Grip strength is determined by the interaction of all the fingers working collectively. The muscle contraction of one finger generates tension in others and together they produce overall gripping strength.
The ulna and the radius are the bones of the forearm. When standing tall arms at your side, palms facing forward (standard anatomical position), the ulna is on the medial or pinky-finger side of the forearm and the radius on the index finger side. The ulna-sided digits, that is the little and ring finger contribute less than than the index and middle finger to the strength of the overall grip, approximately 40% of the force comes from the ulnar and 60% from the radial digits.
Studies estimate the percentage contributions of the index, middle, ring, and little fingers to the total grip power are approximately 25%, 35%, 25% and 15% respectively. It is important to remember that the interplay among muscle fibers increases tension in other fingers when maximizing force output and each finger’s application of force to a task can not truly be measured by the above values. If you were to grasp an object and exclude the small finger, the drop in total strength would not be 15%, but 30-35%. This exemplifies the importance of training the hands with a variety of grips and objects to maximize the potential power of each digit.
Neglect nothing – to Get Strong.
The Pendulum Grip Cart