Influence of wrist constraints on shoulder muscle coordination during shoulder dynamic tasks

• Grant number: 17/26147-9
• Support Opportunities: Scholarships abroad - Research
• Start date: July 01, 2018
• End date: May 31, 2019
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal Investigator: Helga Tatiana Tucci
• Grantee: Helga Tatiana Tucci
• Host Investigator: Eric Jon Perreault
• Host Institution: Instituto de Saúde e Sociedade (ISS). Universidade Federal de São Paulo (UNIFESP). Campus Baixada Santista. Santos , SP, Brazil
• Institution abroad: Northwestern University, Evanston, United States

Abstract

The wrist constrained during upper extremity activities may alter the pattern of activation not only of forearm muscles but may also cause shoulder muscle imbalance. Thus, to understand the influence of wrist constrained in the shoulder synergism is important, since patients with shoulder pathology present altered muscle activation and kinematics, considered risk factors for shoulder dysfunction. The main aim is to compare shoulder muscle coordination before and after a continued 24-hour of using wrist orthosis in dynamic tasks. Muscle synergy analysis will be used to quantify patterns of muscle coordination. Nonnegative matrix factorization (NNMF) will be used to identify groups of muscles that are activated together (muscle synergies) and determine how the activity of these groups change during the given tasks. Muscle synergies will be estimated from EMG data pooled across subjects before and after use of wrist orthosis to obtain an orthosis-use-specific description of muscle coordination. For each data set of dynamic tasks, variance accounted for (VAF) will be used to quantify how accurately the orthosis synergies (before and after) is able to reconstruct individual subjects' EMG data. Linear mixed-effect model (fixed factors: reconstruction group, and subject´s time of using orthosis (before and after); random factor: subject), with VAF as the dependent variable will be used for statistical analysis. We believe the results of this project may not only help to understanding shoulder muscle synergism after a continued time of wrist constriction but also direct clinicians to evaluate, observe, and even design shoulder-oriented rehabilitation protocols while a person undergo to a constrained wrist treatment. (AU)