Reliability and Validity of the Athletic Shoulder (ASH) Test Performed Using Portable Isometric-Based Strength...

Area of Science:

• Biomechanics
• Sports Medicine
• Rehabilitation

Background:

• The Athletic Shoulder (ASH) test quantifies shoulder girdle force production and transfer.
• Assessing the reliability and validity of portable devices for the ASH test is crucial for practical application.

Purpose of the Study:

• To determine the reliability and validity of the Active5™ isometric strength training device for ASH testing.
• To compare Active5™ performance against a gold standard force plate (K-Force plates).

Main Methods:

• Fifty-one healthy participants completed the ASH test using both Active5™ and K-Force plates across three sessions.
• Maximal bilateral force was measured in a prone position at 180°, 135°, and 90° shoulder abduction angles.
• Intraclass correlation coefficient (ICC) assessed reliability; Pearson's correlation coefficient (r) evaluated validity.

Main Results:

• Active5™ demonstrated good to excellent reliability (ICC = 0.77–0.99).
• High to very high correlations were found between Active5™ and force plates at 180° and 90° abduction (r = 0.75–0.95).

Conclusions:

• The Active5™ device is a reliable and valid tool for performing the ASH test.
• This finding supports the use of Active5™ as a practical alternative to force plates for shoulder strength assessment.