Intra-rater reliability, inter-rater reliability and minimal detectable change of the posterior shoulder endurance test in elite athletes.

OBJECTIVE

Investigate intra-rater and inter-rater reliability of the posterior shoulder endurance test (PSET) and calculate minimal detectable change (MDC) to establish measurement properties and inform use of the PSET in practice.

STUDY DESIGN

Test-retest reliability.

SETTING

British Canoe Slalom National Training Centre.

PARTICIPANTS

Twelve participants (7 male, 5 female; 22.5 ± 4.48 years; 73.4 ± 6.36 kg) were investigated by two physiotherapists with >10 years' experience.

MAIN OUTCOME MEASURE

Intraclass correlation coefficients (ICC) were calculated for intra-rater reliability (ICC 3,1) and inter-rater reliability (ICC 2,1) and used to calculate MDC.

RESULTS

Intra-rater reliability scores were 0.84 and 0.85 for rater A and B, respectively, with 95% confidence interval (CI) crossing moderate to excellent reliability for both raters (0.5-0.75 and > 0.9). Inter-rater reliability scores were 0.74 and 0.63 at baseline and follow-up, respectively, with 95% CI crossing poor to good reliability in both time points (<0.5 and >0.75). MDC95% for intra-rater scores was 6 repetitions, MDC95% for inter-rater scores was 8 repetitions at baseline and 9 repetitions at follow-up.

CONCLUSION

The PSET has acceptable intra-rater reliability but further work is needed to narrow the CI to an appropriate level for inter-rater reliability. The MDC calculated helps clinicians interpret changes in tests scores.