Effects of wrist kinematic coupling movements during dart-thrower's motion

Recently, researchers have been paying more attention to the dart-throwers' motion since this oblique motion is intrinsic to humans; and it leads to distinct advantages in early human evolutionary development. Despite the pivotal role of this motion, it has received relatively few formal investigations in regards to real-time data measurement due to the limitations in image acquisition speeds. This study used inertial measurement unit (IMU) sensors to examine the ranges of flexion-extension and radial-ulnar deviation movements measured in anatomical plane and oblique plane. The trials involved 15 healthy subjects and 8 patients having four-corner fusion and radioscapholunate fusion. The results from the experiments demonstrated a significant difference between the range of flexion-extension motion in the anatomical plane and in the oblique plane while the results did not imply the same conclusion for the radial-ulnar deviation range. Thus, our findings emphasized the importance of using dart-thrower's motion to examine the functionality of the wrist rather than basic motions in the anatomical plane.