The Reliability of Strength Tests Performed In Elevated Shoulder Positions Using a Handheld Dynamometer

Area of Science:

• Sports Medicine
• Biomechanics
• Rehabilitation Science

Background:

• Reliable measurement of shoulder strength is vital for assessing athletes in overhead sports.
• Swimmers are at high risk for shoulder pain and movement issues due to repetitive overhead activities.
• Existing research has not established the reliability of isometric shoulder strength tests in elevated positions without manual stabilization.

Purpose of the Study:

• To determine the relative and absolute intrarater reliability of shoulder strength tests.
• To assess the functional relevance of these tests for swimming.
• To evaluate reliability across three common clinical body positions (supine, prone, sitting).

Main Methods:

• A repeated-measures reliability study was conducted in a research laboratory.
• Fifteen healthy university students and staff (mean age 24 years) were tested.
• Isometric shoulder strength tests (flexion, extension, internal/external rotation) were performed in elevated humeral positions using a handheld dynamometer, with retesting after 48 hours.

Main Results:

• All tested shoulder strength measures demonstrated good to excellent intrarater reliability (ICC values ranging from .87 to .99).
• Intrarater reliability remained consistent across all tested body positions.
• The minimal detectable change percentage (MDC%) was below 16% for all tests, and below 11% for tests in the supine position.

Conclusions:

• Isometric shoulder strength tests in elevated positions (flexion, extension, rotation) show excellent intrarater reliability.
• Reliability is maintained irrespective of the body position used (supine, prone, sitting).
• A strength change exceeding 15% in any tested position indicates a meaningful difference, useful for clinical assessment.