Muscle Activation Differences Between CKCUEST and Modified CKCUEST: A Pilot Study

Area of Science:

• Biomechanics
• Exercise Physiology
• Orthopaedic Rehabilitation

Background:

• The diagnostic validity of traditional shoulder orthopaedic tests is increasingly questioned.
• Functional tests like the Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST) are gaining traction in clinical practice.
• Electromyography (EMG) provides objective measures of muscle activity during functional tasks.

Purpose of the Study:

• To compare the electromyography (EMG) activity of key shoulder muscles during the CKCUEST and a modified version.
• To evaluate muscle activation patterns in a healthy adult population using these two functional tests.

Main Methods:

• Ten males and ten females from a university setting participated.
• Participants underwent the CKCUEST and modified CKCUEST.
• EMG activity of the infraspinatus, anterior deltoid, and upper trapezius was measured for both upper limbs.

Main Results:

• The CKCUEST demonstrated significantly higher EMG activation (p < 0.01) for the infraspinatus, anterior deltoid, and upper trapezius compared to the modified CKCUEST.
• No significant differences in muscle activation were found based on laterality (p > 0.05) for any of the analysed muscles during the CKCUEST.

Conclusions:

• The CKCUEST elicits greater EMG activation in the analysed shoulder muscles than the modified CKCUEST.
• This suggests the CKCUEST may be a more effective functional test for evaluating shoulder muscle engagement in healthy individuals.
• The findings are consistent across both sides of the body, indicating no significant laterality effect.