UNLABELLED: Lumbar range of motion (ROM) is essential to develop effective movements during the underwater undulatory swimming technique. Core exercises are used to improve the strength of the muscles that participate in that technique, and variations in sensory input and attentional focus may modulate neuromuscular responses and impact training outcomes. The aim of this study was to investigate the impact of an 11-week program of repeated maximal lumbar movements with closed eyes and without focused attention on lumbar sagittal ROM in elite swimmers versus executing them solely with proper exercise technique with controlled breathing. METHODS: A sample of 57 professional swimmers, including 34 males (20.2 ± 4.2 years) and 23 females (20.7 ± 3.3 yrs), volunteered to complete this study. They were randomly divided into two experimental groups (EG1 and EG2) and one control group (CG). All subjects underwent the same type of training program in parallel with the EG intervention. EG1 and EG2 performed three sets of ten repetitions of lumbar flexion and extension exercises at breathing pace, 6 days a week for 11 weeks. EG1 performed the core workout with closed eyes and focused attention on the lumbar movement, while EG2 only followed the technique of the exercises at a controlled breathing pace. Lumbar flexion (F), extension (E), and total ROM (TROM) were assessed by an electrogoniometer in a seated, relaxed position over a Swiss ball. RESULTS: Repeated measures ANOVA showed significant differences in the multivariate profiles across groups and over time. F (8, 48) = 3.495, CONCLUSIONS: The results suggest that repeating maximal lumbar movement at a controlled breathing pace, with opened eyes and non-focusing attention on the movement, increases lumbar ROM in the sagittal plane.