Coefficient of variation in maximal and feigned static and dynamic grip efforts

Area of Science:

• Biomechanics
• Kinesiology
• Rehabilitation Science

Background:

• Assessing genuine effort in grip strength testing is crucial for accurate diagnosis and treatment.
• The coefficient of variation (CV) has been proposed as a potential indicator of feigned effort.

Purpose of the Study:

• To evaluate the validity of the coefficient of variation (CV) in identifying feigned grip effort.
• To determine if CV can reliably distinguish between maximal and simulated grip strength.

Main Methods:

• Seventeen healthy females (20-25 years) performed maximal and feigned isometric and isokinetic (concentric, eccentric) grip efforts.
• Grip strength was measured using Jamar and KinCom dynamometers.
• The coefficient of variation was calculated for both maximal and feigned efforts.

Main Results:

• The CV was significantly lower for maximal effort compared to feigned effort across all measurement conditions (P < 0.0001).
• A substantial overlap in CV values between maximal and feigned efforts was observed.
• This overlap resulted in very low test sensitivities.

Conclusions:

• The coefficient of variation is not a valid tool for identifying feigned grip effort in healthy individuals.
• Measurement method (isometric, isokinetic) did not improve the validity of CV for detecting feigned effort.
• Further research may be needed to identify more sensitive methods for detecting non-genuine grip effort.