Matching Items (3)
Filtering by
- All Subjects: Biomechanics
Description
Individuals fluent in sign language who have at least one deaf parent are considered native signers while those with non-signing, hearing parents are non-native signers. Musculoskeletal pain from repetitive motion is more common from non-natives than natives. The goal of this study was twofold: 1) to examine differences in upper extremity (UE) biomechanical measures between natives and non-natives and 2) upon creating a composite measure of injury-risk unique to signers, to compare differences in scores between natives and non-natives. Non-natives were hypothesized to have less favorable biomechanical measures and composite injury-risk scores compared to natives. Dynamometry was used for measurement of strength, electromyography for ‘micro’ rest breaks and muscle tension, optical motion capture for ballistic signing, non-neutral joint angle and work envelope, a numeric pain rating scale for pain, and the modified Strain Index (SI) as a composite measure of injury-risk. There were no differences in UE strength (all p≥0.22). Natives had more rest (natives 76.38%; non-natives 26.86%; p=0.002) and less muscle tension (natives 11.53%; non-natives 48.60%; p=0.008) for non-dominant upper trapezius across the first minute of the trial. For ballistic signing, no differences were found in resultant linear segment acceleration when producing the sign for ‘again’ (natives 27.59m/s2; non-natives 21.91m/s2; p=0.20). For non-neutral joint angle, natives had more wrist flexion-extension motion when producing the sign for ‘principal’ (natives 54.93°; non-natives 46.23°; p=0.04). Work envelope demonstrated the greatest significance when determining injury-risk. Natives had a marginally greater work envelope along the z-axis (inferior-superior) across the first minute of the trial (natives 35.80cm; non-natives 30.84cm; p=0.051). Natives (30%) presented with a lower pain prevalence than non-natives (40%); however, there was no significant difference in the modified SI scores (natives 4.70 points; non-natives 3.06 points; p=0.144) and no association between presence of pain with the modified SI score (r=0.087; p=0.680). This work offers a comprehensive analysis of all the previously identified UE biomechanics unique to signers and helped to inform a composite measure of injury-risk. Use of the modified SI demonstrates promise, although its lack of association with pain does confirm that injury-risk encompasses other variables in addition to a signer’s biomechanics.
ContributorsRoman, Gretchen Anne (Author) / Swan, Pamela (Thesis advisor) / Vidt, Meghan (Committee member) / Peterson, Daniel (Committee member) / Lockhart, Thurmon (Committee member) / Ofori, Edward (Committee member) / Arizona State University (Publisher)
Created2018
Description
Research on joint control during arm movements in adults has led to the development of the Leading Joint Hypothesis (LJH), which states that the central nervous system takes advantage of interaction torque (IT) and muscle torque (MT) to produce movements with maximum efficiency in the multi-jointed limbs of the human body. A gap in knowledge exists in determining how this mature pattern of joint control develops in children. Prior research focused on the kinematics of joint control for children below the age of three; however, not much is known about interjoint coordination with respect to MT and IT in school-aged children. In the present study, joint control at the shoulder, elbow, and wrist during drawing of five shapes was investigated. A random sample of nine typically developing children ages 6 to 12 served as subjects. The task was to trace with the index finger a template placed on a horizontal table. The template consisted of a circle, horizontal, vertical, right-diagonal, and left-diagonal line. Analysis of muscle torque contribution (MTC) revealed the individual roles of MT and IT in the shoulder, elbow, and wrist joints. During drawing of the horizontal line, which requires the most difficult joint control pattern in adults because it does not allow the use of IT for joint rotation, joint control was found to change through development. For the youngest children, the function of elbow MT modified to suppress IT, thereby producing large elbow rotation. The oldest children simplified this by using the shoulder as the principal joint of movement production and with decreased assistance from the elbow. For the other four drawing movements, differences in the pattern of joint control used by all of the subjects was unaffected by an increase in age. Overall, the results suggest that in children above 6 years of age, minor changes in joint control occur during drawing of relatively simple movements. The limited effect of age that was observed could be related to the restriction of movements to the horizontal plane. For a future study, three-dimensional movements that provide more freedom in joint control due to redundancy of degrees of freedom could be more informative about developmental changes in joint coordination.
ContributorsKemmou, Nadaa (Co-author) / Way, Victoria (Co-author) / Dounskaia, Natalia (Thesis director) / Vidt, Meghan (Committee member) / School of Nutrition and Health Promotion (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
This purpose of this study was to develop reliable methods for ultrasound measurements of skeletal muscle architecture, and to identify which specific quadriceps measurements most closely relate to peak isometric torque of the leg extensors. These data were obtained as part of a larger research study and consist of 9 total subjects (4 males, 5 females; age (30.6 ± 13.6yr). Ultrasound images for muscle thickness and pennation angle were obtained for each subject during two separate testing days (separated by 5-10 days). Images were acquired at various anatomical sites of the quadriceps and each image was analyzed using Image J software. Quadriceps muscles assessed for muscle thickness and pennation angle included the vastus lateralis (VL), and vastus intermedius (VI), while rectus femoris (RF) was assessed only for muscle thickness. Peak isometric torque measurements were obtained at 60 degrees of knee angle for knee extension using an isokinetic dynamometer. Results show that the methods chosen for ultrasound measurement produced reliable inter-day results for muscle thickness and pennation angle. VL muscle thickness and pennation angle obtained at the lateral site corresponding to 39% of leg length was highly related to peak isometric torque for knee extension. The results of this study identify specific measurement sites that are related to muscle function. In addition, these data further validate that ultrasound measurement is reliable to measure muscle thickness and pennation angle in skeletal muscle.
ContributorsSkotak, Nathaniel James (Author) / Dickinson, Jared (Thesis director) / Vidt, Meghan (Committee member) / Luden, Nick (Committee member) / School of Nutrition and Health Promotion (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05