensitive Is The Deltoid Moment Arm To Joint Center Changes With Rtsa?, David Walker, Allison Kinney, Aimee Struk, Benjamin J. Fregly, Thomas Wright, Scott Banks

Mechanical and Aerospace Engineering Faculty Publications

The goal of this study was to assess the sensitivity of the deltoid muscle moment arms as a function of joint configuration for an existing RTSA subject. High variations were found for all three deltoid components. Variation over the entire abduction arc was greatest in the anterior and lateral deltoid, while the posterior deltoid moment arm was mostly sensitive to joint center changes early in the abduction arc. Moment arm changes of 10-16mm represent a significant amount of the total deltoid moment arm. This means there is an opportunity to dramatically change the deltoid moments arms through surgical placement of …

Deltoid Moment Arms During Abduction: A Subject-Specific Musculoskeletal Modeling Study In Healthy Shoulders And Shoulders With Rtsa, David Walker, Allison Kinney, Aimee Struk, Benjamin J. Fregly, Thomas Wright, Scott Banks

Mechanical and Aerospace Engineering Faculty Publications

Reverse total shoulder arthroplasty (RTSA) is increasingly used in the United States since approval by the FDA in 2003. RTSA relieves pain and restores mobility in arthritic rotator cuff deficient shoulders. Though many advantages of RTSA have been demonstrated, there still are a variety of complications (implant loosening, shoulder impingement, infection, frozen shoulder) making apparent much still is to be learned how RTSA modifies normal shoulder function. The goal of this study was to assess how RTSA affects deltoid muscle moment generating capacity post-surgery using a subjectspecific computational model driven by in vivo kinematic data.

A Novel Approach To Estimation Of Patient-Specific Muscle Strength, David Walker, Allison Kinney, Benjamin J. Fregly, Thomas Wright, Scott Banks

Mechanical and Aerospace Engineering Faculty Publications

Current modeling techniques have been used to model the Reverse Total Shoulder Arthroplasty (RTSA) to account for the geometric changes implemented after RTSA. Though these models have provided insight into the effects of geometric changes from RTSA these is still a limitation of understanding muscle function after RTSA on a patient-specific basis. The goal of this study sought to overcome this limitation by developing an approach to calibrate patient-specific muscle strength for an RTSA subject.

Stride Length-Speed Relationship During Body Weight Supported Running, Carmen Chona

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to determine if body weight support influences the stride length-speed relationship. Additionally, the purpose was to determine if impact characteristics of running are influenced by body weight support and speed. Subjects (n=10; 6 female, 4 male) volunteered to participate in this study. All subjects were injury free and were comfortable running on a treadmill for 30 minutes. Subjects ran on a lower body positive (LBPP, Alter-G, G-Trainer) treadmill for 4 conditions of body weight (100, 40, 30 and 20% of body weight) and 4 running speeds (100, 110, 120 and 130% of the preferred …