• The Effects of a Menthol-Based Topical Analgesic on Delayed Onset Muscle Soreness-Induced Changes to Running Biomechanics and Pain Perception

      Gagnon, Ryan; Applied Health Sciences Program
      The purpose of this thesis was to evaluate the effects of a menthol-based topical analgesic on delayed onset muscle soreness (DOMS) induced changes to running biomechanics and pain perception in well-trained runners. A menthol-based topical analgesic (n=10) was compared against a placebo group (n=10) on measures of kinematics, spatio-temporal parameters, and the perception of pain. Three-Dimensional (3D) kinematics of the ankle, knee and hip as well as subjective pain (Comparative Pain Scale and Pressure Threshold) were measured during level treadmill running at baseline, 48 hours after a 30-minute DOMS-inducing downhill run, and after the application of a menthol analgesic. DOMS was induced from the downhill run as identified by our pain measures, however it had little effect on kinematic variables. Pressure threshold was significantly lower at both measurement sites for both groups and Comparative Pain Scale scores were significantly higher after inducing DOMS. There were significant interactions for condition x group, regardless of running speed; average knee and hip range of motion (ROM) during stance and swing were significantly different than baseline after inducing DOMS. The application of a menthol-based topical analgesic had no significant effect on kinematics or pain perception. Our well-trained participants may have been more well-adapted to manage DOMS-induced soreness while limiting changes to running biomechanics. Variability in gait mechanics may have also played a role in the unexpected changes between participants after inducing DOMS. Regardless of the effectiveness of the DOMS-inducing protocol, the menthol analgesic appeared to have no effect on kinematics or pain variables in well-trained runners. Key Words: Biomechanics, Gait, Menthol, Analgesic, Delayed Onset Muscle Soreness