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Biomechanics Commons

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Full-Text Articles in Biomechanics

Using Music To Modify Step-Rate And Running Biomechanics In Healthy Runners, Erin Marie Lally Aug 2023

Using Music To Modify Step-Rate And Running Biomechanics In Healthy Runners, Erin Marie Lally

Theses and Dissertations

Context: Running-related injury (RRI) is a significant public health issue that may be caused by injurious running biomechanics. Increasing step-rate (SR) using gait retraining may prevent and treat RRI. The Optimizing Performance Through Intrinsic Motivation and Attention for Learning (OPTIMAL) theory indicates enhanced expectancies, autonomy, and external focus of attention will optimize motor learning. Music has been shown to create enhanced expectancies, can provide incidental choices (autonomy), directs attention externally, and may increase compliance. No studies have investigated if music can be used to alter SR and running biomechanics or strategies that may improve compliance to gait retraining. Objective: The …


The Effects Of Task Complexity On Knee Mechanics And Joint Coordination Variability During A Side-Step Cutting Task, Carter Michael Schmitz Aug 2023

The Effects Of Task Complexity On Knee Mechanics And Joint Coordination Variability During A Side-Step Cutting Task, Carter Michael Schmitz

Theses and Dissertations

Injury to the anterior cruciate ligament (ACL) is a very common and debilitating injury suffered by athletes of all ages, genders, and abilities. Practitioners attempt to minimize risks by implementing ACL prevention programs designed to physically prepare athletes for the demands of sport, however, the success of these programs is very inconsistent. The majority of past ACL prevention programs prioritize constrained run and cut activities, the removal of motor variability - attempting to “idealize” mechanics - and limited task complexity. Due to the inherent complexities that exist within sport, it is possible that more task complexity and motor variability is …


The Effects Of Cheerleading Surfaces On Landing Characteristics During Vertical And Flip Landings, Anthony Vu Nguyen Aug 2022

The Effects Of Cheerleading Surfaces On Landing Characteristics During Vertical And Flip Landings, Anthony Vu Nguyen

Theses and Dissertations

Lateral ankle sprains are common injuries in cheerleading and typically occurring during tumbling. The landing surface can impact injury risk by modulating loading parameters and risky joint positions. Most surface-landing studies have used vertical landing tasks to study acrobatic populations, and few studies have compared vertical and flipping tasks. Therefore, the purpose of this study was to compare the effects of two cheerleading surfaces between vertical drop landing and flip landing tasks. Doing so explained surface characteristic influences on landing and the validity of using vertical landing tasks to represent acrobatic sports. Twelve collegiate cheerleaders (7 females, 5 males; age: …


Full-Body Biomechanical Characterization Of Children With Hypermobile Ehlers-Danlos Syndrome During Gait And Activities Of Daily Living, Anahita Alahmoradiqashqai May 2022

Full-Body Biomechanical Characterization Of Children With Hypermobile Ehlers-Danlos Syndrome During Gait And Activities Of Daily Living, Anahita Alahmoradiqashqai

Theses and Dissertations

Hypermobile Ehlers-Danlos syndrome (hEDS) is an inherited connective tissue disorder, often under-diagnosed, and presenting with frequent chronic pain and severe musculoskeletal symptoms that can drastically reduce the quality of life during one’s life span. While there are limited quantitative approaches in the literature on adult movements, the biomechanics of movements during activities of daily living (ADLs) in children have not been investigated comprehensively. Therefore, the primary purpose of this dissertation was to characterize the biomechanics of the musculoskeletal system and investigate the biomechanics of hEDS by quantifying joint dynamics and muscle activations during ADLs and gait in the pediatric population. …


Effects Of Seat And Axle Position On Pain, Pathology, And Independence In Pediatric Manual Wheelchair Users With Spinal Cord Injury, Hannah Frank Dec 2021

Effects Of Seat And Axle Position On Pain, Pathology, And Independence In Pediatric Manual Wheelchair Users With Spinal Cord Injury, Hannah Frank

Theses and Dissertations

Manual wheelchair (MWC) users with spinal cord injury (SCI) rely heavily on their upperextremities to complete daily occupations. Due to repetitive shoulder use during wheelchair mobility and propulsion, MWC users are at greater risk of shoulder pain and shoulder pathology, and thus decreased independence, and lower quality of life. The relative fit of the wheelchair and its parameters are critical and can further impact the user’s propulsion biomechanics. Parameters such as seat angle and axle position may put the user in detrimental shoulder positions for longer periods of time, impacting health outcomes even more. Although the effects of wheelchair setup …


Central Sensitization, Muscle Function, And Knee Kinematics In Females With Patellofemoral Pain, Kemery Jean Sigmund Dec 2021

Central Sensitization, Muscle Function, And Knee Kinematics In Females With Patellofemoral Pain, Kemery Jean Sigmund

Theses and Dissertations

Context: Females with patellofemoral pain (PFP) are at higher risk, have higher rates, and experience worse long-term outcomes than males. Structural and functional changes have been observed in pain networks and neuromuscular systems in individuals with PFP. Central sensitization describes dysfunctional pain modulation which could lead to altered neuromuscular control. Evidence examining relationships between central sensitization and muscle function in PFP is lacking.

Objective: The purpose of this study is to determine whether females with PFP exhibit signs of central sensitization compared to pain-free females. Then, after grouping each individual based on her quantitative sensory test results into a centrally …


Upper Extremity Kinematics And Pain Outcomes During Activities Of Daily Living In Pediatric Hypermobile Ehlers-Danlos Syndrome, Olivia Yanez Wilwert Dec 2020

Upper Extremity Kinematics And Pain Outcomes During Activities Of Daily Living In Pediatric Hypermobile Ehlers-Danlos Syndrome, Olivia Yanez Wilwert

Theses and Dissertations

Ehlers-Danlos syndrome (EDS) is a group of heritable connective tissue disorders, consisting of thirteen different subtypes. Among the thirteen, Hypermobile Ehlers Danlos Syndrome (hEDS) is the most common. Individuals with this condition present with frequent joint instability that results in ongoing subluxations and dislocations. Secondary diagnoses of this condition include chronic pain, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), Major Depressive Disorder (MDD), and Generalized Anxiety Disorder (GAD). The diagnostic process of hEDS is convoluted by the lack of a genetic identifier (Malfait et al., 2017). Individuals with hEDS are often not diagnosed until later in adulthood, leaving their adolescent life full …


The Effect Of Kinesiology Tape Application Duration On Endurance Of Knee During An Isotonic Fatiguing Flexion/Extension Exercise, En Yi Wu Aug 2020

The Effect Of Kinesiology Tape Application Duration On Endurance Of Knee During An Isotonic Fatiguing Flexion/Extension Exercise, En Yi Wu

Theses and Dissertations

Kinesiology Tape (KT) is an elastic athletic tape and is popular among athletes as it was claimed that it can to be worn for several days and is capable of preventing injuries, improving rehabilitation processes, improving muscle oxygenation levels, and enhancing muscle performance. The goal of this study was to determine if there was any potential enhancing effect of KT on joint endurance in healthy subjects, in particular with respect to time to fatigue (TTF), muscle oxygenation, and muscle activity in fatiguing knee flexion/extension exercise across sessions.

Fourteen healthy male subjects with no previous history of knee injury participated in …


Use Of Wearable Technology To Detect And Alter Subtle Gait Asymmetries Following Anterior Cruciate Ligament Reconstruction, Alexander Matthew Morgan Aug 2020

Use Of Wearable Technology To Detect And Alter Subtle Gait Asymmetries Following Anterior Cruciate Ligament Reconstruction, Alexander Matthew Morgan

Theses and Dissertations

Knee osteoarthritis is a significant problem post-anterior cruciate ligament (ACL) reconstruction. Knee osteoarthritis can develop due to subtle changes in knee mechanics that affect loading on knee joint cartilage. Gait deficits during the loading phase have been observed up to four years post-surgery. However, changes in peak shank angular velocity have not been established long-term post-surgery. Peak shank angular velocity could be increased via an inertial measurement unit (IMU) based-biofeedback protocol to ultimately improve knee mechanics. Therefore, the objective of this project was to understand gait characteristics one to four years post-ACL reconstruction and to examine the effect of an …


Transition Step Mechanics: How Influential Are Age And Fall History?, Emily Elizabeth Gerstle May 2020

Transition Step Mechanics: How Influential Are Age And Fall History?, Emily Elizabeth Gerstle

Theses and Dissertations

The purpose of this dissertation was to identify modifiable lower extremity kinematic and neuromuscular factors associated with step clearance and foot placement during transition step negotiation in older adult females with a history of falling. Specifically a full understanding of the contributions of bilateral joints of the hip, knee, and ankle during step clearance and landing was investigated (Chapter 2). Additionally to further understand how the task is accomplished, we examined the neuromuscular demands required to perform the previously mentioned kinematics (Chapter 3). Finally, to expand upon the knowledge of the multi-segment foot, the kinematics of the distal foot were …


Characterizing The Material Properties Of Abdominal Organs, Blake Allen Johnson Dec 2019

Characterizing The Material Properties Of Abdominal Organs, Blake Allen Johnson

Theses and Dissertations

Understanding the behavior of abdominal organs under load will greatly improve several fields involving injury biomechanics. In order to determine the behavior of abdominal organs under load and be able to predict the response, the mechanical properties need to be properly characterized. The characterization of these properties will provide researchers the ability to create finite element models that will provide a better understanding of the mechanism of injury resulting from traumatic events.

Finite element models of today, that simulate traumatic injuries, lack properly characterized material properties. The current body of literature contains a large range of material property values which …


Sexual Dimorphism And The Shape Of The Proximal Tibia In A Radiographic Sample, Emily Eiseman Dec 2019

Sexual Dimorphism And The Shape Of The Proximal Tibia In A Radiographic Sample, Emily Eiseman

Theses and Dissertations

SEXUAL DIMORPHISM AND THE SHAPE OF THE PROXIMAL TIBIA IN A RADIOGRAPHIC SAMPLE

This study investigates the use of radiographs to determine sexual dimorphism in the shape of the tibia. The goal of the research was to identify a small set of markers that would allow researchers to efficiently and accurately determine a person’s sex from a radiograph of the proximal tibia.

The sample consisted of radiographs including 75 females and 46 males ranging in age from 21 to 81. Measurements were taken on 27 points around the area of the knee including the tibia, patella, and femur. The measurements …


Multi-Tap Extended Kalman Filter For A Periodic Waveform With Uncertain Frequency And Waveform Shape, And Data Dropouts, Justin Saboury Aug 2019

Multi-Tap Extended Kalman Filter For A Periodic Waveform With Uncertain Frequency And Waveform Shape, And Data Dropouts, Justin Saboury

Theses and Dissertations

Gait analysis presents the challenge of detecting a periodic waveform in the presence of time varying frequency, amplitude, DC offset, and waveform shape, with acquisition gaps from partial occlusions. The combination of all of these components presents a formidable challenge. The Extended Kalman Filter for this system model has six states, which makes it weakly identifiable within the standard Extended Kalman Filter network. In this work, a novel robust Extended Kalman Filter-based approach is presented and evaluated for clinical use in gait analysis. The novel aspect of the proposed method is that at each sample, the present and several past …


Quantitative Evaluation Of Geared Manual Wheelchair Mobility In Individuals With Spinal Cord Injury: An Integrative Approach, Omid Jahanian May 2019

Quantitative Evaluation Of Geared Manual Wheelchair Mobility In Individuals With Spinal Cord Injury: An Integrative Approach, Omid Jahanian

Theses and Dissertations

The purpose of this dissertation is to quantify the effects of using geared wheelchair wheels on upper extremity biomechanics and energy expenditure during functional mobility tasks in individuals with spinal cord injury (SCI). The effects of using geared wheels on hand-rim biomechanics, glenohumeral joint dynamics, and shoulder muscle activity were investigated during manual wheelchair propulsion over tiled and carpeted level-floors and up a ramp in low gear (1.5:1) and standard gear (1:1) conditions. The results for the hand-rim biomechanics indicated that regardless of the terrain, using the geared wheels in the low gear condition significantly decreased the propulsion speed, stroke …


Investigating The Hip And Trunk Kinematic And Strength Differences Between Those With A History Of Exertional Medial Tibial Pain And Healthy Controls, Allison Hocking Aug 2018

Investigating The Hip And Trunk Kinematic And Strength Differences Between Those With A History Of Exertional Medial Tibial Pain And Healthy Controls, Allison Hocking

Theses and Dissertations

Introduction: Exertional medial tibial pain (EMTP) has been shown to be one of the leading injuries in females who have weakened hip strength. Increased trunk and hip kinematic excursion and decreased hip external rotation and hip abductor strength are related to injury in the athletic population but there is a lack of research in the role of hip strength in the development of exertional medial tibial pain in competitive female runners. Purpose: Therefore, the purpose of this study is to investigate differences in hip strength, hip kinematics, and trunk kinematics between those with a previous history of exertional medial tibial …


Novel Algorithms For Merging Computational Fluid Dynamics And 4d Flow Mri, Ali Bakhshinejad Aug 2018

Novel Algorithms For Merging Computational Fluid Dynamics And 4d Flow Mri, Ali Bakhshinejad

Theses and Dissertations

Time-resolved three-dimensional spatial encoding combined with three-directional velocity-encoded phase contrast magnetic resonance imaging (termed as 4D flow MRI), can provide valuable information for diagnosis, treatment, and monitoring of vascular diseases. The accuracy of this technique, however, is limited by errors in flow estimation due to acquisition noise as well as systematic errors. Furthermore, available spatial resolution is limited to 1.5mm - 3mm and temporal resolution is limited to 30-40ms. This is often grossly inadequate to resolve flow details in small arteries, such as those in cerebral circulation. Recently, there have been efforts to address the limitations of the spatial and …


An Array Of Circular Dielectrophoresis Traps To Separate And Charaterize Individual Microparticles From Population, Hwangjae Lee Aug 2017

An Array Of Circular Dielectrophoresis Traps To Separate And Charaterize Individual Microparticles From Population, Hwangjae Lee

Theses and Dissertations

Dielectrophoretic traps have been broadly studied in light of their many advantages of high controllability, ease of operation, and high efficiency. In the previous studies, however, it was challenging to count captured particles or required work to capture particles. In the thesis, an array of circular dielectrophoresis (DEP) traps was developed and tested to manipulate population of microparticles in single particle level. The circular DEP traps enable more precise control of the force field than conventionally used interdigitated electrodes due to its omnidirectional and symmetric properties. The location of the captured microparticle inside the trap was confirmed by both of …


Identifying Gait Deficits In Stroke Patients Using Inertial Sensors, Lauren Benson Aug 2016

Identifying Gait Deficits In Stroke Patients Using Inertial Sensors, Lauren Benson

Theses and Dissertations

Falls remain a significant problem for stroke patients. Tripping, the main cause of falls, occurs when there is insufficient clearance between the foot and ground. Based on an individual’s gait deficits, different joint angles and coordination patterns are necessary to achieve adequate foot clearance during walking. However, gait deficits are typically only quantified in a research or clinical setting, and it would be helpful to use wearable devices – such as accelerometers – to quantify gait disorders in real-world situations. Therefore, the objective of this project was to understand gait characteristics that influence the risk of tripping, and to detect …


Investigation Of Neural Mechanisms Of Grip Relaxation, Binal Motawar May 2016

Investigation Of Neural Mechanisms Of Grip Relaxation, Binal Motawar

Theses and Dissertations

Neural mechanisms for grip relaxation are relatively unknown and understudied, as compared to mechanisms for grip initiation. Yet, termination of motor activity is as important as initiation in daily function. This knowledge gap presents incomplete understanding of neural control of hand function and its impairment with aging and neurologic disorders. The purpose of this dissertation was to identify and examine neural mechanisms of grip relaxation in healthy young adults, with aging, and in chronic stroke survivors. A series of experiments in healthy young adults showed that the relaxation from a maximum power grip was mediated by increase in the short-interval …


A Study Of The Hydrostatic And Hydrodynamic Properties Of Aeoliscus Straigatus, Jeremy J. Keifenheim May 2016

A Study Of The Hydrostatic And Hydrodynamic Properties Of Aeoliscus Straigatus, Jeremy J. Keifenheim

Theses and Dissertations

Aeoliscus strigatus is a highly maneuverable fish found in the Indo-Pacific region. It boasts a unique head down posture and employs median paired fin propulsion to perform precise movements. The need for highly maneuverable underwater AUVs for exploration and testing drove the examination of the hydrostatics and hydrodynamics influencing Aeoliscus. To determine the stability of Aeoliscus the center of gravity and buoyancy were found. Center of gravity was experimentally located using the three plumb line method while center of buoyancy was located using two separate methods. The first method utilized the measured buoyant force, a rigidly mounted fish and a …


Foot Kinematics And Neuromuscular Preactivation In Habitual Forefoot And Rearfoot Runners, Rhiannon Seneli May 2016

Foot Kinematics And Neuromuscular Preactivation In Habitual Forefoot And Rearfoot Runners, Rhiannon Seneli

Theses and Dissertations

As the rate of running related injuries has failed to decline despite advances in footwear, many researchers have begun focusing on different foot strike patterns possible contribution to injury risk. While many studies have focused on the differences between RFS and FFS running, few have investigated kinematic differences within the distal foot in habitual RFS and FFS runners and have failed to consider mechanical and neuromuscular changes due to fatigue. The purpose of this study, therefore, was to investigate foot kinematics and neuromuscular differences between RFS and FFS runners at the beginning and end of an exhaustive run. Fifteen habitual …


Upper Extremity Kinematic And Kinetic Comparison Of Anterior Versus Posterior Walkers During Functional Activities In Children With Cerebral Palsy, Chris Burckardt Dec 2015

Upper Extremity Kinematic And Kinetic Comparison Of Anterior Versus Posterior Walkers During Functional Activities In Children With Cerebral Palsy, Chris Burckardt

Theses and Dissertations

Introduction: Investigating the differences in upper extremity (UE) joint biomechanics between anterior and posterior walkers has been explored in limited contexts, even though research has shown that prolonged use of walking aids can lead to UE joint weakening or musculoskeletal injuries. Recent studies have investigated some of these differences in children with spastic diplegic cerebral palsy (CP) during gait; however, no research has been conducted that compare these UE joint biomechanical differences during functional activities or activities of daily living (ADLs). The aim of this study is to use motion analysis to compare kinematic and kinetic differences between anterior and …


Adaptation Of Moiré Phase Tracking To A Mobile Device For Field 3d Data Collections, Amar Nikhanj Dec 2015

Adaptation Of Moiré Phase Tracking To A Mobile Device For Field 3d Data Collections, Amar Nikhanj

Theses and Dissertations

The accelerating technologies of mobiles devices such as tablets and phones provide an ability to

perform high intensity calculations all while obtaining precise data with increasingly more accurate

sensors. Image metrology and 3D motion tracking can take advantage of these improvements as

they require both significant processing power and camera controls not seen in mobile devices until

very recently. This thesis discusses the development of 3D motion tracking using Google Nexus

tablets and applying the technology to the Rapid Upper Limb Assessment (RULA) to demonstrate

the technology’s application to field measurements. RULA analysis determines the stress placed on

a human …


The Development Of The Single-Leg Landing Error Scoring System (Sl-Less) For Lower Extremity Movement Screening, Maegan L. O'Connor Dec 2015

The Development Of The Single-Leg Landing Error Scoring System (Sl-Less) For Lower Extremity Movement Screening, Maegan L. O'Connor

Theses and Dissertations

Introduction: Musculoskeletal knee injuries are some of the most common sports-related injuries. Movement screening assessments are often implemented to identify high-risk individuals in order to prevent the injury and the negative long-term consequences related to sustaining these injuries. While there are numerous established field-based assessments none have shown a strong ability to predict future injury. Additionally, there is currently there is no two-dimensional (2D) screening measure to evaluate the movement of multiple body segments in more than one plane during a single-leg task. The purpose of this study was to investigate the validity and reliability of the Single-Leg Landing Error …


Entheses And Activities: The Multivariate Mechanisms Of Entheseal Change For Individuals Represented By The 2013 Excavations Of The Milwaukee County Institution Grounds Cemetery, Jessica L. Skinner Dec 2015

Entheses And Activities: The Multivariate Mechanisms Of Entheseal Change For Individuals Represented By The 2013 Excavations Of The Milwaukee County Institution Grounds Cemetery, Jessica L. Skinner

Theses and Dissertations

ABSTRACT

ENTHESES AND ACTIVITIES: THE MULTIVARIATE MECHANISMS OF ENTHESEAL CHANGE FOR INDIVIDUALS REPRESENTED BY THE 2013 EXCAVATIONS OF THE MILWAUKEE COUNTY INSTITUTION GROUNDS CEMETERY

by

Jessica L. Skinner

The University of Wisconsin-Milwaukee, 2015

Under the Supervision of Professor Fred Anapol

The analysis of the features that mark tendon and muscle insertion sites on bone has been used in an attempt to reconstruct past life activity patterns of individuals and populations represented by skeletal remains. Many of these analyses have focused on comparing evidence from these individuals with known musculoskeletal and biomechanical data. Recent experimental tests have illustrated that defining these …


Classification Of Adequate Impact Protection For Hands, Patrick Dylan Loshek Aug 2015

Classification Of Adequate Impact Protection For Hands, Patrick Dylan Loshek

Theses and Dissertations

ABSTRACT

CLASSIFICATION OF ADEQUATE

IMPACT PROTECTION FOR HANDS

by

Patrick D. Loshek

The University of Wisconsin-Milwaukee, 2015

Under the Supervision of Professor Naira Campbell-Kyureghyan

Historically, hand injuries have been a large burden for the manufacturing, construction, mining, oil and gas industries. Specially designed gloves are commonly used in industry today to protect hands from impacts. These gloves are designed to reduce hand injuries by absorbing the impact forces workers may encounter due to objects striking the hand. However, to date, there is no standard for the testing of these gloves and quantifying the force reduction a user would experience when …


Individual, Occupational And Biomechanical Factors That Affect Slip And Fall Risk From Fixed Ladders, Erika Mae Pliner Aug 2015

Individual, Occupational And Biomechanical Factors That Affect Slip And Fall Risk From Fixed Ladders, Erika Mae Pliner

Theses and Dissertations

Injuries from ladder falls are prevalent and severe. Previous research has examined certain elements of ladder falls such as the ladder base slipping, but few studies have examined the factors that contribute to climbers falling from the ladder, particularly for permanent/fixed ladders. In addition, the biomechanical response to a ladder slip/misstep during ladder climbing and the factors that affect a fall from a ladder are not well understood. This thesis is a two part study that simulated ladder slips and missteps in order to find factors 1) associated with ladder slip risk and 2) that decrease fall severity from a …


An Optimization Method For Estimating Joint Parameters Of The Hip And Knee, Ben Tesch Dec 2014

An Optimization Method For Estimating Joint Parameters Of The Hip And Knee, Ben Tesch

Theses and Dissertations

Biomechanics, generally speaking, concerns the application of engineeringprinciples to the study of living things. This work is concerned withhuman movement analysis, a subfield of biomechanics, where the methodsof classical mechanics are applied to human movement. This field hascontributed to the general understanding of human movement, and itstechniques are used in the diagnosis and treatment of disease. Centralto the field is the process of measuring human movement. Since classicalmechanics deals with the motion of rigid bodies, and ideal measurementsystem would be able to accurately record the exact pose --- combinedposition and orientation --- of the bones. The techniques that reachthis ideal …


Role Of Sensation In Altered Phalanx Grip Force In Persons With Stroke, Leah R. Enders Dec 2014

Role Of Sensation In Altered Phalanx Grip Force In Persons With Stroke, Leah R. Enders

Theses and Dissertations

Many individuals experience hand impairment after stroke leading to decreased ability to perform daily living activities. Previous research studies have investigated how stroke survivors' pinch grip control differs from healthy individuals, even though many individuals can only grasp with power grip after stroke. Furthermore, many stroke survivors experience tactile sensory deficit in their paretic limb in addition to motor deficit. It is currently unknown how stroke induced tactile sensory deficit affects power grip force directional control, which is important in terms of preventing object slippage and power grip normal force generation. Additionally it is unknown if power grip could be …


Biomechanical Evaluation Of A Jackhammering Task With And Without List Assist, Blake Allen Johnson Aug 2014

Biomechanical Evaluation Of A Jackhammering Task With And Without List Assist, Blake Allen Johnson

Theses and Dissertations

The construction and utility industries have relatively high levels of hazardous tasks that impose high physical demands on a worker. For the past decade these industry sectors had one of highest incident rates for non-fatal injuries (BLS, 2013). The task of operating a jackhammer presents several risk factors that promote the high rates of injuries to this industry sector. Until the introduction of the lift assist, relatively few interventions were available to make the task of operating a jackhammer safer. However, no research has been conducted to support that this device is able to make jackhammering safer. The aim of …