Self-talk Influences Vertical Jump Performance and Kinematics in Male Rugby Union Players

We examined the effects of instructional and motivational self-talk on centre of mass displacement and hip kinematics during the vertical jump. Twenty four male rugby union players (age 21.1, s = 3.5 years, weight 81.0, s = 8.9 kg, height 1.80, s = 0.06 m) performed three vertical jump tests, interspersed with a two minute rest. Prior to each jump, participants engaged in one of three counterbalanced interventions (motivational self-talk, instructional self-talk, or no-intervention). Motivational self-talk led to greater centre of mass displacement (0.602, s = 0.076 m, p = 0.012) than the no-intervention control (0.583 ± 0.085 m). Centre of mass displacement did not differ between instructional self-talk and the control condition or between motivational and instructional self-talk. Motivational (100.75, s = 16.05º, p = 0.001) and instructional self-talk (106.14, s = 17.04º, p = 0.001) led to greater hip displacement than the no-intervention control (94.11, s = 17.14º). There was also a significant difference in hip displacement between motivational and instructional self-talk (p = 0.014), although there was no difference between instructional self-talk and the control condition. Motivational (451.69, s = 74.34 º/s, p = 0.008) and instructional self-talk (462.01, s = 74.37 º/s, p = 0.001) led to greater hip rotation velocity than the no-intervention control (434.37, s = 75.37 º/s), although there was no difference between the two self-talk interventions. These results indicate that self-talk may influence performance and technique during the vertical jump in male rugby players.