W. Steven Tucker, Charles W. Armstrong, Erik E. Swartz, Brian M. Campbell and James M. Rankin
Closed kinetic chain exercises are reported to provide a more functional rehabilitation outcome.
To determine the amount of muscle activity in 4 shoulder muscles during exercise on the Cuff Link.
10 men and 10 women, age 18–50.
Subjects performed 3 sets of 5 revolutions on the Cuff Link in non-weight-bearing, partial-weight-bearing, and full-weight-bearing positions.
Main Outcome Measures:
Electromyography data were collected from the upper trapezius, anterior deltoid, serratus anterior, and pectoralis major and were expressed as percentage of maximal isometric contractions.
Significant differences were found across the weight-bearing conditions for all 4 muscles. Exercise on the Cuff Link required minimal to significant amounts of muscle recruitment.
Muscle recruitment increases as weight bearing increases during use of the Cuff Link, suggesting an increase in dynamic stabilization of the glenohumeral joint.
Nicole M. Livecchi, Charles W. Armstrong, Mitchell L. Cordova, Mark A. Merrick and James M. Rankin
To compare average electromyogram (EMG) activity of the vastus medialis obliquus (VMO) and vastus lateralis (VL) during straight-leg raise (SLR) and knee extension (KE) with the hip in neutral and lateral rotation.
1 × 4 factorial repeated-measures.
13 male college students.
SLR with hip flexed at 40°, in neutral position, and maximally laterally rotated and KE with hip in neutral and maximally laterally rotated.
Main Outcome Measure:
Average EMG activity during each of the 4 conditions, normalized against peak muscle activity during that trial.
No differences were observed between exercises in VMO activity (F
3,36 = 0.646, P > .05), VL activity (F
3,36 = 1.08, P > .05), or VMO:VL ratio (F
3,36 = 0.598, P > .05).
Electrical activity of the VMO or VL and VMO:VL ratio do not change with hip position or exercise.