مقاله انگلیسی ویژگی های جنبشی و سینماتیکی دوی سرعت با جلیقه وزن دار
Abstract
Keywords
Introduction
Methods
Results
Discussion
Funding details
Declaration of Competing Interest
Acknowledgements
Appendix A. Supplementary material
References
ABSTRACT
This study elucidated kinetic and kinematic changes between control and weighted vest sprinting with a load of 7% body mass. Fourteen male sprinters completed 60 m control and vest sprints over a long force platform system. Step-to-step ground reaction force and spatiotemporal variables were grouped, representing the initial acceleration (1st–4th steps), middle acceleration (5th–14th steps), later acceleration (15th step–step before maximum velocity reached) and maximum velocity (stride where maximum velocity reached) phase during each trial. Two-way ANOVA with post hoc Tukey HSD and a Cohen’s d effect size with 95% confidence intervals elucidated the difference between trials and phases. Between control and vest trials the velocity decreased (3.41–3.78%) through trivial–small step length (1.95–2.72%) and frequency (0.87–1.54%) decreases. Vertical impulse increased (6.46–6.78%) through moderate support time increases (4.84–6.00%), coupled with no effective vertical mean force differences during the vest trial, compared to the control. There was no significant interaction between trials and phases. Therefore, although weighted vest trials did not increase vertical mean force production, vests did induce an increased vertical force application duration during the support phase stepto-step while supporting a larger total load (body mass plus vest mass).
Introduction
Resisted sprint training (RST) is a popular modality to overload an athlete during sprinting (Alcaraz et al., 2008; Cronin and Hansen, 2006). When coupled with a well thought out training program, RST is believed to increase sprint specific neural activation and force application, compared to control sprints (no resistance), resulting in sprint specific strength benefits that translate to improved performance after RST interventions (Behrens and Simonson, 2011; Cronin and Hansen, 2006; Martínez-Valencia et al., 2015). Weighted vests (WVs) increase total object mass (athlete body mass [BM] plus WV mass) and apply greater force acting vertically due to gravitation, thus, athletes need to apply greater total (not object mass specific) ground reaction forces (GRFs) to overcome the inertia and/or vertical weight during WV sprinting to achieve the same magnitude of horizontal or vertical acceleration, compared to a control sprint. Therefore, benefits due to RST using WVs may be primarily specific to vertical force production, and previous research has demonstrated that larger vertical forces during the maximum velocity phase is important for control sprint performance (Nagahara et al., 2018a; Weyand et al., 2000).