Sustained Grasp Strength Characteristics What Changes with Skeletal Muscle Injuries

Background: Grasping is present in most of the activities of daily living. The estimated total use of the hands in activities of daily living is more than five hours a day, not counting work and sports activities. The hand grasp strength peak is only relevant for short durations of applied forces, in the activities. The sustained strength gives a more realistic assessment of strength capabilities, during daily tasks. Objective: To characterize the sustained grasp strength over 5 seconds, in different grasps configurations, and identify changes in these when a musculoskeletal injury is present. Patients: Thirty right-handed participants, fifteen healthy (Control Group), and fifteen injured (Experimental Group) with musculoskeletal hand conditions, on the right side, 18 men and 12 women, were integrated into this study. In both groups, there were 9 men and 6 women. Methods: The Biometrics E-link® Dynamometer G200, was used, being kilograms as the measurement unit. The test position, to assess the hand grasp sustained strength, was recommended by the American Society of Hand Therapists. The strength was collected for 5 seconds, in the right hand, on eight grasp configurations, which can be performed on the dynamometer. Results: Men have more sustained strength than women, in all the grasp configurations assessed. The Experimental Group has inferior results regarding the peak strength, and the behavior of the strength is less stable. The man obtains the maximum endurance, and it is always over zero. The Inferior Pincer and the Parallel Extension are the grasp configurations that require less strength, being both precision grasps. The Medium Wrap is the grasp configuration that requires more strength, and it is also the one that has more differences between groups, regarding the strength and the peak strength. The three strongest grasps have the same configuration being the difference in the diameter of the grabbed object. Conclusion: The strength behavior for 5 seconds is similar between participants, with or without musculoskeletal conditions, being less high, less regular, and decreasing faster when there is an injury.