Effects of Strength Training on Sleep Parameters of Adolescents: A Randomized Controlled Trial

Santiago, LCS, Lyra, MJ, Germano-Soares, AH, Lins-Filho, OL, Queiroz, DR, Prazeres, TMP, Mello, MT, Pedrosa, RP, Falcão, APST, and Santos, MAM. Effects of strength training on sleep parameters of adolescents: a randomized controlled trial. J Strength Cond Res XX(X): 000-000, 2020-This study aimed to examine the effects of 12-weeks of strength training (ST) on sleep quality and daytime sleepiness in adolescents with sleep complaints. Thirty adolescents were randomly assigned to 2 groups: ST group (ST, n = 18) and control group (CG, n = 12). Anthropometric, body composition, one-repetition maximum test, and sleep parameters (Pittsburgh Sleep Quality Index [PSQI] and Epworth Sleepiness Scale [ESS]) were evaluated. Training consisted of 55 min·d (3 times a week, for 12-weeks), 3 sets of 10-12 repetitions with a 1-minute rest interval between sets and exercises. Baseline and postintervention differences were analyzed using Generalized Estimating Equations and the effect size (ES) with Cohen's d coefficient. Significance was set at (p < 0.05). After 12-weeks of ST, a significant decrease in the PSQI score (7.3 ± 0.7 vs. 5.1 ± 0.6; ES = 4.10) was observed in the ST group, but not in the CG (6.3 ± 0.8 vs. 7.4 ± 0.7; ES = 1.53). A significant decrease in ESS score was found in the ST group (10.1 ± 0.7 vs. 8.2 ± 0.7; ES = 3.08), without differences in the CG (10.7 ± 0.8 vs. 11.0 ± 0.7; ES = 0.56). The ST group presented increased total sleep duration (h·min) (6.2 ± 0.2 vs. 6.9 ± 0.2; ES = 3.60), but not the CG (7.0 ± 0.2 vs. 6.8 ± 0.1; ES = 1.32). Individual analyses showed ≈67% of adolescents experienced a reduction in PSQI (8.3; confidence interval [CI] 95% 6.8-10.1) and ESS (8.3; CI 95% 6.7-9.9) scores after ST, whereas only ≈17% of control participants presented reduced scores (PSQI [11.1; CI 95% 9.5-12.9] and ESS [11.0; CI 95% 9.4-12.6]). Strength training improved sleep quality and increased total sleep duration.