Alterations in peak torque occur without hematological changes after muscle fatigue

Abstract

Introduction: Muscular fatigue during voluntary muscle contractions is a complex and multifactorial phenomenon associated with central changes and adaptations of the neuromuscular system. Objective: The aim of this study was to analyze the changes in both peak torque and hematological parameters in active and inactive healthy subjects following a muscular fatigue protocol. Methods: Twenty-one healthy adult males performed a muscle fatigue protocol (10 sets, 10 repetitions of knee extension at 75% of the maximal isometric torque (MIT), 120º s-1 and 40 seconds of rest). Hematocrit (Ht), red blood cells (RBC) and leukocytes (L) analysis were evaluated before (B) and after (A) a fatigue test. Results: The inactive group presented impairment only in concentric muscular action of -41±4% in relation to the active (-23±3%) group. No differences were found in hematological parameters in inactive group (Ht, B: 45.00±0.01 vs. A: 47.00±0.01; RBC, B: 442±40 vs. A: 487±41; L, B: 7,565±2,878 vs. A: 8,015±4,224) and the active group (Ht, B: 45.00±0.63 vs. A: 47.00±0.01; RBC, B: 477±30 vs. A: 559±37; L, B: 6,418±3,557 vs. A: 6,632±4,460). Conclusion: Differences were found only in concentric actions between groups. Additionally, there were no relationships found in hematological parameters between groups.

Effects of warm-up and stretching on the peak torque using electromyography - A randomized controlled clinical trial

“…The work was carried out on the premises of Guairacá Integrated Clinics in the faculty Guairacá located in the City of Guarapuava, Paraná, with the prior authorization of those responsible. In data collection, trichotomy and skin cleaning were performed to avoid impedance (14) . The electrodes were positioned on motor points of the posterior thigh muscles, halfway between the ischial tuberosity to the popliteal line, and the volunteers were in the prone position, with the hip stabilized by the examiner and with the knee of the dominant limb flexed at 90° and attached to the load cell, to record the electromyographic activity of the muscles, using the SENIAM protocol (15) (Surface ElectroMyoGraphy for the Non-Invasive Assessment of Muscles) was performed the test with maximum force with the load cell in isometry for 60 seconds (Figure 2:a), in which the patients remained lying down with the fixed load cell.…”