PREVIOUS DYNAMIC AND BALISTIC CONDITIONING CONTRACTIONS CAN ENHANCE SUBSEQUENT THROWING PERFORMANCE Theodoros M. Bampouras 1 , Alex Gill 2 , Irini Tzidimopoulou 3 , Dr Joseph I. Esformes 2 1 Faculty of Health and Wellbeing, University of Cumbria, Lancaster, UK 2 Cardiff School of Sport, University of Wales Institute, Cardiff, Cardiff, UK 3 Tae-Kwon-Do Athletic Club Egaleo, Athens, Greece 19th International Congress of Physical Education and Sport Democritus University of Thrace Komotini, Greece, 20-22 May 2011 Introduction Previous muscle activity can potentiate subsequent muscle performance, a phenomenon known as postactivation potentiation (Tillin and Bishop, 2009). Although heavy load dynamic exercise has been successfully used to acutely enhance subsequent explosive performance (Esformes et al, 2010), little information exists for ballistic activity as a conditioning contraction (CC). The purpose of this study was to determine whether throwing performance could be enhanced if preceded by heavy dynamic (DYN) or ballistic (BAL) CCs. Methods Eleven male, competitive rugby players (mean±SD: age 21.0±1.1; body mass 91.3±10.2 kg; height 179.7±3.7 cm) performed a ballistic bench press throw (pre-BBPT) at 40% of 1 repetition maximum (1RM) followed by a 10-min rest and one of the CCs. The CCs, applied on separate days and in counterbalanced randomized order, were 1 set of 3 repetitions of bench press (DYN) at ~85% of 1RM or BBPT at 30% of 1RM (BAL). After a 4-minute rest, the subjects performed another BBPT (post-BBPT). A schematic diagram of the experimental procedures can be seen in Fig. 1. Peak power (Ppeak), force (Fpeak), distance (Dmax), and velocity (Vpeak), and rate of force development (RFD), force at peak power (F@Ppeak), and velocity at peak power (V@Ppeak) were measured using a linear position transducer (Ballistic Measurement System, Fitness Technology, Skye, South Australia, Australia). Fig. 1. Schematic diagram of the experimental procedures. Measures of performance during a ballistic bench press throw (BBPT) were taken before (baseline; pre-BBPT) and after (post-contraction; post-BBPT) the conditioning stimuli, which were either 1 set of 3 repetitions of bench press at ~85% of 1RM or a BBPT at 30% of 1RM performed on separate days and in randomised, counterbalanced order. Statistical analysis As some data were not normally distributed, Friedman’s test was employed to examine for differences within each variable, followed by Wilcoxon’s test when significant differences were identified. No correction for pairwise comparison was applied and significance level was set at 0.05. Results No significant differences were revealed for Fpeak, F@Ppeak, Ppeak, and RFD (P>0.05) for any CC (Table 1). However, significant differences were revealed for Dpeak for the BAL only (P<0.05), and for Vpeak (P<0.05) and V@Ppeak (P<0.05) for both interventions (Table 1). Table 1. Pre- and post-BBPT performance variables scores (mean±SD) following heavy load dynamic (DYN) and ballistic (BAL) conditioning contractions. Discussion Our findings indicate that ballistic conditioning contractions can improve subsequent throwing performance, while performance improvements that relate to velocity can be enhanced by both ballistic and dynamic contractions. Although, on this occasion, the change in velocity was not sufficient to cause a change in power or indeed a shift of the power curve (Cormie et al, 2009), future studies should explore different loads and rest intervals, as power- curve changes have been shown to be of great importance in monitoring and performance. References Cormie P, McBride JM, McCaulley GO. (2009). J Strength Cond Res, 23, 177-186. Esformes JI, Cameron N, Bampouras TM. (2010). J Strength Cond Res, 24, 1911-1916. Tillin NA, Bishop D. (2009). Sports Med, 39, 147-166. Contact Theodoros M. Bampouras Senior Lecturer in Sport Mechanics and Performance Analysis E-mail: [email protected] Pre-BBPT 10’ rest Conditioning Contraction 4’ rest Post-BBPT BAL DYN Variables Pre Post Pre Post Ppeak (W) 378.7 ± 68.5 436.8 ± 71.5 350.1 ± 118.7 451.9 ± 103.2 Fpeak (N) 380.2 ± 75.6 413.3 ± 110.2 416.1 ± 71.7 390.8 ± 94.9 Dpeak (m) 0.20 ± 0.05 0.25 ± 0.05* 0.25 ± 0.14 0.26 ± 0.06 Vpeak (ms -1 ) 1.1 ± 0.4 1.2 ± 0.3* 1.0 ± 0.5 1.3 ± 0.2* RFD (Ns -1 ) 9291 ± 1904 9563 ± 1980 10550 ± 1562 9441 ± 1866 F@Ppeak (ms -1 ) 319.0 ± 58.6 328.1 ± 63.0 349.5 ± 47.0 326.3 ± 70.1 V@Ppeak ((ms -1 ) 1.0 ± 0.4 1.2 ± 0.2* 0.9 ± 0.5 1.2 ± 0.2* Ppeak, Peak power; Fpeak, peak force; Dpeak, maximal displacement; Vpeak, peak velocity; RFD, rate of force development; F@Ppeak, force at peak power; V@Ppeak, velocity at peak power. * indicates significant pre-post difference (P<0.05).