title: Validity and reliability of the abdominal test and evaluation systems tool (ABTEST) to accurately measure abdominal force.
abstract: OBJECTIVE
  Ability 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.
  
  
  METHODS
  This 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.
  
  
  METHODS
  Participants 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.
  
  
  RESULTS
  Test, 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).
  
  
  CONCLUSIONS
  Data 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.
authors.affiliation: Human Performance Laboratory, Department of Health, Human Performance, and Recreation, University of Arkansas, United States.
authors.forename: Jordan M
authors.initials: JM
authors.lastname: Glenn
authors.affiliation: Human Performance Laboratory, Department of Health, Human Performance, and Recreation, University of Arkansas, United States.
authors.forename: Madeline
authors.initials: M
authors.lastname: Galey
authors.affiliation: Human Performance Laboratory, Department of Health, Human Performance, and Recreation, University of Arkansas, United States.
authors.forename: Abigail
authors.initials: A
authors.lastname: Edwards
authors.affiliation: Human Performance Laboratory, Department of Health, Human Performance, and Recreation, University of Arkansas, United States.
authors.forename: Bradley
authors.initials: B
authors.lastname: Rickert
authors.affiliation: Human Performance Laboratory, Department of Health, Human Performance, and Recreation, University of Arkansas, United States; Exercise Muscle Biology Laboratory, Department of Health, Human Performance, and Recreation, University of Arkansas, United States. Electronic address: tawashin@uark.edu.
authors.forename: Tyrone A
authors.initials: TA
authors.lastname: Washington
mesh_terms: D064131:Back Muscles / Q000502:physiology; D004576:Electromyography; D005080:Exercise Test; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D053580:Muscle Strength; D052097:Quadriceps Muscle / Q000502:physiology; D017568:Rectus Abdominis / Q000502:physiology*; D015203:Reproducibility of Results; D055815:Young Adult
keywords: Abdomen; Abdominal muscles; Back; Core strength; Electromyography; Power