The effects of plyometric jump training on jump and sport-specific performances in prepubertal female swimmers

Background/objective: Dry land-training (e.g., plyometric jump training) can be a useful mean to improve swimming performance. This study examined the effects of an 8-week plyometric jump training (PJT) program on jump and sport-specific performances in prepubertal female swimmers. Methods: Twenty-two girls were randomly assigned to either a plyometric jump training group (PJTG; n = 12, age: 10.01 +/- 0.57 years, maturity-offset = -1.50 +/- 0.50, body mass = 36.39 +/- 6.32 kg, body height = 146.90 +/- 7.62 cm, body mass index = 16.50 +/- 1.73 kg/m(2)) or an active control (CG; n = 10, age: 10.50 +/- 0.28 years, maturity-offset = -1.34 +/- 0.51, body mass = 38.41 +/- 9.42 kg, body height = 143.60 +/- 5.05 cm, body mass index = 18.48 +/- 3.77 kg/m(2)). Pre- and post-training, tests were conducted for the assessment of muscle power (e.g., countermovement-jump [CMJ], standing-long-jump [SLJ]). Sport-specific-performances were tested using the timed 25 and 50-m front crawl with a divingstart, timed 25-m front crawl without push-off from the wall (25-m WP), and a timed 25-m kick without push-off from the wall (25-m KWP). Results: Findings showed a significant main effect of time for the CMJ (d = 0.78), the SLJ (d = 0.91), 25-m front crawl test (d = 2.5), and the 25-m-KWP (d = 1.38) test. Significant group x time interactions were found for CMJ, SLJ, 25-m front crawl, 50-m front crawl, 25-m KWP, and 25-m WP test (d = 0.29-1.63) in favor of PJTG (d = 1.34-3.50). No significant pre-post changes were found for CG (p > 0.05). Conclusion: In sum, PJT is effective in improving muscle power and sport-specific performances in prepubertal swimmers. Therefore, PJT should be included from an early start into the regular training program of swimmers. (C) 2020 The Society of Chinese Scholars on Exercise Physiology and Fitness. Published by Elsevier (Singapore) Pte Ltd.