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- Title
Similar Fatigue-Induced Changes in Neuromuscular Patterns of Responses for Contralateral Legs during Maximal Bilateral Leg Extensions.
- Authors
Neltner, Tyler J.; Housh, Terry J.; Smith, Cory M.; Anders, John Paul V.; Keller, Joshua L.; Hill, Ethan C.; Schmidt, Richard J.; Johnson, Glen O.
- Abstract
Neltner TJ, Housh TJ, Smith CM, Anders JP, Keller JL, Hill EC, Schmidt RJ, Johnson GO. Similar Fatigue-Induced Changes in Neuromuscular Patterns of Responses for Contralateral Legs during Maximal Bilateral Leg Extensions. JEPonline 2020;23(2):1-17. The purpose of the present study was to compare individual and composite neuromuscular patterns of responses between the contralateral legs during maximal, fatiguing, bilateral, isokinetic leg extensions. Fourteen men (22.6 × 4 yrs) performed repeated bilateral, isokinetic leg extensions at 180's-1 until their peak torque was reduced by 70% (67 × 19 repetitions). The amplitude (AMP) and frequency (mean power frequency = MPF) contents of the electromyographic (EMG) and mechanomyographic (MMG) signals from the vastus lateralis (VL) muscles of both legs were recorded simultaneously during each repetition of the fatiguing bout. The EMG AMP, EMG MPF, MMG AMP, MMG MPF, and torque values were normalized to the values corresponding to 10% of the total number of repetitions completed and statistically compared at 5% intervals. Four, 2 (right and left VL) x 19 (10-100% of the total repetitions) repeated measures ANOVAs were used to determine mean differences for each neuromuscular parameter. Two, 1 x 19 repeated measures ANOVAs were used to analyze torque and average power changes across repetitions. The results indicated no significant interactions involving the right and left VL for any of the neuromuscular parameters. However, there was a significant main effect for repetitions, collapsed across the muscles, where EMG MPF decreased (P<0.001; X2 p = 0.376). Bilateral peak torque (271.1 ± 44.6 Nμm, P<0.001; X2 p = 0.695) and average power (350.2 × 78.6 W, P<0.001; X2 p = 0.734) decreased significantly from 40-100%, and 70-100% of the total repetitions, respectively. The results of this study revealed no differences between the right and left VL muscles for the patterns of neuromuscular responses during the fatiguing bilateral leg extensions. The decreases across repetitions for EMG MPF without changes in EMG AMP, MMG AMP, or MMG MPF suggested that the modulation of torque during a fatiguing task may be different for bilateral versus unilateral muscle actions.
- Subjects
VASTUS lateralis; LEG; LEG muscles; TORQUE
- Publication
Journal of Exercise Physiology Online, 2020, Vol 23, Issue 2, p1
- ISSN
1097-9751
- Publication type
Article