Based on our results, a hyper-flexible spine would receive a lower peak thrust force than a hypo-flexible spine at the same power setting.
#AN IMPULSIVE FORCE OF 100 N MANUAL#
This has been a major concern in manual spinal manipulation.
#AN IMPULSIVE FORCE OF 100 N ACTIVATOR#
Moreover, the Activator V-E device provided evidence that the device performs consistently despite operator experience level. While most devices deviated from the ideal profile on the return path, the Impulse device exhibited a secondary peak.
The Activator V-E device matched the ideal half-sine thrust profile to 94%, followed by the Impulse device (84%), the Activator IV/FS (74%), and the Activator II (48%). The results indicated a significant dependence of thrust output on the compliance of the test media. We conducted two different types of testing: (1) bench testing to evaluate the devices themselves, and (2) clinical equivalent testing to determine the influence of the operator. The objectives of this study were to determine the ability of several commercial shockwave devices to achieve a desired thrust profile in a benchtop setting, determine the thrust profile in a clinical analog, and determine the influence of operator experience level on device performance. Knowledge of the performance characteristics of these devices, correlated with clinical outcome studies, may lead to better patient selection, improvement of device functionality, and knowledge of the underlying working principals of therapy. The exact mechanism by which shockwave therapy acts is not known. Targeting these frequencies has been the focus in extracorporeal shock wave lithotripsy, but these concepts are relatively new in orthopedic and rehabilitation therapies. From biomechanical studies we know that biological tissue is viscoelastic and preferably excited around its resonance frequency. While most often used to treat back pain, our understanding of their biomechanical performance is very limited. Mechanical shockwave therapy devices have been in clinical use for almost 40 years. Finally, due to the intricate relation between impedance and muscle activity, methods for the explicit expression of impedance of contractile tissue are reviewed. This is particularly relevant in the design of spring-based artificial legs and robotic arms.
For system approaches, special attention is given to methods aimed at revealing the correct and sufficient degree of nonlinearity of impedance. Methods for the derivation of mechanical impedance, both those for within the system and material-structural approaches, are reviewed. Basic questions related to the linearity and nonlinearity of impedance and to the factors that affect mechanical impedance are treated with relevance to upper and lower limb functions, joint performance, trunk stability, and seating under dynamic conditions. This review presents an updated account of the works on mechanical impedance and its relations with motor control, limb dynamics, and motion biomechanics. In the lower limb, impedance is responsible for the transmission and attenuation of impact forces in tasks of repulsive loadings.
Specifically for the upper limb, impedance enables controlling manual tasks and reaching motions. The set of impedance components, including effective mass, inertia, damping, and stiffness, is important in determining the performance of the many tasks assigned to the limbs and in counteracting undesired effects of applied loads and disturbances. A major component of impedance, stiffness, is defined as the ratio between the force change to the displacement change and is strongly related to muscle activation. The concept of mechanical impedance represents the interactive relationship between deformation kinematics and the resulting dynamics in human joints or limbs.
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