Matching Items (10)
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- All Subjects: Biomechanics
- Creators: Peterson, Daniel
- Resource Type: Text
Description
Oscillatory perturbations with varying amplitudes and frequencies have been found to significantly affect human standing balance. However, previous studies have only applied perturbation in either the anterior-posterior (AP) or the medio-lateral (ML) directions. Little is currently known about the impacts of 2D oscillatory perturbations on postural stability, which are more commonly seen in daily life (i.e., while traveling on trains, ships, etc.). This study investigated the effects of applying 2D perturbations vs 1D perturbations on standing stability, and how increasing the frequency and amplitude of perturbation impacts postural stability. A dual-axis robotic platform was utilized to simulate various oscillatory perturbations and evaluate standing postural stability. Fifteen young healthy subjects were recruited to perform quiet stance on the platform. Impacts of perturbation direction (i.e., 1D versus 2D), amplitude, and frequency on postural stability were investigated by analyzing different stability measures, specifically AP/ML/2D Center-of-Pressure (COP) path length, AP/ML/2D Time-to-Boundary (TtB), and sway area. Standing postural stability was compromised more by 2D perturbations than 1D perturbations, evidenced by a significant increase in COP path length and sway area and decrease in TtB. Further, the stability decreased as 2D perturbation amplitude and frequency increased. A significant increase in COP path length and decrease in TtB were consistently observed as the 2D perturbation amplitude and frequency increased. However, sway area showed a considerable increase only with increasing perturbation amplitude but not with increasing frequency.
ContributorsBerrett, Lauren Ann (Author) / Lee, Hyunglae (Thesis director) / Peterson, Daniel (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / School of International Letters and Cultures (Contributor) / Dean, W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Given the importance of arm mechanics in sprinting and the utility of F-V profiles, the purpose of the following study was to determine the effects of forearm WR on the horizontal F-V profile during sprinting. To determine the effect of forearm WR on the horizontal F-V profile during sprinting, a cross-sectional, repeated measure within subjects design was used, with athletes assessed both with and without forearm WR. The WR condition used 2% BM attached to the forearms. In a randomized order, subjects performed a series of maximal effort 30 m sprints; two unloaded sprints and four with WR. Three sprints were executed from a block start: one unloaded, and two with WR. The additional three sprints were executed from a split-stance start: one unloaded and two with WR. From this study, 2%BM WR was found to significantly increase sprint times from both block and standing starts. It also significantly decreased V0 and Fsystem from a block start and Psystem from a standing start. The significance from a block start may imply the arm’s greater role during the start and acceleration phases of sprinting during that position. The overloading of V0 from a block start in the F-V profile points to forearm WR as a possible tool for athletes to use during training who are overly force dominant from a block start and need to shift their profile to V0 dominance or balance in general.
ContributorsMishra, Megna (Author) / Nolan, Nicole (Thesis director) / Feser, Erin (Committee member) / College of Health Solutions (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Shoulder injuries are common in major league baseball (MLB) players due to the explosive and unnatural throwing motion. The goal of the thesis was to provide quantitative information about factors that influence pitching outcomes, to better understand risk management of rotator cuff tears/injuries. Typically, shoulder injuries are due to the stress placed on the glenohumeral joint. While the kinetic chain and joint muscular forces produce the explosive overhead throw. There’s a vast range when it comes to shoulder injuries for pitchers. Rotator cuff injuries are common, and multiple factors contribute to either impingement/strains, tendinitis, or tears. The purpose of this study was to assess shoulder injuries sustained by MLB pitchers between 2015-2021, to identify changes between performance metrics, collected from a publicly available database for differences between pre and post injury. Selected factors of interest are: playing years in the league, injury history, average pitch types thrown for both preinjury and postinjury, release speed, release position in the x, y, and z directions, horizontal and vertical movement, horizontal and vertical positions of the ball when it crosses home plate (plate_x and plate_z), resultant velocities and accelerations, release spin rate, release extension, spin axis and return-to-sport determined by length of time spent on the injured list (IL) for more than 100 days or less than 100 days. Resultant velocities and accelerations were calculated using the provided metrics for velocity and acceleration in the x, y, z global dimensions. Resultant velocities were significant only for off-speed pitches (P= 0.053). Multiple linear regression analysis was preformed to relate ball flight kinematics (displacement, ball velocity, and acceleration), angular kinematics (spin rate and spin axis) per each pitch bin (e.g., fastballs, breaking balls, and off-speed pitches) to relate performance metrics found prior to injury and those after the sustained injury. Ball speed in miles per hour presented significance in the off-speed pitches, though spin rate was only significant for breaking ball pitches. Two distinct spin axis orientations were significant: breaking balls and off-speed pitches. The horizontal release position was significant for both fastballs and breaking balls than in the vertical release position which was significant for all pitch bins. From the analysis of variance, inferences were made to additional factors of interest that are out of the scope such as, kinematic sequence velocities and ground reaction forces.
ContributorsWalsh, McKenzie (Author) / Ofori, Edward (Thesis advisor) / Siegler, Jason (Committee member) / Peterson, Daniel (Committee member) / Arizona State University (Publisher)
Created2022
Description
This thesis work presents two separate studies:The first study assesses standing balance under various 2-dimensional (2D) compliant environments simulated using a dual-axis robotic platform and vision conditions. Directional virtual time-to-contact (VTC) measures were introduced to better characterize postural balance from both temporal and spatial aspects, and enable prediction of fall-relevant directions. Twenty healthy young adults were recruited to perform quiet standing tasks on the platform. Conventional stability measures, namely center-of-pressure (COP) path length and COP area, were also adopted for further comparisons with the proposed VTC. The results indicated that postural balance was adversely impacted, evidenced by significant decreases in VTC and increases in COP path length/area measures, as the ground compliance increased and/or in the absence of vision (ps < 0.001). Interaction effects between environment and vision were observed in VTC and COP path length measures (ps ≤ 0.05), but not COP area (p = 0.103). The estimated likelihood of falls in anterior-posterior (AP) and medio-lateral (ML) directions converged to nearly 50% (almost independent of the foot setting) as the experimental condition became significantly challenging.
The second study introduces a deep learning approach using convolutional neural network (CNN) for predicting environments based on instant observations of sway during balance tasks. COP data were collected from fourteen subjects while standing on the 2D compliant environments. Different window sizes for data segmentation were examined to identify its minimal length for reliable prediction. Commonly-used machine learning models were also tested to compare their effectiveness with that of the presented CNN model. The CNN achieved above 94.5% in the overall prediction accuracy even with 2.5-second length data, which cannot be achieved by traditional machine learning models (ps < 0.05). Increasing data length beyond 2.5 seconds slightly improved the accuracy of CNN but substantially increased training time (60% longer). Importantly, averaged normalized confusion matrices revealed that CNN is much more capable of differentiating the mid-level environmental condition.
These two studies provide new perspectives in human postural balance, which cannot be
interpreted by conventional stability analyses. Outcomes of these studies contribute to the advancement of human interactive robots/devices for fall prevention and rehabilitation.
ContributorsPhan, Vu Nguyen (Author) / Lee, Hyunglae (Thesis advisor) / Peterson, Daniel (Committee member) / Marvi, Hamidreza (Committee member) / Arizona State University (Publisher)
Created2021
Description
This thesis reviewed variables of baseball mechanics and performance as discussed in current literature. This included investigating factors of biomechanics, the health of players, and comparisons across demographics. At the biomechanical level, components of the kinetic chain were observed as the energy transferred from the lower body to the upper body. Additionally, the upper body appeared to compensate for deficits in the rotation of the trunk. Injuries to the abdominal and low back were correlated with trunk rotation, while arm injuries were traced back to overuse and fatigue. When considering experience level, variation tended to decrease. Youth players demonstrated different patterns of fatigue and different injury correlates compared to adults. At a geographic level, American pitchers may be associated with an increased risk of elbow injuries, with Japanese and Korean pitchers to shoulder injuries; these differences are thought to be due to differences in instruction. Applying this research and findings to current baseball players may help guide training and performance or continue research.
ContributorsPennebaker, Jamie (Author) / Ramos, Christopher (Thesis director) / Siegler, Jason (Committee member) / Barrett, The Honors College (Contributor) / College of Health Solutions (Contributor)
Created2022-05
Description
Multiple Sclerosis (MS) is a debilitating neurological disease that affects millions of individuals across the world. There is no current cure for the disease, so much of the patient treatment is focused on management of the disease. One of the potential effects of having MS is having a decrease in balance which leads to a greater risk in sustaining a fall. It has been found in previous studies that MS patients have slower reaction times compared to healthy controls. Furthermore, electromyography (EMG) is an effective way to measure a subject's reaction to a perturbation. This study aims to see if MS subjects can improve their reaction times through a series of perturbation-based training visits. 18 MS patients and 11 healthy controls were recruited for this study. Each subject went through two baseline visits, six training visits, and two post-assessment visits. During each visit, subjects went through a series of forward and backward perturbations from a stand to react position administered by a dual-belt perturbation treadmill. The subjects' reaction times were measured by taking the difference between the onset of the treadmill movement and the onset of the muscle activation. This muscle activation was measured by placing EMG sensors on the tibialis anterior muscle and medial gastrocnemius muscle on each leg. After running a repeated measures ANOVA test, it was found that there were no significant differences in the reaction times between MS participants and healthy controls. However, the overall trend in the data was promising, as MS patients did improve their performance in backward-stepping slightly. Adding more participants to the study could strengthen this trend. It was also found that males across both groups significantly improved their reaction times compared to females. However, it is unknown why this occurred. Future goals would be to add more participants to the study and follow-up with MS patients to see if they have a decrease in falls post-training.
ContributorsSalek, Aydin (Author) / Peterson, Daniel (Thesis director) / Lee, Hyunglae (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2024-05
Description
Low back pain (LBP) is the most common symptom leading to hospitalization and medical assistance. In the US, LBP is the fifth most prevalent case for visiting hospitals. Approximately 2.06 million LBP incidents were reported during the timeline between 2004 and 2008. Globally, LBP occurrence increased by almost 200 million from 1990 to 2017. This problem is further implicated by physical and financial constraints that impact the individual’s quality of life. The medical cost exceeded $87.6 billion, and the lifetime prevalence was 84%. This indicates that the majority of people in the US will experience this symptom. Also, LBP limits Activities of Daily Living (ADL) and possibly affects the gait and postural stability. Prior studies indicated that LBP patients have slower gait speed and postural instability. To alleviate this symptom, the epidural injection is prescribed to treat pain and improve mobility function. To evaluate the effectiveness of LBP epidural injection intervention, gait and posture stability was investigated before and after the injection. While these factors are the fundamental indicator of LBP improvement, ADL is an element that needs to be significantly considered. The physical activity level depicts a person’s dynamic movement during the day, it is essential to gather activity level that supports monitoring chronic conditions, such as LBP, osteoporosis, and falls. The objective of this study was to assess the effects of Epidural Steroid Injection (ESI) on LBP and related gait and postural stability in the pre and post-intervention status. As such, the second objective was to assess the influence of ESI on LBP, and how it influences the participant’s ADL physical activity level. The results indicated that post-ESI intervention has significantly improved LBP patient’s gait and posture stability, however, there was insufficient evidence to determine the significant disparity in the physical activity levels. In conclusion, ESI depicts significant positive effects on LBP patients’ gait and postural parameters, however, more verification is required to indicate a significant effect on ADL physical activity levels.
ContributorsMoon, Seong Hyun (Author) / Lockhart, Thurmon (Thesis advisor) / Honeycutt, Claire (Committee member) / Peterson, Daniel (Committee member) / Lee, Hyunglae (Committee member) / Soangra, Rahul (Committee member) / Arizona State University (Publisher)
Created2023
Description
Chronic ankle instability (CAI) is caused by the failure to seek treatment and rehabilitation after an acute ankle sprain. Typically, clinical assessment of ankle sprains is done under unloaded conditions, despite the fact that ankle sprains occur during weight loading. Characterization of ankle stiffness, a representation of ankle stability during weight loading, is crucial to quantify ankle stability. Patients with CAI suffer from gait asymmetry, and the descriptions of the asymmetry ratio vary widely throughout the research community. Bilateral ankle stiffness could be a systematic metric to describe the gait asymmetry of CAI patients. Additionally, women generally have higher ankle joint and ligamentous laxity than men, and lower ankle stiffness, which has been thoroughly investigated in previous literature. However, differences in bilateral ankle stiffness between sexes still need to be investigated. Using twin dual-axis robotic platforms, this study investigated the weight loading effect on ankle stiffness in the frontal plane during standing, the bilateral difference in stiffness between the dominant and non-dominant ankle, and the sex difference in bilateral ankle stiffness during standing for varying weight distribution. The group average results of 20 healthy subjects showed that ankle stiffness increased with increasing weight loading on the ankle, which is speculated to be caused by active muscle contraction and changes in passive structure due to weight loading. For the bilateral difference of the group, the statistical analysis showed that there was no significant difference between dominant and non-dominant ankle stiffness for all the weight distributions considered. Although the group average result of the difference in bilateral ankle stiffness was statistically insignificant, individual analysis confirmed the importance of subject-specific investigation of bilateral ankle stiffness, as there were more cases of dominant ankle stiffness being larger than non-dominant ankle stiffness, and the bilateral difference was subject-specific. Investigations into sex differences in bilateral ankle stiffness showed that ankle stiffness in males is significantly greater than in females, even after normalizing the stiffness by weight, which is speculated to be caused by higher joint and ligamentous laxity in females regardless of laterality.
ContributorsPaing, Soe Lin (Author) / Lee, Hyunglae (Thesis advisor) / Berman, Spring (Committee member) / Peterson, Daniel (Committee member) / Arizona State University (Publisher)
Created2023
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
Muscular weakness is a common manifestation for Stroke survivors and for patients with Anterior Cruciate Ligament reconstruction leading to reduced functional independence, especially mobility. Several rigid orthotic devices are being designed to assist mobility. However, limitations in majority of these devices are: 1) that they are constrained only to level walking applications, 2) are mostly bulky and rigid lacking user comfort. For these reasons, rehabilitation using soft-robotics can serve as a powerful modality in gait assistance and potentially accelerate functional recovery. The characteristics of soft robotic exosuit is that it’s more flexible, delivers high power to weight ratio, and conforms with the user’s body structure making it a suitable choice. This work explores the implementation of an existing soft robotic exosuit in assisting knee joint mechanism during stair ascent for patients with muscular weakness. The exosuit assists by compensating the lack of joint moment and minimizing the load on the affected limb. It consists of two I-cross-section soft pneumatic actuators encased within a sleeve along with insole sensor shoes and control electronics. The exosuit actuators were mechanically characterized at different angles, in accordance to knee flexion in stair gait, to enable the generation of the desired joint moments. A linear relation between the actuator stiffness and internal pressure as a function of the knee angle was obtained. Results from this characterization along with the insole sensor outputs were used to provide assistance to the knee joint. Analysis of stair gait with and without the exosuit ‘active’ was performed, using surface electromyography (sEMG) sensors, for two healthy participants at a slow walking speed. Preliminary user testing with the exosuit presented a promising 16% reduction in average muscular activity of Vastus Lateralis muscle and a 3.6% reduction on Gluteus Maximus muscle during the stance phase and unrestrained motion during the swing phase of ascent thereby demonstrating the applicability of the soft-inflatable exosuit in rehabilitation.
ContributorsMuthukrishnan, Niveditha (Author) / Polygerinos, Panagiotis (Thesis advisor) / Lockhart, Thurmon (Committee member) / Peterson, Daniel (Committee member) / Arizona State University (Publisher)
Created2018