Effects of a Sustained, Isometric Forearm Flexion Task to Failure on Torque and Neuromuscular Responses at 3 Elbow Joint Angles.

Autor:	Ortega DG; Department of Nutrition and Health Sciences, Exercise Physiology Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska; and., Housh TJ; Department of Nutrition and Health Sciences, Exercise Physiology Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska; and., Smith RW; Department of Nutrition and Health Sciences, Exercise Physiology Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska; and., Arnett JE; Department of Nutrition and Health Sciences, Exercise Physiology Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska; and., Neltner TJ; Department of Nutrition and Health Sciences, Exercise Physiology Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska; and., Anders JPV; Department of Human Sciences, The Exercise Science Program, The Ohio State University, Columbus, Ohio., Schmidt RJ; Department of Nutrition and Health Sciences, Exercise Physiology Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska; and., Johnson GO; Department of Nutrition and Health Sciences, Exercise Physiology Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska; and.
Jazyk:	angličtina
Zdroj:	Journal of strength and conditioning research [J Strength Cond Res] 2024 Jan 01; Vol. 38 (1), pp. e25-e33.
DOI:	10.1519/JSC.0000000000004599
Abstrakt:	Abstract: Ortega, DG, Housh, TJ, Smith, RW, Arnett, JE, Neltner, TJ, Anders, JPV, Schmidt, RJ, and Johnson, GO. The effects of a sustained, isometric forearm flexion task to failure on torque and neuromuscular responses at 3 elbow joint angles. J Strength Cond Res 38(1): e25-e33, 2024-This study examined the effects of a sustained, isometric forearm flexion task anchored to torque to task failure on maximal voluntary isometric contraction (MVIC) and neuromuscular responses at 3 elbow joint angles. Eleven women (mean ± SD: age = 20.8 ± 2.7 years, height = 169.3 ± 7.4 cm, body mass = 67.7 ± 6.9 kg) performed two 3s forearm flexion MVICs at elbow joint angles (JAs) of 75°, 100°, and 125° before and after a sustained, isometric forearm flexion task to failure at a fatiguing joint angle of 100° anchored to a torque value that corresponded to a rating of perceived exertion of 8 (RPE = 8). The amplitude (AMP) and mean power frequency (MPF) of the electromyographic (EMG) and mechanomyographic (MMG) signals were recorded from the biceps brachii. Repeated-measures ANOVAs were used to compare mean differences for MVIC and neuromuscular parameters. Collapsed across JAs, MVIC (p < 0.001) and EMG MPF (p = 0.006) pretest values were greater than posttest values. Collapsed across time, EMG MPF at JA75 was greater than JA100 (p < 0.001) and JA125 (p < 0.001), and JA100 was greater (p = 0.007) than JA125. For EMG AMP, there was a fatigue-induced decrease at JA75 (p = 0.003). For neuromuscular efficiency (NME = normalized torque/normalized EMG AMP), there were decreases from pretest to posttest at JA100 (p = 0.002) and JA125 (p = 0.008). There were no significant interactions or main effects for MMG AMP and MMG MPF. From these findings, it was hypothesized that the decline in MVICs at JA75, JA100, and JA125 was due to fatigue-induced metabolic perturbations that resulted in JA-specific neuromuscular responses. Thus, neuromuscular parameters may provide insight into the JA-specific mechanisms of fatigue. (Copyright © 2023 National Strength and Conditioning Association.)
Databáze:	MEDLINE
Externí odkaz:	Zobrazit plný text záznamu