[show abstract][hide abstract] ABSTRACT: ABSTRACT: The aim of this study was to examine the chronic effects of single and repeated jumps training on vertical landing force (VGRF) and jump height in untrained men. The VGRF and jump height were compared after a six-week plyometric training programme containing single and repeated jumps, together with two additional parameters: landing time (LT) and range of the knee flexion during landing (KF). Thirty-six untrained physical education students with a plyometric training background were randomly assigned to a single jump group (SJG, n =12), repeated jumps group (RJG, n =12), and control group (CON, n =12). The SJG performed only single jumps, the RJG executed repeated (consecutive) jumps, whereas the CON did not perform any exercises at all. A countermovement jump (CMJ), repeated countermovement jumps (RCMJ), and a drop jump (DJ) were tested before and after the training. Only the RJG showed a significantly reduced VGRF (p<0.05) in all tests. Both plyometric groups significantly improved (p<0.05) their jump height in all tests. The LT was significantly greater in the RJG, compared to the SJG, in all tests. The KF was also significantly (p<0.05) greater in the RJG than in the SJG for CMJ and RCMJ. The results suggest that repeated jumps are beneficial for simultaneous landing force reduction and jumping performance enhancement.
Biology of Sport 10/2013; 30(4). · 0.42 Impact Factor
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to examine how focusing attention during nine weeks of plyometric training influence jumping performance. It was hypothesized that participants utilizing an external focus of attention during practice would produce greater improvements in jumping behavior compared to participants practicing in the internal and control conditions.
Thirty-six untrained but physically active male college students were randomly assigned to 1 of 3 plyometric groups with a different focus of attention: external (EXF; N.=12), internal (INF; N.=12), and control (CON; N.=12). All participants subsequently participated in the same an 9-week periodized training program. Standing long jump (SLJ), countermovement jump (CMJ) and drop jump (DJ) were tested pre- and posttraining intervention.
The EXF group exhibited greater improvement (P<0.05) in jumping distance for SLJ and height for CMJ than both the INF and CON groups, while the enhancement in jumping height for DJ was not superior (P<0.05) in the EXF group in comparison with the INF and CON groups. However, the CON group showed a greater increase (P<0.05) in jumping height for DJ than the INF group. The EXF group increased the range of knee flexion (KF), whereas both the INF and CON groups decreased the KF during the CMJ. Additionally, only the CON group reduced KF during the execution of the DJ. The EXF group (P<0.05) increased contact time, whereas both the INF and CON groups decreased (P<0.05) contact time in DJ. The EXF group had significantly (P<0.05) greater vertical ground reaction force in CMJ and DJ when compared with the INF and CON groups.
These results suggest that the external focus of attention during plyometric training may provide a greater stimulus to jump performance in slow stretch shortening cycle (SSC) tasks by producing greater force than adopting the internal and no specific focus.
The Journal of sports medicine and physical fitness 06/2012; 52(3):319-27. · 0.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Makaruk, H, Winchester, JB, Sadowski, J, Czaplicki, A, and Sacewicz, T. Effects of unilateral and bilateral plyometric training on power and jumping ability in women. J Strength Cond Res 25(12): 3311-3318, 2011-The purpose of this study was to examine the effects of unilateral and bilateral plyometric exercise on peak power and jumping performance during different stages of a 12-week training and detraining in women. Forty-nine untrained but physically active female college students were randomly assigned to 1 of 3 groups: unilateral plyometric group (n = 16), bilateral plyometric group (BLE; n = 18), and a control group (n = 15). Peak power and jumping ability were assessed by means of the alternate leg tests (10-second Wingate test and 5 alternate leg bounds), bilateral leg test (countermovement jump [CMJ]) and unilateral leg test (unilateral CMJ). Performance indicators were measured pretraining, midtraining, posttraining, and detraining. Differences between dependent variables were assessed with a 3 × 4 (group × time) repeated analysis of variance with Tukey's post hoc test applied where appropriate. Effect size was calculated to determine the magnitude of significant differences between the researched parameters. Only the unilateral plyometric training produced significant (p < 0.05) improvement in all tests from pretraining to midtraining, but there was no significant (p < 0.05) increase in performance indicators from midtraining to posttraining. The BLE group significantly (p < 0.05) improved in all tests from pretraining to posttraining and did not significantly (p > 0.05) decrease power and jumping ability in all tests during detraining. These results suggest that unilateral plyometric exercises produce power and jumping performance during a shorter period when compared to bilateral plyometric exercises but achieved performance gains last longer after bilateral plyometric training. Practitioners should consider the inclusion of both unilateral and bilateral modes of plyometric exercise to elicit rapid improvements and guard against detraining.
The Journal of Strength and Conditioning Research 11/2011; 25(12):3311-8. · 1.80 Impact Factor