Browsing by Author "Jaric, Slobodan"
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Item Control Strategy of Maximum Vertical Jumps: the Preferred Countermovement Depth May Not Be Fully Optimized for Jump Height(De Gruyter Open, 2016-09-10) Mandic, Radivoj; Knezevic, Olivera M.; Mirkov, Dragan M.; Jaric, Slobodan; Radivoj Mandic, Olivera M. Knezevic, Dragan M. Mirkov, Slobodan Jaric; Jaric, SlobodanThe aim of the present study was to explore the control strategy of maximum countermovement jumps regarding the preferred countermovement depth preceding the concentric jump phase. Elite basketball players and physically active non-athletes were tested on the jumps performed with and without an arm swing, while the countermovement depth was varied within the interval of almost 30 cm around its preferred value. The results consistently revealed 5.1-11.2 cm smaller countermovement depth than the optimum one, but the same difference was more prominent in non-athletes. In addition, although the same differences revealed a marked effect on the recorded force and power output, they reduced jump height for only 0.1-1.2 cm. Therefore, the studied control strategy may not be based solely on the countermovement depth that maximizes jump height. In addition, the comparison of the two groups does not support the concept of a dual-task strategy based on the trade-off between maximizing jump height and minimizing the jumping quickness that should be more prominent in the athletes that routinely need to jump quickly. Further research could explore whether the observed phenomenon is based on other optimization principles, such as the minimization of effort and energy expenditure. Nevertheless, future routine testing procedures should take into account that the control strategy of maximum countermovement jumps is not fully based on maximizing the jump height, while the countermovement depth markedly confound the relationship between the jump height and the assessed force and power output of leg muscles.Item Force-velocity relationship of leg muscles assessed with motorized treadmill tests: two-velocity method(Elsevier, 2017-05-04) Dobrijevic, Slobodanka; Ilic, Vladimir; Djuric, Sasa; Jaric, Slobodan; Slobodanka Dobrijevic, Vladimir Ilic, Sasa Djuric, & Slobodan Jaric; Jaric, SlobodanLinear regression models applied on force (F) and velocity (V) data obtained from loaded multi-joint functional movement tasks have often been used to assess mechanical capacities of the tested muscles. The present study aimed to explore the properties of the F-V relationship of leg muscles exerting the maximum pulling F at a wide range of V on a standard motorized treadmill. Young and physically active male and female subjects (N=13+15) were tested on their maximum pulling F exerted horizontally while walking or running on a treadmill set to 8 different velocities (1.4-3.3 m/s). Both the individual (median R=0.935) and averaged across the subjects F-V relationships (R=0.994) proved to be approximately linear and exceptionally strong, while their parameters depicting the leg muscle capacities for producing maximum F, V, and power (P; proportional to the product of F and V) were highly reliable (0.84Item Muscle Force-Velocity Relationships Observed in Four Different Functional Tests(DE GRUYTER OPEN LTD, 2017-03-13) Zivkovic, Milena Z.; Djuric, Sasa; Cuk, Ivan; Suzovic, Dejan; Jaric, Slobodan; Milena Z. Zivkovic, Sasa Djuric, Ivan Cuk, Dejan Suzovic, Slobodan Jaric; Jaric, SlobodanThe aims of the present study were to investigate the shape and strength of the force-velocity relationships observed in different functional movement tests and explore the parameters depicting force, velocity and power producing capacities of the tested muscles. Twelve subjects were tested on maximum performance in vertical jumps, cycling, bench press throws, and bench pulls performed against different loads. Thereafter, both the averaged and maximum force and velocity variables recorded from individual trials were used for force-velocity relationship modeling. The observed individual force–velocity relationships were exceptionally strong (median correlation coefficients ranged from r = 0.930 to r = 0.995) and approximately linear independently of the test and variable type. Most of the relationship parameters observed from the averaged and maximum force and velocity variable types were strongly related in all tests (r = 0.789-0.991), except for those in vertical jumps (r = 0.485-0.930). However, the generalizability of the force-velocity relationship parameters depicting maximum force, velocity and power of the tested muscles across different tests was inconsistent and on average moderate. We concluded that the linear force-velocity relationship model based on either maximum or averaged force-velocity data could provide the outcomes depicting force, velocity and power generating capacity of the tested muscles, although such outcomes can only be partially generalized across different muscles.