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Peripheral muscular fatigue of upper limbs in children and adolescents with neuromuscular diseases: assessment by the handgrip dynamometer (bulb)

Grant number: 22/01644-8
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): April 01, 2022
Effective date (End): March 31, 2023
Field of knowledge:Health Sciences - Physiotherapy and Occupational Therapy
Principal researcher:Ana Cláudia Mattiello-Sverzut
Grantee:Ester da Silva Estevam
Home Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
Associated research grant:17/17596-4 - Aerobic capacity, muscle strength and power of children and adolescents with chronic disease: characterization and treatment, AP.TEM


During muscle fatigue, there is a significant reduction in strength, low muscle performance, and exhaustion of muscle contraction function. Peripheral fatigue has been evaluated through dynamometric analysis (maximum voluntary contraction tests - MVC) and electromyographic response (EMG) analysis. It is observed in several situations of physical inactivities, such as those associated with chronic and debilitating diseases that affect children and adolescents. Objective: To evaluate muscle fatigue during handgrip, using the bulb dynamometer related to analyzing the electromyographic signal in children and adolescents with Charcot-Marie-Tooth and congenital myopathies and dystrophies. Methods: The study included 40 children and adolescents (convenience sample), aged 8 to 16 years, diagnosed with Charcot-Marie-Tooth (CMT) and congenital myopathies and dystrophies (CDM), of both sexes, which are followed up in the Charcot-Marie Tooth and Childhood Myopathies Outpatient Clinics of the Rehabilitation Center (CER) of the Hospital das Clínicas of the Faculty of Medicine of Ribeirão Preto (HCFMRP) of the University of São Paulo (USP). For the evaluation of handgrip strength (HPF) and the fatigue test, the bulb dynamometer (North Coast) will be used, and, simultaneously, an electromyographic signal will be collected from the flexor and extensor muscles the fingers, using the Delsys Trigno® electromyograph. The procedure will comprise four steps, and only the non-preferred hand will be evaluated: a) collection of 3 measures of handgrip strength (HGS) that will represent baseline handgrip strength (b-HGS); b) fatigue test will be performed through successive handgrip MVCs until the volunteer reports a feeling of maximum fatigue (according to the visual fatigue scale) and/or inability to synchronize MVCs. Every 1 minute, the MVC value will be recorded, and the absolute values of the first minute, called initial period (i-HGS) and the last minute, called final period (f-HGS), will be analyzed to identify a decline in muscle performance; c) after fatigue has occurred, the post-fatigue MVC will be collected (up to 30 seconds after f-HGS), called posf-HGS, to verify the effect of the test on HGS; d) finally, 3 minutes after finishing the posf-HGS collection, the volunteer should develop the last MVC lasting 5 seconds (recovery handgrip strength r-HGS) to verify the immediate late effect of the test on the strength of palm grip. The variables that will be analyzed and compared are HGS (at different times) and fatigue test time. Then, data collected from children and adolescents with chronic diseases will be compared to data from typical volunteers (data published in the scientific literature and data contained in another research group project), matched by age, sex, or sexual maturation. In the statistical analysis, the means and standard deviation will be presented, and the t-student test will be applied, considering the significance level p<0.05.(AU)

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