Biomechanics Commons^™

Biomechanical Adjustments During Landing In Response To Task Perturbations, John Robert Harry

UNLV Theses, Dissertations, Professional Papers, and Capstones

Landing strategies are evaluated to determine a performer’s favored neuromusculo-skeletal solution for the performance of the task. Depending on the strategy employed, a performer might increase his or her musculoskeletal injury potential, as defined by increased impact forces and/or demands on the involved joints. In recent history, the manner in which a performer modifies his or her strategy has been evaluated following the application of an added external mass during the impact phase of landings performed from atop an elevated platforms or a hanging position from a raised bar. Furthermore, the strategies evaluated in contemporary research are quantified using biomechanical …

The Effects Of An Inclined And Declined Slope On Backward Locomotion: A Kinematic And Electromyographic Analysis Of Retrowalking, Song Dan Vo

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to investigate the effects of an inclined and declined slopeon kinematic properties and muscle activation magnitudes. This purpose was achieved by using a +10% grade for inclined backward walking (IBW) and -10% grade for declined backwardwalking (DBW) on a treadmill. Eleven participants (24.6 ± 4.1 yrs, 68.5 ± 14.6 kg, 1.7 ± 0.1 m) were recruited from the UNLV student body and were subject to a three day adaptation protocol to allow them to choose a preferred walking speed and to familiarize themselves with such a novel task. Two consecutive practice days included a …

Investigation Of Sequential Intermittent Pneumatic Compression Effect On Run Performance, Max Evan Jones

UNLV Theses, Dissertations, Professional Papers, and Capstones

The main aim of this study was to determine if IPC after a 5000 m run influences maximal effort 1600 m run performance. A secondary purpose was to determine if the level of IPC pressure used influences run performance. Nine subjects (6 male and 3 female were included in the study; 30 years±5.19 years; Height 173.72cm±8.25; Weight; 72.54±9.97 kg). These subjects were recruited to be in this study via word of mouth or social media advertisement in the Las Vegas area. Participant inclusion criteria was 18- 50 year old apparently healthy, had been running a minimum of 20 miles a …

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 …

Reliability Of A Multisegment Foot Model In Shod Running, Austin Coupe

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to determine kinematic and marker placement reliability of the Leardini multisegment foot model (LMFM) for tracking foot kinematics during barefoot and shod running without alteration of footwear. Eleven participants, five males (25.6±5 yrs, 73±15.8 kg, 1.75±0.05m) and six females (22.5±2.9 yrs, 66.6±7.2 kg, 1.71±0.05 m) granted institutionally approved written consent to participate. Three-dimensional motion capture (10 Vicon T40-S cameras) was used to capture kinematic data at 200Hz. Kinetic data was captured with an in-ground force platform (Kistler Instruments AG, Switzerland Model 9281B 60x40cm, 2000Hz). Participants were instructed to run at 3.5m/s ±5%. Velocity was …

Comparison Of Muscle Latencies For Diabetic Neuropathy Patients Versus Healthy Controls During A Perturbed Balance Task, Kyle Mefferd

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to compare muscle latencies for patients diagnosed with diabetic neuropathy versus healthy controls during a perturbed balance task, with a secondary purpose to distinguish postural control strategies the groups used based on the muscle latencies. Five participants diagnosed with diabetic neuropathy (DN; 4 male, 99.7 ± 7.95 kg, 176 ± 9.58 cm, 46.6 ± 16.55 years) and 5 healthy control (HC; 4 male, 100.36 ± 12.61 kg, 173.76 ± 9.66 cm, 47 ± 13.42 years) participants were recruited. Participants granted institutionally approved written consent before participating. Delsys Trigino Wireless EMG sensors were placed on …

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 …

An Evaluation Of Kinematic Variables During Stance Phase Of A Training Endurance Run, Joshua Paul Bailey

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of the study was to evaluate kinematics of the lower extremity during the stance phase of an endurance training run. Fifteen participants (8 male, 7 female; 30.5 ± 8.4 years; 71.8 ± 11 kg; 1.73 ± 0.07 m) reported that they were currently signed up for, or planned on signing up for, an endurance race within the next six months of participation in the study (9 half marathon, 3 marathon, 1 triathlon, 2 21k trail run). All had a weekly running mileage greater than 20 miles (23.8 ±4.6 miles). Participants were required to complete the 15–kilometer training run …

A Comparative Evaluation Of The Effects Of Incline On Kinematics And Muscle Function During Backward Walking, Daniel Brent Jensen

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to investigate lower extremity kinematics and muscle activation patterns in inclined backward walking (IBW) versus traditional backward walking (BW). This purpose was achieved by evaluating performance of individuals walking backward on a treadmill at inclines of 0%, 6%, 8%, 10%, and 12%. Eleven participants (24.9 ± 4.8 yrs, 71.9 ± 11.6 kg, 1.7 ± 0.09m) recruited from the UNLV student body went through a familiarization training program before any data were collected. The familiarization training, which took place across 3 different days, served to: 1) help the participants become comfortable and familiar with BW …

Field Testing The Upright Versus The Aero Cycling Position, Curtis Scrugham

UNLV Theses, Dissertations, Professional Papers, and Capstones

Body position can be of great importance to athletes who want to maximize their performance on the bike. Aerodynamic resistance can account for 70-90% of resistance encountered by cyclists, and a strategy used to reduce this resistance is riding in the aero position Research has been done in the lab to determine if there are trade-offs to using this position (Jobson et al. 2008, Welbergen and Clijsen 1990, Hubenig, Game and Kennedy 2011, Peveler 2004, Origenes et al. 1993, Ryschon and Stray-Gunderson 1991, Gnehm et al. 1997, Ashe et al. 2003). . Researchers have reported that riders untrained in the …

Effects Of Footstrike Pattern On Low Back Posture, Shock Attenuation, And Comfort During Running, Traci L. Delgado, Emilia Kubera-Shelton, Robert R. Robb

UNLV Theses, Dissertations, Professional Papers, and Capstones

Purpose: Barefoot running (BF) is popular in the running community. Biomechanical changes occur with BF, especially when initial contact changes from rearfoot strike (RFS) to forefoot strike (FFS). In addition, changes in lumbar spine range of motion (ROM), particularly involving lumbar lordosis, have been associated with increased low back pain (LBP). However it is not known how changing from RFS to FFS affects lumbar lordosis or LBP. Thus, the purpose of this study was to determine if a change from RFS to FFS would change lumbar lordosis, and/or decrease shock attenuation, and/or change comfort levels in healthy recreational/experienced runners.

Methods: …

Effect Of Racing Flats On Running Economy In Male Adolescent Runners, Paul Hafen

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to investigate whether running economy differs in racing flats versus standard running shoes in high school cross-country runners. In order to measure running economy the oxygen cost of running (mL O₂∙kg^-1∙min^-1) was measured in 20 male adolescent runners (mean age = 16.25 ± 0.97 years, 5 km best time = 17.52 ± 0.78 min) when running two separate trials at a controlled speed. The speed was determined by estimating treadmill running speed at 85% of each runner's VO_2max. Each trial required the participants to run while …

Examination Of Lower Extremity Muscle Activity During An Overhand Lacrosse Shot In Females, Brianna Millard

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study intends to provide a basic biomechanical understanding of a specific movement within the sport of lacrosse, an overhand goal shot. Its purpose is to identify the different muscles of the lower extremity and the roles they perform during each phase of the lacrosse shot. Specifically, the study will compare how active muscles are between phases as well as between two different shot speeds. This research provides insight into the importance of timing muscle contractions that lead to a more accurate and faster shot.

Subjects (n=5 females, age: 21.8 ± 2 years, height: 162.56 ± 15.24cm, mass: 63.68 ± …

The Effects Of Arch Taping On Shock Attenuation During Landing, Shun Jinnouchi

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to investigate the effects of two different arch taping techniques on shock attenuation during landing. Each subject (n=12, age 25.5 ± 3.37 years, height 1.73 ± 0.04 m, mass 82.06 ± 16.23) was instrumented with accelerometers at the leg and forehead (sample rate = 1000 Hz). Subjects performed landings from a 30 cm box under three taping conditions: no tape, Low Dye, and Weave. For each condition, subjects completed 5 landing trials. Rest was provided between each trial and order of conditions was counterbalanced. During each landing, accelerations were recorded at 1000 Hz for …

Biomechanical Comparison Of A Rounded Outsole Shoe And Traditional Outsole Shoe, Sarah Horsch

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of the study was to determine the effects of shoe outsole design on maximum vertical acceleration and select kinematic parameters during level and uphill walking across phases of stance. Twelve participants, 7 males (75.1±9.3 kg, 173.6±3.6 cm, 22.9±3.5 yrs) and 5 females (56.5±5.1 kg, 158.3±4.5 cm, 25.4±11.1 yrs) granted written consent and preferred walking speed was determined. An accelerometer (480 Hz) was attached to the distal leg to measure maximum leg acceleration (Aleg) and an electrogoniometer (480 Hz) was placed on the back to measure sagittal lumbar motion (LumbarROM). Sagittal video capture (60 Hz) included thigh range of …

Shock Attenuation In Landing, Bryon Christopher Applequist

UNLV Theses, Dissertations, Professional Papers, and Capstones

Shock attenuation (SA) has been well studied in activities such as walking and running (Chu, et al. 2004; Derrick, et al. 2004; Mercer, et al. 2003); however, there is a lack of research regarding SA during landing. Furthermore, there is lack of information regarding which structures attenuate shock. The purpose of this study was to examine SA among the leg-hip, hip-head, and leg-head segments during landing. Each subject (n=10, Age 26.3 ± 2.71 years, Height 1.68 ± 0.08 m, Mass 70.49 ± 16.03 kg) was instrumented with accelerometers at the leg, hip and forehead. Subjects then performed landings from three …

Frictional Forces Of A Fixed, Esthetic Orthodontic Appliance System, Brady Michael Nance

UNLV Theses, Dissertations, Professional Papers, and Capstones

Purpose: The demands of an all esthetic fixed orthodontic appliance system are ever increasing in today's world. Frictional values of an esthetic, fixed orthodontic appliance system are needed to evaluate their clinical effectiveness for orthodontic treatment. The aim of this study is to evaluate the frictional values of various esthetic orthodontic archwires ligated to an esthetic orthodontic bracket.

Methods: Three types of stainless steel and nickel titanium alloy (niti) esthetic orthodontic archwires (epoxy, poly, plastic) in four sizes (.016, .018, .017 x .025, .019 x .025 inches) were ligated to both a stainless steel bracket system and a ceramic (esthetic) …

The Effect Of Footwear On The Mechanics Of The Lower Back During Treadmill Running, Jeffrey Ray Mcclellan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Little is known regarding the effect that footwear cushioning can have on the mechanics of the low back. The purpose of this study was to 1) determine the material characteristics of a minimalist running shoe tested with and without a commercially available shoe insole, 2) determine if there are differences in lower back or knee kinematics when minimalist shoes are worn with and without a shoe insole during treadmill running, and 3) determine if there are differences in levels of muscle activation when minimalist shoes are worn with and without a shoe insole during treadmill running. Following the receipt of …

Agonist And Stabilizer Muscle Activity During A Push Up On Unstable Surfaces, Anthony J. Dyrek

UNLV Theses, Dissertations, Professional Papers, and Capstones

A recent trend among fitness professionals is to have clients perform resistance exercises on unstable equipment. Anecdotally, this is done with the intent that stabilizing and agonist muscles are more active while doing certain exercises on unstable surfaces. However, there are limited data as to whether or not this is the case and no studies have investigated muscle activity while doing the same exercise on surfaces that offer different levels of stability. Therefore, the purpose of this study is to measure electromyography (EMG) during push up exercise performed on unstable surfaces as well as on the ground. Surface EMG was …

Development Of Software To Estimate Pressures On The Residual Limbs Of Amputees By Means Of A Pylon Mounted Transducer, Malli K. Yalamanchili

UNLV Theses, Dissertations, Professional Papers, and Capstones

The alignment of prosthesis has been recognized as one of the main factors that determine successful prosthetic outcomes for trans-tibial amputees. Alignment is defined as the relative position and orientation of the prosthetic components. Misalignment can result in changes in the position and orientation of the joints of the leg and moments experienced by them during gait, increases in energy use, and discomfort or even tissue breakdown at the socket/stump interface. Hence it is very important to align the prosthesis in correct manner. Gait analysis can be used to examine the effects of incorrect alignment of the prosthesis during gait. …

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 …

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 …

The Effect Of Concurrent Cell Phone Use And Walking On Gait Characteristics, Jennifer Marie Aldridge

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study examined the effects that cell phone use has on gait and situation awareness. Subjects (n=18; 24.67±3.60 yrs) completed three five-minute treadmill walking conditions (self-selected speed): (1) CONTROL (walking only), (2) TALK (walking and talking), and (3) TEXT (walking and texting). The number of detected lights presented in the visual field was recorded, as were kinematic data of the feet. Using a one-way repeated measure ANOVA it was determined light detection (F _(2,17) =39.777, p<0.001) and TC_min (F_(2,17) =8.574, p=0.001) were different between conditions. Specifically, light detection decreased during TEXT (2.6±2.2 lights) versus TALK (5.8±0.05 lights, p<0.001) or CONTROL (5.9±0.05 lights, p<0.001); TC_min decreased …