Article

OBJECTIVE: To identify the smallest combinations of maximum voluntary isometric
contraction (MVIC) tests that produce near-maximum voluntary activation (MVA) for
a large proportion of participants for the shoulder girdle muscles. DESIGN: Cross-sectional study.
SETTING: Research center. PARTICIPANTS: Healthy
participants (N=38). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The
electromyography of 12 shoulder muscles was recorded while participants performed
15 MVIC tests. The smallest combinations of MVIC tests that met our acceptance
criterion (ie, produce 90% of MVA for 90% of participants) were identified.
Optimal combinations were identified for each of the 12 muscles individually and
for the 12 muscles simultaneously. Electromyographic activation levels of the
95th highest percentile obtained with our optimal combinations and with the Four
Normalization Tests previously recommended were compared using paired t tests.
RESULTS: Between 2 and 6 MVIC tests were required for each of the 12 muscles, and
12 MVIC tests were required for the 12 muscles to meet the acceptance criterion.
These optimal combinations produced electromyographic activation levels of the
95th highest percentile comprised between 97% and 100% of MVA. These
electromyographic activation levels were significantly higher than the
electromyographic activation levels obtained with the Four Normalization Tests.
CONCLUSIONS: Although the number of MVIC tests to normalize 12 shoulder muscles
was increased compared with previous recommendations, the proposed method ensures
that near-MVA (>90%) was obtained for a large proportion of participants (>90%).
Moreover, because electromyographic activation levels of the 95th highest
percentile were at least 97% of MVA, the identified combinations could reduce the
interparticipant variability. The proposed combinations could help to improve
electromyographic normalization and therefore reduce the misinterpretations
regarding shoulder muscle activation levels.
CI - Copyright (c) 2016 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS