Electromyography investigation of eccentric and concentric phases of the biceps dumbbell curl movement after four weeks of transcranial direct current stimulation in healthy men

Document Type : Original research papers

Authors

1 Exercise Physiology Department, Sports Sciences Faculty, University of Mazandaran, Babolsar, Iran

2 Department of Physical Education, Imam Khomeini International University, Qazvin, Iran

3 Department of Motor Behavior, Faculty of Sports Science, University of Mazandaran, Babolsar, Iran

10.22098/jast.2024.15068.1349

Abstract

Transcranial direct current stimulation (tDCS) is a safe method that employs a low-intensity current to induce stimulation in the brain. The utilization of tDCS has the potential to enhance both muscular strength and performance. This study investigated the effects of transcranial direct current stimulation (tDCS) on the electromyographic (EMG) activity of the biceps during concentric and eccentric contractions.

Twenty-two healthy subjects were randomly assigned to either a tDCS group or a control group. The tDCS group received anodal tDCS over the primary motor cortex for 15 minutes, while the control group received nothing. The subjects performed maximal isometric contractions (MVIC) as well as concentric and eccentric contractions of the biceps with 80% of their one-repetition maximum (1RM). After preliminary tests, a covariance analysis was conducted.

Results showed that 1RM in tDCS group was significantly higher than control group (p < 0.05). After 4 weeks of tDCS interventions in full range of motion and in the concentric phase of movement, tDCS group showed a significant decrease in the normalized RMS of biceps brachii (P<0.05). The data illustrates a reduction of 22% during the concentric phase and 18% during the eccentric phase.

Our findings indicate that tDCS improve muscular strength and neuromuscular efficiency. Nevertheless, it is important to use caution when interpreting the findings of this study, given its limited time period and the small sample size of the group.

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History

  • Receive Date: 14 May 2024
  • Revise Date: 19 January 2025
  • Accept Date: 10 August 2024

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