THE INTRA-RATER AND INTER-RATER RELIABILITY OF SCAPULAR ASSYMETRY ASSESSMENT IN VOLLEYBALL ATHLETES WITH CLINICAL EVALUATION METHODS

E. Paraskevopoulos¹, G. Plakoutsis¹, G. Gioftsos¹, G. Georgoudis¹, M. Papandreou¹

Background: It has been suggested that Scapular Asymmetries (SA) can have a significant effect on shoulder function and in the development of shoulder pain. SA present with increased protraction and depression in the dominant side and can be seen in either symptomatic or asymptomatic athletes. These are much more prominent in unilateral overhead athletes.
Several clinical evaluation methods of SA have been used in the past in order to detect SA. However, less is known about the intra-rater and inter-rater reliability of these methods in professional volleyball players.

Purpose: The aim of this retrospective study was to establish the intra-rater reliability of five different methods for quantifying SA in asymptomatic professional volleyball players.

Methods: Ten male asymptomatic professional volleyball players were recruited (Age 30.5±2.67 years, BMI 23.1±0.32). In regards to sample size, for an expected reliability of 92%, based on the findings of previous studies, and an acceptable reliability of at least 60%, in order to represent substantial reliability, 9 athletes were required for 5% significance level and a power of 80% for two examiners or at two different time points. These five methods measured a series of anthropometric characteristics of the scapula including
1) Height asymmetries of the Scapulae (SH),
2) the difference in the distance between the scapulae from the spine (DS),
3) the difference in the Posterior Displacement of each Scapula from the thoracic cage with a modified caliper (SPD), as well as,
4, 5) the posterior displacement of both scapulae from the thoracic cage in a static (SPDR) and a dynamic position (SPD-PUE). A written informed consent, which was approved by the University, was obtained from all the athletes who participated in this study. All experimental procedures conformed to the Declaration of Helsinki. The research protocol was approved by the University of West Attica.

Results: Reliability values for the first and the second method were excellent for the inter-rater (ICC 0.90-0.97; SEM 0.17-0.16) and the intra-rater (ICC 0.90-0.98; SEM 0.16-0.13) evaluation. For the third method, the inter-rater and the intra-rater values were good to excellent (ICC 0.84-0.92; SEM 0.23-0.13). The last two methods showed good to acceptable inter-rater (ICC 0.70-0.68; SEM 0.23-0.27) and intra-rater values (ICC 0.66-0.77; SEM 0.20 for both). The Bland and Altman analysis did not reveal any systematic bias in any method.

Conclusion(s): The findings of the present study propose several reliable methods for evaluating SA of asymptomatic male professional volleyball players in clinical practice. The Bland and Altman plots constructed in the study, along with the SEM and the SDD calculations, allowed to conclude that the methods proposed should reliably measure male asymptomatic overhead athletes.

Implications: It would be regarding the reliability of several evaluation methods in scapula asymmetry assessment as an important diagnostic tool in overhead athletes.

Funding, acknowledgements: No funded this work

Keywords: Scapula asymmetry, Volley ball players, Clinical evaluation

Topic: Sport & sports injuries

Did this work require ethics approval? Yes

Institution: University of West Attika, Athens, Greece

Committee: President: Dr. Anna Deltsidou

Ethics number: 29230/27-04-2020