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- Title
Decomposition-enhanced spike-triggered averaging: contraction level effects.
- Authors
Conwit, Robin A.; Tracy, Brian; Jamison, Chris; Mchugh, Megan; Stashuk, Dan; Brown, William F.; Metter, E. Jeffrey; Conwit, R A; Tracy, B; Jamison, C; McHugh, M; Stashuk, D; Brown, W F; Metter, E J
- Abstract
Decomposition-enhanced spike-triggered averaging (DE-STA) was applied to the vastus medialis muscle to examine size distributions of surface-detected motor-unit action potentials (S-MUAPs) at various force levels. Using DE-STA, 15-20 S-MUAPs were identified during 5%, 10%, 20%, and 30% of maximum voluntary contraction. Average S-MUAPs showed increase in peak to peak (and negative peak) amplitude with force (In microV): 5% = 37.9 +/- 6.1 (16.6 +/- 2.5), 10% = 44.0 +/- 4.0 (20.4 +/- 1.8), 20% = 80.7 +/- 9.3 (41.3 +/- 4.5), and 30% = 102.5 +/- 10.3 (53.6 +/- 5.0). Test-retest variability of peak to peak (and negative peak amplitude) between repeated trials was 0.10 (0.14), 0.14 (0.14), 0.17 (0.15), and 0.21 (0.20) at 5%, 10%, 20%, and 30% respectively. A relationship was found between the S-MUAP amplitude and force (r2 = 0.78, df = 90, F = 160, P < 0.001). Increase in average S-MUAP amplitude with force suggests that STA performed only at low levels of contraction may result in a biased sampling and small average S-MUAP amplitudes.
- Publication
Muscle & Nerve, 1997, Vol 20, Issue 8, p976
- ISSN
0148-639X
- Publication type
journal article
- DOI
10.1002/(SICI)1097-4598(199708)20:8<976::AID-MUS7>3.0.CO;2-3