Effect of verbal reinforcement on electromyographic activity and performance in the traditional front plank exercise

Verbal reinforcement may influence neuromuscular responses during exercises, but its specific effects on electromyographic activity and performance during the traditional front plank exercise remain unclear. This study aimed to investigate the effects of verbal reinforcement on muscle activation amplitude, median frequency, execution time, and perceived exertion during the front plank exercise.

Thirty physically active adults performed the front plank under two randomized conditions: with and without verbal reinforcement. Electromyography signals were processed to extract amplitude and median frequency using a 1-s window and analyzed with quadratic polynomial models.

While no significant differences were found between conditions with and without verbal reinforcement in electromyographic amplitude or median frequency (p > 0.05), significant differences were observed among muscles in amplitude and frequency coefficients. Verbal reinforcement led to significantly longer execution time (median: 125.9 s vs. 97.0 s, p < 0.001; Cohen's d = 0.49, moderate effect) and increased perceived exertion (odds ratio: 5.09; p = 0.03; Cohen's d = 0.29, small effect).

These findings suggest that verbal reinforcement does not alter electromyographic behavior; however, it enhances performance duration and perceived exertion, supporting its use in isometric core training.