Study Providing Normative Data of Objective Upper Extremity Strength Measured with a Handheld Dynamometer
Wanda VanHarlinger, OTT/L; John L. Merritt, MD
Background: Muscle strength is the most important predictor of function, mobility, independence in activities of daily activities and quality of life. Manual muscle testing systems, such as the modified Kendall scale, are tools most used in clinical settings. But these scales provide only descriptive and cardinal, nor ordinal data. Such limitations impact their usefulness in objective and statistical assessments of the impact of muscle strengthening rehabilitation programs. However, tools are available that can provide objective, ordinal data for measuring key upper extremity muscle group strength. Here we provide an initial database for one such system, readily available in a clinical setting.
Method: Using the Nicholas Manual Muscle Tester (NMMT), muscle strength of 11 upper extremity muscle groups, right and left, were measured in 180 healthy subjects, 90 men, 90 women, 20-65 years old, using standardized methodologies. Data was recorded for each muscle group bilaterally in each subject.
Results: Data confirmed some expected patterns: in all muscle groups men have significantly higher strength than women, and the dominant side is stronger in men and women. A potentially clinically relevant finding included a decline in shoulder external rotator strength with age in men.
Conclusion: This study provides a normative database for clinicians and researchers who evaluate injured or impaired patients and monitor their progress. Means, standard deviations, and ranges are categorized by age, gender and hand dominance. This research provides an initial database for this handheld system. There remains a need for further and expanded database studies, for this and other dynamometer systems.