Reliability and concurrent validity of the Active Movement Scale (AMS) in adults with musculoskeletal disorders

The Active Movement Scale (AMS) is a brief screen for identifying movement impairments affecting functional task performance.

To assess inter-rater reliability, test-retest reliability, floor and ceiling effects, and concurrent validity of the AMS in adults with musculoskeletal disorders.

Fifty-five subjects (mean age: 61.3±15.3 years) transitioning from physical therapy attended two sessions. The 14-item AMS was assessed by two therapists, resulting in a total score (AMST) and two sub-scores: upper body (AMSU) and lower body (AMSL). Moreover, subjects completed PROMIS Physical Function-10a (PPF), Lifestyle Physical Function (LPF), Cardio Activity Level (CAL) surveys, Two Square Agility Test (TSAT), WorkAbility Rate of Manipulation Turning (WRMT) and Placing (WRMP), Grip Strength (GS), 10-Meter Walk Usual (GSU) and Fast (GSF) pace, and Grooved Pegboard Placing (GPP) and Remove (GPR) tests.

Inter-rater reliability coefficients for AMST, AMSU, and AMSL were 0.96, 0.92, and 0.96, respectively, with individual item reliability ranging from 0.58 to 1.0. Test-retest reliability for these assessments yielded coefficients of 0.93, 0.84, and 0.94, with individual item reliability ranging from 0.47 to 0.88. No floor effects were observed, but mild ceiling effects were noted. AMST showed a high correlation with LPF (r = 0.72) and moderate correlation with PPF (r = 0.64) surveys. AMSU had moderate correlations with GPP (r = 0.61) and WRMP (r = 0.57) tests, while AMSL correlated moderately with GSF (r = 0.55) and TSAT (r = 0.50) tests.

This study provides evidence of the reliability and validity of AMS in adults with musculoskeletal disorders to support transitions between rehabilitation and fitness programs.