Movement perpendicular distance for subjects who grasped the same handle in three consecutive blocks of the CWFF.

<p>Each data point represents the mean perpendicular distance over 6 movements, averaged over subjects.</p

Experimental setup.

<p>Subjects grasped the handle of the InMotion robotic device (Interactive Motion Technologies, Cambridge, MA) with their right arm abducted at the shoulder and supported by a custom made air sled. Subjects produced horizontal-plane arm movements involving shoulder and elbow rotation to guide the motion of a cursor to a series of visual targets, projected using a computer controlled LCD projector onto a screen suspended 20 cm above the hand and reflected into view by a semi-silvered mirror positioned 10 cm below the screen. This created the illusion that the targets were positioned in the plane of the subject's arm movements.</p

Mean perpendicular distance (mm) for null field movements and for initial and final performance in each force field, for subjects who grasped the same handle in all force fields and those who grasped a different handle for each force field.

<p>Values in parentheses indicate one standard deviation.</p

Experiment 2: Mean proprioceptive acuity.

<p>Mean (± 1 standard deviation) proprioceptive acuity (mm) in Experiment 2 as a function of testing location, testing direction and limb.</p

Mean perpendicular distance (mm) for catch-trials in each force field, for subjects who grasped the same handle in all force fields and those who grasped a different handle for each force field.

<p>Values in parentheses indicate one standard deviation.</p

Proprioceptive Bias as a function of limb and distance from the body.

<p>Proprioceptive bias in the left-right direction is shown as a function of distance from the body (near, middle, far) for the left and right arms, in Experiments 1 (A) and 2 (B). Data shown are averaged over lateral position.</p

Participants.

<p>Information about participants in the two experiments.</p

Movement perpendicular distance is shown over the course of movements in the CWFF, CCWFF and CWFF.

<p>Data plotted in dark grey represent subjects who grasped the same handle in all three sessions. Data plotted in light grey represent subjects who grasped a given handle shape for the CWFF and a different handle shape for the CCWFF. Each data point represents the mean perpendicular distance over 6 movements, averaged over subjects.</p

Catch-trial performance in the CWFF, CCWFF and CWFF for subjects who grasped the same handle in all three sessions (dark grey) and subjects who grasped a different handle for each force field (light grey).

<p>Each data point represents mean perpendicular distance averaged over subjects for single movements.</p

Subject Groups.

<p>Subjects were randomly assigned to one of six groups. Each group underwent proprioceptive tests at three distances from the body: 20%, 50% and 80% of their maximum reach.</p