VALIDATION OF TWO CLINICAL MEASURES OF CORE STABILITY

Abstract

Background: Emerging evidence suggests poor core stability is a risk factor for low back and lower extremity injuries in athletes. Recently the trunk stability test (TST) and unilateral hip bridge endurance test (UHBE) were developed to clinically assess core stability. Although these and other clinical tests of core stability exist, how well they assess core stability when compared to biomechanical measures of isolated core stability has not been thoroughly evaluated.

Purpose/hypothesis: The purposes of this study were to 1) determine concurrent validity of two novel clinical core stability assessments (TST and UHBE), and 2) assess relationships between these assessments and the trunk endurance and Y-Balance tests. The authors' hypothesized that the TST and UHBE would be highly correlated to the lab-based biomechanical measure of isolated core stability. Also, the TST and UHBE would be moderately correlated with each other, but not with the trunk extensor endurance and Y-Balance.

Study design: Cross-Sectional design.

Methods: Twenty healthy active individuals completed the TST (recorded number of errors), UHBE (s), trunk extensor endurance (s), Y-Balance (% leg length) test (YBT), and biomechanical test of core stability.

Results: Correlational analyses revealed a small, non-significant association between TST and biomechanical measures (rs = 0.2 - 0.22), while a moderate, significant relationship existed between UHBE and biomechanical measures (rs = -0.49 to -0.56, p < 0.05). There was little to no relationship between TST and UHBE (r = -0.07 to - 0.21), or TST and extensor endurance (r = -0.18 to -0.24). A moderate, significant association existed between TST and two reach directions of the YBT (r = -0.41 to -0.43, p < 0.05).

Conclusions: Study data support the utility of UHBE as a clinical measure of core stability. The poor relationship between the TST and biomechanical measures, combined with observation of most control faults occurring in the lower extremity (LE) suggest the TST may not be an appropriate clinical test of core stability.

Levels of evidence: Level 3.

Keywords: athletic injuries; core stability; neuromuscular control.

Figures

Figure 1.

Unilateral Hip Bridge Endurance Test. Test requires an individual to maintain a neutral pelvis in both the transverse and sagittal planes for as long as possible with one leg planted and one leg extended.

Figure 2.

A. Trunk Stability Test (TST). B. Lab-based biomechanical test of isolated core stability. The lab-based test reduces influence of the lower extremities by strapping the legs together and supporting the feet on the footplate that is attached to the chair thereby eliminating control of the chair through the lower extremities. The TST requires the same trunk and arm position as the lab-based test; however, one foot is allowed to remain in contact with the floor.

Figure 3.

Trunk Extensor Endurance Test. The trunk extensor endurance test requires an individual to maintain neutral trunk and pelvic alignment in the sagittal plane for as long as possible.

Figure 4.

Y-Balance Test (YBT). A) Anterior Reach (YBT ANT); B) Posteromedial Reach (YBT PM); C) Posterolateral Reach (YBT PL). YBT tests require balance and control in dynamic single-limb stance while reaching as far as possible in three directions.