Protocol for forearm pronosupination strength measuring in different postures: reliability and influence of relevant factors

Importance: Despite the importance of pronosupination strength, which is key in daily activities, current evaluation protocols are disparate, and results differ regarding the influence of factors such as gender, age, limb dominance, or posture. Objective: To design a reliable device to measure pronation and supination torques in different forearm positions, the influence of gender, age, and limb dominance. Design: Reliability study with analysis of intrarater and interrater repeatability and examination of the influence of different factors on the strength of pronation and supination. Setting: Biomechanical analysis laboratory of the Instituto de Biomecánica de Valencia. Participants: Convenience sample of 39 healthy male and female participants, ages 18 to 65 yr. Outcomes and Measures: Pronation strength and supination strength were studied in five forearm positions: 30 degrees and 60 degrees of supination, neutral rotation, and 30 degrees and 60 degrees of pronation. The influence of gender, age, and limb dominance was studied using repeated-measures analysis of variance. Intrarater and interrater reliabilities were studied in 17 participants, and the intraclass correlation coefficients (ICCs) were calculated from three measurement sessions. Results: Except for 60 degrees of pronation, all ICCs ranged from .72 to .97. Gender, limb dominance, and posture significantly affected pronosupination strength (p < .05), with the highest supination strength at 60 degrees of pronation and the highest pronation strength at 60 degrees of supination. Conclusions and Relevance: In using this reliable pronosupination torque assessment device and standardized protocol in the clinical setting, clinicians must consider the influence of gender, limb dominance, and forearm posture. What This Article Adds: The results of this study will allow occupational therapists to establish differences between patients' functionality in comparison with healthy individuals and to design recovery treatments and facilitate performance of manual tasks, considering which are the most advantageous positions to exert force. Furthermore, the developed device can be used to monitor the evolution of these torques in an objective and reliable manner.