Reliability and validity of the multiaxis profile dynamometer with younger and older participants

Abstract

Study design: Clinical Measurement.

Introduction: Grip strength has been administered for many years with a wide variety of instruments and for very different purposes.

Purpose of the study: To examine the reliability and validity of a new grip measurement device, the multiaxis profile (MAP) dynamometer, compared with the Baseline dynamometer (Fabrication Enterprises Inc., White Plains, NY) and vigorimeter.

Methods: Twenty-eight participants (<30 yr, n=14; and >65 yr, n=14) completed grip strength testing using all three devices. Measurements were obtained at baseline and one to two weeks later.

Results: Intraclass correlation coefficients (ICCs) for the MAP ranged from 0.94 to 0.99. The other two devices had ICCs of 0.95-0.98. Correlations among the MAP dynamometer, the Baseline dynamometer, and the vigorimeter were 0.78-0.90. The results indicate high concurrent validity among all the three devices and that all devices are reliable instruments to measure the grip strength of both younger and older adults.

Conclusions: In addition to measuring grip strength, the MAP dynamometer measures other grip-related information, such as grip force vectors, rate of force buildup, and force variability. This additional grip information may improve our understanding of hand function and changes because of aging.

Level of evidence: n/a.

Figure 1

A. Baseline Dynamometer and B. Vigorimeter

Figure 2

MAP with instrumented beams identified

Figure 3

Participant hand size determined how the 6.35 cm cover was segmented

Figure 4

Vector summation of the grip forces

Figure 5

Overall grip force vector with magnitude (F) and angle (θ)

Figure 6

Representative force profile illustrating the build-up and plateau phases