The reliability of two different cybex isokinetic systems

Area of Science:

• Biomechanics
• Exercise Physiology
• Rehabilitation Science

Background:

• Accurate muscle strength assessment is crucial for various professional fields.
• Isokinetic dynamometry is a common tool for measuring muscular strength.
• Understanding the reliability of different systems and data reduction methods is essential for consistent clinical application.

Purpose of the Study:

• To determine the intertest reliability of muscular strength measurements using two Cybex II isokinetic dynamometry systems.
• To assess the reliability of peak torque values (PTV) obtained from two data reduction methods: Cybex Data Reduction Computers (CDRC) and Cybex Strip Chart Recorders (SCR).

Main Methods:

• Fifty subjects performed knee extension/flexion cycles at two speeds (60 and 240 degrees/sec) over two test days.
• Correlation coefficients and ANOVA were used to analyze the reliability between two Cybex systems and between CDRC and SCR data reduction methods.
• Peak torque values were collected and compared across different testing conditions.

Main Results:

• Strong correlations were found between CDRC and SCR peak torque values within systems (r = 0.987, 0.985) and across systems (r = 0.983, 0.982).
• ANOVA revealed significantly higher CDRC peak torque values from the Cybex II system compared to the Cybex II+ system (p < 0.05).
• No significant differences were found between systems for SCR peak torque values (p > 0.05).

Conclusions:

• Clinicians should exercise caution as Cybex Data Reduction Computer (CDRC) peak torque values may not be comparable across different Cybex II systems.
• Peak torque values obtained using Cybex Strip Chart Recorders (SCR) appear comparable between different Cybex II systems.
• Both CDRC and SCR data reduction methods show comparable results within the same Cybex system.