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First Jump of Microgel: Actuation Speed Enhancement by Elastic Instability  [PDF]
Howon Lee,Chunguang Xia,Nicholas X. Fang
Physics , 2010, DOI: 10.1039/C0SM00092B
Abstract: Swelling-induced snap-buckling in a 3D micro hydrogel device, inspired by the insect-trapping action of Venus flytrap, makes it possible to generate astonishingly fast actuation. We demonstrate that elastic energy is effectively stored and quickly released from the device by incorporating elastic instability. Utilizing its rapid actuation speed, the device can even jump by itself upon wetting.
Effect of the Kinesio tape to muscle activity and vertical jump performance in healthy inactive people
Chen-Yu Huang, Tsung-Hsun Hsieh, Szu-Ching Lu, Fong-Chin Su
BioMedical Engineering OnLine , 2011, DOI: 10.1186/1475-925x-10-70
Abstract: Thirty-one healthy adults (19 males and 12 females with mean age, body weight and height for 25.3 ± 3.8 years old, 64.1 ± 6.2 kg, and 169.4 ± 7.3 cm, respectively) were recruited. All participants performed vertical jump tests prior to (without taping) and during elastic taping. Two elastic tapes, Kinesio tape and Mplacebo tape from two different manufacturers, were applied to the participants, respectively.The results showed that the vertical ground reaction force increased when Kinesio tape was applied even when the height of jump remained about constant. However, the height of the jump decreased, and there was no difference on the vertical ground reaction force in Mplacebo taping group. Although the EMG activity of medial gastrocnemius tended to increase in Kinesio taping group, we did not see differences in EMG activity for the medial gastrocnemius, tibialis anterior and soleus muscles in either group.Based on the varied effects of Kinesio tape and Mplacebo tape, different intervention technique was suggested for specific purpose during vertical jump movement. Mplacebo tape was demanded for the benefits of stabilization, protection, and the restriction of motion at the ankle joint. On the other hand, the findings may implicate benefits for medial gastrocnemius muscle strength and push-off force when using Kinesio tape.Vertical jumping is a kind of movement often seen in sports and exercise skill tests, and it has been discussed frequently in past related studies [1-4]. In most situations, before the push off movement begins, vertical jumping is carried out by the rapid extension of the hip, knee, and ankle joints [2]. Vertical jumping height is often demanded in the performance of sports and is an ability usually used in the test for basic capability to engage in sports or exercise [5].Motion analysis provides a detailed picture of the muscular effort expended at the joints during the performance of exercise [6]. Several studies have attempted to identify mechan
Vertical jump as a tool in assessment of muscular power and anaerobic performance
Ostoji? Sergej M.,Stojanovi? Marko,Ahmetovi? Zlatko
Medicinski Pregled , 2010, DOI: 10.2298/mpns1006371o
Abstract: Muscular strength and anaerobic power could be assessed by single and multiple vertical jump testing procedures. Anaerobic capacity measured by vertical jump testing is highly correlative with athletic performance, as compared to other anaerobic testing procedures. The most frequently used protocol with contact mat or force platform consists of single jump (i.e. squat jump, drop jump, countermovement jump) and serial jump testing with different duration. Measured variables include jump height and duration along with absolute and relative peak muscular power. Several investigators have clearly shown superior jump performance variables in elite athletes as compared to non-elite subjects. Differences obtained could be due to genetic factors and acute or prolonged efects of training regimen.
Elastic Modulus of Muscle and Tendon with Shear Wave Ultrasound Elastography: Variations with Different Technical Settings  [PDF]
Brian Chin Wing Kot, Zhi Jie Zhang, Arthur Wai Chun Lee, Vivian Yee Fong Leung, Siu Ngor Fu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0044348
Abstract: Standardization on Shear wave ultrasound elastography (SWUE) technical settings will not only ensure that the results are accurate, but also detect any differences over time that may be attributed to true physiological changes. The present study evaluated the variations of elastic modulus of muscle and tendon using SWUE when different technical aspects were altered. The results of this study indicated that variations of elastic modulus of muscle and tendon were found when different transducer’s pressure and region of interest (ROI)’s size were applied. No significant differences in elastic modulus of the rectus femoris muscle and patellar tendon were found with different acquisition times of the SWUE sonogram. The SWUE on the muscle and tendon should be performed with the lightest transducer’s pressure, a shorter acquisition time for the SWUE sonogram, while measuring the mean elastic modulus regardless the ROI’s size.
EFFECTS OF PLYOMETRIC TRAINING ON THE DEVELOPMENT THE VERTICAL JUMP IN VOLLEYBALL PLAYERS  [PDF]
Soundara rajan R,Pushparajan, A.
Citius Altius Fortius , 2010,
Abstract: :The present study investigated the effect of plyometric training on development of the vertical jump of volleyball players. The study consisted of 30 male volleyball players from PSG College of Arts & Science, Coimbatore, their age ranged from 18 to 25 years. Participants articipants were randomly assigned Group I underwent plyometric training group and Group II control group. The plyometric training group carried out a set of plyometric exercises also designed by the researcher twice a week for six weeks. The control group was allowed to play their game, but they were not given any treatments. For the purpose of this research, two tests forthe evaluation of the volleyball vertical jump were validated: the block jump and spike jump. The data was analysed using Paired t-tests which were used to test the effect of treatment groups individually between pre and post –tests, of all the groups, on variables used in the present study. The analysis of covariance was used toanalsze the collected data. The result of the study reveals that there was significant difference in 0.05 levels.Based on the findings of the research and the discussion, one could conclude that the exercise model for the development of the vertical jump that had been used, as the fundamental factor of the experimental group, has contributed to the statistically significant difference in the increase of the vertical jump in comparison to thecontrol group, which had used technically tactical contents to develop the vertical jump.
EFFECT OF TWO TYPES OF POWER TRAINING IN THE VERTICAL JUMP PERFORMANCE IN VOLLEYBALL PLAYERS  [PDF]
Gisele Lombardi,Naiara da Silva Vieira,Daniele Detanico
Brazilian Journal of Biomotricity , 2011,
Abstract: LOMBARDI, G.; VIEIRA, N. S.; DETANICO, D. Effect of two types of power training in the vertical jump performance in volleyball players. Brazilian Journal of Biomotricity. v. 5, n. 4, p. 230-238, 2011. The aim of this study was to analyze the effect of two types of strength training (plyometric and weightlifter) in vertical jump performance in volleyball athletes. Sixteen female athletes (13 to 14 years) took part of this study. They underwent a training period of 4 weeks with a frequency of three days per week. We used three distinct groups to sample: plyometric group (PG; n=5), weight training group (WG; n=6) and control group (CG; n=5) that did not participate in specific training for power. The athletes were evaluated for the Counter Movement Jump (CMJ). The t-test for dependent samples and analysis of variance (ANOVA one way) with Tukey test were used with level of significance set at 5%. The results showed significant increase in the vertical jump of WG between pre and post-test (p < 0.05). When analyzing the three groups (PG, WG and CG), no significant differences (p > 0.05) was showed, indicating that the three methods can be used for power training for athletes analyzed.
CHANGE ON VERTICAL JUMP AFTER COMPETITIVE PERIOD IN PROFESSIONALS SOCCER PLAYERS  [PDF]
Diogo Henrique Constantino Coledam,Douglas dos Santos,Júlio Wilson dos-Santos
Brazilian Journal of Biomotricity , 2010,
Abstract: COLEDAM, D. H. C.; SANTOS, D.; DOS-SANTOS, J. W. Change on vertical jump after competitive period in professionals soccer players. Brazilian Journal of Biomotricity, v. 4, n. 2, p. 140-147, 2010. Soccer is a sport that demands different intensities of run, with decisive actions of a match being held in maximum intensity. Vertical jump test is widely used in soccer players due to the strong relationship with speed and agility. Futhermore, there are little information about change on vertical jump after the competitive season in soccer players. The aim of this study was to analyze change on vertical jump after the competitive season in professional soccer players. Took part in this study 21 male athletes (20.82 ± 3.16 years, 72.28 ± 8.74 kg and 179.91 ± 6.14 cm) subscribers to the 4th division of the Paulista championship of 2009. The competitive season had a duration of 20 weeks, with a total of 20 official matchs done. The test used was the counter-movement vertical jump (VJ), that was performed in the first (PRE) and last (POS) training session of the competitive period. After confirmation of data normality by Kolmogorov-Smirnov, the inferential analysis of the results of VJ between PRE and POS was performed using the paired t-test, considering the significance level of 5%. There was a significant increase (p<0,05) on VJ after the competitive period (PRE=54,19±4,46 and POS=57,94±5,23). According to the results of this study, it is possible to increase the performance of VJ in professional soccer players after the competitive period of 20 weeks duration.
Acute effects of static stretching on vertical jump performance in children
Ertu?rul Gelen,?zcan Sayg?n,Kür?at Karacabey,Fatih K?l?n?
International Journal of Human Sciences , 2008,
Abstract: This research has been made to define the acute effects of static streching on vertical jump performance in children. The research has been applied on 49 healthy male volunteer athletes who have been taking basketball education for 2.1±0.2 years.(age:12.6±0.7 years, height: 157.9±6.9 cm, weight: 49.7±6.7 kg) Two different protocols have been made in this research. In the first protocol, 5 minutes aerobic density and 5 x 10 m forward, backward, side general warming up exercice in submaximal level has been applied on each child and in the second protocol, after general warming up, static streching practice has been applied to the same children. After each warming up and streching practice, countermovement jump performance have been measured. Active static streching practice has been applied in a strech sensitivity for 3 times 30 seconds and 15 seconds brakes between repetitions. Descriptive statistical methods and Paired-Samples T test have been applied on statistical analysis of vertical jump data that belong to children. Children jump 28.6 ± 1.1 cm. after a general warming up without any streching practice whereas the children who have made static streching application after warming up jump 27.1 ± 1.3 cm. The1.5 cm. difference (%5.2) has been found significant (t = -10.476; p<0.001). As a result, static streching practice after general warming up effects vertical jump performance negatively.
Effect of 2 different jump types on vertical leg stiffness and performance parameters in healthy young women
Seyede Maryam Hejazi,Azadeh Shadmehr,Gholam Reza Olyaei,Saeed Talebian
Modern Rehabilitation , 2012,
Abstract: Background and Aim: To investigate effects of 2 different jump types on vertical leg stiffness and performance parameters in healthy young women. People usually use various types of high jumping. It seems any model may have different effects on biomechanical parameters of the human body. Present study determined the effect of 2 jump types on performance parameters and vertical leg stiffness as a mechanical response of body to perturbations which occur during jumping. Materials and Methods: Vertical leg stiffness and performance parameters (jump height, flight time, contact time and power) were calculated in 25 healthy female subjects, under 2 conditions of Squat Jump (SJ) and Counter Movement Jump (CMJ). Results: Vertical leg stiffness (P= 0.028) and jump height (P= 0.039) were significantly higher in CMJ than SJ. Jump type has not any significant effects on the flight time (P= 0.1), contact time (P= 0.7) and power (P= 0.3). Conclusion: Counter movement jump increases the muscle force production, work output and GRF and may cause improvement in jump performance. Increased vertical leg stiffness improves performance as well as the risk of injury. Key words: Vertical leg stiffness, Performance, Vertical jump, Force plate
ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION: CLINICAL OUTCOMES OF PATELLA TENDON AND HAMSTRING TENDON GRAFTS  [cached]
Dawn T. Gulick,Heather N. Yoder
Journal of Sports Science and Medicine , 2002,
Abstract: An injury to the ACL can result in significant functional impairment. It has been estimated that more than 100,000 new ACL injuries occur each year. Surgeons employ numerous techniques for reconstruction of the ACL. Of critical importance is the source of the graft to replace the damaged ACL. The graft choices include autografts (the patient's own tissue), allografts (donor tendon), and synthetic/prosthetic ligaments. Tissue harvest sites for autografting include the middle third of the patella tendon, the quadriceps tendon, semitendinosus tendon, gracilis tendon, iliotibial band, tensor fascia lata, and the Achilles tendon. Selection of the type of graft material is predicated upon the tissue's ability to tolerate high levels of stress. Likewise, the clinical presentation and functional outcome is related to the graft material selected. This manuscript specifically examined the patella tendon and hamstring tendon grafts. Numerous manuscripts that studied the outcomes of these graft materials were compiled to help the clinician appreciate the advantages and disadvantages of each of the graft materials. Outcome measures such as thigh circumference, knee range of motion, isokinetic strength, knee stability, pain, and vertical jump/1-leg hop were incorporated. The purpose of this manuscript was to compare and contrast the clinical presentation of patients who underwent an ACL reconstruction using the patella tendon versus the hamstring tendons. This information can be valuable to the clinician when considering the rehabilitation protocol after ACL reconstruction
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