[Purpose] To examine the reliability of using a manual goniometer for measuring the range
of dart-throwing motion. [Participants and Methods] The range of dart-throwing motion in
24 healthy participants was measured by three raters on the same day, and one rater
repeated the measurement on another day of the same week. The stationary arm of the
goniometer was placed along the radius, and the moveable arm was placed along the shaft of
the second metacarpal, approximately 45° supinated from Lister’s tubercle. All of the
participants performed the dart-throwing motion on a plane that passed through the
anatomical neutral wrist position, inclined 45° to the orthogonal anatomical plane.
[Results] The intra-rater reliability was moderate (0.5–0.75) only for some parameters of
the radial extension, and the intraclass correlation coefficients (ICCs) of all other
parameters were <0.5. For the inter-rater reliability, the ICCs of all parameters were
<0.5. Brand-Altman analysis revealed some fixed biases between the raters, although no
proportional bias was observed. [Conclusion] The goniometric measurement procedure
examined in this study appeared to be unsuitable for clinical use because of its poor
reliability.