The Test-Retest Reliability of a Low-Cost, Portable Tension Dynamometer (2024)

Undergraduate: Skyler Peterson

Faculty Advisor: Jeffrey Turner
Department: Exercise and Sport Science

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Introduction: Muscle strength is a risk factor for injuries of the lower extremity. Tension dynamometry is a common method for measuring muscle strength. However, many portable tension dynamometers are costly (>$1,000). Newer affordable tension dynamometers, such as the Progressor 150 by Tindeq ($150), have little research concerning their reliability. Thus, the purpose of this study was to determine the test-retest reliability of the Progressor 150 in the measurement of thigh muscle strength in healthy individuals. _x000D_
Methods: 30 participants were recruited (12 male, 18 female). Written consent was obtained, and strength tests were performed across two separate visits 1-week apart. Knee flexion and extension maximal isometric strength were tested at a 90-degree knee angle. The Progressor 150 device was attached to the participant’s working limb with an ankle strap and was anchored perpendicular to them resisting the direction of force. Intraclass correlation coefficients (ICC 2,1) were used to assess absolute agreement between the visits and within-person. The measures of interest included average peak torque, average rate of torque development (RTD) peak, and average RTD 20-80% of peak torque. _x000D_
Results: All knee extension measurements indicated good to excellent reliability (ICC: 0.746 - 0.944). All knee flexion measurements had a consistently lower reliability than knee extension indicating moderate to good reliability (ICC: 0.676 - 0.898). Bland-Altman plots indicated minimal bias. Peak RTD demonstrated large limits of agreement indicating large measurement error. _x000D_
Conclusion: The Progressor 150 by Tindeq was a reliable form of measuring muscle strength, particularly peak torque and RTD 20-80%.