Effects of instructional and motivational self-talk on the vertical jump.

The purpose of this study was to investigate the effects of instructional and motivational self-talk on performance and the kinematics of the vertical jump. After completing a 10-minute warm-up on a stationary bike, 12 men (mean +/- SD; 20.8+/- 3.0 years, 77.8 +/- 13.5 kg, 1.78 +/- 0.07 m) and 12 women (22.1 +/- 5.8 years, 62.6 +/- 6.7 kg, 1.65 +/- 0.05 m) performed 4 vertical jumps, 3 minutes apart, on a force plate set at a 1000-Hz sampling frequency. Before each trial, participants engaged in 1 of 4 counterbalanced interventions, verbalized out loud, which included motivational self-talk, instructional self-talk, neutral self-talk, or no instruction. One-way analysis of variance with repeated measures, followed by paired t-tests with a Bonferroni adjustment, were used to analyze data. Both instructional (0.415 m) and motivational (0.414 m) self-talk led to greater center-of-mass displacement than neutral self-talk (0.403 m, p = 0.001 and 0.003, respectively, alpha set at 0.008). Both instructional (263.9 N x s) and motivational self-talk (261.2 N x s) led to greater impulse than neutral self-talk (254.1 N x s, p = 0.005 and 0.004, respectively, alpha set at 0.025). Both instructional self-talk (582.6 degrees x s-1) and motivational self-talk (592.3 degrees x s-1) led to quicker angular rotation about the knee than neutral self-talk (565.8 degrees x s-1, p = 0.001 and 0.018, respectively, alpha set at 0.025). These results may indicate that self-talk leads to greater angular velocity about the knee, thus generating greater impulse and increased jump height-a conjecture that needs empirical testing. Self-talk may contribute to improved performance in sports requiring power-based skills.