Adaptation to prisms can produce a change in felt arm position, termed proprioceptive shift. We studied the effects of prism-induced proprioceptive shift on interlimb rhythmic coordination performed under proprioceptive guidance, in the absence of vision. Relative to interlimb rhythmic coordination performed before prism exposure, the observed steady states of relative ...

The laws of bowling in cricket state 'a ball is fairly delivered in respect of the arm if, once the bowler's arm has reached the level of the shoulder in the delivery swing, the elbow joint is not straightened partially or completely from that point until the ball has left ...

Standard tests of murine unconditioned anxiety such as the elevated plus-maze and light-dark test are based on a dichotomy of avoidance behaviour (walled vs. open arms and dark vs. light compartments). We combined the principles of both tests by modifying the elevated plus-maze as follows: one walled arm was made ...

BACKGROUND: In patients who have an injury of the cervical spinal cord, the brachioradialis tendon may be transferred to the extensor carpi radialis brevis tendon to restore voluntary wrist extension. We hypothesized that the active range of motion of the wrist depends on the position of the elbow after this ...

Arm-raising movements at the shoulder made to overhead locations were investigated in a weight-hearing stance with forward vision available. When discrimination of different points of contact was measured after arm elevations to the unseen overhead targets, no dominant arm advantage was found, but contacts made after the shortest (90 degrees) ...

OBJECTIVE: To compare scapular orientation during both the concentric (elevation) and eccentric (lowering) phases of scapular plane abduction in subjects with and without shoulder impingement. DESIGN: Mixed model analysis of variance with one between-subjects factor (group) and within-subjects factors of phase, humeral angle, and trial. BACKGROUND: Abnormal scapular kinematics have ...

Recent findings from our laboratory suggest that a major factor distinguishing dominant from nondominant arm performance is the ability by which the effects of intersegmental dynamics are controlled by the CNS. These studies indicated that the dominant arm reliably used more torque-efficient patterns for movements made with similar speeds and ...

The primary objective of this study was to examine the kinematics and kinetics of the shoulder during wheelchair propulsion at a slow and moderate speed. Twenty-seven individuals with paraplegia propelled their wheelchairs at speeds of 0.9 m/s and 1.8 m/s while a motion analysis system captured movements of their upper ...

Influence of mechanical interactions between the shoulder and elbow on production of different coordination patterns during horizontal arm movements is investigated in the present study. Subjects performed cyclical movements along a circle and along lines of 4 different orientations. Cycling frequency was manipulated to highlight control features responsible for interactive ...

The relative contributions of scapulothoracic and glenohumeral motion at different rates of shoulder motion were studied through adduction to abduction in the scapular plane. Nineteen shoulders of 10 healthy individuals (all men, 24-30 years of age) were analyzed using an image intensifier and a high-resolution digital video system. High- and ...

We investigated the effects of ageing on balance corrections induced by sudden stance perturbations in different directions. Effects were examined in biomechanical and electromyographic (EMG) recordings from a total of 36 healthy subjects divided equally into three age groups (20-34, 35-55 and 60-75 years old). Perturbations consisted of six combinations ...

Characteristics of control at the shoulder and elbow during nine types of drawing movements were studied in the present work. The task was to repetitively track a template, depicted on a horizontal table, with the index finger at a cyclic frequency of 1.5 Hz. The templates were a circle, four ...

The effects of a radial head component on total elbow arthroplasty kinematics and stability were evaluated using an anatomic design unlinked total elbow prosthesis. An electromagnetic tracking device recorded motion and varus and valgus displacements under various conditions in 10 cadaveric elbows. The motion patterns of the intact elbows and ...

The aim of the present study was to answer the question whether adaptations to local perturbations are restricted to the perturbed limb or whether they induce a reorganization of all co-moving limbs. Specifically, we studied the adaptations in arm movements to mass perturbations in seven healthy adults during walking on ...

OBJECTIVE: To compare the effects of shoulder bracing on active joint-reposition sense in subjects with stable and unstable shoulders. DESIGN AND SETTING: Two subject groups, with stable and unstable shoulders, participated in an active joint-reposition test of the shoulder under braced and unbraced conditions. SUBJECTS: Forty subjects (22 men, 18 ...

The lever arm of the ground reaction force (GRF) about the talocrural joint axis is a functionally important indicator of the nature of foot loading. Walking initiation experiments (ten subjects; age, 23-29 years) were completed to demonstrate that rotational foot placement is a possible strategy to specify the lever arm. ...

Using two-dimensional (2D) angles composed of two straight, 8-cm-long arms that formed an angle, we investigated the importance of cutaneous feedback from the exploring index finger, and proprioceptive feedback from the shoulder (scanning movements made with the outstretched arm), to the human ability to discriminate small differences in the angles. ...

The human ability to recognize objects on the basis of their shape, as defined by active exploratory movements, is dependent on sensory feedback from mechanoreceptors located both in the skin and in deep structures ( haptic feedback). Surprisingly, we have little information about the mechanisms for integrating these different signals ...

This study used the uncontrolled manifold (UCM) approach to study joint coordination underlying the control of task-related variables important for success at reaching and pointing to targets. More combinations of joint motions are available to the control system to achieve task success than are strictly necessary. How this abundance of ...

Reaching and grasping has been widely studied in both macaques and humans, mainly with the aim of finding similar patterns of behavior in the two species. Little attention has yet been given to how morphological and behavioral differences between the two species might affect the kinematics of the movement. In ...

It is known that the illusory displacement of a vibrated limb can be transferred to a nonvibrated contacted limb. The purpose of this study was to quantify and compare the transferred illusory displacements occurring in the intrapersonal and near-personal space. In two tasks, 8 male and 8 female blindfolded subjects ...

Movements are likely guided by the nervous system in task-specific spatial frames of reference (FRs). We tested this hypothesis by analyzing fast arm pointing movements involving the trunk made to targets located within the reach of the arm. In the first experiment, subjects pointed to a motionless target and, in ...

PURPOSE: To assess the immediate effect of two different handling. techniques on range of flexion in the hemiplegic shoulder. METHOD: A randomized controlled design with within-subject comparison was used. Range of shoulder flexion was measured using a bubble goniometer. Range of passive movement was compared as the weak arm was ...

When place cells are recorded from rats running on an elevated T-maze inside a curtained enclosure that contains distinct, experimenter selected stimuli, rotations of the maze plus stimuli cause equal rotations of firing fields. Here, we examined the effects of conflicting rotations of a T-maze relative to a laboratory frame ...

Anticipatory control of upright posture is the focus of this study that combines experimental and modeling work. Individuals were asked to raise or lower their arms from two initial postures such that the final posture of the arm was at 90 degrees with respect to the body. Holding different weights ...

Using galvanic vestibular stimulation (GVS), we tested whether a change in vestibular input at the onset of goal-directed arm movements induces deviations in arm trajectory. Eight head-fixed standing subjects were instructed to reach for memorized visual targets in complete darkness. In half of the trials, randomly-selected, a 3 mA bipolar ...

STUDY DESIGN: A cross-sectional study was conducted. OBJECTIVE: To determine the activity of the deep and superficial fibers of the lumbar multifidus during voluntary movement of the arm. SUMMARY OF BACKGROUND DATA: The multifidus contributes to stability of the lumbar spine. Because the deep and superficial parts of the multifidus ...

When reaching towards objects placed outside the arm workspace, the trunk assumes an active role in transport of the hand by contributing to the extent of movement while simultaneously maintaining the direction of reach. We investigated the spatial-temporal aspects of the integration of the trunk motion into reaching. Specifically, we ...

Multijoint movements such as reaching are impaired after brain lesions involving sensorimotor areas and pathways. However, the mechanisms by which such lesions affect motor control are not fully understood. Direct effects of the lesion may be partly compensated by both the system's redundancy and its plasticity. Indeed stroke patients with ...

The extreme range of motion at the shoulder, the high angular velocities and torques, and the repetitious nature of the pitching motion combine to make the shoulder vulnerable to injury during the baseball pitch. An understanding of the biomechanics that contribute to shoulder injuries during each phase of the pitching ...

The purpose of this study was to compare upper extremity range of motion when using a straight-handled long-handled sponge versus a bent-handled long-handled sponge. Thirty-eight participants ranging in age from 20 to 55 years were randomly assigned to one of two order groups: straight-bent or bent-straight. The task involved touching ...

The effect of rhythmic cueing on spatiotemporal control of sequential reaching movements of the paretic arm was studied in 21 hemispheric stroke patients. Reaching movements were studied with and without rhythmic metronome cuing in a counterbalanced design. Metronome frequencies were entrained to the naturally selected frequency of the patient. Results ...

The extreme range of motion at the shoulder, the high angular velocities and torques, and the repetitious nature of the pitching motion combine to make the shoulder vulnerable to injury during the baseball pitch. An understanding of the biomechanics that contribute to shoulder injuries during each phase of the pitching ...

We compared the mediolateral (M/L) responses to perturbations during locomotion of vestibulopathic (VP) subjects to those of controls. Eight subjects with unilateral vestibular loss (100% Reduced Vestibular Response from the caloric test) resulting from surgery for vestibular schwannoma and 11 controls were selected for this study. Despite their known vestibulopathy, ...

The throwing shoulder in pitchers frequently exhibits a paradox of glenohumeral joint motion, in which excessive external rotation is present at the expense of decreased internal rotation. The object of this study was to determine the role of humeral head retroversion in relation to increased glenohumeral external rotation. Glenohumeral joint ...

Kinematic aspects of the reduced shooting ability of tetraplegic (TP) wheelchair basketball players were investigated and compared with those of able-bodied (AB) basketball players. TP showed significantly smaller values for the vertical component of ball release velocity (4.26 (degree/s) versus 5.45 (degree/s)) and maximum wrist flexion angular velocity (878.4 (degree/s) ...

Studies of multijoint arm movements have demonstrated that the nervous system anticipates and plans for the mechanical effects that arise from motion of the linked limb segments. The general rules by which the nervous system selects appropriate muscle activities and torques to best deal with these intersegmental effects are largely ...

In walking humans, arm to leg coordination is a well established phenomenon. The origin of this coordination, however, remains a matter for debate. It could derive from the intrinsic organisation of the human CNS, but it could also consist of a movement induced epiphenomenon. In order to establish which of ...

Based on measurements of relative phase and frequency coordination between the firings of neurons in the human central nervous system (CNS) with the single-nerve fibre action potential recording method a coordination dynamic recording method could be developed with which it is possible to measure the coordination dynamics between arms, legs ...

The goal of this work was to determine how force loads applied at the hand change the elastic mechanical properties of the arm. Endpoint stiffness, which characterizes the relationship between hand displacements and the forces required to effect those displacements, was estimated during the application of planar, stochastic displacement perturbations ...

Handedness is a prominent behavioral phenomenon that emerges from asymmetrical neural organization of human motor systems. However, the aspects of motor performance that correspond to handedness remain largely undetermined. A recent study examining interlimb differences in coordination of reaching demonstrated dominant arm advantages in controlling limb segment inertial dynamics (Sainburg ...

OBJECTIVE: The development of a thorax-fixed regression model for the shoulder which statistically predicts the orientation of the clavicle and the scapula from the humerus orientation. BACKGROUND: The application of three-dimensional position recording systems to the shoulder mechanism is limited to laboratory conditions. Studies in the field of ergonomics and ...

We have previously shown that healthy adults require a few trials to adapt to a changed ball weight during catching. It is not known whether this adaptation generalizes to the opposite arm or to different configurations of the same arm. We tested healthy adult subjects catching balls of different weight ...

The present study explored the effect of different movement orientations on the arm end-effector kinematic features, levels of muscle activity and intermuscular coordination between shoulder and elbow muscles during cyclical movement. Subjects were instructed to trace cyclical lines with their dominant arm along vertical, horizontal, and right (low inertia) or ...

Research on sensory perception now often considers more than one sense at a time. This approach reflects real-world situations, such as when a visible object touches us. Indeed, vision and touch show great interdependence: the sight of a body part can reduce tactile target detection times [1], visual and tactile ...

Two experiments were conducted in order to determine the patterns of transfer of visuomotor adaptation between arm and head pointing. An altered gain of display of pointing movements was used to induce a conflict between visual and somatosensory representations. Two subject groups participated in Experiment 1: group 1 adapted shoulder ...

Voluntary arm-raising movement performed during the upright human stance position imposes a perturbation to an already unstable bipedal posture characterised by a high body centre of mass (CoM). Inertial forces due to arm acceleration and displacement of the CoM of the arm which alters the CoM position of the whole ...

Voluntary arm movements frequently perturb body equilibrium in an upright posture. The motions of leg joints need to be coordinated according to the properties of voluntary arm movements in order to maintain body equilibrium, and this may cause a change in postural pattern. The purpose of this study was to ...

Upper-limb orthotic systems have been designed for restoring the upper-limb functions of individuals with disabilities resulting from spinal cord injury (SCI), stroke and muscular dystrophy. These systems employ either functional electrical stimulation or external power. It is proposed that, instead of time-consuming and complicated monitoring using sensors and motion analysis, ...

How allelic diversity affects neural mechanisms to produce behavioral variation is largely unknown. The elevated plus maze, consisting of open and closed arms, has been used as a model of behavioral variation in rodent exploration. Under dim illumination the nature of the sensory stimuli that influence arm choice is uncertain. ...