There are currently about 262,000 spinal cord injured (SCI) individuals in the United States, with roughly 12,000 new injuries sustained each year at an average age of injury of 40.2 years. Of these, at least 44% (at least 5300 cases per year) result in paraplegia. One of the most significant impairments resulting from paraplegia is the loss of mobility, particularly given the relatively young (average) age at which such injuries occur. Surveys of persons with paraplegia indicate that mobility concerns are among the most prevalent, and that chief among mobility desires is the ability to walk and stand. In addition to impaired mobility, the inability to stand and walk entails severe physiological effects, including muscular atrophy, loss of bone mineral content, frequent skin breakdown problems, increased incidence of urinary tract infection, muscle spasticity, impaired lymphatic and vascular circulation, impaired digestive operation, and reduced respiratory and cardiovascular capacities.

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Simple engineered mechanisms that can emulate human-like biomechanics are essential for robust performance of a number of engineered locomotion systems including anthropo-morphic bipedal robots lower-limb wearable exoskeletons and biologically-inspired prosthetic limbs. Ideally, successful emulation of human locomotion in artificial systems is built upon a foundation of simple models (theoretical or empirical) that can accurately characterize the normal mechanical behavior of the human limb in the gait.
The most common modern ankle-foot and knee prostheses, such as the works of Prof. Herr at MIT and Prof. Kuo at Univ. of Michigan, employ a limited number of spring stiffnesses in their design. The gait of an amputee who uses these quasi-passive compliant prostheses could approximately mimic the unaffected limb. However, the current devices still need to exhibit user and task adaptability. The success in the field of exoskeletal devices has been even more limited. Lower extremity exoskele-tons have not yet been able to augment human performance, and advanced orthoses have been mostly limited to latching mechanisms that rigidly support the joints when loaded.

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The electromyography (EMG) of a male teenager performing isokinetic exercise is conducted to realize the characteristics of femoral muscles in human knee movement. The raw EMG data of rectus femoris muscle and biceps femoris muscle are full-wave rectified to demonstrate the electromechanical delay that ranges from 50 to 100 ms. The mean of biceps femoris EMG in isokinetics knee flexion is approximately 3-4 times as much as that of rectus femoris EMG in isokinetics knee extension. The rectified EMG signals are smoothed by using moving average method to receive a linear envelope that outlines the mean trend of EMG signals. It gives a clear perspective to observe the relation between the micro-scale EMG signal and the macro-scale kinetic data. This paper presents an important basis to establish a mechanical model of muscle for human knee movement.

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National security organizations in the United States, including the armed services and the intelligence community, have developed a close relationship with the scientific establishment. The latest technology often fuels warfighting and counterintelligence capacities, providing the tactical advantages thought necessary to maintain geopolitical dominance and national security. Neuroscience has emerged as a prominent focus within this milieu, annually receiving hundreds of millions of Defense Department dollars. Its role in national security operations raises ethical issues that need to be addressed to ensure the pragmatic synthesis of ethical accountability and national security.

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Disabilities that follow cerebrovascular accidents and spinal cord injuries severely impair motor functions and thereby prevent the affected individuals from full and autonomous participation in activities of daily living. Rehabilitation therapy is needed in order to recover from those severe physical traumas. (далее…)

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