The Biomechanics Laboratory (178N Forker) is a 1750 square foot facility that is part of the Human Performance Laboratories housed within the Department of Kinesiology. The major pieces of laboratory equipment include:
- Twelve 450 Hz, 6 megapixel Oqus 6+ cameras for rapid, high resolution 3D tracking of retroreflective markers (Qualisys AB, Sweden)
- Two 464 mm x 508 mm AMTI force platforms are positioned centrally on a 35-m walkway (Advanced Mechanical Technology Inc., Watertown, MA)
- Two 400 mm x 600 mm portable AMTI force platforms (Advanced Mechanical Technology Inc., Watertown, MA)
- Sixteen channel wireless Delsys Trigno electromyography data collection system (Delsys, Natick, MA)
- Tactilus stretch fabric pressure sensor, 3.4” x 5”, 60 Hz, 0 – 5 psi calibration (Sensor Products, Madison, NJ)
- Opal Movement Monitoring System with two IMU sensors (APDM, Portland, OR)
- XSENSOR wireless foot pressure mapping system (X4) with foot and gait software
- Biodex System 3 Pro Orthopedic Testing & Rehabilitation System
- Exeter Research Impact Tester for simulating walking and running impacts
- Playground Clearinghouse head impact system for simulating falls onto various surfaces
- Data logger (Biomedical Monitoring) used in conjunction with accelerometers as a portable data collection system capable of high-speed recording for extended periods of time
- Vishay Instruments strain gauge measurement system for measuring principal strains are in bone
- Software: SPSS, Matlab, OpenSim, Visual 3D, QTM data collection/motion analysis software (Qualisys), EMGworks data acquisition/analysis software (Delsys)
Impact biomechanics (Dr. Tim Derrick)
The Biomechanics Laboratory has close ties with industry in the area of impacts. We have tested the cushioning properties of footwear for such organizations as Fila, Air Walk, Remington, Speedo, Wilson and the US Military. We have tested impact attenuation in gymnastics mats, vault tables and pads for companies such as Hadar Manufacturing and American Athletics. Shock attenuation has also been assessed in wheelchairs and basketball rims. Current research in this area involves the effects that the geometry of the body during the impact has on the effective mass and the impact attenuation.
Osteogenic exercise (Dr. Tim Derrick)
Older adults and astronauts during long duration spaceflight have decreased bone strength that can lead to fracture. Exercise has been shown to increase bone strength and could be used as a preventative measure if the boundaries of safe and effective use can be identified. We are using biochemical blood markers that are associated with bone resorption and formation in an effort to identify optimal patterns of impacts. We are also collecting impacts from various sport and exercise activities so that we can eventually identify those activities that produce the greatest osteogenic effect. The pattern of impacts can also play a role in stress fractures in athletes and military recruits. These are serious injuries that result in significant health care costs, lost training time, and interference with job performance and competition.
Lower extremity foot function (Dr. Tim Derrick)
Foot disorders are difficult to study in humans because the foot is complex and resistant to internal examination. We have built a machine that allows us to move the muscles and skeleton of a cadaver foot in a natural motion so that we can measure bone movements and strains. We are working on using this information to build an accurate model of the foot so that function and dysfunction can be studied.
Upper body exoskeleton assessments (Dr. Jason Gillette)
Exoskeletons are an emerging technology, but are difficult to assess using standard biomechanical and ergonomic techniques. One of our current research focus areas involves assessing a passive shoulder support exoskeleton in on-site and lab-based settings using electromyography (EMG) to quantify effects on muscle activation and fatigue. We have collaborated with an exoskeleton developer, Levitate Technologies, on how to practically and objectively test the benefits and drawbacks of an upper body exoskeleton. Field exoskeleton data collections have been completed at John Deere (multiple locations) and Toyota manufacturing sites, along with Emcor and Granite Construction work sites.
Occupational muscle fatigue (Dr. Jason Gillette)
Video and observation can predict which jobs have higher risk of fatigue, but may not take into account how much support an assistive device such as an exoskeleton provides. While field-based studies provide ‘real world’ data, lab-based studies allow for systematic testing that can be widely applied to predictive models. When assessing in the field, we measure EMG amplitudes and duty cycles to determine whether a job is above the threshold limit value (TLV) for fatigue, often with and without an exoskeleton. When using predictive models, we use IMU, video, or observational data to determine job task movements and duty cycles that are matched with lab-based EMG values for postures, tool weights, and exoskeleton usage to predict fatigue risk.
Anterior Crucicate Ligament (ACL) Injury Risk (Dr. Jason Gillette)
We study ACL injury risk factors from biomechanical and neuromotor control perspectives. Video, force platform, and anthropometric measurements are used to determine joint angles and moments during jump-land-jump movements. EMG is used to determine timing and intensity of agonist and antagonist muscle activation. Biomechanical factors such as jump entry and exit angles are manipulated to determine their effects on ACL injury risk. In addition, neuromotor control ACL injury risk factors such as decision making and response time during the jump-land-jump movement are adjusted through dynamic visual cues. The goal of these studies is to learn more about ACL injury mechanisms and how we might train to prevent such injuries.
Fatigue, Cognition, and Gait Balance Control (Dr. Li-Shan Chou)
Fatigue is a prevalent symptom in work settings and often found in the older population. It negatively impacts the quality of life and associates with elevated mortality rates in the older population. In addition, cognitive dysfunction is another important intrinsic factor of fall accidents. This study is aimed to examine effects of fatigue, induced by a laboratory-based fatigue protocol or an occupational activity, on balance control, cognitive performance, and their interaction. We will validate the use of whole-body fatigue protocol, establish biomechanical parameters used to indicate fatigue-induced balance deficits, compare these parameters before and after work in older male and female workers, and lastly, seek to establish a connection between differences in parameters and mechanisms induced by the laboratory-based fatigue protocol and occupational activity. Project outcome will identify the impact of fatigue as a risk factor for movement-related accidents, form a solid basis for future studies examining how biomechanical screening and assessment may preemptively identify individuals at risk, and help develop effective interventions to prevent fatigue-related injuries.
Gait Function, Wearable Sensor Technology and Mild Traumatic Brain Injury (mTBI) (Dr. Li-Shan Chou)
Identification of mTBI and detection of incomplete functional recovery through readily available, objective evaluation will enhance short-term operational readiness via rapid recovery, and reduce mTBI recurrence, musculoskeletal injury, and occupational mishaps. Increased long-term readiness could be achieved through reduced incidence of long-term post-concussive symptom development. Objectives of this study are to identify acceleration-based biomechanical markers associated with mTBI related gait imbalance, develop an automated grading algorithm, and package gait analysis hardware and algorithms into a smart phone-based application easily and reliably employed in the clinical or forward deployed settings.
Attention and Gait (Dr. Li-Shan Chou)
The purpose of the study is to investigate the role of visuospatial attention during walking. We use obstacle avoidance as a model to examine how humans allocate and use visual information from the environment while walking, and how the body interacts with the object while planning and executing an obstacle crossing. We employ a visuospatial attention task that provides access to examine how visuospatial attention interacts with obstacle crossing during walking. In particular, by manipulating where one is paying attention in space, we are able to probe how attention and the stepping response interact. Furthermore, we apply transcranial direct current stimulation (tDCS) in several brain sites to investigate the cortical control driven by visual attention during locomotion.
The Biomechanics Lab has collaborated on numerous projects with colleagues from industry, other disciplines, and other universities. For example:
- Erin Ward of Central Iowa Foot Clinic to establish the kinematics of foot bones during human gait and to develop a gait simulator
- Levitate Technologies to assess an upper body exoskeleton (Levitate Airframe) in assembly and construction job tasks
- Kristin Lowry of Des Moines University to program a harmonic ratio analysis using triaxial accelerometer data