Fine adaptive precision grip control without maximum pinch strength changes after upper limb neurodynamic mobilization

Abstract

Before and immediately after passive upper limb neurodynamic mobilizations targeting the median nerve, grip ( GF ) and load ( LF ) forces applied by the thumb, index and major fingers (three-jaw chuck pinch) were collected using a manipulandum during three different grip precision tasks: grip-lifthold- replace (GLHR), vertical oscillations (OSC), and vertical oscillations with up and down collisions (OSC/COLL/u, OSC/COLL/d). Several parameters were collected or computed from GF and LF . Maximum pinch strength and fingertips pressure sensation threshold were also examined. After the mobilizations, LF max changes from 3.2 0.4 to 3.4 0.4 N (p = 0.014), d GF from 89.0 66.6 to 102.2 59.6 N s −1 (p = 0.009), and d LF from 43.6 17.0 to 56.0 17.9 N s −1 ( p <0.001) during GLHR. LF SD changes from 0.9 0.3 to 1.0 0.2 N (p = 0.004) during OSC. LF peak changes from 17.4 8.3 to 15.1 7.5 N ( p <0.001), GF from 12.4 6.7 to 11.3 6.8 N (p = 0.033), and LF from 2.9 0.4 to 3.00 0.4 N (p = 0.018) during OSC/COLL/u. GF peak changes from 13.5 7.4 to 12.3 7.7 N (p = 0.030) and LF from 14.5 6.0 to 13.6 5.5 N (p = 0.018) during OSC/COLL/d. Sensation thresholds at index and thumb were reduced (p = 0.001, p = 0.008). Precision grip adaptations observed after the mobilizations could be partly explained by changes in cutaneous median-nerve pressure afferents from the thumb and index fingertips.