Affiliations: School of Human Kinetics and Recreation, Memorial
University of Newfoundland, St. John's, Newfoundland, Canada
Note:  Address for correspondence: David Behm PhD, School of Human
Kinetics and Recreation, Memorial University of Newfoundland, St. John's,
Newfoundland, Canada, A1C 5S7. Tel.: +1 709 737 3408; Fax: +1 709 737 3979;
Abstract: The objective of this study was to determine the effects of muscle
contraction intensity, neuromuscular fatigue, and noise on vigilance
performance. Dependent variables included simple (reaction time and movement
time) and complex (video game: Tetris) vigilance tasks (SVT and CVT
respectively) and maximum voluntary contraction (MVC) force and activation.
Vigilance tasks and MVC were randomly allocated to 5 minute blocks during a
pre-test. Following the pre-test, the tests were again randomly allocated
within three, 15 minute testing sessions over 65 minutes, while 1) being
exposed to high (95 dB (A)) or low (53 dB (A)) levels of noise, and 2)
performing muscle contractions at 20% and 5% of MVC, or no contractions.
Ninety-five (95) dB (A) noise increased (p ≤ 0.01) SVT
(reaction time and movement time combined) by 11.2% and decreased (p
≤ 0.01) CVT by 20%. Both 20% and 5% MVC impaired SVT and CVT to
a similar extent, while no changes were seen with no contractions. Furthermore,
neuromuscular fatigue had no apparent effect on vigilance task performance.
These findings suggest that the distraction of noise and divided attention
between muscle contraction and a vigilance task decreases performance.
Keywords: noise, muscle contraction, vigilance task, reaction time, movement time, electromyography