In the last decade, there has been an exponential growth in the number of rehabilitation and assistive technologies for people with neuromuscular impairments. Such technologies range from wearable human movement monitoring devices to exoskeletons and rehabilitation robots aimed at maximizing motor function recovery. Most of these technologies require a comprehension of mechanical aspects of the human neuromusculoskeletal system and its interaction with the device, which can be modelled by means of multibody dynamics techniques. This keynote lecture will explore how multibody human models could be used in clinical practice to improve diagnosis and treatment of patients with movement disorders. Particularly, the lecture will discuss the different steps and challenges involved in the development of personalized neuromusculoskeletal models. Moreover, attention will be paid on how these models can be used to predict physically-consistent novel motions. Finally, two application examples that could potentially be used in real clinical practice will be presented. The first example is a computational approach to personalize controller parameters for a knee-powered lower limb exoskeleton that actively assists walking in people with spinal cord injury. The proposed method could be a better choice compared to the current trial-and-error approach based on the therapist experience. The second example is an IMU-based wearable system to capture arm kinematics in real-life conditions for pediatric patients with muscular dystrophy. This device runs a multibody kinematic model to quantify objective biomechanical metrics that could help clinicians monitor disease progression and treatment efficacy, and guide therapy decisions to maximize the patient’s mobility.

Muscle-tendon units are the actuators that drive human movement. However, despite many decades of work, we still cannot readily assess the forces that muscles transmit within the human body. Direct measurement approaches are invasive and modeling approaches require many assumptions. We have been investigating both imaging and wearable sensor approaches to characterize in vivo kinetics of muscle-tendon units. In this seminar, we will first review our use of shear wave elastography to probe spatial and load-dependent variations in tendon tissue elasticity. We then show both analytically and experimentally that, under loading, shear wave propagation in tendon increases directly with axial stress. The complexity of the relationship between wave propagation, fibrous structure, elasticity, and loading is explored through computational models of multi-layered tissues. Based on this work, we have introduced a wearable shear wave tensiometer that uses micron-scale taps and skin-mounted accelerometers to track tendon wave speeds, and hence loading, during dynamic movements. We will discuss the application of the tensiometers for investigating the biomechanics and motor control of movement, and the potential to use the technology to enhance the surgical and conservative treatment of musculoskeletal injuries and movement disorders.