Dynamic and Isometric Force-Time Curve Characteristics Influencing Change of Direction Performance of State-Level Netball Players.

ABSTRACT: Smolarek, T, Haff, GG, Poon, WCK, Nagatani, T, Barley, OR, and Guppy, SN. Dynamic and isometric force-time curve characteristics influencing change of direction performance of state-level netball players. J Strength Cond Res 37(12): 2397-2404, 2023-Although multiple lower-body strength capacities are required to change direction rapidly, there is limited knowledge about the relative importance of these factors. Therefore, the purpose of this study was to assess the relationship between dynamic and isometric lower-body strength capacities and change of direction (COD) time in state-league netball players. Seventeen female athletes completed maximal isometric midthigh pull (IMTP), countermovement jump (CMJ), and modified 5-0-5 COD tests. Pearson's product moment correlations were used to determine the relationship between COD time and several IMTP and CMJ force-time curve characteristics. To assess the level of contribution of each force-time curve characteristic to COD time, multivariate-linear stepwise regression analyses were performed. A significant moderate correlation was noted between net relative peak force (PF) during the IMTP and COD time ( r = 0.488, p = 0.047), accounting for 23.8% of the variance in COD time. Moreover, concentric relative impulse during the CMJ was strongly correlated with COD time ( r = 0.718; p = 0.001), explaining 81.9% of the variance in COD time when combined with net relative braking PF in a stepwise regression. Based on these findings, female netball players who display higher concentric and isometric strength, as well as the ability to express higher impulses during the concentric phase of the CMJ, are likely to perform CODs faster. This may occur because COD requires the generation of greater propulsive forces, as well as reduced braking and contact times, along with greater isometric strength enabling effective repositioning of center of mass during COD tasks.

Effect of 3 Different Set Configurations on Kinematic Variables and Internal Loads During a Power Snatch Session.

ABSTRACT: Nagatani, T, Kendall, KL, Guppy, SN, Poon, WCK, and Haff, GG. Effect of 3 different set configurations on kinematic variables and internal loads during a power snatch session. J Strength Cond Res 37(10): 1929-1938, 2023-The aim of this study was to investigate the effect of 3 different set configurations on kinematic variables and internal loads during multiple sets performed with the power snatch. Ten strength-power athletes with at least 6 months of training experience performing the power snatch participated in this study, which consisted of 3 experimental protocols performed in a randomized repeated-measures design. The 3 protocols involved performing the power snatch for 3 sets of 5 repetitions at an average load of 75% 1 repetition maximum with a traditional (TRAD), cluster (CLU), or ascending cluster (A-CLU) protocol, where the training load was progressively increased across the set. Kinematic variables and internal loads (heart rate, blood lactate, and rate of perceived exertion) were measured during each protocol. The athletes maintained peak velocity (PV) and peak power (PP) and exhibited lower internal loads during CLU sets when compared with TRAD sets, whereas they displayed significant decreases in PV during TRAD sets. However, there were no statistically significant differences in PV and PP responses between the TRAD and CLU protocol. The athletes exhibited a significant decrease in PV, whereas PP was increased across each set in the A-CLU protocol, with lower internal loads observed compared with the TRAD protocol. Overall, the training loads used in this study do not appear to maximize the benefits of using CLU set during 3 sets of power snatches performed for 5 repetitions. In addition, A-CLU sets may potentially be useful as a means of maximizing the power output of the athlete.