The response of cortical alpha activity to pain and neuromuscular changes caused by exercise‐induced muscle damage

Abstract

Exercise-induced muscle damage (EIMD) is characterized by pain, swelling, and shortening of the muscle; increased serum creatine kinase; decreased force output; and altered neuromuscular function. The aim of this study was to investigate the effects of EIMD to determine the relationship between the peripheral symptoms, neuromuscular changes, and delayed pain sensation during a submaximal movement of the biceps brachii on cortical alpha (α) activity. In contrast to the control (n = 12) group, the experimental (n = 16) group participated in an EIMD protocol, and both groups were monitored for 132 h post-EIMD protocol. At 12 h, neuromuscular functioning was already disturbed while the sensation of pain was perceived, but not fully developed. Muscle pain scores in the experimental group peaked after 36 h with the lowest torque reported at 12 h. α-1 activity increased significantly in the motor and somatosensory area 12 h post-EIMD while α-2 activity increased in the contralateral fronto-central area. At 36 h, pain had further increased and neuromuscular function improved while α-1 and α-2 activities had decreased. We hypothesize that α-1 activity over the motor and somatosensory cortex of the experimental group displays a compensatory increase in response to the changes in neuromuscular function during movement, while an increase in α-2 activity is related to the suppression of pain experienced within the first 12 h.

Post-exercise ingestion of a carbohydrate and casein hydrolysate supplement reduces perceived muscle soreness but not fatigue in Sevens Rugby Players

“…5-7). The effect was estimated to be about one unit (on the 1-10 point scale [17,18] ), which could potentially have short-term practical implications from a training perspective, as well as long-term implications in the adaptation of muscle to training load. This effect was first noticeable at the end of the third week of camp when the cumulative training load may have reached a critical level.…”

“…No other supplements were used for the duration of the training camp. Testing protocol/Measurements Data were collected via a self-administered questionnaire including a 1-10 visual analogue scale targeting perception of muscle soreness and muscle fatigue as has been used in previous research [17,18] and shown to be valid and reliable. Specifically, perceived muscle soreness and muscle fatigue were assessed in three different muscle groups (quadriceps, hamstrings, and gastrocnemius), under four different conditions in this study.…”

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

“…Most studies have investigated the effects of pain on endurance exercise performance either through an exerciseinduced muscle pain model in which pain arises from the exercise (Astokorki & Mauger, 2017a, 2017b or a delayed onset muscular soreness model (Plattner et al, 2012(Plattner et al, , 2014. Although these models may be useful to investigate muscle pain effects on exercise capacity in different contexts, they may be inappropriate to investigate the interplay between muscle pain and muscle fatigue during exercise.…”

“…Moreover, the presence of pain before the onset of exercise, rather than induced by the exercise in progression, may be clinically relevant for exercise medicine scenarios. Whereas the delayed onset muscular soreness model is sound to investigate longterm muscle pain effects, it also changes the muscle fiber electrophysiological properties and central command responses, thereby leading to a reduced exercise capacity irrespective of the muscle pain (Plattner et al, 2012(Plattner et al, , 2014. Consequently, a challenge for studies investigating the muscle pain-muscle fatigue relationship is the induction of a stable and controlled tonic pain at the onset of exercise, free from changes in fiber membrane properties, to investigate the muscle pain effects before the muscle fatigue is set in.…”

“…Besides changes in agonist-antagonist muscle activation (co-contraction) during exercise (Falla et al, 2007), the assessment of cortical alterations to hypertonic-induced muscle pain may reveal how pain is centrally mediated, as a previous study showed that pain induced by repeated hypertonic injections at rest was associated with slower-to-faster electroencephalography (EEG) frequency band shift in frontal and posterior cortex areas (Chang et al, 2003). Results obtained with different pain models also showed that EEG alpha and beta waves were sensitive to muscle pain (Plattner et al, 2012(Plattner et al, , 2014. Therefore, as central processing of pain involves the activation of frontal and posterior cortex areas, it is hypothesized that hypertonic saline-induced muscle pain induces a slower-to-faster EEG frequency band shift in areas of the cortex involved with integrating movement perception and proprioception (Chang et al, 2001;Plattner et al, 2014).…”