A model of muscle spasticity in opensim

Krogt, Marjolein van der; Seth, Ajay; Steele, Katherine M.; Bar‐On, Lynn; Desloovere, Kaat; Harlaar, Jaap; Delp, Scott L.

doi:10.1016/j.gaitpost.2013.07.039

Cited by 5 publications

(3 citation statements)

References 3 publications

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“…However, tuning of the muscle models based on muscle-specific (51) and subject-specific (52, 53) experimental measures and the relationship between force and intrinsic muscle properties (54) still require improvement for better accuracy. Since our aim was to characterize the neuromuscular mechanism behind the observed response using the simulation, we have not modified the neural control portion of the model with a stretch reflex controller (55) or models of spasticity (56, 57) to avoid manipulating the muscle states. As a result, simulations require validation with measured muscle activity.…”

Section: Discussionmentioning

confidence: 99%

Neuromusculoskeletal Simulation Reveals Abnormal Rectus Femoris-Gluteus Medius Coupling in Post-stroke Gait

2019

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Post-stroke gait is often accompanied by muscle impairments that result in adaptations such as hip circumduction to compensate for lack of knee flexion. Our previous work robotically enhanced knee flexion in individuals post-stroke with Stiff-Knee Gait (SKG), however, this resulted in greater circumduction, suggesting the existence of abnormal coordination in SKG. The purpose of this work is to investigate two possible mechanisms of the abnormal coordination: (1) a reflex coupling between stretched quadriceps and abductors, and (2) a coupling between volitionally activated knee flexors and abductors. We used previously collected kinematic, kinetic and EMG measures from nine participants with chronic stroke and five healthy controls during walking with and without the applied knee flexion torque perturbations in the pre-swing phase of gait in the neuromusculoskeletal simulation. The measured muscle activity was supplemented by simulated muscle activations to estimate the muscle states of the quadriceps, hamstrings and hip abductors. We used linear mixed models to investigate two hypotheses: (H1) association between quadriceps and abductor activation during an involuntary period (reflex latency) following the perturbation and (H2) association between hamstrings and abductor activation after the perturbation was removed. We observed significantly higher rectus femoris (RF) activation in stroke participants compared to healthy controls within the involuntary response period following the perturbation based on both measured (H1, p < 0.001) and simulated (H1, p = 0.022) activity. Simulated RF and gluteus medius (GMed) activations were correlated only in those with SKG, which was significantly higher compared to healthy controls (H1, p = 0.030). There was no evidence of synergistic coupling between any combination of hamstrings and hip abductors (H2, p > 0.05) when the perturbation was removed. The RF-GMed coupling suggests an underlying abnormal coordination pattern in post-stroke SKG, likely reflexive in origin. These results challenge earlier assumptions that hip circumduction in stroke is simply a kinematic adaptation due to reduced toe clearance. Instead, abnormal coordination may underlie circumduction, illustrating the deleterious role of abnormal coordination in post-stroke gait.

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Section: Discussionmentioning

confidence: 99%

Neuromusculoskeletal Simulation Reveals Abnormal Rectus Femoris-Gluteus Medius Coupling in Post-stroke Gait

2019

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“…In the study there participated only ten female fitness instructors, who performed the exercise at the same step height at one music frequency. However, in many studies [19,21,27,32,33] that address the issue of muscles properties' simulation, or analysis of step aerobics movement [15,16,24,26], the number of 10 participants is sufficient.…”

Section: Discussionmentioning

confidence: 99%

Lower limb loading during knee up in step aerobics: a pilot study

Błażkiewicz

Wiszomirska

Kaczmarczyk

et al. 2016

Biomedical Human Kinetics

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Summary Study aim:Step aerobics is a form of aerobic power distinguished from other types of aerobic exercise by its use of an elevated platform. The purpose of this study was to examine how the aerobic exercise "knee up" affects kinematic and kinetic parameters and, above all, the length of the muscle contractions. Material and methods:The study analysed ten female fitness instructors with at least six years of experience. The task consisted in the knee up move performed using a 15 cm step and music with the beat frequency of 148 BPM. Kinematic and kinetic parameters were recorded using the Vicon system synchronized with two Kistler force plates. OpenSim software was used for calculation of the length of involved muscles. Results: Ranges in angles and torques suggest that the location that is the most prone to injuries and overtraining is the knee joint, followed by the hip and ankle joints. Greater values of the vertical component of ground reaction forces were observed during stepping down, which suggests greater load to the joints. The greatest work in the move analysed in this study was performed by the sartorius muscle and the tensor fasciae latae muscle. Conclusions: Despite the benefits that have been demonstrated when step classes are structured correctly and adapted to the participants, further research is needed concerning biomechanical load, exercise prescription, and injury prevention.

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“…clinically useful insights are difficult to interpret from these investigations (Gerus et al, 2013;Liu et al, 2008;Reinbolt et al, 2011;Steele et al, 2013;Steele et al, 2010;Van Der Krogt et al, 2013).…”

Section: Literaturementioning

confidence: 99%