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Introduction. The purpose of this study was to compare the acute effects of traditional jumps and rope jumps during warm-up on power and jumping ability in trained men. Material and methods. A group of 12 national-level track and field athletes participated in the study. Peak power and jumping ability were assessed by having participants perform five alternate leg bounds, a countermovement jump (CMJ) and a drop jump (DJ). Three different warm-up protocols were used in random order, with 3-day intervals between them. The first involved traditional jumps, the second rope jumps and the control consisted of general warm-up only (jogging and stretching). Results. The rope-jump warm-up protocol significantly improved jumping distance (p<0.05) as compared to the traditional protocol. There were no significant differences in peak power or jump height among experimental groups in the CMJ and DJ. The study also revealed that traditional and ropejump protocols significantly (p<0.001) increased peak power and jump height for the CMJ and DJ, and jump distance for the five alternate leg bounds compared to the control condition. Conclusion. The results of this study suggest that a warm-up including rope jumps may be more effective for horizontal jumping tasks than a protocol with traditional jumps, and that traditional and rope-jump warm-up protocols provide similar levels of enhancement for vertical jumping tasks.
The main objective of the study was to determine to what degree higher muscular activity, achieved by increased load in the extension phase (eccentric muscle action) of the vertical jump, affects the efficiency of the vertical jump. Sixteen elite biathletes participated in this investigation. The biathletes performed tests that consisted of five, single “maximal” vertical jumps (counter movement jump - CMJ) and five, single vertical jumps, in which the task was to touch a bar placed over the jumping biathletes (specific task counter movement jump - SCMJ). Then, they performed five, single drop jumps from an elevation of 0.4m (DJ). Ground reaction forces were registered using the KISTLER 9182C force platform. MVJ software was used for signal processing (Król, 1999) and enabling calculations for kinematic and kinetic parameters of the subject’s jump movements (on-line system). The results indicate that only height of the jump (h) and mean power (Pmean) during the takeoff are statistically significant. Both h and Pmean are higher in the DJ. The results of this study may indicate that elite biathletes are well adapted to eccentric work of the lower limbs, thus reaching greater values of power during the drop jump. These neuromuscular adaptive changes may allow for a more dynamic and efficient running technique.
Purpose. Muscle post-activation potentiation (PAP) is a mechanism by which power twitch is increased after previous conditioning contractions. In this study, we determined the time-dependent effect of a loaded drop-jump protocol on sprint time and countermovement jump height in well-trained athletes. Methods. Ten athletes randomly performed the control and experimental protocols on two different days. As a pre-test, the athletes performed the vertical jump and 50 m sprint test for preload measurements. Then, the experimental or control protocol was randomly applied, where the control protocol was composed of the athletes remaining at rest for 10 min. In the experimental protocol, the athletes performed two sets of 5 drop jumps (0.75 m), with a 15 s interval between the jumps and a 3 min rest after each set. Then the vertical jump and 50 m sprint tests were performed again 5, 10, and 15 min after the protocol. Results. The experimental condition (drop jump potentiation protocol) increased performance in the vertical jump by 6% after 15 min (p < 0.01) and in the sprint by 2.4% and 2.7% after 10 and 15 min, respectively (p < 0.05). Conclusions. These findings suggest that the drop jump potentiation protocol increases countermovement vertical jump and sprint performance in high-performance athletes at different times, suggesting that PAP induction depends not only on the design of the protocol, but also on the effect of time and the type of exercise involved.
Core stability training (CST) has increased in popularity among athletes and the general fitness population despite limited evidence CST programmes alone lead to improved athletic performance. In female athletes, neuromuscular training combining balance training and trunk and hip/pelvis dominant CST is suggested to reduce injury risk, and specifically peak vertical ground reaction forces (vGRF) in a drop jump landing task. However, the isolated effect of trunk dominant core stability training on vGRF during landing in female athletes had not been evaluated. Therefore, the objective of this study was to evaluate landing kinetics during a drop jump test following a CST intervention in female capoeira athletes. After giving their informed written consent, sixteen female capoeira athletes (mean ± SD age, stature, and body mass of 27.3 ± 3.7 years, 165.0 ± 4.0 cm, and 59.7 ± 6.3 kg, respectively) volunteered to participate in the training program which consisted of static and dynamic CST sessions, three times per week for six weeks. The repeated measures T-test revealed participants significantly reduced relative vGRF from pre- to post-intervention for the first (3.40 ± 0.78 vs. 2.85 ± 0.52 N·NBW-1, respectively [p<0.05, effect size = 0.60]), and second landing phase (5.09 ± 1.17 vs. 3.02 ± 0.41 N·NBW-1, respectively [p<0.001, effect size = 0.87]). The average loading rate was reduced from pre- to post-intervention during the second landing phase (30.96 ± 18.84 vs. 12.06 ± 9.83 N·NBW·s-1, respectively [p<0.01, effect size = 0.68]). The peak loading rate was reduced from pre- to postintervention during the first (220.26 ± 111.51 vs. 120.27 ± 64.57 N· NBW·s-1 respectively [p<0.01, effect size = 0.64]), and second (99.52 ± 54.98 vs. 44.71 ± 30.34 N· NBW·s-1 respectively [p<0.01, effect size = 0.70]) landing phase. Body weight, average loading rate during the first landing phase, and jump height were not significantly different between week 0 and week 6 (p=0.528, p=0.261, and p=0.877, respectively). This study provides evidence that trunk dominant core stability training improves landing kinetics without improving jump height, and may reduce lower extremity injury risk in female athletes.
Content available remote Relative power of the lower limbs in drop jump
The purpose of this paper was to determine the power produced by the lower limbs in the take-off phase in drop jumps (DJ) and the correlation between the power and load measured by dropping height after take-off. The research group (N = 17) contained students practicing football, volleyball, basketball, athletics, high jump, swimming and fencing. The individual characteristics "power-load" of the players and the observation of the changes during the training process enable the coaches to choose precise loads and at the same time to improve the training. The criterion of choosing loads in the plyometric training may be relative power output of lower limbs referred to the DJ height. While the condition allowing player to perform this type of training may depend on obtaining greater power in drop jump than in counter movement jump.
Purpose: Lower extremity power is an important physical capacity of a soccer athlete. Power represents, and can be modified by, the training of strength and speed. Pre-season and in-season training differs in the relative emphasis on these two quantities. It is nevertheless desirable that the mechanical power remain the same or become higher during the in-season period. The purpose of this study was to identify changes in quantities related to “explosive strength” and to check whether, in collegiate female soccer players, pre- and inseason lower extremity power will remain unaltered. Methods: Twenty collegiate female soccer players, representing all field positions, participated. Lower extremity power was assessed by a series of drop jumps executed from four different heights (15, 30, 45, and 60 cm). Mechanical power was calculated using subject’s mass, jump height, and acceleration due to gravity. This value was further normalized by body mass of each athlete to obtain the relative (or normalized) mechanical power. Results: The normalized lower extremity mechanical power was highest when landing from the 30 cm height for both pre- and inseason periods. However, contrary to expectations, it turned out lower during the in-season than during the pre-season test, even though no significant differences were found between the corresponding jump heights. Conclusions: It is concluded that altered, perhaps inadequate, training strategies were employed during the in-season period. Besides, advantages of adding the relative mechanical power as a season readiness indicator are underlined compared with relying on the jump height alone.
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.
The aim of this research was to evaluate the biomechanical parameters of lower limbs and their influence on height of vertical jump. The research was conducted on a group of females practicing basketball and volleyball. The following equipment was used during the experiment: a force plate by Kistler, a Biometrics electrogoniometer and a specially designed chair to measure static torque by OPIW Opole. The results indicated that the jumping abilities of the examined athletes were poor. No statistically significant correlations were observed between knee static torque and heights of vertical jumps: CMJ and DJ. The authors suggest modification of the McClymont index (RSI) to evaluate the selection of platform height during plyometric training. Such modification would enable better choice of loads and better training control of the subject.
Content available remote Effect of increased load on vertical jump mechanical characteristics in acrobats
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.
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