Use of a treadmill, lift, and carry battery as a composite functional performance test: analysis of data from a pragmatic randomized controlled trial in a military population participating in a functional restoration program

ABSTRACT

Background

The treadmill, lift, and carry (TLC) battery is a composite functional performance test created to measure the effectiveness of a functional restoration (FR) program in a military population.

Purpose

To determine the validity, reliability, and minimal clinically important differences (MCIDs) of the individual tests and the composite TLC battery.

Methods

We assessed the validity by mean differences, effect sizes, and standardized response means pre- and post-FR; and by correlations between the TLC battery and other established measures. We assessed reliability by correlating pre- and post-FR scores. We used principal component analysis (PCA) to create a composite measure. We determined MCIDs via distribution methods and receiver operator curve analysis.

Results

There were significant (p < .001) mean changes and large effect sizes (0.6–0.8) pre- to post-FR. Pre- and posttest Spearman’s correlations ranged from 0.5 to 0.6. Spearman’s correlations between TLC battery scores and other measures were small (± 0.3–0.4) and significant (p < .001). PCA supported use of a single-component composite. MCIDs were treadmill time: 3 minutes; metabolic equivalent of task: 1.5 units; floor-to-waist lift: 15 lbs; waist-to-shoulder lift: 10 lbs; 40-foot carry: 10 lbs; and composite score: 6 units.

Conclusion

This secondary data analysis provides preliminary support for the validity and reliability of the TLC battery for use in military populations.

KEYWORDS:

• Functional restoration
• pain
• military
• validity
• reliability

Acknowledgments

This work was supported by grants from the U.S. Army Medical Research and Materiel Command under grant number W81XWH-14-DMRDP-CRI-IRA-MTI and the National Institutes of Health under grant number K24NR015340 and grant number K24AT011995. Tandem Editing LLC provided professional editing support. The investigators have adhered to the policies for protection of human subjects as prescribed in 45 CFR 46. The views expressed are those of the authors and do not reflect the official policy of the Department of the Army, the Department of Defense, or the United States National Institutes of Health. The National Institutes of Health had no role in the design or conduct of the study; the collection, management, analysis, or interpretation of the data; the preparation, review, or approval of the manuscript; or the decision to submit the manuscript for publication.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Institute of Nursing Research [K24NR015340]; U.S. Army Medical Research and Materiel Command [W81XWH-14-DMRDP-CRI-IRA-MTI].