Influence of volar and dorsal static orthoses in different wrist positions on muscle activation and grip strength in healthy subjects

Abstract

Introduction Orthoses are indicated for injuries of the wrist, although there is weak evidence for its influence on extensor muscle activation patterns. The purpose of this study was to compare two designs of volar and dorsal wrist orthoses in several positions, from flexion to extension, by surface electromyography wrist extensor muscle activation and grip strength in healthy subjects. Methods We analysed extensor carpi radialis brevis and longus, extensor carpi ulnaris and extensor digitorum comunis muscle activity by surface electromyography. The volunteers performed maximum and submaximum (50%) isometric grips, which were evaluated with a Jamar™ dynamometer using volar and dorsal orthoses with several positions of the wrist (0°, 15° and 30°), both in flexion and extension (p < 0.05). Results Our results showed a significant decrease in extensor muscle activation at 15° and 30° of wrist extension in both volar and dorsal orthoses at 100% and 50% of maximum task. A decrease was also found at rest at 15° of wrist flexion volar orthoses. Decreased grip strength was found at 15° and 30° of wrist flexion in both volar and dorsal orthoses. Conclusions Based on the results of this sample, we would suggest, as orthotic prescriptions, 15° or 30° wrist extension orthoses as a supporting therapeutic modality for performance in new studies with lateral epicondylitis in association with low-intensity grip activity; or 15° of wrist flexion volar orthoses for rest, depending on the chronicity of the disease and individual assessment. Future studies with symptomatic patients are needed to confirm these findings.

Fadiga dos músculos extensores do punho diminui a força de preensão palmar

“…Even with a wide variety of studies, we can observe that there is still no consensus on the positioning of electrodes and the influence of different wrist angles in the palmar grip task 32,34,38,39 . The muscular physiological processes can be analyzed by electromyographic signal during standardized activities.…”

“…Electrodes with bipolar contact Ag/AgCl (Silver/silver chloride) and 20 mm distance between poles -Medtrace® were positioned in the muscles: extensor carpi radialis (ECR) -longus and brevis -, extensor carpi ulnaris (ECU) and flexor digitorum superficialis (FD) 32 ( Figure 2). Three maximum voluntary isometric contractions (MVIC) maintained by six seconds were requested, with one minute rest interval between each task for both groups.…”

Influência da órtese estática de punho na atividade muscular e amplitude de movimento de ombro e cotovelo durante uma tarefa funcional: estudo biomecânico

“…For this study, we considered the hypothesis that the standardized static wrist orthosis could alter the activation of the muscles and the range of motion of the upper limb. The selection of this orthosis was based on the studies conducted by Jansen et al 25 and Marcolino et al 26 , who analyzed the influence of these orthoses at several wrist angles through electromyography of the wrist extensor muscles and observed reduced extensor muscle activation with orthoses at 30° extension, while performing a functional task of isometric grip.…”

“…The volunteers were evaluated while performing the functional task in two conditions in random order, with 2-minute interval: without the orthosis and with dorsal wrist orthosis at 30° extension. This angle was defined in previous electromyographic studies 25,26 as the one of the greatest muscular inhibition of wrist extensors, but allowing the grip of the fingers. The use of the orthosis on the dorsal side of the hand and forearm was selected to release the palmar face of the hand, for easy grasping of the fingers during the functional task.…”

Effect of Low-Level Laser Therapy and Strength Training Protocol on Hand Grip by Dynamometry

“…The positioning of the individual to assess the handgrip followed the recommendation given by the American Society of Hand Therapists (ASHT) and the Brazilian Society of Hand Therapists (BSHT), based on the studies of Mathiowetz et al 26 The individual was positioned comfortably in a chair without support for the arms, feet flat on the floor, parallel to the body arm, shoulder adducted, elbow at 90 o and forearm in neutral position, and the Jamar ® dynamometer in second place. 27 The evaluation was performed in both groups at baseline and after the end of the experiments ( Strengthening Protocol For the strength training protocol of the dominant limb, a finger exerciser was used, with the volunteer's arm resting on a table, elbow flexed at 90°, forearm in neutral, with a light extension handle. This calculated the maximum resistance (10 MR) of the flexor fingers.…”