Effects of Motor Imagery Training on Shooting Performance Under Cognitive-Motor Dual-Task Conditions in Adolescent Basketball Players: A Randomized Controlled Trial

Background/Objectives: Motor imagery is a widely used mental training method in sport, yet basketball-specific evidence is heterogeneous, and its effects under concurrent cognitive load remain largely unexamined. This study examined the effects of eight weeks of PETTLEP-based motor imagery training on two- and three-point successful shot counts under single-task and cognitive-motor dual-task conditions in adolescent male basketball players. Methods: Thirty male basketball players aged 16–17 years from the youth academy of a single nationally competitive club took part in a randomized controlled, two-arm, parallel-group pretest–posttest trial, registered retrospectively at ClinicalTrials.gov (NCT07798843). Participants were allocated to a motor imagery group (IMG, n = 15) or a control group (CG, n = 15) by computer-based simple randomization. Both groups followed the same routine basketball training; IMG additionally completed three structured imagery sessions per week for eight weeks. Dynamic two- and three-point shooting performance and their dual-task versions (concurrent serial-three subtraction aloud from 100) were assessed before and after the intervention. Data were analyzed with 2 × 2 mixed design repeated measures analyses of variance, and dual-task cost (DTC) was computed at the participant level. Cognitive task accuracy and speed were not recorded. Results: Group × time interactions were significant for two-point single-task (F(1, 28) = 35.44, p < 0.001, ηp2 = 0.559), three-point single-task (F(1, 28) = 11.49, p = 0.002, ηp2 = 0.291) and two-point dual-task performance (F(1, 28) = 30.12, p < 0.001, ηp2 = 0.518), but not for three-point dual-task performance (F(1, 28) = 1.50, p = 0.231, ηp2 = 0.051). Between-group differences in change were 1.33 (95% CI 0.87 to 1.79), 0.87 (0.34 to 1.39), 2.13 (1.34 to 2.93), and 0.47 (−0.31 to 1.25) successful shots per 60 s, respectively. Under dual-task conditions, two-point performance in IMG increased in absolute terms (9.73 to 11.07 successful shots), while its relative DTC did not change significantly (14.60% to 13.13%, p = 0.461); DTC increased in CG (11.93% to 19.41%, p < 0.001), and the between-group difference in DTC change was −8.94 percentage points (95% CI −13.92 to −3.96, p = 0.001). Conclusions: Motor imagery training was associated with greater improvements in successful shot counts under both single-task conditions and the two-point dual-task condition. The between-group difference in relative dual-task cost reflected an increase in performance loss among controls rather than a decrease in the imagery group. Because cognitive task performance was not measured, these findings describe motor performance during a dual-task protocol rather than dual-task ability.