Biodynamics and Human Performance Center

Determining the Most Effective Feedback Method in Teaching the Abdominal Drawing-in Maneuver in Subjects with Low Back Pain: A Randomized Clinical Trial

Authors: Smith, M, Farthing, D, Jackson, A, Wofford, N


Purpose/Hypothesis: The classification approach is a reliable and valid method of treating individuals with low back pain (LBP). Core stabilization is one facet of this approach, and the transverse abdominis (TrA) is thought to be the foundation. Preferential activation is defined as the ability to contract the TrA with minimal contraction of the internal and external obliques (IO and EO). Different teaching techniques for TrA activation are commonly used in the clinic, but little evidence exists to suggest one is superior. The purpose of this randomized clinical trial is to determine whether verbal feedback, verbal feedback with sphygmomanometer, or verbal feedback with rehabilitative ultrasound imaging (RUSI) is most effective in teaching individuals with LBP to selectively activate their TrA.

Number of Subjects: 55

Materials/Methods: Inclusion criteria included the following: age 18-40, LBP for three months or more, no symptoms distal to the knee, normal lower-quarter neurological screen, no previous TrA training, and not pregnant. After signing informed consent, subjects were randomized into one of the following feedback groups: verbal, verbal with sphygmomanometer, or verbal with RUSI. Examiner #1, blinded to intervention group, measured baseline rested and contracted values of TrA and EO+IO using RUSI. Examiner #2, blinded to measurements taken, administered a five minute teaching session with the randomly selected feedback method. Examiner #1 then re-measured TrA and EO+IO values. A home exercise program (HEP) was provided with an associated compliance log, consisting of the abdominal drawing-in maneuver (ADIM) twice daily. Follow-up measurements were taken, using the pretest protocol,  after four weeks of a HEP program. Three two-way repeated measures ANOVAs were performed to assess between and within group differences.

Results: Pilot study results of TrA and EO+IO measurements yielded .77-.91 intrarater and .85-.95 interrater reliability. At baseline, there was no difference in ability to contract TrA among the three groups. Preferential TrA activation showed significant within group differences over time (p=.017) regardless of intervention group, even after applying a Bonferroni correction. Post-hoc t-tests revealed significant post-training to follow-up (p=.017) and pre-training to follow-up values (p=.026). After applying a Bonferroni correction, post-training to follow-up values remained significant.

Conclusion: In teaching symptomatic subjects to preferentially activate the TrA, all three feedback methods were effective. Significant results were found comparing the ability to preferentially activate the TrA before and after a four week HEP.

Clinical Relevance: Verbal instruction and sphygmomanometers are both convenient and low cost methods for stabilization instruction and were found to be equally as effective as RUSI in subjects with LBP.

Keywords: transverse abdominis, rehabilitative ultrasound imaging, lumbar stabilization

National Meeting Presentation:

Research poster presentation at the American Physical Therapy Association Combined Sections Meeting in Las Vegas, NV, February, 2014.