Differences in maximum voluntary excitation between isometric and dynamic contractions are age-dependent

Remco J. Baggen*, Jaap H. Van Dieën, Sabine M. Verschueren, Evelien Van Roie, Christophe Delecluse

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Obtaining true maximum voluntary excitation appears to be more difficult in older populations than in young populations. The aims of this study were (1) to determine whether differences in maximum voluntary excitation obtained from maximum voluntary isometric contraction (MVIC) and (sub-)maximum voluntary dynamic contraction [(s-)MVDC] are age dependent, and (2) to determine how normalizing electromyographic signals to corresponding maximum voluntary excitations affects variance between participants and the likelihood of normalized signals exceeding 100%. MVIC, s-MVDC, and MVDC were recorded in 10 young women, and MVIC and s-MVDC were recorded in 19 older women. A significant age × contraction mode interaction effect was found for vastus lateralis (P = .04). In young women, MVDC elicited the highest maximum voluntary excitation for vastus lateralis and rectus femoris (P < .05). In older women, no differences in maximum voluntary excitation were found (P > .05). Normalization to dynamic contractions resulted in lower between-participant variance of electromyography amplitudes, though not for all muscles, and decreased the number of normalized signals exceeding 100% in young women. These findings indicate that differences in maximum voluntary excitation across contraction modes are age dependent. Therefore, one should be cautious when comparing normalized signals between age groups; however, overall dynamic contractions may be preferable over isometric contractions for normalization purposes.

Original languageEnglish
Pages (from-to)196-201
Number of pages6
JournalJournal of Applied Biomechanics
Volume35
Issue number3
DOIs
Publication statusPublished - Jun 2019

Keywords

  • Normalization
  • Older adults
  • Surface electromyography
  • Young adults

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