[Assessment of force patterns of different primary grips through dynamic force measurement using a sensor glove]

The present study analyses force distribution patterns during primary grips. 10 subjects were examined using the TUB-sensor glove, which was equipped with 10 pressure sensors. 5 proximal sensors at the MCP joints and 5 distal sensors at the DIP joints were attached palmarly. 9 different gripping motions were examined: the cylinder grip using 4 different objects, the pinch grip and 4 different kinds of precision grips. The force distribution patterns can be clearly divided into 2 groups. On the one hand there are the "power grips", in which the force is distributed over the proximal and distal sensors. On the other hand there are the "precision grips", which only show a force distribution at the distal sensors. Therefore Napier's concept of the existence of primarily 2 gripping patterns, which is based on visual analysis, can be verified objectively. For the "power grips" the force distribution is shifted further distally with increasing size of the objects. In conclusion, their distribution pattern shifts towards the pattern of the "precision grips". At the small finger the distal sensor is already dominant during the "power grips" of smaller objects. The thumb plays a subordinate role during the "power grip" of smaller objects, since these grips are similar to the "closing fist motion" and the objects can be held between the fingers and the palm of the hand. However, with increasing object sizes the thumb gains more importance, since its opposing movement is now required to accomplish the grip.