This study compared the effects of following a pacer versus following a self-paced plan on psychological responses and pacing behavior in well-trained distance runners. Pacing in the present study was individually tailored where each participant developed a personal strategy to ensure their goal time was achieved. We expected that following a pacer would associate with goal achievement, higher pre-run confidence, positive emotions and lower perceived exertion during performance. In a mixed-design repeated-measures study, nineteen well-trained runners completed two 1600m running time trials. Ten runners had a pacer (paced group) who supported their individual pacing strategy, and nine participants self-paced running alone (control group). Both groups could check pace using their wrist watch. In contrast to our expectation, results indicated that the paced group reported higher pre-run anxiety with no significant differences in finish time, goal confidence, goal difficulty, perceived exertion, and self-rated performance between groups. We suggest that following a pacer is a skill that requires learning. Following a personalised pacer might associate with higher anxiety due to uncertainty in being able to keep up with the pacer and public visibility of dropping behind, something that is not so observable in a self-paced run completed alone. Future research should investigate mechanisms associated with effective pacing.

• The presence of a pacer associated with greater pre-run anxiety and a fast-start pacing strategy during a 1600m time trial, but did not improve performance.

• The findings offer insight as to how runners self-regulate their pacing behavior to achieve a challenging goal, and the role of factors such as confidence, goal difficulty, emotions, and perceived exertion.

• Although the use of a pacer is proposed to offer a performance benefit, the evidence from this study suggests that being paced represents a novel run experience and may therefore require greater self-regulation through continuous monitoring of behavior against the pacer’s actions.