Validity and reliability of the abdominal test and evaluation systems tool (ABTEST) to accurately measure abdominal force

ObjectivesAbility to generate force from the core musculature is a critical factor for sports and general activities with insufficiencies predisposing individuals to injury.This study evaluated isometric force production as a valid and reliable method of assessing abdominal force using the abdominal test and evaluation systems tool (ABTEST). Secondary analysis estimated 1-repetition maximum on commercially available abdominal machine compared to maximum force and average power on ABTEST system.DesignThis study utilized test–retest reliability and comparative analysis for validity. Reliability was measured using test–retest design on ABTEST. Validity was measured via comparison to estimated 1-repetition maximum on a commercially available abdominal device.MethodsParticipants applied isometric, abdominal force against a transducer and muscular activation was evaluated measuring normalized electromyographic activity at the rectus-abdominus, rectus-femoris, and erector-spinae.ResultsTest, re-test force production on ABTEST was significantly correlated (r = 0.84; p < 0.001). Mean electromyographic activity for the rectus-abdominus (72.93% and 75.66%), rectus-femoris (6.59% and 6.51%), and erector-spinae (6.82% and 5.48%) were observed for trial-1 and trial-2, respectively. Significant correlations for the estimated 1-repetition maximum were found for average power (r = 0.70, p = 0.002) and maximum force (r = 0.72, p < 0.001).ConclusionsData indicate the ABTEST can accurately measure rectus-abdominus force isolated from hip-flexor involvement. Negligible activation of erector-spinae substantiates little subjective effort among participants in the lower back. Results suggest ABTEST is a valid and reliable method of evaluating abdominal force.