Previous studies suggest that a pre-performance left-hand contraction protocol can lead to better performance under pressure compared to a right-hand contraction protocol (Beckmann, Gröpel, & Ehrlenspiel, 2013; Gröpel & Beckmann, 2017). Left-hand contractions possibly suppress engagement of cognitive verbal processes in the left-brain hemisphere, which reduces conscious control of movement. In this study, we examined whether left-hand contractions suppress engagement of cognitive verbal processes when preparing to move. N = 28 participants performed three hand contraction protocols in a randomised order; left, right and no hand contractions. Each protocol was followed by a golf-putting task, consisting of 25 putts to a given target. Electroencephalography connectivity between the left hemisphere verbal-analytical (T7) brain region and the frontal motor planning (Fz) brain region was analysed for the three seconds leading up to golf putting, to evaluate cognitive verbal processes engaged in motor planning (Gallicchio, Cooke, & Ring, 2016). Left-hand contractions led to significantly lower T7-Fz connectivity during movement preparation compared to right-hand and no hand contractions. Right-hand contractions led to significantly higher T7-Fz connectivity, compared to no hand contractions. Pre-performance hand contraction protocols, therefore, had different effects on verbal cognitive processes during preparation for a golf-putting task by activating the contralateral brain hemisphere. The left-hand contraction protocol lowered engagement in cognitive verbal processes, whereas the right-hand contraction protocol increased engagement in cognitive verbal processes. This study increases understanding of the cognitive processes potentially responsible for stable performance under pressure after a left-hand contraction protocol.