Reliability and validity of medicine ball toss tests as clinical measures of core strength

BACKGROUND: Core strengthening is a significant component of training programs utilized to optimize athletic performance, reduce injury, and facilitate return from injury. Reliable and valid clinical measures of core strength are necessary to determine the effectiveness of these programs. OBJECTIVE: The purpose was to determine the reliability and validity of three medicine ball toss tests (MBTs). METHODS: A total of 20 healthy, physically active individuals participated. Session one included isokinetic strength testing (trunk flexion/extension, and right/left rotation) and MBTs (forward, backward, and right/left rotation); session two included only the MBTs. Average peak torque during strength testing and the average distance of three MBTs in each direction were analyzed. Intraclass correlations were calculated to determine the reliability of the MBTs between sessions, while validity between MBTs and strength was assessed though Pearson correlations. RESULTS: Significant ICCs were observed between forward, backward, and right/left rotation MBTs (ICC = 0.835; ICC = 0.835; ICC = 0.870; ICC = 0.909; p < 0.001, respectively). No significant correlations were observed between the MBTs and corresponding measures of strength. CONCLUSION: Results illustrate that MBTs have excellent reliability but are not related to isokinetic strength as measured by average peak torque. This lack of relationship may be due to differences in muscles examined, contraction type, and/or motion