Abstract Archive

We show that the metabolic cost of asymmetrical walking is greater for step time asymmetry than step length asymmetry and that the costs are not additive; rather, the metabolic cost of walking with concurrent step time and step length asymmetry is best explained by the cost of step time asymmetry al...

Human-in-the-loop optimization is a powerful strategy for customizing exoskeleton assistance for an individual, but optimization of many control parameters becomes resource-intensive. We used simulations to determine if coupling assistance between lower-limb degrees-of-freedom (DOFs) could produce l...

By studying the biomechanical structures and neuromuscular control underlying movement, we can discover strategies to prevent injury, treat disease, and enhance performance. We developed OpenSim 4.0 to model human movement and to simulate the effects of surgery and devices on performance. We are enh...

Like breathing, standing balance is mostly effortless but the motion related to maintaining an upright posture can be perceived consciously. Because standing balance involves subcortical processes, the motion perceived while maintaining standing balance may differ from the motion detected by the bal...

Chiari type I malformations (Chiari I) are congenital deformities characterized by migration of the cerebellar tonsils through the foramen magnum. The condition is associated with headaches, chronic fatigue syndrome, orthostatic intolerance, and other neurologic syndromes. Despite patients’ descri...

The gross metabolic cost of walking was predicted based on dynamic simulations generated using a 3-D musculoskeletal model. While predicted costs were reasonable, the magnitude was sensitive to how closely the simulations matched the experimental data, and were also likely elevated due to simplifica...

Lower-limb amputees are at an increased risk for falls due to balance impairments and lack of sensory feedback. Dysvascular amputation is especially associated with a lack of sensory feedback from both limbs, although studies measuring balance impairments after amputation have primarily focused on t...

The purpose of this study was to compare knee joint moments, kinematics and muscle activation between male and female team sport athletes during unanticipated sidestepping to further the understanding of sex-specific differences and their potential influence on anterior cruciate ligament (ACL) injur...

The human gait dynamics in sagittal plane can be reproduced by a spring-loaded inverted pendulum (SLIP) model. If the center of mass (CoM) dynamics in frontal plane are describable by spring-mass dynamics, 3D expansion of the SLIP model will be valid. In this paper, we described CoM dynamics of fron...

Development of gait and balance dysfunction is part of the progressive nature of Parkinson’s Disease (PD). Balance dysfunction is often self-reported by individuals only after it has developed. Greater postural sway by individuals with PD has been shown even early in disease progression and thus m...

Muscle excitations are distributed heterogeneously within the muscle, resulting in local differences in the amplitude of surface electromyograms. The functional significance of regionalized muscle excitation may be studied with high-density recordings, but these data are high-dimensional, making the...

Professional player feedback and regulations implemented by the National Hockey League (NHL) dictate equipment modifications for ice hockey goaltenders. Recent regulation changes for goaltender chest and arm equipment in the NHL has sparked concern about player safety and performance. The objective ...

Designing wearable devices for use on deformable terrain is an ongoing engineering challenge. This is particularly apparent when we examine locomotion on dissipative surfaces such as sand or snow. These surfaces have complex, variable dynamics which lead to increased fatigue and metabolic cost durin...

A rotating platform (RP) total knee replacement (TKR) design increased total contact area and reduced peak contact pressures compared to a fixed-bearing (FB) design in a finite element analysis (FEA) of turning gait. Considering physiological knee biomechanics through FEA may provide important desig...

Muscle weakness due to disuse could impair the ability of older adults to prevent a backward fall. A musculoskeletal model is thus being used to predict the effect of strength training of selected muscle groups on older adults’ ability to restore static balance after a recovery step from a backwar...

The study of the coordination of classical ballet dancers is of great relevance because this group does activities that can generate a higher asymmetric overuse in certain joints or muscles. The aim of this study is to evaluate the coordination variability in the classical ballet dancers during runn...

This study reports the effectiveness of a 6-week ankle training program using a stiffness-controlled robotic platform on paretic ankle motor control and lower extremity function in stroke patients. Two chronic stroke subjects with right hemiparesis participated in training for 12 sessions over 6 wee...

This study described the short term effects of breast cancer surgery (BCS) on scapula kinematics, perceived pain and shoulder disabilities after two months of upper limb rehabilitation (PT). Five patients received PT in the first week following BCS and were evaluated twice in baseline (B), after a m...

Diabetes mellitus (DM) is the most common metabolic disorder worldwide that might be associated with peripheral neuropathy (DPN). This study aimed to compare the spatiotemporal and impulse characteristics of DM and DPN patients during gait. Using electrodiagnostic test, DPN patients were distinguish...

Summary: Residual torque depression (TD) refers to the deficit in isometric torque following active muscle shortening, and has been associated with increased spinal excitability. In support of these observations, we demonstrated that tendon-evoked reflexes are attenuated in the TD state, which is at...

The purpose of this investigation was to determine whether parameters which describe the rate of collagen fibre damage accumulation in a collagen distribution model are dependent on the strain-rate. Fifty rat tail tendons were subjected to one of five different strain rates until failure. Using a co...

This study tests the feasibility of a cost-effective concept for measuring plantar pressure in people with diabetic foot during activities of daily living. A 3D-printable cushioning material with complex mechanical behaviour was produced and tested. The results indicated that mapping the changes in ...

The effect of trochlear groove depth on lateral patellar stability following simulated tibial tubercle osteotomy was investigated using a combined statistical shape modelling and musculoskeletal simulation approach. Knee models with trochlear grooves ranging from shallow to deep were generated using...

In patients with Diabetes, the accurate identification of plantar regions with abnormal loading is a crucial issue in the plantar ulcer prevention program[1,2]. We designed a peculiar mask to complement the validated anatomical mask based on the Oxford Foot Model (OFM) with a more specific forefoot ...

Aims of this study is to classify degenerative osteoarthritis patients by logistic regression and neural network techniques using only 3-axis (medial-lateral, anterior-posterior, vertical) GRF (ground reaction force) and to develop an algorithm for predicting degenerative osteoarthritis. This test w...

The present study was aimed to investigate effects of kinematics of the knee and hip joints on energy cost during supporting phase in different slope running. Twelve male middle- and long-distance runners were asked to run for three minutes on a treadmill at the speed of 13.5 km/h under three differ...

Endurance athletes commonly believe that shifting from running to cycling participation will reduce injury risk. However, overuse injury rates in these two sports are very similar [1,2]. A dynamical systems approach was performed to assess how segment coordination variability differs between running...

Simulation studies of human gait often model a single subject. Here we show that categorically different results from the population-level result were seen in 36% of N = 200 simulated subjects, including the "average" subject, when simulating the metabolic cost of walking with transtibial limb los...

The purpose of the study was to assess the accuracy of measuring knee kinematics using 3D fluoroscopy with statistical shape models (SSM) of the bones to minimize radiation. The accuracy was determined by comparing results between SSM and CT bone models. The results showed that 3D knee kinematics us...

The Concurrent Optimization of Muscle Activations and Kinematics (COMAK) simulation routine to predict knee joint mechanics during movement was implemented in OpenSim. We will present the underlying theory of COMAK and the relevant sensitivity analyses and in vivo validation studies.