Mind-Muscle Connection: Limited Effect of Verbal Instructions on Muscle Activity in a Seated Row Exercise

Author(s)

Fujita, Rafael A. ^{[1, 2]} ; Silva, Nilson R. S. ^[2] ; Bedo, Bruno L. S. ^[3] ; Santiago, Paulo R. P. ^[2] ; Gentil, V, Paulo R. ; Gomes, Matheus M. ^{[1, 2]}

Affiliation

^[1] Univ Sao Paulo, Ribeirao Preto Coll Nursing, Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Sch Phys Educ & Sport Ribeirao Preto, Av Bandeirantes 3900, BR-14040907 Ribeirao Preto, SP - Brazil

^[3] Univ Sao Paulo, Ribeirao Preto Med Sch, Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: PERCEPTUAL AND MOTOR SKILLS; v. 127, n. 5 MAY 2020.
• Web of Science Citations: 1

Abstract

Verbal instruction increases electromyographic (EMG) activity in the first three repetitions of an exercise, but its effect on an entire exercise set until failure is unknown. Once there are changes in motor unit recruitment due to fatigue, the effect of verbal instructions can change during different intervals of a set. This study analyzed whether verbal instruction emphasized the contraction of back muscles (i.e., myoelectric activity) during initial, intermediate, and final exercise repetitions performed until failure. Twenty participants with little or no experience in strength training performed a seated row exercise with and without verbal instruction. Surface electrodes were fixed over the latissimus dorsi, teres major, biceps brachii, and posterior deltoid (PD) muscles. Myoelectric activity was computed by mean amplitude and by the median frequency. We analyzed data with repeated measures multivariate analysis of variance and found that, with verbal instruction, there was increased EMG mean amplitude in the latissimus dorsi (15.21%, p = .030) and reduced EMG mean amplitude in the PD (14.39%, p = .018) on initial repetitions. Other muscle EMG amplitudes did not change. On intermediate repetitions, there was reduced signal amplitude only in the PD (15.03%, p = .022). The verbal instruction did not interfere with signal amplitude on final repetitions nor in the median frequency throughout the series. Verbal instruction seems to have little effect on increasing myoelectric activity of these targeted muscles in an entire set of a resistance training. (AU)

• FAPESP's process: 17/05174-8 - Correlation between the maximum force symmetry and the force variability symmetry of the plantar muscles flexors with the posture control
• Grantee: Nilson Ribeiro dos Santos Silva
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 10/20538-7 - Kinematic analysis of movements of rotation of the knee joint during a single-leg drop-landing by quaternions: gender differences
• Grantee: Paulo Roberto Pereira Santiago
• Support Opportunities: Regular Research Grants