Sport-specific endurance plank test for evaluation of global core muscle function

Objective: To examine the validity and reliability of a sports-specific endurance plank test for the evaluation of global core muscle function. Design: Repeated-measures study. Setting: Laboratory environment. Participants: Twenty-eight male and eight female young athletes. Main outcome measures: Surface electromyography (sEMG) of selected trunk flexors and extensors, and an intervention of pre-fatigue core workout were applied for test validation. Intraclass correlation coefficient (ICC), coefficient of variation (CV), and the measurement bias ratio */÷ ratio limits of agreement (LOA) were calculated to assess reliability and measurement error. Results: Test validity was shown by the sEMG of selected core muscles, which indicated >50% increase in muscle activation during the test; and the definite discrimination of the ~30% reduction in global core muscle endurance subsequent to a pre-fatigue core workout. For test-retest reliability, when the first attempt of three repeated trials was considered as familiarisation, the ICC was 0.99 (95% CI: 0.98-0.99), CV was 2.0±1.56% and the measurement bias ratio */÷ ratio LOA was 0.99*/÷1.07. Conclusion: The findings suggest that the sport-specific endurance plank test is a valid, reliable and practical method for assessing global core muscle endurance in athletes given that at least one familiarisation trial takes place prior to measurement.