Doctor of Philosophy (PhD)



Document Type



Core stability is a concept in the health and fitness professions which became popular in the early 1990s. Despite its popularity, core stability remains a generalized term, which is poorly understood and lacks a universal definition and gold standard assessment. This makes it difficult to identify the role of core stability in athletic injury prevention and performance. To better assess core stability, the objective for this dissertation was to construct a reliable core stability index using measurements which best define and evaluate core stability. The purpose of our first experiment was to introduce and determine the intra-tester reliability of clinical measurements which may relate to core stability. Thirty-five tests which may assess core stability were identified and grouped in five catagories: strength, endurance, flexibility, motor control, and function. Intraclass correlation coefficients were calculated to establish intra-rater reliability. There were highly reliable tests in each of the five groups. Overall, core endurance tests were the most reliable measurements, followed by the flexibility, strength, motor control, and functional tests. Experiment 2 was divided into two parts. The objective of the first part was to determine the relationships between the Star Excursion Test and the Frontal Plane Projection Angel (FPPA) of the knee during a single leg squat and drop, and the 35 tests which may relate to core stability introduced in Experiment 1. Pearson correlation coefficient analysis was performed to determine the relationships between the assessments and the core stability related tests. Overall the relationship between the clinical assessments and core stability related tests had low correlations. Therefore, the three clinical assessments we selected may not thoroughly assess core stability. In the second part of Experiment 2 an index was developed that thoroughly evaluates core stability. The results in this study are beneficial to the practice of assessing core stability as well as the fields of sports medicine, occupational medicine, and fitness. Core stability is a complex concept that is composed of different components including strength, endurance, flexibility, and motor control. In the present study, a core stability index was but more work is needed to validate the model.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Li, Li



Included in

Kinesiology Commons