Article

OBJECTIVE: To determine the amount of muscle activation in 4 scapular muscles in
overhead athletes with and without a history of secondary shoulder impingement,
during 3 upper extremity closed chain exercises. DESIGN: One-between (group),
one-within (exercise) repeated measures. SETTING:
Controlled laboratory study.
PARTICIPANTS: Overhead athletes (n=15; mean age +/- SD, 21.0+/-2.5 y; mean height
+/- SD, 176.0+/-7.8 cm; mean weight +/- SD, 76.1+/-13.4 kg) demonstrating with
symptoms of shoulder impingement and overhead athletes (n=15; mean age +/- SD,
20.4+/-3.8 y; mean height +/- SD, 174.1+/-9.7 cm; mean weight +/- SD, 73.3+/-11.7
kg) with no shoulder pathologies. INTERVENTIONS: Subjects completed 5 individual
trials of a standard push-up, a push-up on an unstable surface, and a revolution
on a shoulder rehabilitation device while electromyography (EMG) recorded muscle
activity of the serratus anterior, upper trapezius, middle trapezius, and lower
trapezius. MAIN OUTCOME MEASURES: The mean EMG data for the 4 muscles from the
standard push-up, push-up on an unstable surface, and shoulder rehabilitation
device trials were normalized as a percentage of a maximum voluntary isometric
contraction for each muscle. RESULTS: There was a statistically significant
interaction for the middle trapezius (F(2,56)=3.856; P=.027). The shoulder
impingement push-up on an unstable surface (33.76%+/-26.45%) had significantly
greater activation compared with the shoulder impingement standard push-up
(25.88%+/-13.76%), the shoulder impingement shoulder rehabilitation device
(9.40%+/-5.86%), and the nonpathology push-up on an unstable surface
(19.49%+/-7.73%). The shoulder impingement standard push-up had significantly
greater activation compared with the shoulder impingement shoulder rehabilitation
device and nonpathology standard push-up (17.99%+/-7.31%). The nonpathology
standard push-up and nonpathology push-up on an unstable surface had
significantly greater activation compared with the nonpathology shoulder
rehabilitation device (7.95%+/-4.30%). CONCLUSIONS: These results suggest that
the muscle activation of the middle trapezius differs in overhead athletes with a
history of secondary shoulder impingement compared with those who lack this
history during closed chain exercise, as well as within the 3 closed chain
exercises. The levels of muscle activation of the serratus anterior and upper
trapezius during these closed chain exercises were similar between the 2 groups.
These results support the use of closed chain exercises in the rehabilitation
process of overhead athletes with secondary shoulder impingement. However,
clinicians should consider the muscle(s) of interest when selecting an exercise.
CI - Copyright 2010 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS