Abstract

Introduction: Plyometric training significantly improves strength performance, including in aquatic sports. Objective: To compare changes in thigh girth, hamstring flexibility, squat jump height, and 200m swimming trial time induced by plyometric training in recreationally-trained swimmers. Methods: Eighteen recreationally-trained male swimmers (age=18-20 years) were randomly divided into a plyometric training group (PTG) and a control group (CG). All the swimmers completed a six-week speed swimming training plan. In the PTG only, the last similar to 15 min of each session was replaced with plyometric exercises. The physical characteristics and the thigh girth were measured before and after the six weeks of training. In addition, sit-and-reach flexibility and squat jump tests were conducted, as well as a 200m swimming trial. Results: Two-way ANOVA with post-hoc analysis revealed an increase in sit-and-reach flexibility (PRE: 4.5 +/- 5.3 cm; POST: 10.9 +/- 5.9 cm, p0.01) and squat jump height (PRE: 24.9 +/- 3.7 cm; POST: 28.3 +/- 4.2 cm, p0.01) and a decrease in 200m-swimming time (PRE: 220 +/- 26.5 sec; POST: 204 +/- 24.4 sec, p0.01) for the PTG only. Comparing the absolute changes (post-pre) between the groups by the Student's t-test, the PTG showed a greater increase in distance reached in the sit-and-reach flexibility (PTG: 6.34 +/- 0.6 cm vs. CG: 2.4 +/- 1.2 cm, p0.01) and squat jump height (PTG: 3.4 +/- 0.7 cm vs. CG: 0.7 +/- 0.3 cm, p0.01) than the CG. In addition, the 200m swimming time decreased significantly more than in the CG (PTG: -15.1 +/- 2.4 sec vs. CG: -0.8 +/- 2.7 sec, p0.01). Conclusion: Plyometric training improves jump height, flexibility, and 200m swimming performance in recreationally-trained adult swimmers.