Randomized Clinical Trial
Copyright ©The Author(s) 2025. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Methodol. Mar 20, 2025; 15(1): 92943
Published online Mar 20, 2025. doi: 10.5662/wjm.v15.i1.92943
Effect of external and internal cues on core muscle activation during the Sahrmann five-level core stability test
Skyla Stifter, Jessie McCaffrey, Tyler Nichols, Ayse Ozcan Edeer, Justine Ward
Skyla Stifter, Jessie McCaffrey, Tyler Nichols, Ayse Ozcan Edeer, Justine Ward, Physical Therapy, Dominican University New York, Orangeburg, NY 10962, United States
Co-corresponding authors: Ayse Ozcan Edeer and Justine Ward.
Author contributions: Literature review, methodology, review of data and written paper were performed equally between Stifter S, McCaffrey J and Nichols T. Nichols T marked the exact locations for each of the electrodes indicating TA/IO, EO and RA (details provided in methods). He then provided a razor to each participant so they could shave off excess hair where electrodes were to be placed. He also pre-recorded an audio recording of both internal and external cues. These cues were then placed into a video that included subtitles for participants to hear and read for each level (details provided in the methods.) Nichols T also explained the flow of the study and where the ASIS landmarks were for internal cue groups. Stifter S collected informed consent and intake forms from all participants and randomly allocated group numbers. She strategically placed PBU between lumbar spine segments L4-L5 and asked participants to position themselves into Level 1 of the five-level core stability test where the PBU was then inflated to 40 mmHG (research indicated in background). She created all graphs and figures for written paper. Jessie McCaffrey performed all required tasks using the Trigno surface EMG machine and data software, as well as downloading it to the hard drive for transfer to statistician. All the authors have read and approved the final manuscript. Ayse Ozcan Edeer played important roles in the supervision of the literature review, experimental design, training the researchers on the Trigno EMG system, EMG WorksAcqusition, EMG WorksAnalysis, data organization, interpretation of data analysis and writing the manuscript. Ward J played a key role in conceptualizing the research idea, providing clinical reasoning for the cueing, training the researchers on the application of the pressure biofeedback unit, and revising the manuscript's first draft. Co-corresponding authors Ozcan Edeer A and Ward J oversaw the entire project, providing mentorship to researchers throughout the data collection process and supporting data organization and analysis. Their contributions to revising and resubmitting the manuscript, as well as their collaboration on its publication, were essential.
Institutional review board statement: The study protocol was approved by the Dominican University New York Institutional Review Board (IRB# 2021-0329-01).
Clinical trial registration statement: There is no clinical registration number for this study.
Informed consent statement: All study participants provided informed written consent prior to study enrollment.
Conflict-of-interest statement: The authors certify that they have NO affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript.
Data sharing statement: Technical appendix, statistical code, and dataset are available from the corresponding author at ayse.edeer@duny.edu.
CONSORT 2010 statement: The authors have read the CONSORT 2010 statement, and the manuscript was revised according to the CONSORT 2010 statement.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Ayse Ozcan Edeer, PhD, Associate Professor, Physical Therapy, Dominican University New York, 470 Western Highway, Orangeburg, NY 10962, United States. ayse.edeer@duny.edu
Received: February 12, 2024
Revised: August 16, 2024
Accepted: August 26, 2024
Published online: March 20, 2025
Processing time: 229 Days and 13.6 Hours
Abstract
BACKGROUND

Pain in the back or pelvis or fear of back pain may affect the timing or co-contraction of the core muscles. In both static and dynamic movements, the Sahrmann core stability test provides an assessment of core muscle activation and a person's ability to stabilize the lumbopelvic complex. Preparatory cues and images can be used to increase the activation of these muscles. To attain optimal movement patterns, it will be necessary to determine what cueing will give the most effective results for core stability.

AIM

To investigate the effects of external and internal cues on core muscle activation during the Sahrmann five-level core stability test.

METHODS

Total 68 participants (21.83 ± 3.47 years) were randomly allocated to an external (n = 35) or internal cue group (n = 33). Participants performed the Sahrmann five-level core stability test without a cue as baseline and the five-level stability exercises with an internal or external cue. External cue group received a pressure biofeedback unit (PBU), and the internal cue group received an audio cue. A Delsys TrignoTM surface electromyography unit was used for muscle activation from the rectus abdominis, external oblique, and transverse abdominis/internal oblique muscles.

RESULTS

Linear mixed effects model analysis showed that cueing had a significant effect on core muscle activation (P = 0.001); however, there was no significant difference between cue types (internal or external) (P = 0.130).

CONCLUSION

Both external and internal cueing have significant effects on core muscle activation during the Sahrmann five-level core stability test and the PBU does not create higher muscle activation than internal cueing.

Keywords: External cue; Internal cue; Muscle activation; Core muscles; Lumbopelvic stability; Pressure biofeedback unit

Core Tip: Lumbopelvic pain can alter optimal sequencing of muscle activation leading to inadequate synergies and disrupted biomechanics within the lumbopelvic region. Retraining to regain optimal sequencing through external and internal cues can help an individual return to their prior level of function and improve optimal movement patterns. Although this study was conducted in healthy young subjects, we conclude that the use of internal and/or external cues when retraining abdominal core muscles in individuals with lumbopelvic pain would be beneficial to increase core muscle activation.