Functional range of motion during grasp: impact of the object location

We determined the functional range of motion (F-ROM) of arm and hand joints for various functional tasks and different locations of the objects to be grasped. The data for F-ROM were collected in six healthy volunteers who used seven selected objects typical for daily activities. Subjects grasped the objects from six different locations marked at the working desk. The recorded data comprised nine hand and arm joint angles measured by Penny & Gilles flexible goniometers and torziometers during the reach/grasp/release tasks. The F-ROM was defined as the difference between the maximum and the minimum joint angle; it was calculated for each task and for each object location. The active range of motion (A-ROM) was also measured for each of nine joints´ motion. Here we present only characteristic results for the elbow flexion, the thumb adduction, and the index finger proximal-inter-phalangeal (PIP) flexion, and two object locations. In order to characterize numerically the recordings we defined the location impact (LI) and task impact (TI). There is a statistically significant difference in both indices; thus, it was possible to use the indices as a measure of the difficulty for accomplishing a task based on the location. This measure is of special importance for selecting the exercise during rehabilitation of humans with disability, as well as for assessing the improvement in function during rehabilitation.