Post-contraction potentiation can react inversely to post-activation potentiation depending on the test contraction force. (28th March 2023)

• Record Type: Journal Article
• Authors: Ishii, Tomoya; Sasada, Syusaku; Komiyama, Tomoyoshi
• Is Part Of: Neuroscience letters. Volume 801(2023)
• Publication Date: 2023-03-28
• Subjects: Post-contraction potentiation -- Post-activation potentiation -- Electromyography -- Force -- Biceps brachii; BB biceps brachii -- CC conditioning contraction -- EMG electromyography -- MU motor unit -- MVC maximum voluntary contraction -- PAP post-activation potentiation -- PCP post-contraction potentiation -- RM-ANOVA repeated-measures analyses of variance -- SD standard deviation of the mean -- TCI test contraction intensity; Neurology -- Periodicals; Neurology -- Periodicals; Research -- Periodicals; Neurologie -- Périodiques; Neuroanatomie -- Périodiques; Neuropharmacologie -- Périodiques; Neurophysiologie -- Périodiques; Neurology; Periodicals; Electronic journals; 617.48
• DOI: 10.1016/j.neulet.2023.137132
• Languages: English
• ISSNs: 0304-3940

Abstract

Highlights: We evaluated how the post-contraction potentiation was altered by changing the force. The EMG amplitude at 2% MVC increased after a conditioning contraction. The EMG amplitude at 20% MVC decreased after a conditioning contraction. The α- and β-band power ratios changed according to the test contraction force. The test contraction intensity affected the EMG-force relationship. Abstract: The surface electromyographic (EMG) activity of the biceps brachii during weak elbow flexion reportedly increases immediately after strong elbow flexion, even during the exertion of a given force. This phenomenon is called post-contraction potentiation (EMG–PCP). However, the effects of test contraction intensity (TCI) on EMG–PCP remain unclear. This study evaluated PCP levels at various TCI values. Sixteen healthy participants were asked to perform a force matching task (2%, 10%, or 20% of the maximum voluntary contraction [MVC]) before (Test 1) and after (Test 2) a conditioning contraction (50% of MVC). With a 2% TCI, the EMG amplitude was higher in Test 2 than in Test 1. With a 20% TCI, the EMG amplitude was lower in Test 2 than in Test 1. Furthermore, EMG spectral analyses showed that the α- and β-band power ratios in Test 2 were enhanced by 2% TCI compared with Test 1. These findings suggest that TCI is crucial in determining the EMG–force relationship immediately after a brief intensive contraction.