The relationship between two power-grip testing devices and their utility in physical capacity evaluations

Area of Science:

• Rehabilitation Medicine
• Orthopedics
• Physical Therapy

Background:

• Accurate assessment of physical capacity is crucial for diagnosing and managing upper-extremity impairments.
• Evaluating consistency of effort is challenging but vital for reliable physical capacity evaluations (PCEs).
• Existing methods for grip strength assessment may have limitations in capturing functional status and effort consistency.

Purpose of the Study:

• To compare the reliability of two isometric grip testing devices: the Jamar dynamometer and the Isometric Strength Testing Unit (ISTU).
• To determine the efficacy of combining data from these devices for assessing functional status and consistency of effort in PCEs.
• To develop and evaluate a novel index (2-ratio) for functional status and effort consistency.

Main Methods:

• Recruited 26 healthy subjects and 40 patients with upper-extremity impairments.
• Measured maximal isometric grip force using both the Jamar dynamometer and the ISTU.
• Analyzed the relationship between force outputs from the two devices.
• Developed and applied a 2-ratio index using data from both devices.

Main Results:

• High correlation was found between power-grip force outputs from the Jamar dynamometer and the ISTU.
• This indicates the utility of both devices for PCEs involving wrist-hand function.
• A simple 2-ratio index was developed, demonstrating potential for assessing functional status and effort consistency.

Conclusions:

• Isometric grip testing devices demonstrate reliable and related force outputs for wrist-hand involvement.
• Combining data from multiple devices enhances the assessment of functional status and effort consistency.
• The developed 2-ratio index shows promise for improving the sensitivity of PCEs.