Purpose:
Effective control of swimming speed can increase training effectiveness and therefore enhance training adaptations. The aim of the present study was to investigate the effects of concurrent visual feedback on swimming speed at an exercise intensity above the onset of blood lactate accumulation (OBLA).

Methods:
The study involved 12 healthy male and female swim team members. The participants executed two 200-m freestyle trials within an individually predetermined swim time matching an exercise intensity above OBLA (exercise zone 4). In one trial, no additional information was provided, whereas concurrent visual feedback was given on swimming speed in the other.

Results:
Concurrent visual feedback narrowed the discrepancy between the predetermined and obtained swimming times (p < 0.001). This improvement in swimming time (accuracy) showed a negative correlation with the increase in post-trial lactate concentration. The correlation between the difference in the predetermined and obtained times and the increase in lactate was R = –0.46 when no visual feedback was provided but R = –0.64 with visual feedback, with the latter result statistically significant (p = 0.024).

Conclusions:
Concurrent visual feedback allows swimmers to consistently maintain a predetermined swimming speed and therefore keep the specified exercise intensity as evidenced by the increase in lactate concentration. This can result in more effective execution of training goals and thereby enhance training outcomes.