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Purpose: To assess the effects of periodized versus nonperiodized dry-land strength training (DLST) on indices of swimming performance in well-trained adolescent swimmers. Methods: Sixteen athletes (10 boys and 6 girls; age 14.9 [1.1] y) performed similar endurance training for 16 weeks (29.1 [7.5] km·wk−1). During weeks 1 to 7, all athletes additionally performed 2 or 3 times weekly whole-body DLST (3 × 6–10 repetitions at 75–85% 1-repetition maximum [1RM]). Thereafter, the DLST frequency was maintained, but athletes were stratified into periodized (experimental, n = 9) and nonperiodized (control, n = 7) DLST groups. The experimental group performed maximal (3 × 3–4 repetitions at 85–90% 1RM) and explosive DLST (throws and unloaded jumps), while in the control group, DLST was maintained. Results: Swimming time at 4 mmol·L−1 of blood lactate improved after 7 weeks in both the experimental (+2.6% [1.8%], P = .033) and the control groups (+3.2% [2.4%], P = .081) and plateaued thereafter. Ten-meter start improved in both the experimental (−3.6% [2.5%], P = .039) and the control groups (−5.1% [2.2%], P = .054) throughout the entire intervention. Both groups improved in maximal weight lifted in half-squat (experimental, +19.6% [14.9%], P = .021; control, +25.7% [18.4%], P = .054) and bench press (experimental, +14.1% [4.8%], P = .018; control, +19.3% [11.1%], P = .051). Countermovement-jump height increased only in the experimental group throughout the intervention (+19.4% [7.0%], P = .024). The associations for the pooled changes in half-squat performance and 4 mmol·L−1 of blood lactate were statistically significant (r = .560, P = .024). Conclusions: The findings do not support the superior effects of DLST periodization in adolescent swimmers. However, the association between improvements in lower-body strength and swimming performance still indicates the importance of muscle strength in this age group.
Schumann and Notbohm are with the Dept of Molecular and Cellular Sports Medicine, German Sport University Cologne, Cologne, Germany. Bäcker and Clephas are with the Inst of Sport Science, Christian-Albrechts-University Kiel, Kiel, Germany. Klocke and Fuhrmann are with the Olympic Training Facility Hamburg/Schleswig-Holstein, Hamburg, Germany.