DeLuca Virtual Symposium

Abstract: Mechanics is a fundamental driver of musculoskeletal adaptation, affecting material properties and morphology of tissues. Inappropriate mechanical loading is associated to maladaptation and consequent initiation and progression of numerous musculoskeletal conditions. Conversely, appropriate loading leads to improved tissue mechanical properties, and it is a desirable target to guide efficacious and personalized rehabilitation interventions and injury prevention. However, it is currently unfeasible or even impossible to directly measure some of these biomechanical quantities, preventing clinical intervention to target established mechanisms of tissue adaptation or prevent injury. Recent studies from our research group demonstrated the ability of our computational models to predict physiologically plausible mechanics of selected musculoskeletal tissues. The next challenge is enabling this same level of precision outside the research laboratory.
The Digital Athlete Australia is a computational approach combining medical imaging, electromyography, modelling of the neuromusculoskeletal system, artificial intelligence, and field-based measures to enable monitoring of tissue states (i.e., stress and strain) during activities of daily living, rehabilitation, and sport. Salient aspects of The Digital Athlete Australia development and validation will be presented, alongside current and future research directions and opportunities to apply this technology to sport performance and rehabilitation.

Title: Muscle forces and fascicle behavior during three popular hamstring exercises

Abstract: Knowledge about muscular forces and fascicle behavior during hamstring exercises can optimize exercise prescription, but information on these outcomes across different exercises is lacking. This talk will present the lower-limb muscle forces and biceps femoris long head muscle fascicle behavior during three hamstring exercises: the Nordic hamstring curl (NHC), single-leg Roman chair (RCH), and single-leg deadlift (DL). The implications of these findings for exercise prescription will also be discussed.

Title: Parasport classification – strengths, weaknesses and a way forward 

Abstract: Established in 1948, the Paralympic Movement, is a long-standing, internationally significant sports movement. Currently more than 80% of the world’s nations (164/204) compete in international para sport events and the Paralympic games is the third largest sporting event in the world. Parasport classification systems play an indispensable role in the movement. Sean Tweedy is an international authority on Para sport classification: he was an International classifier from 1993-2012, classified at four Paralympic games, has been a member of the International Paralympic committee’s Classification Compliance and Oversight Committee since 2008 and is on the World ParaAthletics Classification Advisory Group. He is also the Principal Investigator for the IPC Classification Research and Development Centre (Physical Impairment). In this presentation he will outline the indispensable role that classification plays in Para sport, the strengths of current methods of classification, some of the key weaknesses and how these might be addressed through the application of scientific principles and tailored application of current technologies.

Title: Shifting the paradigm: modelling the human for enhancing the robot.

Abstract: Neuromuscular injuries leave millions of people disabled worldwide every year. Robotics has the potential to restore a person’s movement capacity following injury. However, the impact of current technologies is hampered by the limited understanding of how robots interact the human neuromuscular system. That is, current movement-support robots such as exoskeletons interact with the human body with no feedback of how biological targets (e.g., tendons, muscles, neurons) react and adapt to robot-induced mechanical or electrical stimuli over time. This talk will outline current work conducted in my Lab to create a new framework for ‘closing-the-loop’ between wearable technology and human biology. Our approach involves combining bio-electrical recordings, numerical modeling, and real-time closed-loop control to investigate the response of the human neuro-muscular system over time to robotic interventions in vivo. This paradigm has the potential to revolutionize the development of effective and safe movement-support technologies for individuals with neuromuscular injuries.

Title: A Novel Approach to Target Functional Restoration after Spinal Cord Injury

Abstract: Spinal cord injury disconnects corticospinal axons from their motor neuron targets, resulting in devastating paralysis. Throughout life, synapses, including those that transmit spinal motor commands, can be modified by Hebbian plasticity (i.e., “neurons that fire together, wire together”) suggesting that this could be used to rebuild damaged connections. Our laboratory developed a noninvasive Hebbian stimulation protocol that targets multiple upper- and lower-limb muscles in parallel by activating spinal motor neurons a few milliseconds after the arrival of corticospinal action potentials. I will discuss a series of proof of principle studies that showed evidence for spike-timing-dependent plasticity at spinal synapses in humans with and without spinal cord injury, including the pros and cons of this novel noninvasive approach. This discussion will be followed-up by a description of the results of our clinical trials. We found that participants with chronic SCI receiving Hebbian stimulation targeting multiple limb muscles combined with exercise training improved largely than a group receiving sham stimulation in the performance of functional tasks and physiological outcomes. These improvements persisted for several months post-therapy. We propose that Hebbian stimulation represents an effective strategy to promote the recovery of multiple functions following SCI.

Title: Towards the design of lighter, smaller, and smarter prostheses

Abstract: There are nearly 1 million people with major lower limb amputations in the US currently, with a projected increase over the next decades due to increased rates of diabetes and cardiovascular disease. Asymmetry in gait patterns and an increased load on the sound limb can lead to an increase in rates of knee pain, osteoarthritis, back pain, and decreased fitness levels for people with lower limb amputation. Powered prostheses have been developed which provide physiological levels of ankle torque and power, but despite their many potential benefits are inaccessible to many due to the current lack of insurance reimbursement and high cost. These devices are also heavy, large, and noisy during operation. Passive prostheses are much more widely available and lighter than powered systems, but they provide insufficient push-off power and are unable to adapt to changing walking speeds or terrain. A third category of device exists – quasi-passive prostheses are devices that use mechanical energy to change properties of the device but do not do net positive work on the user’s stride. This talk explores the large potential benefit of quasi-passive prostheses, how we can use fundamental engineering principles to develop devices that restore key biomechanical function during walking, and the main challenges in robotic prosthesis development.