Limited Effects of a 6-Month Training Period on Repeated-Sprint Performance, Blood Lactate, and Jump Performance in Competitive Swimmers.

Purpose: This study prospectively monitored changes in repeated-sprint swimming performance, blood lactate ([La]) concentration, and countermovement-jump (CMJ) performance during a 6-month training period with traditionally periodized endurance training in competitive swimmers.

Methods: Twenty well-trained sprint and middle-distance swimmers (mean [SD]; age = 18 [2] y, body mass = 69.6 [8.0] kg, height = 179 [6.1] cm) underwent body-composition assessment and completed a 7 × 50-m repeated-sprint test, with measurements of [La] and CMJ, before (October, preparation period) and after (April, early-competition period) a 6-month training period using traditional periodization.

Results: There were no significant improvements in swimming velocity, CMJ height, or changes in [La] from October to April, with considerable individual variation. However, there was a small but significant increase in fat-free mass (mean difference ± SD: 0.9 ± 2.2 kg), albeit with a small effect size, and no changes in body fat or body mass. Significant and expected decreases in performance (swimming and CMJ) across the repetitions of the 7 × 50-m repeated-sprint tests were observed, accompanied by increases in [La], all with large effect sizes, but there was no evidence that training affected these results (no significant interactions).

Conclusion: A 6-month training period with traditionally periodized endurance training failed to significantly improve repeated-sprint swimming performance, [La] response, or CMJ height in trained swimmers across the 2 training phases.