(29) CHANGES IN FORCE-VELOCITY CHARACTERISTICS OF HEX-BAR LOADED JUMPS IN COLLEGIATE LACROSSE ATHLETES DURING A COMPETITION SEASON

A proportionate reduction in time designated to resistance training is common due to tactical and technical shifts in on-field training during competitive lacrosse seasons. Thus, monitoring potential changes in training-based performance outcomes may provide strength and conditioning practitioners and team sport coaches with helpful information concerning appropriate training stimuli necessary to enhance physical qualities underpinning performance throughout a competitive season. 

Purpose:  The purpose of this study was to examine the force-velocity (F-V) performance changes of hexagonal bar (HEX) jumps that occur in collegiate male lacrosse athletes over the course of a competition season. 

Methods:  Twenty-two male lacrosse athletes (Body mass: 85.57 + 9.74 kg) performed two maximal effort countermovement HEX jumps with five different loads (0%, 30%, 50%, 70%, 100%) relative to body mass. Each participant performed jump trials on bilateral force plates (Hawkin Dynamics Inc., Maine, USA) with a sampling rate set at 1000 Hz. Paired sample t-tests were used to analyze the statistical significance (p < 0.05) (Wilcoxon’s signed-rank test for non-parametric data) between F-V metrics before the first game and after the last regular season game. 

Results:  System weight significantly (p = 0.009) increased along with peak propulsive force (p = 0.01) and peak propulsive power (p = 0.03) with the unloaded condition. The relative peak propulsive force during the 0% condition, although not significant (p = 0.06), did increase throughout the season. The non-parametric Wilcoxon signed-rank test was used, indicating non-significant differences (p = 0.26) in jump height but significant differences in peak propulsive force (p = 0.01) and mRSI (p = 0.01) yielding rank-biserial correlation effect sizes (rB) of small-medium (0.27), large (0.62), and large (0.56), respectively. The 30% loaded condition yielded significant increases in system weight (p = 0.02) and mRSI (p = 0.01) with significant decreases in time to takeoff (p = 0.009). The 50% loaded condition produced significant increases in system weight (p = 0.003), peak propulsive power (p = 0.02), mRSI (p = 0.03), and significant decreases in time to takeoff (p = 0.02). The 70% load yielded significant increases in system weight (p = 0.003) and propulsive impulse (p = 0.03), while significant decreases in braking time (p = 0.04) were observed. The 100% loaded condition yielded significant increases in system weight (p = 0.005), peak propulsive power (p = 0.03), and propulsive impulse (p = 0.04). 

Conclusions:  The results of the jumps provided the context for longitudinal assessment strategies for strength and power metrics during a college lacrosse season. All outcome test metrics did not decline throughout the season despite the reduced in-season strength and power training volume and the increased demands of practices, games, and travel. Therefore, coaches can use in-season monitoring to ensure the maintenance and/or improvement of base-level F-V attributes that underpin on-field performance. PRACTICAL APPLICATION: Practitioners may use the results as a potential starting point in optimizing power production with effective dosing while managing accumulated fatigue during congested practice and competition schedules to enhance the underpinning neuromuscular qualities for performance enhancement during a competition season.
 

Acknowledgements: None