The aim of this study was to evaluate the sensorimotor interactions between unaffected and affected sides of post-stroke subjects during locomotion. In healthy subjects, stimulation of the tibial nerve during the mid-stance phase is followed by electromyography responses not only in the ipsilateral tibialis anterior, but also in the proximal arm muscles of both sides, with larger amplitudes pri...

Gait initiation (GI) involves passing from bipedal to unipedal stance. It requires a rapid movement of the center of foot pressure (CoP) towards the future swing foot and of the center of mass (CoM) in the direction of the stance foot prior to the incoming step. This anticipatory postural adjustment (APA) allows disengaging the swing leg from the ground and establishing favorable conditions for...

In running, the spring-like axial behavior of stance limbs is a well-known and remarkably general feature. Here we consider how the rotational behavior of limbs affects running stability. It is commonly observed that running animals retract their limbs just prior to ground contact, moving each foot rearward towards the ground. In this study, we employ a conservative spring-mass model to test th...

When we walk, there are infinite number of possible trajectories for leg swing. How does the brain design the trajectory? As a candidate for the strategy of the trajectory selection, we assessed the criterion of the minimization of the energy cost in this study. We computed the optimal leg trajectory that minimizes the energy cost during the swing phase under the boundary condition that enables...

The purpose of this study was to compare the effect of knee unlocked medially linked Knee-Ankle-Foot Orthoses (MLKAFO) to the conventional knee locked MLKAFO during walking by means of Functional Electrical Stimulation (FES). A 33-year-old male with complete T8 paraplegia participated in this study. The stimulator has two hand switches to change the stimulation pattern. When the switch was turn...

Energy storage and return (ESAR) foot-ankle prostheses have been developed in an effort to improve gait performance in lower-limb amputees. However, little is known about their effectiveness in providing the body segment mechanical energetics normally provided by the ankle muscles. The objective of this theoretical study was to use muscle-actuated forward dynamics simulations of unilateral tran...

This paper presents two planning methods for generating fast walking gaits for the quadruped robot RoboSimian and analyzes their feasibility and performance as a function of joint velocity limits. One approach uses a two-at-a-time swing leg motion gait, generated using preview control of the zero moment point (ZMP) on a narrow, double-support base of support. The second method uses a one-at-a-t...

In stick insects walking forwards or backwards, a treading-on-tarsus (TOT) reflex of the middle leg could be elicited by mechanical stimulation of the ipsilateral front leg tarsus. The probability of eliciting a TOT reflex in the middle leg depended on the phase of the stimulus within the middle leg's step cycle and on the position of the middle leg relative to its normal anterior and posterior...

The purpose of this study was to test the effect of arm swing on modulation of soleus H-reflexes amplitudes during walking. Fifteen subjects walked (1.07 m/s) on a treadmill in 4 arm swing conditions: 1-natural arm swing (control), 2-active restraint, 3-passive restraint, and 4-passive-assisted. Tibial nerve was electrically stimulated and soleus EMG was recorded. H-reflex amplitude was signifi...

Animals rely on an adaptive coordination of legs during walking. However, which specific mechanisms underlie coordination during natural locomotion remains largely unknown. One hypothesis is that legs can be coordinated mechanically based on a transfer of body load from one leg to another. To test this hypothesis, we simultaneously recorded leg kinematics, ground reaction forces and muscle acti...