Analysis of Human Gait Based on Multibody Formulations and Optimization Tools # (original) (raw)
Comparison of the Gait Biomechanical Constraints in Three Different Type of Neuromotor Damages
Frontiers in Human Neuroscience, 2022
Background and Objective: Absolute angle represents the inclination of a body segment relative to a fixed reference in space. This work compares the absolute and relative angles for exploring biomechanical gait constraints. Methods: Gait patterns of different neuromotor conditions were analyzed using 3D gait analysis: normal gait (healthy, H), Cerebral Palsy (CP), Charcot Marie Tooth (CMT) and Duchenne Muscular Dystrophy (DMD), representing central and peripheral nervous system and muscular disorders, respectively. Forty-two children underwent gait analysis: 10 children affected by CP, 10 children by CMT, 10 children by DMD and 12 healthy children. The kinematic and kinetic parameters were collected to describe the biomechanical pattern of participants' lower limbs. The absolute angles of thigh, leg and foot were calculated using the trigonometric relationship of the tangent. For each absolute series, the mean, range, maximum, minimum and initial contact were calculated. Kinematic and kinetic gait data were studied, and the results were compared with the literature. Results: Statistical analysis of the absolute angles showed how, at the local level, the single segments (thigh, leg and foot) behave differently depending on the pathology. However, if the lower limb is studied globally (sum of the kinematics of the three segments: thigh, leg and foot), a biomechanical constraint emerges. Conclusion: Each segment compensates separately for the disease deficit so as to maintain a global biomechanical invariance. Using a model of inter-joint co-variation could improve the interpretation of the clinical gait pattern.
BIOMECHANICAL CHARACTERISTICS OF WALKING OF PATIENTS WITH CEREBRAL PALSY
The main differences of the dynamic stereotype of walking of children with cerebral palsy are delayed travel of the center of gravity forward (it takes place in the second half of a step) and disorganization of the lower extremity movements (especially knees) in the vertical plane. The prevailing adduction-flexion position of legs during the locomotor cycle associated with the restriction of movements in the hip joint, is made up by more intensive bodyrocking, weakened activity in the rear push phase and its sharp increase in the fourth phase. Changes in the structure of shoulder girdle and arm movement can be considered as compensatory: vertical shoulder movements adjust to those of the center of gravity while remaining in the reversed phase to the latter. A mismatch of the elbow and wrist movements takes place - they move in the reversed phase too. We can assume that in case of patients with cerebral palsy simultaneous activity of extensor and flexor muscles is not incidental, but the key feature of the locomotion control, being both a manifestation of pathological disorders and a compensatory mechanism.
Human Movement Science, 2000
Previously, we suggested that neurological insults will change the dynamic resources available to an individual, and a pattern will emerge that is speci®ed by, and facilitates the use of the available resources [K.G. Holt, J. Obusek, S.T. Fonseca, Human Movement Science, 15 (1996) 177]. Dynamic resources refer to the sources of energy (e.g., muscular force, elasticity energy return from soft tissues, and pendulum-like transfers) that are available to an individual to perform a function. It was hypothesized that in children with spastic hemiplegic cerebral palsy (CP), neurological impairments would result in increases in global body stiness on the aected side that could be quanti®ed using an escapement-driven, damped hybrid pendulum and spring model. It was also hypothesized that increases in stiness and an assumed decrease in the forcing capability would result in, respectively, a decreased stance time on the aected side, and smaller angular displacement of the body center of mass around the ankle joint. Five children with spastic hemiplegic CP and ®ve age, height and weight matched non-disabled children walked overground at their preferred speed and at metronome-driven frequencies that were AE10% and AE20% of their preferred. Signi®cantly greater stiness on the aected limb of CP was found when compared to the non-aected limb, and to the limbs of non-disabled : S 0 1 6 7 -9 4 5 7 ( 0 0 ) 0 0 0 1 9 -1 children. Signi®cantly smaller amplitudes and shorter stance periods on the aected side were also observed. Results provide initial support for the claim that gait patterns and their adaptations re¯ect the capability of persons with disabilities to exploit the dynamic resources available to them. These ®ndings raise two issues for discussion. First, we discuss the clinical implications of the notion that dynamic resources provide a causal link between the neurologic and morphologic changes due to upper motor neuron diseases and abnormal kinematics of gait. Second, we discuss the broader implications of biomechanical modeling in the ability to lawfully capture the interplay of the relevant constraints that contribute to the emergence of speci®c movement patterns. Ó
Cerebral palsy gait, clinical importance
Mædica, 2013
Cerebral palsy refers to a lesion on an immature brain, that determines permanent neurological disorders. Knowing the exact cause of the disease does not alter the treatment management. The etiology is 2-2.5/1000 births and the rate is constant in the last 40-50 years because advances in medical technologies have permitted the survival of smaller and premature new born children. Gait analysis has four directions: kinematics (represents body movements analysis without calculating the forces), kinetics (represents body moments and forces), energy consumption (measured by oximetry), and neuromuscular activity (measured by EMG). Gait analysis can observe specific deviations in a patient, allowing us to be more accurate in motor diagnoses and treatment solutions: surgery intervention, botulinum toxin injection, use of orthosis, physical kinetic therapy, oral medications, baclofen pump.
Neuromuscular adjustments of gait associated with unstable conditions
Journal of Neurophysiology, 2015
A compact description of coordinated muscle activity is provided by the factorization of electromyographic (EMG) signals. With the use of this approach, it has consistently been shown that multimuscle activity during human locomotion can be accounted for by four to five modules, each one comprised of a basic pattern timed at a different phase of gait cycle and the weighting coefficients of synergistic muscle activations. These modules are flexible, in so far as the timing of patterns and the amplitude of weightings can change as a function of gait speed and mode. Here we consider the adjustments of the locomotor modules related to unstable walking conditions. We compared three different conditions, i.e., locomotion of healthy subjects on slippery ground (SL) and on narrow beam (NB) and of cerebellar ataxic (CA) patients on normal ground. Motor modules were computed from the EMG signals of 12 muscles of the right lower limb using non-negative matrix factorization. The unstable gait o...
Gait Pattern Recogni Tion in C Erebral P Alsy Patients Using N Eural N Etwork M Odelling
2015
Background: Interpretation of gait data obtained from modern 3D gait analysis is a challenging and time consuming task. The aim of this study was to create neural network models which can recognise the gait patterns from pre-and post-treatment and the normal ones. Neural network is a method which works on the principle of learning from experience and then uses the obtained knowledge to predict the unknowns. Methods: Twenty-eight patients with cerebral palsy were recruited as subjects whose gait was analysed in pre and post-treatment. A group of twenty-six normal subjects also participated in this study as control group. All subjects' gait was analysed using Vicon Nexus® to obtain the gait parameters and kinetic and kinematic parameters of hip, knee and ankle joints in three planes of both limbs. The gait data was used as input to create neural network models. A total of approximately 300 trials were split into 70% and 30% to train and test the models, respectively. Different models were built using different parameters. The gait modes were categorised as three patterns, i.e., normal, pre-and post-treatments. Results: The results showed that the models using all parameters or using the joint angles and moments could predict the gait patterns with approximately 95% accuracy. Some of the models e.g., the models using joint power and moments, had lower rate in recognition of gait patterns with approximately 70-90% successful ratio. Conclusion: Neural network models can be used in clinical practice to recognise the gait pattern for cerebral palsy patients.