Objective: Core stability is a complex concept within sports medicine and is thought to play a role in sports injuries. There is a lack of reliable and valid clinical tests for core stability. The inter- and intraobserver reliability of 6 tests commonly used to assess core stability was determined.
Design: A video of the tests was shown to 6 observers. A second observation took place 5 weeks later with the same observers.
Setting: Sports medicine department of a hospital.
Participants: Forty male athletes.
Assessment of Variables: Core stability was rated as poor, moderate, good, or excellent by each observer for each of the 6 tests.
Main Outcome Measures: Inter- and intraobserver reliability.
Results: The mean score of all tests was 13.4% poor, 33.3% moderate, 40.1% good, and 13.2% excellent. The intraclass correlation coefficients (ICCs 2,1) for the interobserver reliability for frontal, sagittal, and transverse plane evaluation were 0.09, 0.32, and 0.51, respectively. The ICCs for the unilateral squat, the lateral step-down, and the bridge were 0.41, 0.39, and 0.36, respectively. The ICCs for the intraobserver reliability for frontal, sagittal, and transverse plane evaluation were 0.31, 0.40, and 0.55, respectively. The ICCs for the unilateral squat, the lateral step-down, and the bridge were 0.55, 0.49, and 0.21, respectively.
Conclusions: The 6 clinical core stability tests are not reliable when a 4-point visual scoring assessment is used. Future research on movement evaluation should be focused on more specific rating methods and training for the observers.