Pinch and the Precision Grip in Ergonomic Mice- Whats the difference?
This short presentation explains the myth concerning the pinch grip and its use with ergonomic computer mice. The two principal forms of grip and pinch and precision and there are three essential differences between them. The first is that different muscle groups predominate each from of grip. The pinch grip mainly makes use of a group of muscles which are known as extrinsic muscles. These muscles are located in the forearm and control crude movements that produce a powerful grip. The precision grip intrinsic muscles of the hand are entirely locates within the hand itself and responsible for the fine motor functions of the hand during which little power is produced.
A good example of a precision grip is where you position a key into a lock using the intrinsic muscles with little power, but then as you engage the key into the lock and turn you use a pinch grip which engages the extrinsic with high power. The second difference is that each grip involves a different type of muscle activity. The pinch grip uses static muscle activity when an object is grasped firmly in the hand without any movement of the muscles or object. The precision grip uses dynamic muscle activity when an object is held my the fingertips and moved such as when manipulating a pen. The third and cardinal difference between pinch and precision grip is that there is very little power generated in the precision grip at all.
Pinch grip is a form of power grip and involves the extrinsic muscles, static muscle activity and a lot of muscle power.The precision grip involves the intrinsic muscles, dynamic muscle activity and little muscle power. To illustrate the difference in power between the two forms of grip, the threshold at which damage appears to occur is 10 newtons which is just over 1 kg. The force to click a mouse button is generally of the order of 75 grams which is 1/13 or 0.075 of threshold force required to cause damage.
To reduce the force to re position the mouse the DXT Ergonomic Mouse has a unique ans subtle overhang above the thumb that enables the device to be lifted with less force than a button click. If the user where to attempt to hold the mouse to tightly, the mouse would initiate a click reducing the users ability to increase the force required to move the mouse.
In summary the DXT Ergonomic Mouse has been designed to use the precision grip and does not utilise the pinch grip.