Effects of experimentally induced muscle pain on endurance performance: A proof‐of‐concept study assessing neurophysiological and perceptual responses

Abstract

Pain arising from exercise potentiates fatigue and impairs the performance of endurance exercise. We assessed neurophysiological and perceptual responses to endurance exercise performed under experimentally induced muscle pain by a model that separates muscle pain from muscle fatigue. After a series of pilot studies investigating different hypertonic saline volumes, 17 healthy males performed a preliminary VO 2PEAK test before performing a familiarization of the cycling time-to-exhaustion exercise (80% of the peak power output in the VO 2PEAK test). Participants, performed a baseline exercise session before the sessions with hypertonic and isotonic saline injections in the vastus lateralis of both legs, in a crossover and counterbalanced design. Neurophysiological and perceptual responses such as electroencephalography (EEG) in frontal, prefrontal, parietal, and motor cortex, electromyography (EMG) of the vastus lateralis and biceps femoris muscles, ratings of perceived exertion (RPE), pain sensation, and affective valence were measured at rest and during exercise. The hypertonic injection reduced the resting EEG alpha-beta ratio in the frontal and prefrontal cortex. When compared to exercise performed after the isotonic injection (430.5 ± 152.6 s), hypertonic injection shortened the time-to-exhaustion (357.5 ± 173.0 s), reduced the EMG of the assessed muscles, and increased the muscle co-contraction during exercise. The hypertonic injection also reduced the EEG alpha-beta ratio in the prefrontal and parietal cortex, increased RPE and pain sensation, and reduced affective valence during exercise. This proof-of-concept study showed that hypertonic injection-induced muscle pain reduced endurance performance, promoting centrally mediated alterations in motor command and cortical activation, as well as an interplay of perceptual responses.

A Narrative Review of Current Concerns and Future Perspectives of the Carbohydrate Mouth Rinse Effects on Exercise Performance

“…Hence, studies aiming at CHO mouth rinse ergogenic effects on sprint and strength exercise performance should make efforts to minimize possible sources of variability in exercise protocols, recruiting trained and experienced individuals and performing adequate familiarization sessions with experimental procedures before the experimental trials. In order to provide unbiased evidence with a higher level of reliability on CHO mouth rinse results, future studies are recommended to use familiarization trials until assessing performance outcomes within acceptable variation or conduct preliminary studies to calculate the typical error of measurement 51 , 52 before the CHO mouth rinse intervention.…”

Pain Perception in Contact Sport Athletes: A Scoping Review

“…Team sport [7,8,11] Combat sport [3,4,7,8] Non-athletes [3,4,7,8,11] Non-contact athletes [7,8,11] Higher pain tolerance in contact sport athletes…”

“…Team sport [6] Combat sport [3,4,5] Non-athletes [3,4,5] Non-contact athletes [6] Similar pain threshold to control…”

“…Sports practice can however encourage athletes to push past those signals in pursuit of performance goals [2]. Pain can interfere with athletes' motor control, endurance and cognitive performance, making it an important component of training or competition outcomes [3,4]. It, therefore, stands that the relationship between athletes and pain is complex.…”

Pain Perception in Contact Sport Athletes: A Scoping Review

“…Sport participation can however encourage athletes to push past those signals in pursuit of performance goals [2]. Pain can interfere with athletes' motor control, endurance, and cognitive performance, making it an important component of training or competition outcomes [3,4]. It, therefore, stands that the relationship between athletes and pain is complex.…”