Wyniki wyszukiwania - Biblioteka Nauki

1

Physical effort ability in counter movement jump depending on the kind of warm-up and surface temperature of the quadriceps

100%

Adamczyk J. G. , Boguszewski D. , Siewierski M.

Baltic Journal of Health and Physical Activity

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2012

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tom 4

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nr 3

164-171

EN

Background: The aim of this research was an attempt at qualifying the influence of various kinds of warm-up on physical effort ability, as well as examining whether there exists any dependence between the surface temperature of the quadricipital muscle of the thigh and the power expressed with the height of counter movement jump (CMJ). Material/Methods: In the research thermographic imaging and dynamometric platform were used. The subjects performed the CMJ test in 3 separate sessions - without any warm-up and then after preparation (1st session - jogtrot; 2nd session - jogtrot and stretching exercises; 3 session - dynamic warm up exercises). Results: In the examined group there was no lineal dependence between the surface temperature of the quadriceps and the power expressed with the height of a jump. Regardless of the kind of the applied warm-up, subjects improved their own results in the CMJ test; however, no such regularity concerning the temperature rise on the surface of a muscle was observed. In a dynamic warm-up lower surface temperature of the quadriceps meant a higher value of CMJ (r=0.64; p<0.05). This warm-up proved to be most efficient in the preparation for effort. Conclusions: The fact that highest values of a jump and surface temperature were attained after various kinds of warm-up permits supposing that finding individual forms of preparation for effort by an athlete, in order to increase the competition efficiency, is possible.

2

Effects of a Low-Load Gluteal Warm-Up on Explosive Jump Performance

86%

Comyns T. , Kenny I. , Scales G.

Journal of Human Kinetics

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2015

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tom 46

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nr 1

177-187

EN

The purpose of this study was to investigate the effects of a low-load gluteal warm-up protocol on countermovement and squat jump performance. Research by Crow et al. (2012) found that a low-load gluteal warm-up could be effective in enhancing peak power output during a countermovement jump. Eleven subjects performed countermovement and squat jumps before and after the gluteal warm-up protocol. Both jumps were examined in separate testing sessions and performed 30 seconds, and 2, 4, 6 & 8 minutes post warm-up. Height jumped and peak ground reaction force were the dependent variables examined in both jumps, with 6 additional variables related to fast force production being examined in the squat jump only. All jumps were performed on a force platform (AMTI OR6-5). Repeated measures analysis of variance found a number of significant differences (p ≤ 0.05) between baseline and post warm-up scores. Height jumped decreased significantly in both jumps at all rest intervals excluding 8 minutes. Improvement was seen in 7 of the 8 recorded SJ variables at the 8 minute interval. Five of these improvements were deemed statistically significant, namely time to peak GRF (43.0%), and time to the maximum rate of force development (65.7%) significantly decreased, while starting strength (63.4%), change of force in first 100 ms of contraction (49.1%) and speed strength (43.6%) significantly increased. The results indicate that a gluteal warm-up can enhance force production in squat jumps performed after 8 minutes recovery. Future research in this area should include additional warm-up intervention groups for comparative reasons.

3

Evaluation of reliability and concurrent validity of of two optoelectric systems used for recording maximum vertical jumping performance versus the gold standard

72%

Słomka K. J. , Sobota G. , Skowronek T. , Rzepko M. , Czarny W. , Juras G.

Acta of Bioengineering and Biomechanics

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2017

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tom Vol. 19, nr 2

141--147

EN

The objective of this study was to evaluate the reliability and validity of two alternative systems used for jumping performance measurement. Methods: Two groups of subjects were tested. The first group consisted of 15 male adults (21.3 ± 1.7 years ) and the second group consisted of 16 female volleyball players (17.2 ± 0.9 years). We used three different systems of data collection in the study. Two of the used systems are based on optoelectric components. The Optojump Next system is referred to as the optoelectric system, and BTS Smart-E is refered to as the video system. Concurrent validity of these systems was verified with the use of “gold standard” which is force platform. All systems were used to estimate the height of vertical jumps. Results: Both optoelectric systems occurred to be highly reliable with the ICCs=0.98 for Optojump and 0.9 for BTS Smart. Their concurrent validity with the force platform data was also very high r=0.99 and r=0.97 respectively. Conclusions: Comparison of these two systems shows distinct differences between them where Optojump system is more suitable for quick and reliable sports testing, when BTS-Smart for research and clinical testing.

4

Effect of increased load on vertical jump mechanical characteristics in acrobats

72%

Król H. , Mynarski W.

Acta of Bioengineering and Biomechanics

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2010

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tom Vol. 12, nr 4

33-37

EN

In this study, we attempt to answer the following question: To what degree the higher muscular activity determined by increased load in the extension phase (eccentric muscle action) of vertical jump affects its efficiency? Ten high performance acrobats participated in this investigation. The acrobats performed tests that consisted of five single “maximal” standing vertical jumps (counter movement jump – CMJ) and five single vertical jumps, in which the task was to touch a bar placed over the jumping acrobats (special counter movement jump – SCMJ). Subsequently, they performed five single drop jumps from an elevation of 0.40 m (DJ). Ground reaction forces were registered using the KISTLER 9182C force platform. MVJ software was used for signal processing [1] and enabling calculations of kinematic and kinetic parameters of the subject’s jumping movements (on-line system). The results obtained show that the height of jump (h), the mean power (Pmean) and the maximum power (Pmax) are statistically significant, and higher in DJ. The results prove fine adaptation of the nervous system in acrobats to muscle extension and workload, due to the 40 cm high drop jump. Presumably, this height is closest to that which acrobats experience during landing, after performing flic-flacs or round-off.