Subjective sleep quality and sustained attention before and after a 24-hour smartphone restriction in adolescent swimmers: a single-group pretest–posttest study

Excessive smartphone use among adolescents has been associated with poorer sleep and attention, but evidence on short-term restriction in young athletes is limited. This study examined changes in subjective sleep quality and sustained attention in adolescent swimmers before and after a 24-hour smartphone restriction period. In this single-group pretest–posttest study, 43 competitive swimmers aged 10–16 years (12.84 ± 1.90 years; 26 male) completed a 24-hour smartphone restriction, verified with tamper-evident sealed bags. Subjective sleep quality was assessed with a 10-cm visual analogue scale (VAS; 0 cm = good, 10 cm = poor sleep) and sustained attention with the Bourdon Attention Test (accuracy and completion time) immediately before and after the restriction period. VAS sleep scores decreased from 2.93 ± 1.96 to 1.91 ± 1.80 cm (mean difference − 1.01, 95% CI − 1.46 to − 0.56; p < .001; dz = 0.69), indicating better self-rated sleep quality after the restriction period. Bourdon total accuracy increased by 6.30 correct responses (95% CI 3.80 to 8.80; p < .001; dz = 0.78) and total completion time decreased by 32.4 s (95% CI 20.5 to 44.3; p < .001; dz = 0.84). Pre–post changes did not differ detectably by sex or habitual screen time; swimmers with higher habitual screen time reported poorer sleep across both sessions ( p = .023, ηp² = 0.12). In adolescent swimmers, self-rated sleep quality, Bourdon Attention Test accuracy and completion time improved after a 24-hour smartphone restriction period. Because the study had no control condition, these changes cannot be attributed specifically to smartphone restriction and may partly reflect practice effects; randomised controlled studies are needed. Not applicable. (This study evaluated a behavioral intervention in an athletic training setting rather than a clinical trial).