Summary:
This study examined the effect of 8 weeks of plyometric training, on lower limb muscle power and agility, in preadolescent athletes. Fifty, female ‘Gymnastics for All’ gymnasts (age: 8.0 ± 0.7 years, training experience: 2.4 ± 0.6 years,) were randomly assigned to a training group (n=33) that performed plyometric training twice a week, in addition to gymnastics training, and a control group (n=17). Gymnasts underwent the following tests: one and two-leg counter movement jumps, drop jump, squat jump, standing long jump, 10 and 20 m sprints, and two change of direction tests: 10 m (5 + 5 m with a 180° turn) and 20 m (10 + 10 m with a 180° turn). The tested variables were measured pre, post 8 weeks of training and 2 weeks into detraining. Τhere was a main effect for time (p= 0.01) in all the examined variables, except for 10 + 10 m with a 180° turn (p˃0.05). There were no significant group Χ time interactions in all the examined variables, except for 20 m sprint speed (p= 0.02). In the training group, effect sizes for pre- and post- intervention values were small for 10 + 10 m with a 180° turn (d= 0.2-0.5), moderate for one and two-leg counter movement jumps, drop jump, squat jump (d= 0.5 – 0.8), and large for standing long jump, 5 + 5 m with a 180° turn, and sprints tests (d˃0.8). In the control group, effect sizes were small (d= 0.2-0.5) for one leg counter movement jump and squat jump, moderate for drop jump and 10 sprint (d= 0.5 – 0.8), and large for standing long jump (d˃ 0.8). In conclusion, eight weeks of plyometric training induces small but practically significant increases in lower limb muscle power and agility in young female gymnasts.
