The interactive effect of delayed-onset muscle soreness (DOMS) and a topical analgesic on corticospinal excitability was investigated.
Thirty-two participants completed Experiments A (no DOMS) and B (DOMS). For each experiment, participants were randomly assigned to two groups: 1) topical analgesic gel (topical analgesic, n = 8), or 2) placebo gel (placebo, n = 8) group. Before the application of gel (pregel), as well as 5, 15, 30, and 45 min postgel, motor-evoked potential (MEP) area, latency, and silent period, as well as cervicomedullary MEP and maximal compound motor unit action potential areas and latencies were measured. In addition, pressure–pain threshold (PPT) was measured pre-DOMS and at the same timepoints in experiment B.
In experiment A, neither group showed a significant change for any outcome measure. In experiment B, both groups exhibited a significant decrease in PPT from pre-DOMS to pregel. After the application of topical analgesic, but not placebo, there was a significant increase in PPT at 45 min postgel, respectively, compared with pregel and a main effect of time for the silent period to increase compared with pregel. Participants with DOMS had reduced MEP and cervicomedullary MEP areas and increased corticospinal silent periods compared with those who did not have DOMS.
These findings suggest that DOMS reduced corticospinal excitability and after the administration of menthol-based topical analgesic, there was a reduction in pain, which was accompanied by increased corticospinal inhibition.
1School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL, CANADA
2Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL, CANADA
Address for correspondence: Duane C. Button, Ph.D., School of Human Kinetics and Recreation, Memorial University of Newfoundland, 230 Elizabeth Ave, St. John’s, Newfoundland, Canada A1C 5S7; E-mail: firstname.lastname@example.org.
Submitted for publication January 2019.
Accepted for publication May 2019.
Online date: May 31, 2019