Contralateral palmar grip strength increase overflow induced by index finger isometric contraction

• Grant number: 18/26007-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2019
• End date: December 31, 2019
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal Investigator: João Eduardo de Araujo
• Grantee: Giovanna Cristina Toffano
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Overflow is a natural phenomenon that potentiates the motor response during a resisted isometric muscle contraction in the opposite limb. In this sense, this work proposes to advance with the understanding of the facilitatory mechanisms produced by the isometric contraction of the non-homologous and contralateral muscles in a task of palmar grip strength. Thus, in this work we will attempt to identify and quantify the presence of overflow in the upper limbs of healthy subjects during an instructed task of palmar flexion on a dynamometer, concomitant with an isometric flexion activity in the contralateral index finger, using 70% of the maximum voluntary isometric contraction (MVIC). Sixty-four subjects of both sexes, with ages ranging from 18 to 30 years and right motor preference, will participate in this study. The subjects will be divided randomly into 4 groups: right palmar grip control group (RC), left palmar grip control group (LC), right resisted contralateral isometric group palmar grip (RRCP) and left resisted isometric contralateral palmar grip (LRCP). The subjects will remain seated and should make three maximal palmar grip contractions on a dynamometer (5 seconds and 9 seconds interval between them), constituting the baseline. After the three initial contractions, subjects will make a final contraction with the same parameters (test). In the resisted isometric groups, to perform the palmar grip test, we will use elastic bands linked to a load cell, so that the flexion force of the contralateral index finger can be measured and maintained in 70% of the MVIC. For the statistical analysis, a two-way analysis of variance (ANOVA), p <0.05, will be used. We expected that the isometric flexion of the index finger increases the contralateral palmar grip strength, indicating the possibility of facilitative mechanisms that can be used in physiotherapeutic rehabilitation.