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Validity and reliability of the BTE dynatrac
J G Richards1, E J Quigley, P W Castagno
1Sport Science Laboratory, University of Delaware, Newark 19716, USA.
Medicine and Science in Sports and Exercise
|July 1, 1996
Summary
The BTE Dynatrac is a reliable and objective isotonic machine for measuring joint work and power. Its position and velocity measures are valid, though moment measures consistently underestimate results.
Area of Science:
- Biomechanics
- Kinesiology
- Rehabilitation Engineering
Background:
- Isotonic machines are crucial for assessing joint function.
- The BTE Dynatrac is designed to measure isolated joint work and power.
- Validating its performance is essential for clinical and research applications.
Purpose of the Study:
- To validate the static and dynamic response characteristics of the BTE Dynatrac.
- To assess the within-tester reliability of the Dynatrac.
- To determine the between-tester objectivity of the Dynatrac.
Main Methods:
- External force and position sensors were used for validation.
- 20 subjects performed power and work tests under four different testers.
- Intraclass correlation coefficients (ICC) were calculated for reliability and objectivity.
Main Results:
- Dynatrac's position and velocity measures showed close agreement with external sensors.
- Moment measures from the Dynatrac consistently underestimated external sensor values.
- High within-tester (ICC > 0.70) and between-tester (ICC > 0.68) reliability/objectivity were observed for power and work variables, with exceptions for specific knee extension torques.
Conclusions:
- The BTE Dynatrac demonstrates good reliability and objectivity for measuring joint power and work.
- Lever arm position and velocity measures are valid.
- Moment measurements require careful interpretation due to consistent underestimation.