In cognitive–motor dual-task situations, the extent of performance decrements
is influenced by the attentional requirements of each task. Well-learned motor
skills should be automatized, leading to less interference. This study presents two
studies combining an episodic memory encoding task with well-practiced motor
tasks in athletes. Study 1 asked 40 rowers (early teenagers to middle adulthood)
to row on ergometers at slow or fast speeds. In study 2, Taekwondo athletes
(n = 37) of different skill levels performed a well-practiced sequence of martial
arts movements. Performing the motor task during encoding led to pronounced
performance reductions in memory in both studies, with costs of up to 80%.
Cognitive costs were even larger when rowing with the fast compared to the slow
speed in study 1. Both studies also revealed decrements in motor performances
under dual-task conditions: Rowing became slower and more irregular (study 1),
and the quality of the Taekwondo performance was reduced. Although higherlevel athletes outperformed others in motor skills under single-task conditions,
proportional dual-task costs were similar across skill levels for most domains. This
indicates that even well-practiced motor tasks require cognitive resources
