Mechanical analysis of movement plays an important role in clinical management of neurological and orthopedic conditions. There has been increasing interest in performing movement analysis in real-time, to provide immediate feedback to both therapist and patient. However, such work to date has been limited to single-joint kinematics and kinetics. Here we present a software system, named human body model (HBM), to compute joint kinematics and kinetics for a full body model with 44 degrees of freedom, in real-time, and to estimate length changes and forces in 300 muscle elements. HBM was used to analyze lower extremity function during gait in 12 able-bodied subjects. Processing speed exceeded 120 samples per second on standard PC hardware. Joint angles and moments were consistent within the group, and consistent with other studies in the literature. Estimated muscle force patterns were consistent among subjects and agreed qualitatively with electromyography, to the extent that can be expected from a biomechanical model. The real-time analysis was integrated into the D-Flow system for development of custom real-time feedback applications and into the gait real-time analysis interactive lab system for gait analysis and gait retraining.Electronic supplementary materialThe online version of this article (doi:10.1007/s11517-013-1076-z) contains supplementary material, which is available to authorized users.

Lower-extremity kinematics adapted to increased midsole hardness, surface stiffness, and running duration. Changes in limb posture at impact were interpreted as active adaptations that compensate for passive mechanical effects. The adaptations appeared to have the goal of minimizing metabolic cost at the expense of increased exposure to impact shock.

Abstract-Implanted functional electrical stimulation (FES) systems for walking are experimentally available to individuals with incomplete spinal cord injury (SCI); however, data on short-term therapeutic and functional outcomes are limited. The goal of this study was to quantify therapeutic and functional effects of an implanted FES system for walking after incomplete cervical SCI. After robotic-assisted treadmill training and overground gait training maximized his voluntary function, an individual with incomplete SCI (American Spinal Injury Association grade C, cervical level 6-7) who could stand volitionally but not step was surgically implanted with an 8-channel receiver stimulator and intramuscular electrodes. Electrodes were implanted bilaterally, recruiting iliopsoas, vastus intermedius and lateralis, tensor fasciae latae, tibialis anterior, and peroneus longus muscles. Twelve weeks of training followed limited activity post-surgery. Customized stimulation patterns addressed gait deficits via an external control unit. The system was well-tolerated and reliable. After the 12-week training, maximal walking distance increased (from 14 m to 309 m), maximal walking speed was 10 times greater (from 0.02 m/s to 0.20 m/s), and physiological cost index was 5 times less (from 44.4 beats/m to 8.6 beats/m). Voluntary locomotor function was unchanged. The implanted FES system was welltolerated, reliable, and supplemented function, allowing the participant limited community ambulation. Physiological effort decreased and maximal walking distance increased dramatically over 12 weeks.

a b s t r a c tThis paper discusses the CO 2 footprint of California's drought during 2012-2014. We show that California drought significantly increased CO 2 emissions of the energy sector by around 22 million metric tons, indicating 33% increase in the annual CO 2 emissions compared to pre-drought conditions. We argue that CO 2 emission of climate extremes deserve more attention, because their cumulative impacts on CO 2 emissions are staggering. Most countries, including the United States, do not have a comprehensive a nationwide energy-water plan to minimize their CO 2 emissions. We argue that developing a national water-energy plan under a changing climate should be prioritized in the coming years.

The purpose of this study was to investigate the influence of midsole durometer on mechanical and hematological responses during a prolonged downhill run. Twenty-four men completed a 30-min downhill run (-12% grade) wearing either soft, medium, or hard midsole shoes. Data describing mean peak tibial acceleration (PTA), stride frequency, plasma free hemoglobin, hemoglobin concentration, hematocrit, and creatine kinase (CK) were collected. While there were no significant differences in PTA among midsole durometer shoes, PTA increased by 20% after the first 5 min of the run over all other time intervals during the run (p < .05). Hemolysis showed a 50.2% increase from prerun to postrun values (p <.05). CK increased from the prerun state to 24 hr after the run (p <. 05). Downhill running, irrespective of midsole durometer, showed increased levels of legshock, hemolysis, and muscle damage over values that are present in the literature for a level running protocol.

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We present the design, control, and experimental evaluation of an energy regenerative powered transfemoral prosthesis. Our prosthesis prototype is comprised of a passive ankle and a powered knee joint. The knee joint is actuated by an ultracapacitor based regenerative drive mechanism. A novel varying impedance control approach controls the prosthesis in both the stance and swing phase of the gait cycle, while explicitly considering energy regeneration. This control method varies the impedance of the knee joint based on the amount of force exerted on the shank of the prosthesis. Furthermore, the controller promotes energy regeneration by precisely injecting a designated amount of negative damping into the system. Our control approach leads to a few tuning parameters that cover all of the gait phases for walking and all of the tested walking speeds and eliminates the need for tedious target impedance scheduling. Experimental evaluation is done with an amputee test subject walking at different speeds on a treadmill. The results validate the effectiveness of the control method. In addition, net energy regeneration is achieved while walking with near-natural gait across all speeds.

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