Tests of Muscle Strength and Physical Function: Reliability and Discrimination of Performance in Younger and Older Men and Older Men with Mobility Limitations

Authors

  • Nathan K. LeBrasseur PT, PhD,

    1. Section of Endocrinology, Diabetes and Nutrition, Department of Medicine, Boston University Medical Center, Boston, Massachusetts
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  • Shalender Bhasin MD,

    1. Section of Endocrinology, Diabetes and Nutrition, Department of Medicine, Boston University Medical Center, Boston, Massachusetts
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  • Renee Miciek MS,

    1. Section of Endocrinology, Diabetes and Nutrition, Department of Medicine, Boston University Medical Center, Boston, Massachusetts
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  • Thomas W. Storer PhD

    1. Section of Endocrinology, Diabetes and Nutrition, Department of Medicine, Boston University Medical Center, Boston, Massachusetts
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Address correspondence to Nathan K. LeBrasseur, PT, PhD, Pfizer Global Research and Development, Cardiovascular and Metabolic Disease, Eastern Point Road, MS 8220-3001, Groton, CT 06340. E-mail: nathan.lebrasseur@pfizer.com

Abstract

OBJECTIVES: To compare the reliability of muscle strength and physical function measures in younger and older men.

DESIGN: Cross-sectional.

SETTING: Academic research center.

PARTICIPANTS: Thirty younger men, 31 older men, and 39 older men with mobility limitations.

MEASUREMENTS: Test–retest measures of one repetition maximum (1 RM), unloaded and loaded 50-m walk and stair climb, and a lift-and-lower task. Reliability was assessed using intraclass correlation (ICC) analysis and the Bland-Altman method.

RESULTS: Leg and chest press 1 RM measures identified significant differences between the groups, exhibited excellent test–retest reliability in younger men, older men, and older men with mobility limitations (ICCs=0.946–0.994) and minimal bias between Trials 1 and 2 (Bland-Altman=improvement of 21.1 and 1.1 N for leg and chest press, respectively). Test–retest measures of the time to walk 50 m and climb 12 steps also demonstrated excellent agreement (ICCs=0.980–0.988 and 0.942–992, respectively) and minimal bias (Bland-Altman=0.755–1.007 and 0.141–0.361 seconds faster, respectively). When a subject repeated these measures carrying a modest load, ICCs remained greater than 0.940, bias was similar, and the tests better discriminated between the groups. The lift-and-lower measure demonstrated excellent agreement (ICCs=0.925–0.947) and minimal bias (1.4–2.9 more shelves) and revealed significant differences between groups.

CONCLUSION: Measures of muscle strength and physical function can be performed in younger men, older men, and older men with mobility limitations with high reliability. In future clinical trials, more-challenging measures of performance may better discriminate between higher-functioning study participants.

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