Perceived Muscle Soreness Does Not Modulate Corticospinal Excitability

Soreness due to exercise-induced muscle damage temporarily impairs motor performance. Transcranial magnetic stimulation (TMS) is often used assess subtle changes in corticospinal excitability (CSE) and system input-output properties demonstrates sensitivity chronic pain. Nevertheless, the acute effects of soreness on TMS-based measures require further investigation. PURPOSE: To examine relationship between perceived CSE postural lower-extremity muscles. METHODS: 12 healthy adults (3 W, age: 27.2 ± 5.4 yr, ht: 175.6 11.0 cm, wt: 72.6 13.4 kg) completed three visits with maximal anaerobic lower extremity exercise. At start each visit, participants confirmed they abstained from any physical activity 24 hr prior, rated their overall residual using a 100 mm visual analog scale. Visits were ranked based highest lowest retained for analysis. CSE, electromyographic motor-evoked potentials (MEPs) recorded right rectus abdominis (RA) vastus lateralis (VL). Active thresholds (AMT) determined during 15% voluntary isometric force biphasic stimulator 96 curved double coil. determine ten TMS pulses applied M1 hotspot at 120% AMT resultant MEPs averaged peak-to-peak amplitude 15-65 ms post-stimulus. Paired-samples t-test mean differences soreness, AMT, MEP amplitudes. RESULTS: As expected, differed (mean difference: 25.3 mm, t = 5.08, p < 0.01). Similar motor-thresholds observed RA 0.3%, 0.26, 0.80) VL 0.5%, 0.45, 0.66). amplitudes also similar 0.13 mV, 1.74, 0.12) 0.01 0.30, 0.77). CONCLUSION: Day-to-day variation axial contractions not explained by soreness. Future work should multiple timepoints after exercise use various submaximal intensities clarify whether responsive