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Wyszukujesz frazę "shortening" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Monitoring Plyometric Exercise Intensity Using Rating of Perceived Exertion Scale
Autorzy:
Asadi, Abbas
Powiązania:
https://bibliotekanauki.pl/articles/1031792.pdf
Data publikacji:
2014
Wydawca:
PPHU Projack Jacek Wąsik
Tematy:
maximal effort
perceived exertion
stretch-shortening cycle
Opis:
The aim of this investigation was to determine the effectiveness of rating of perceived exertion (RPE) scale to measure plyometric exercise intensity during low (L), moderate (M) and high (H) intensity. Fourteen physically active students (age; 21±1.1 y, height; 178.7±8.2 cm and body mass; 74.6±9.1 kg) volunteered to participate in this study and performed each intensity once separated with 24 h recovery. The H consisted of 1 set of 5 repetitions at 90% of the subject’s vertical jump height (VJH). The M consisted of 10 repetitions at 70% VJT, and the L consisted of 1 set of 15 repetitions at 50% VJH. RPE was measured following the completion each intensity using 0-10 Borg RPE scale. Data was analyzed using repeated measures ANOVA and the level of significant was set at p < 0.05. The results indicated increases in RPE following enhancing exercise intensity (p < 0.05). Performing fewer repetitions at a higher intensity was perceived to be more difficult than performing more repetitions at a lower intensity. The results of the current investigation revealed that the RPE method is effective in monitoring different plyometric exercise and training intensities and it can be recommend that strength and conditioning professionals and athletes use the RPE method based on the effectiveness tool for monitoring their plyometric exercise and training sessions at different intensities.
Źródło:
Physical Activity Review; 2014, 2; 10-15
2300-5076
Pojawia się w:
Physical Activity Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of potential elastic energy during the countermovement phase of a vertical jump based on the force-displacement curve
Autorzy:
Struzik, Artur
Zawadzki, Jerzy
Powiązania:
https://bibliotekanauki.pl/articles/306373.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
skoki
elastyczność
sztywność
rozciąganie
countermovement jump
elasticity
quasi-stiffness
stretch-shortening cycle
Opis:
Purpose: One inconvenience in finding experimental evidence for the relationship between potential elastic energy and vertical jump height is the difficulty of estimating the value of the stored potential elastic energy. Therefore, the aim of this study is to present a simple method of estimating the potential elastic energy stored by lowering the center of mass during the countermovement phase of a vertical jump. Methods: The research was conducted on 30 able-bodied male university students (age: 20 years, body height: 183.1 ± 7.9 cm, body mass: 80.3 ± 10.4 kg). Each participant performed 10 single countermovement jumps with arms akimbo to maximal height. Measurements employed a Kistler force plate. The value of potential elastic energy was estimated based on the curve of dependence of the ground reaction force on the vertical displacement of the jumper’s center of mass. Results: The mean value (±SD) of potential elastic energy collected due to lowering of the center of mass during the countermovement phase of a vertical jump was 183 ± 69 J. 24.3% of this value can be considered the part of the potential elastic energy (44 ± 21 J) that comes from the transformation of kinetic energy. The total change in gravitational potential energy due to lowering the center of mass was 240 ± 58 J. Conclusions: This estimation of potential elastic energy is only general and rough. However, certain estimations of potential elastic energy may offer some insight into the phenomenon relating vertical quasi-stiffness and the ability to store potential elastic energy with vertical jump height.
Źródło:
Acta of Bioengineering and Biomechanics; 2019, 21, 1; 153-160
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fatigue alters the biomechanical contribution of lower extremity joints during a stretch-shortening cycle task
Autorzy:
Sun, Xiaole
Xia, Rui
Zhang, Ximi
Zhen, Luo
Fu, Weijie
Powiązania:
https://bibliotekanauki.pl/articles/949743.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
skoki
zmęczenie
sztywność
stretch-shortening cycle
drop jump
fatigue
stiffness
joint work
Opis:
This study aimed to explore the effect of fatigue on the biomechanical contribution of the lower extremity joints during a typical stretch-shortening cycle (SSC) task. Methods: 15 male athletes completed drop jump (DJ) under pre- and post-fatigue. Vicon motion capture system and 3D Kistler force plates were used to collect kinematics and ground reaction force data simultaneously. Results: Under fatigue condition, 1) the DJ height decreased; the touchdown angle of knee and ankle reduced and the range of motion increased; 2) the maximum push-off moment and power of knee was reduced; 3) the stiffness of knee, ankle, and legs was reduced; 4) the energy generation and the net energy of the ankle decreased; 5) the energy contribution of knee decreased during the eccentric phase. Conclusions: Fatigue altered biomechanical contribution of the lower extremity joints by changing the movement pattern during DJ. The control ability of the knee and ankle were decreased. Eventually, the jump performance was reduced. In addition, the decrease of stiffness as well as the energy contribution of these joints can be used as sensitive indices to evaluate the performance of DJ after fatigue.
Źródło:
Acta of Bioengineering and Biomechanics; 2019, 21, 2; 11-19
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of performance level on lower limb kinematics during table tennis forehand loop
Autorzy:
Qian, J.
Zhang, Y.
Baker, J. S.
Gu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/307434.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
strefa graniczna
łańcuch kinematyczny
sport
lower limb drive
contact area
stretch-shortening cycle
kinetic chain
Opis:
Understanding of biomechanics is important in performance development since each skill has a fundamental mechanical structure. The purpose of this study was to investigate differences in lower limb kinematics during table tennis forehand loop between superior players (SP) and intermediate players (IP). Thirteen male players as superior and thirteen as intermediate participated in this test. A VICON motion analysis system and a Novel Pedar insole plantar pressure measurement system were used to record kinematic and contact area data, respectively. Participants were asked to execute single forehand loop against topspin ball with maximal power. Key findings were that SP showed significantly larger hip flexion and knee external rotation at backward-end and larger hip internal rotation and extension at forward-end compared with IP. Contact areas at both events were larger for SP. In addition, SP showed significantly larger joints angular changing rate during forward swing at the ankle and hip. Results indicated that SP possessed better ability of using lower limb drive in forehand loop.
Źródło:
Acta of Bioengineering and Biomechanics; 2016, 18, 3; 149-155
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neuromechanical control in submaximal drop jumps: The effects of volitional effort demands and drop height magnitude on soleus muscle activation
Autorzy:
Mrdakovic, V.
Pazin, N.
Vulovic, R.
Filipovic, N.
Ilic, D.
Powiązania:
https://bibliotekanauki.pl/articles/307166.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
elektromiografia
sprzężenie zwrotne
staw skokowy
biomechanika
electromyography
stretch-shortening cycle
feedback control
pre activation
feedforward control
ankle biomechanics
Opis:
The purpose of this study was to investigate soleus muscle activation during different phases of drop jump performed at submaximal levels of volitional effort and drop height magnitude. Methods: Fifteen professional volleyball players with minimum of eight years of experience in jumping activities participated in the study. Experimental protocol involved executing submaximal drop jumps at three levels of volitional effort (i.e., 65, 80 and 95% of the maximal height of jump). All submaximal drop jumps were done from three drop heights (20, 40 and 60 cm). The soleus muscle activation was monitored during four jump phases: pre-activation phase before touchdown, early contact phase upon touchdown, early and late push-off phase. Results: The results indicate that volitional effort level did not change the muscle activation during pre activation and early contact phase, but only in early and late push-off phase ( p ≤ 0.05). Conversely, it was observed that muscle activation during all phases of drop jump was adapted to the increased intensity of the external load caused by increasing of drop height magnitude ( p ≤ 0.01). Conclusions: The findings of the present study suggested that soleus muscle activation has selective responses to internal load (i.e., volitional effort level) and external load (i.e., drop height magnitude) intensities when drop jump is executing with submaximal effort.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 4; 101-111
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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