Biomechanics Commons^™

The Effects Of Lifting With Intent On Hip And Knee Moments During Back Squats, Kyle A. Parrish

Human Movement Sciences Theses & Dissertations

Back squatting is a widely used movement in the strength and conditioning community. Within the last few years, velocity-dependent training and its application of tracking intensity have increased in popularity. Biomechanics research has frequently examined force generation, joint loading, and muscle contributions of back squats with different bar placement, stance width, and increasing barbell loads. However, no information exists regarding whether lifting with intent increases velocity and how increased velocity is biomechanically achieved. This study aimed to examine how lifting with intent affects bar velocity and how joint moment alterations could contribute to these potential changes in velocity. Fifteen males …

A Biomechanical Analysis Of Back Squats: Motion Capture, Electromyography, And Musculoskeletal Modeling, Eva Maria Urdiales Maddox

Human Movement Sciences Theses & Dissertations

Previous literature evaluating maximal back squats have failed to identify key components of the study decisions and procedures that would allow for duplication. Firstly, the existence of a sticking region in maximally weighted resistance exercises is frequently discussed and has been described as a force-reduced transition phase between an acceleration phase and a strength phase of a lift. However, the etiology has yet to be agreed upon. Second, Electromyography (EMG) is frequently used to assess muscle activations. However, no best practice for EMG normalization has been proposed. Two methods are commonly implemented for normalizing EMG: a maximum voluntary isometric contraction …

The Relationship Of Strength, Mobility, And Performance Variables On Throwing Speed In Baseball Catchers, Caleigh D. Hall

Human Movement Sciences Theses & Dissertations

Baseball is a popular sport worldwide and has thus garnered significant research focus, predominately of pitchers and hitters. However, research involving catchers is scant despite their major influence and consistent presence throughout a game. Therefore, the purpose of this study was to determine the relationship of lower body strength and mobility and performance with throwing speed in baseball catchers. We hypothesized that strength and mobility would have a positive relationship with ball speed, peak power generated while rising out of the squat position would be positively related to ball speed, shorter ascent time would be inversely related to ball speed, …

The Associations Of Cardiovascular Disease, Physical Activity Intensities, And Measures Of Obesity On Static Balance In Middle-Aged And Older Adults, Hannah Martha Twiddy

Human Movement Sciences Theses & Dissertations

The burden of falls is widely known in older adults, though less research has targeted middle-aged adults (40-64 years of age), particularly at the population level. The purpose of this dissertation was to explore the roles of cardiovascular disease, physical activity (PA) intensity, and body anthropometrics on balance among middle-aged adults. Study 1 sought to determine if balance was impaired in middle-aged adults with poor ankle-brachial pressure index (ABPI), a marker of cardiovascular disease. Study 2 determined the associations between PA intensity with odds of having good static balance. Study 3 explored how strongly a variety of anthropometric measures, including …

Predictions Of Knee Joint Contact Forces Using Only Kinematic Inputs With A Recurrent Neural Network, Kaileigh Elisabeth Estler

Human Movement Sciences Theses & Dissertations

BACKGROUND: Knee joint contact (bone on bone) forces are commonly estimated using surrogate measures such as external knee adduction moments (with limited success) or musculoskeletal modeling (more successful). Despite its capabilities, modeling is not optimal for clinicians or persons with limited experience and knowledge. Therefore, the purpose of this study was to design a novel prediction method for knee joint contact forces that is equal or more accurate than modeling, yet simplistic in terms of required inputs. METHODS: This study included all six subjects’ (71.3±6.5kg, 1.7±0.1m) data from the opensource “Grand Challenge” datasets (simtk.org) and two subjects from the "CAMS" …

Assessment Of Coordination And Proprioception In Youth With Autism Spectrum Disorder, Taylor Kristina Jones

Human Movement Sciences Theses & Dissertations

Autism spectrum disorder (ASD) is characterized by social and communicative delays. It is known that those with ASD exhibit lower activity levels and decreased proprioception to some extent. The biomechanics of movement in ASD has not been assessed thoroughly enough to provide information on ASD specific movement patterns, and no studies have been performed examining work and recovery. The purpose of this study is to examine whether 1) inter-limb and intra-limb coordination patterns during walking and running differ between youth with ASD and neurotypical sex, age, and BMI-matched controls. Youth with ASD (N=8) and their BMI, age, and sex matched …

The Effects Of Anterior Cruciate Ligament Thickness, Knee Joint Laxity, Activity Level, Neuromuscular Imbalances And Lower Extremity Muscular Activation Patterns On Anterior Cruciate Ligament Loading, Zachary A. Sievert

Human Movement Sciences Theses & Dissertations

There are numerous known mechanisms of anterior cruciate ligament (ACL) injury risk that span from knee joint laxity to landing mechanics. However, the relationship of these mechanisms to ACL loading during landing is unclear. In addition to landing mechanics, anthropological aspects such as ACL diameter, which can now be obtained via ultrasound, may also be an important mechanism for ACL loading. However, the relationship between ACL diameter to ACL loading and landing mechanics remains unknown. This study was conducted with three primary purposes. The first purpose of this study was to examine the inter and intra-rater reliability of using ultrasound …

Effects Of A Postural Restoration Focused Intervention On Muscle Activation During Deadlifts, Caleb Richardson

Human Movement Sciences Theses & Dissertations

The purpose of this study was to determine the efficacy of implementing two Postural Restoration exercises and relating principles on deadlifts using a hexagonal barbell. Specifically, we aimed to examine the effects of the intervention on muscle activation and the location of the ground reaction force (GRF) center of pressure. Sixteen subjects (age 18-35 yrs.; male (n=14); female (n=2)), with at least 1 year of deadlifting experience, were randomly assigned into a control and intervention group (both n=8). Both groups performed two sets of three repetitions of deadlifts at 50% and at 80% of their estimated one repetition maximum (1-RM). …

Physiological Tremor In Handgun Aiming And Shooting Tasks, Kyle J. Kellran

Human Movement Sciences Theses & Dissertations

When holding an outstretched limb or aiming at a target, humans produce small involuntary fluctuations that may hamper performance. Current strategies for minimizing the impact of tremulous oscillations predominantly include both extrinsic and intrinsic support. The aim of the current dissertation is to better understand the parameters of physiological tremor associated with handgun aiming with the end goal of improving shooting accuracy. Experiment 1 focused on handgun aiming and the influence of different arm posture adopted during aiming. Experiment 2 expanded upon the findings of experiment 1 by comparing tremor during finger pointing, handgun aiming, and handgun shooting. Experiment 3 …

Effects Of Knee Sleeves On Knee Mechanics During Squats At Variable Depths, Alexandria A. Trypuc

Human Movement Sciences Theses & Dissertations

The squat is a functional, compound and multi-joint exercise that targets several muscles of the lower body and is widely used in both athletics and many exercise programs. This exercise has been the subject of many studies, comparing different squat variations and examining how external gear, such as squat suits and knee wraps impact the exercise. The aim of this study was to assess the effects of wearing neoprene knee sleeves on lower extremity kinematics, kinetics, and muscle activations during weighted back squats. Fifteen resistance trained men and women, aged 28±5 years, from the local fitness community and university campus …

Hip Mechanics Of Unilateral Drop Landings, Bobbie S. Irmischer

Human Movement Sciences Theses & Dissertations

Increased hip forces are a proposed factor for osteoarthritis and femoroacetabular impingement. These forces can be estimated through musculoskeletal modeling using measured kinematics and kinetics. An understanding of hip joint loading during landing in a asymptomatic population will begin to elucidate what, if any, sex differences exist and how changes in landing condition alter hip mechanics. The overall purpose of this dissertation was to explore how sex and landing condition effect landing mechanics. Landing mechanics were quantified using ground reaction forces (GRF), hip joint forces (HJF), and lower extremity kinematics during unilateral drop landings from 30-cm, 40-cm, and 50-cm, as …

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

Human Movement Sciences 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 …

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

Human Movement Sciences 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 …

Neuromechanical Analysis Of Anterior Cruciate Ligament Risk Factors In Female Collegiate Soccer Athletes, Nelson Cortes

Human Movement Sciences Theses & Dissertations

The anterior cruciate ligament (ACL) acts in an essential role to prevent anterior tibial displacement when experiencing jump-landing forces that are applied to the lower extremity; more than 100,000 injuries per year in the United States in sport activities that often require landing, deceleration-acceleration, cutting and pivoting actions have been reported. The aim of this study was to examine the nature of any lower limb coupling differences between a drop-jump and a side-step cutting actions, assess kinematic and kinetic differences between three tasks, and evaluate the effects of two landing techniques in biomechanical risk factors while performing two unanticipated tasks. …