Rapid effect of manual stimulation of the brachial plexus on handgrip strength

Abstract

Introduction: Despite reports about improved nerve conduction after manual therapy, the literature offers no studies in which the impact would be assessed regarding rhythmic manual stimulation of the nerve structures on the functions of the innervated effectors.Research objective: The aim of the study was to evaluate the effects of brachial plexus manual stimulation on handgrip strength (HGS) as an indicator of brachial plexus function.Material and methods: A total of 63 volunteers were randomly divided into 2 groups that received manual stimulation (Intervention Group IG) or sham stimulation (Control Group CG) of the brachial plexus. Pre- and post-stimulation HGS of the dominant hand was measured using the JAMAR hydraulic hand dynamometer.Results: With regard to IG, a statistically significant increase (p<0.002) in HGS of the dominant hand was observed for post- compared to pre-intervention scores (mean: 1.25 kG). In CG, the HGS values for the dominant and the non-dominant hand were statistically significantly lower (-1.61 (p<0.001) and -1.91 (p<0.003), respectively). A comparison of mean changes in the HGS values among both groups revealed statistically significant differences for the dominant (p<0.0001) and the non-dominant (p<0.05) hand.Conclusions: To the best of our knowledge, this has been the first study in which the effects have been assessed concerning manual stimulation of the brachial plexus on HGS. An increase in HGS on the stimulated side has been observed, with a simultaneous decrease of HGS in sham intervention controls, which shows that HGS can be increased by manual stimulation of the brachial plexus.

Keywords

• manual therapy
• brachial plexus
• osteopathic manipulative treatment
• handgrip strength