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Isokinetic, isometric and isotonic strength relationships
Archives of Physical Medicine and Rehabilitation
|February 1, 1983
Summary
This study found that isokinetic, isometric, and isotonic strength tests measure the same core concept: maximal voluntary strength. These different strength testing methods show high correlations in healthy young men.
Area of Science:
- Biomechanics
- Human Physiology
- Exercise Science
Background:
- Understanding the relationships between different strength measurement modes is crucial for accurate physical assessment.
- Isokinetic, isometric, and isotonic contractions represent distinct ways of measuring muscular force production.
Purpose of the Study:
- To examine the correlations between isokinetic, isometric, and isotonic strength measurements.
- To determine if these different strength testing modes assess a common underlying physical capacity.
Main Methods:
- Sixteen healthy young men participated in the study.
- Strength measurements were taken for knee and elbow extension and flexion using isokinetic (Cybex II) and isotonic (NK table) devices.
- Isokinetic testing was performed at multiple velocities (36, 108, 180 degrees/sec).
Main Results:
- High correlations (mean = 0.78) were observed among isokinetic, isometric, and isotonic strength measurements across four muscle groups.
- The common variance indicated that all three testing modes likely measure maximal voluntary strength.
- Correlations decreased as isokinetic velocities and joint angles diverged within muscle groups.
Conclusions:
- Isokinetic, isometric, and isotonic strength testing methods are highly related and can be considered measures of the same phenomenon: maximal voluntary strength.
- These findings support the use of any of these methods for assessing maximal voluntary strength, with considerations for velocity and joint angle effects.