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This study aimed to evaluate whether the development and/or maintenance of chronic-latent muscle hyperalgesia is modulated by P2X3 receptors. We also evaluate the expression of P2X3 receptors and PKCε of dorsal root ganglions during these processes. A mouse model of chronic-latent muscle hyperalgesia, induced by carrageenan and evidenced by PGE 2 , was used. Mechanical muscle hyperalgesia was measured by Randall-Selitto analgesimeter. The involvement of P2X3 receptors was analyzed by using the selective P2X3 receptors antagonist A-317491 by intramuscular or intrathecal injections. Expression of P2X3 and PKCε in dorsal root ganglion (L4-S1) were evaluated by Western blotting. Intrathecal blockade of P2X3 receptors previously to carrageenan prevented the development and maintenance of acute and chronic-latent muscle hyperalgesia, while intramuscular blockade of P2X3 receptors previously to carrageenan only reduced the acute muscle hyperalgesia and had no effect on chronic-latent muscle hyperalgesia. Intrathecal, but not intramuscular, blockade of P2X3 receptors immediately before PGE 2 , in animals previously sensitized by carrageenan, reversed the chronic-latent muscle hyperalgesia. There was an increase in total and phosphorylated PKCε 48 h after the beginning of acute muscle hyperalgesia, and in P2X3 receptors at the period of chronic muscle hyperalgesia. P2X3 receptors expressed on spinal cord dorsal horn contribute to transition from acute to chronic muscle pain. We also suggest an interaction of PKCε and P2X3 receptors in this process. Therefore, we point out P2X3 receptors of the spinal cord dorsal horn as a pharmacological target to prevent the development or reverse the chronic muscle pain conditions.

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Purpose: The aim of the current study was to examine the variation on the kinematic parameters in the basketball shot associated with the shooting distance. Methods: Twenty-seven female adolescent basketball players aged 12.1 ± 0.9 years completed 10 BS trials from a frontal position of 4.75 m and 5.75 m from the basket. Nine anatomical markers were placed on the participants’ dominant side to assess the kinematic variables. The following variables were analyzed: angle, velocity, and height at ball release; centre of mass horizontal displacement and maximum height attained; maximum hip height and hip height at release; shoulder, elbow, and knee angular position and velocity at ball release; deepest knee flexion during the preparatory phase; the peak of the angular velocity of the shoulder, elbow, and knee joints. Results: At release, the angle decreased while velocity increased significantly at 5.75 m. During the release, greater shoulder flexion and increased joint (shoulder and knee) angular velocity were observed. The deepest knee flexion and the centre of mass horizontal displacement were accentuated at 5.75 m. The ball release occurred before the peak of the jump phase. Conclusions: To compensate for the long ball trajectory to the basket, participants perform a set of adjustments in the body segmental organization to increase the ball velocity at release. The coaches’ feedback should focus on the shooting arm’s positioning and in the jump phase (to jump as close to vertical as possible). Also, a consistent shooting technique should be acquired close to the basket before expanding the shooting range.

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