Table II.
Muscle activation timing for serratus anterior and lower trapezius during arm elevation and lowering in the sagittal, scapular and frontal planes. Arm position (degrees) where muscle onset during the elevation phase, and termination of muscle activity during the lowering phase, are presented for the healthy control and shoulder impingement group pre- (Pre-M-C) and post (Post-M-C intervention
| Phase | Group | Arm elevation (degrees) | ||
|---|---|---|---|---|
|
| ||||
| Sagittal plane | Scapular plane | Frontal plane | ||
|
| ||||
| Serratus Anterior | ||||
|
Elevation
(muscle On) |
Healthy | 14.3 ±1.3 | 16.5 ± 3.4 | 19.7 ± 4.5 |
| Pre-MC | 23.3 ±16.6# | 22.4 ± 14.1 | 26 ±14.6 # | |
| Post-MC | 21.4 ± 13.6 | 20.7 ± 13.3 | 15.6 ± 2.7 | |
|
Lowering
(muscle Off) |
Healthy | 45.1 ± 12.9 | 40.1 ± 11.2 | 44.1 ± 5.8 |
| Pre-MC | 60.3 ± 17.9## | 68.8 ± 13.6### | 66.7 ± 15.5### | |
| Post-MC | 45.6 ± 10.8 *** | 53 ± 17.1 ** | 46.9 ± 14.3 *** | |
|
| ||||
| Lower Trapezius | ||||
|
| ||||
|
Elevation
(muscle On) |
Healthy | 18.3 ± 7 | 20.4 ± 8.1 | 29.5 ±10.9 |
| Pre-MC | 29.8 ± 17.1 ## | 30.9 ± 17 # | 35.5 ± 18.9 | |
| Post-MC | 17 ± 4.3* | 22.8 ± 13.3 | 30.5 ± 20 | |
|
| ||||
|
Lowering
(muscle Off) |
Healthy | 46 ± 16.1 | 38.7 ± 12.4 | 56.9 ± 20 |
| Pre-MC | 58.8 ± 16.3 # | 61.2 ± 14.2### | 66.5 ± 16.2 | |
| Post-MC | 42 ± 13.7 ** | 50.7 ± 20* | 59.3 ± 23 | |
Mean ± standard deviation.
*
Significant difference pre- to post intervention.
#
Significant difference between healthy control and participants with pain.
Significance level indicated by; */# p<0.05,
**/##
p<0.001
***/###
p<0.0001.
MC, motor control