Normative values for isometric muscle force measurements obtained with hand-held dynamometers

Background and Purpose. The extent of a patient's impairment can be established by comparing measurements of that patient's performance with normative values obtained from apparently unimpaired individuals. Only a few studies have described normative values for muscle strength measured by hand-held dynamometry. The purpose of this study of older adults, therefore, was to obtain normative values of maximum voluntary isometric force using hand-held dynamometers. Subjects. One hundred fifty-six asymptomatic adults (77 men, 70 women) participated in this study. The subjects' mean age was 64.4 years (SD=8.3, range=50-79). The male subjects' mean age was 64.5 years (SD=8.4, range=50-79), and the female subjects' mean age was 64.3 years (SD=8.2, range=50-79). Methods. Gender, age, dominant side, height, weight, and activity level were recorded. Eight upper-extremity movements (shoulder flexion, extension, abduction, and medial and lateral rotation; elbow flexion and extension; and wrist extension) and five lower-extremity movements (hip flexion and abduction, knee flexion and extension, and ankle dorsiflexion) were resisted by one of three experienced testers using a strain-gauge hand-held dynamometer. Results. Gender, age, and weight were identified as independent predictors of force for all muscle actions on both the dominant and nondominant sides. These variables were used, therefore, to create regression equations and normative values for the force of each muscle action. Conclusion and Discussion. The reference values provided may allow clinicians who follow the described testing protocol to estimate the severity of force-generating impairments in patients aged 50 to 79 years.