Reliability and Practicality of the Core Score: Four Dynamic Core Stability Tests Performed in a Physician Office Setting.

Objective: Pilot study to determine the practicality and inter-rater reliability of the "Core Score," a composite measure of 4 clinical core stability tests.

Design: Repeated measures.

Setting: Academic hospital physician clinic.

Participants: 23 healthy volunteers with mean age of 32 years (12 females, 11 males).

Assessment Of Variables: All subjects performed 4 core stability maneuvers under direct observation from 3 independent physicians in sequence.

Main Outcome Measures: Inter-rater reliability and time necessary to perform examination.

Results: The Core Score scale is 0 to 12, with 12 reflecting the best core stability. The mean composite score of all 4 tests for all subjects was 9.54 (SD, 1.897; range, 4-12). The intraclass correlation coefficients (ICC 1,1) for inter-rater reliability for the composite Core Score and 4 individual tests were 0.68 (Core Score), 0.14 (single-leg squat), 0.40 (supine bridge), 0.69 (side bridge), and 0.46 (prone bridge). The time required for a single examiner to assess a given subject's core stability in all 4 maneuvers averaged 4 minutes (range, 2-6 minutes).

Conclusions: Even without specialized equipment, a clinically practical and moderately reliable measure of core stability may be possible. Further research is necessary to optimize this measure for clinical application.

Clinical Relevance: Despite the known value of core stability to athletes and patients with low back pain, there is currently no reliable and practical means for rating core stability in a typical office-based practice. This pilot study provides a starting point for future reliability research on clinical core stability assessments.