Purpose/aim: This study investigated the intrarater reliability and concurrent validity of active shoulder mobility measurements using a digital inclinometer and goniometer.
Materials/methods: Two investigators used a goniometer and digital inclinometer to measure shoulder flexion, abduction, internal and external rotation on 30 asymptomatic participants in a blinded repeated measures design.
Results: Excellent intrarater reliability was present with Intraclass Correlation Coefficients (ICC- 3,k) for goniometry ≥ 0.94 and digital inclinometry ≥ 0.95. The concurrent validity between goniometry and digital inclinometry was good with ICC (3,k) values of ≥ 0.85. The 95% limits of agreement suggest that the difference between these two measurement instruments can be expected to range from 2° to 20°.
Conclusions: The results cautiously support the interchangeable use of goniometry and digital inclinometer for measuring shoulder mobility measurements. Although reliable, clinicians should consider the 95% limits of agreement when using these instruments interchangeably as clinically significant differences are likely to be present.
Level of evidence: 2b.
Keywords: Goniometry; inclinometry; reliability; shoulder; validity.