Understanding muscle activation during exercises is crucial for devising effective training programs. We examined correlations between self-reported and electromyographic (EMG) muscle activity during upper-body exercises performed at loads corresponding to 4-6 repetition maximums (RMs). Thirteen male sub-elite soccer players who had previously engaged in resistance training participated in two testing sessions. In the initial session, the loads corresponding to 4-6 repetitions were determined for six exercises: Lat Pull Down (LPD), Barbell Bent Over Row (BBOR), Dumbbell Row (DR), Barbell Pull Over (BPO), Dumbbell Reverse Fly (DRF), and Dumbbell Concentration Curl (DCC). At post-exercise, participants rated their perceived muscle activation for three targeted muscles in each exercise on a 1-10 point Likert scale (LS). In the subsequent session, we used EMG to measure the activity of eight agonist and synergist muscles during these exercises. We found that one of two synergist muscles consistently demonstrated higher activity levels. Interestingly, we observed no difference in activity between primary and secondary (or synergist) muscles across all exercises. Most importantly, we found no significant correlation between the perceived muscle activation rate and the EMG measured activation level for any exercise. In conclusion, our findings suggest that, despite differential muscle activity during specific exercises, self-reported muscle activation may not accurately correspond to actual muscle activation, as measured via EMG, due to the participants' poor interoceptive awareness of muscles. These data highlight the potential limitations of relying on perceived muscle activation as a sole gauge of training intensity.
Keywords: interoceptive awareness; mind-muscle connection; perceived muscle activation; resistance training; soccer players.