Optimal Grip Research Articles

Triggering force and measurement of maximal finger flexion force

Long-term isometric and repetitive contractions including tripping a trigger as well as supporting the arms and the tools can be observed when electrically-powered tools are operated. The objective of the present laboratory study was to analyze the magnitude and ratios of the contribution of triggering force by finger II or fingers II + III as well as the contribution of holding force by fingers III + IV + V or fingers IV + V when all digits were flexed simultaneously at the maximum exertion level. The forces' contributions were studied according to: (1) grip span and (2) center mass of the tool. This study supports the idea that the index finger should not be used as the only digit for effectively tripping a trigger when tasks are performed forcefully. The isometric finger flexion strength indicated that additional help from the middle finger would double the triggering force. The highest forces, independent of triggering type, were obtained when the grip span was 50 mm, the forces decreased when the span decreased (40 mm) or increased (60 mm). A non-linear profiling of the handle fitted to optimal finger grip spans would be advantageous to increase the holding force. The resultant torque at the wrist can be lower when the center mass of the tool falls back toward the handle of the tool. On the basis of the results of this study, we recommend that the task demands for tripping a trigger for single and double finger-triggering should be smaller than 2 kg and 4 kg, respectively.

Optimal Grip Force Work/Rest Patterns Developed from a Model to Predict Localized Muscle Fatigue during Maximal and Submaximal Work

Optimal Grip Force Work/Rest Patterns Developed from a Model to Predict Localized Muscle Fatigue during Maximal and Submaximal Work

A sensory gripper using tactile sensors for object recognition, orientation control, and stable manipulation

A sensory gripper is presented which incorporates two tactile sensing matrices. The tactile sensors acquire 3D information about object contours of interest. An algorithm is presented that is used to determine the orientation of various objects lying randomly, regardless of their identity. The robot gripper is then aligned appropriately, and stable hold sites are found. Object identification is carried out if required for subsequent actions that may be desired. The sensory gripper is therefore capable of the manipulation of objects without a need for prior knowledge of their identity and from confined surroundings. An absolute moment invariant of a 3D volumetric image of an object is defined that enables its discrimination in an object-dominated environment. A database or a lookup table containing all objects within an environment is then used to obtain physical information relating to an object of interest after the process of discrimination is completed. The stability of the holding arrangement as well as the optimal grip force is determined by 3D rigid body dynamics method.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The effect of handgrip span on isometric exercise performance.

Fourteen male and eight female volunteers served as subjects in these experiments lo determine the effect of hand tool dimensions on isometric strength, endurance, the surface EMG above the active muscle, and the cardiovascular responses to isometric exercise. As reported by others, we found that for each individual, there existed one handgrip size at which he or she could exert the greatest isometric strength. Endurance was the same at any work load relative to the maximum strength for a given grip dimension. The EMG and blood pressure responses to isometric exercise were the same at any given grip span: however, the heart rate response was lowest when subjects worked with their muscles at the optimal grip span.