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

Abstract

AbstractBefore and immediately after passive upper limb neurodynamic mobilizations targeting the median nerve, grip ($$G_F$$ G F ) and load ($$L_F$$ L F ) 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-lift-hold-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 $$G_F$$ G F and $$L_F$$ L F . Maximum pinch strength and fingertips pressure sensation threshold were also examined. After the mobilizations, $$L_F$$ L F max changes from 3.2 ± 0.4 to 3.4 ± 0.4 N (p = 0.014), d$$G_F$$ G F from 89.0 ± 66.6 to 102.2 ± 59.6 $$N~\text{s}^{-1}$$ N s - 1 (p = 0.009), and d$$L_F$$ L F from 43.6 ± 17.0 to 56.0 ± 17.9 $$N~\text{s}^{-1}$$ N s - 1 ($$p<$$ p < 0.001) during GLHR. $$L_F$$ L F SD changes from 0.9 ± 0.3 to 1.0 ± 0.2 N (p = 0.004) during OSC. $$L_F$$ L F peak changes from 17.4 ± 8.3 to 15.1 ± 7.5 N ($$p<$$ p < 0.001), $$G_F$$ G F from 12.4 ± 6.7 to 11.3 ± 6.8 N (p = 0.033), and $$L_F$$ L F from 2.9 ± 0.4 to 3.00 ± 0.4 N (p = 0.018) during OSC/COLL/u. $$G_F$$ G F peak changes from 13.5 ± 7.4 to 12.3 ± 7.7 N (p = 0.030) and $$L_F$$ L F 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.