RELIABILITY OF SHOULDER ROTATION MOVEMENT MEASURED BY THE SMARTPHONE CLINOMETER APPLICATION

Abstract

Goniometry is widely used to measure range of motion (ROM), but requires skill and training. In this sense, smartphone
apps appear as an alternative. The objective was to assess the reliability and validity of shoulder rotation measurements using a
smartphone clinometer app. This study approved by Ethical and Research Committee of the University of Pernambuco. Thirty six
(36) healthy and physically active adolescents and young adults participated in the study. In the measurement each volunteer
performed external (ER) and internal (IR) rotation of the shoulder in the supine and side lying positions. The shoulder rotation ROM
was measured by a goniometer and an application. ER and IR were measured in two days by two evaluators. Reliability was determined
using intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimum detectable change (MDC). Validity
was assessed using Pearson's correlation coefficients. Both devices had excellent intra- and inter-examiner reliability levels in most
evaluations. However, the goniometer showed moderate inter-examiner reliability in measuring the internal rotation performed in the
lying position (ICC 0.61 to 0.67). The app showed inter-examiner reliability ranging from fair to moderate for the same measurements
(ICC 0.35 to 0.61). Significant differences were observed between the values recorded by the two instruments for all measurements
performed (p <0.001). A strong correlation was observed between measurements in the supine and side lying positions with the
goniometer and a smartphone clinometer app (r> 0.85). The application presented excellent reliability levels as well as demonstrated
a high correlation with the goniometer. However, the assessment of IR lying down position should be avoided.