Interdevice reliability and validity assessment of the Nicholas Hand-Held Dynamometer

Area of Science:

• Biomechanics
• Rehabilitation Engineering
• Musculoskeletal Research

Background:

• The Nicholas Hand-Held Dynamometer (HHD) demonstrates high reliability for repeated measurements using the same device.
• Clinical settings often utilize multiple HHD units for patient assessments.
• Assessing consistency between different HHD units is crucial for accurate and comparable patient data.

Purpose of the Study:

• To evaluate the interdevice reliability of the Nicholas Hand-Held Dynamometer (HHD).
• To determine the validity of the Nicholas HHD by comparing its measurements to a criterion standard.
• To investigate if measurements from two identical HHDs are consistent for hamstring strength assessment.

Main Methods:

• Thirty healthy female subjects participated in the study.
• Hamstring strength was measured using two identical Nicholas Hand-Held Dynamometers (Device A and Device B).
• Measurements were compared against a Kin-Com isokinetic dynamometer as the criterion standard for validity.

Main Results:

• The intraclass correlation coefficient (ICC) between the two HHDs was low (ICC = .58), indicating poor interdevice reliability.
• Pearson correlation coefficients showed strong agreement between each HHD and the Kin-Com (r = .85 for Device A, r = .83 for Device B).
• Analysis of variance revealed no significant difference between Kin-Com and Device A, but a significant difference between Kin-Com and Device B (p < .001).

Conclusions:

• Measurements obtained from two identical Nicholas Hand-Held Dynamometers may not be interchangeable.
• Clinicians should exercise caution when comparing hamstring strength data collected from different HHD units.
• Further research may be needed to understand and mitigate interdevice variability in HHD measurements.