Perceived physical exertion is a good indicator of neuromuscular fatigue for the core muscles

Although several studies have assessed core training, specific prescription recommendations remain lacking. The purpose of the present study was to determine the association between the rate of perceived exertion (RPE) and neuromuscular fatigue of the core muscles during the prone bridging endurance test. Fifteen healthy and moderately active subjects participated. Neuromuscular fatigue was assessed with surface electromyography on the rectus abdominis (RA), external oblique, internal oblique, and lumbar erector spinae. Participants rated the RPE (Borg CR 10) every 5 s. The time to failure was 123.7 ± 58.1 s. From the midpoint of the time to failure, the RPE significantly increased (p < 0.05). The RA muscle showed increased neuromuscular fatigue during the second half of the time to failure (p < 0.05). The other core muscles showed increased neuromuscular fatigue during the last 30% of the time to failure (p < 0.05). The RA muscle showed a strong correlation between neuromuscular fatigue and the RPE (R² 0.85). The other core muscles showed a moderate correlation between neuromuscular fatigue and RPE (R² 0.50-0.69). The measured RPE and neuromuscular fatigue were closely linked for the RA muscle and moderately linked for the other core muscles during the prone bridging endurance test.