Abstract
Purpose
This study assessed the test-retest reliability of TMS motor evoked potentials (MEPs)
and silent periods at early, middle, and late phases of the rising time-torque curve
during explosive voluntary contractions. We also investigated how the number of
consecutively averaged measurements influenced reliability.
Methods
On two separate occasions 3-7 days apart, 14 adults completed 16 isometric
explosive (1-s) contractions of the knee extensors per condition, superimposed with TMS. The TMS elicited an MEP and silent period in the superficial quadriceps muscles at 45 (early), 115 (middle), or 190 ms (late) during each contraction. TMS was also
superimposed at the plateau of 15 separate MVCs. Test-retest intraclass correlation
coefficient (ICC) and coefficient of variation (CV) were calculated for MEPs and silent
periods consecutively averaged over 3 to 15 separate contractions.
Results
No one condition/phase was more reliable than another. For MEP amplitude, in all
conditions except the explosive late phase, ICCs generally increased, and CV
decreased, with an increase in the number of averaged contractions, and were >0.50
ICC and <15% CV within 7 contractions. For silent period, ICCs and CVs were
unaffected by the number of consecutively averaged contractions and remained >0.50 ICC and <10% CV.
Conclusion
Test-retest reliability of TMS responses is comparable between phases of explosive
contraction and at the plateau of MVC. To maximise reliability of MEPs during
explosive contractions or MVCs, we recommend future studies average data acrossmore than the 3-5 contractions typically reported in the literature investigating MEPs at MVC plateau.
This study assessed the test-retest reliability of TMS motor evoked potentials (MEPs)
and silent periods at early, middle, and late phases of the rising time-torque curve
during explosive voluntary contractions. We also investigated how the number of
consecutively averaged measurements influenced reliability.
Methods
On two separate occasions 3-7 days apart, 14 adults completed 16 isometric
explosive (1-s) contractions of the knee extensors per condition, superimposed with TMS. The TMS elicited an MEP and silent period in the superficial quadriceps muscles at 45 (early), 115 (middle), or 190 ms (late) during each contraction. TMS was also
superimposed at the plateau of 15 separate MVCs. Test-retest intraclass correlation
coefficient (ICC) and coefficient of variation (CV) were calculated for MEPs and silent
periods consecutively averaged over 3 to 15 separate contractions.
Results
No one condition/phase was more reliable than another. For MEP amplitude, in all
conditions except the explosive late phase, ICCs generally increased, and CV
decreased, with an increase in the number of averaged contractions, and were >0.50
ICC and <15% CV within 7 contractions. For silent period, ICCs and CVs were
unaffected by the number of consecutively averaged contractions and remained >0.50 ICC and <10% CV.
Conclusion
Test-retest reliability of TMS responses is comparable between phases of explosive
contraction and at the plateau of MVC. To maximise reliability of MEPs during
explosive contractions or MVCs, we recommend future studies average data acrossmore than the 3-5 contractions typically reported in the literature investigating MEPs at MVC plateau.
| Original language | English |
|---|---|
| Journal | EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY |
| DOIs | |
| Publication status | Published - 22 Feb 2025 |