scholarly journals Efecto de modificar la profundidad y velocidad del contramovimiento durante el salto vertical (Effects of countermovement depth and velocity modifications during the vertical jump)

Retos ◽  
2018 ◽  
pp. 287-290
Author(s):  
Alberto Sánchez-Sixto ◽  
Julio López-Álvarez ◽  
Pablo Floría
Keyword(s):  
Vertical Jump ◽  
Center Of Mass ◽  
Jump Height ◽  
Downward Movement ◽  
Movement Velocity ◽  
Jump Performance ◽  
Mass Displacement ◽  
Force Velocity ◽  
Initial Force ◽  
Propulsion Phase

Objetivo. El objetivo de la presente investigación fue evaluar el efecto de modificar la profundidad y la velocidad del contramovimiento en el salto vertical. Material y método. Once jugadores de deportes colectivos participaron en este estudio y realizaron 9 saltos con contramovimiento: 3 en los que ellos seleccionaban la velocidad y profundidad del contramovimiento (CMJ), 3 en los que incrementaban la profundidad del contramovimiento y seleccionaban libremente su velocidad (CMJP) y 3 en los que incrementaban la profundidad y velocidad del contramovimiento (CMJPR). La altura máxima, el tiempo, la fuerza, la velocidad y el desplazamiento del centro de masas fueron calculadas durante la fase de contramovimiento y de propulsión. Resultados. No se encontraron mejoras substanciales entre ninguno de los tres tipos de salto llevados a cabo por los participantes. En el CMJPR se consiguió incrementar substancialmente la fuerza máxima y la fuerza inicial con respecto al CMJ. En el CMJP todas las variables de fuerza fueron inferiores que en el CMJ. El tiempo de la fase de contramovimiento fue inferior en el CMJ en comparación con el CMJP, no existiendo diferencias con el CMJPR. El tiempo de la fase de propulsión fue inferior en el CMJ en comparación con los otros dos saltos. Conclusión. Incrementos en la profundidad del contramovimiento del CMJ a través de una orden simple, no fueron capaces de conseguir un aumento del rendimiento en el salto vertical en la presente investigación.Abstract. Purpose. The aim of the study was to evaluate the effects of countermovement depth and velocity modification in the vertical jump. Materials and methods. Eleven team sport players participated in this investigation performing nine countermovement jumps: 3 self-selected countermovement jumps (CMJ), 3 countermovement jumps with a deeper countermovement depth (CMJP) and 3 countermovement jumps with a deeper countermovement depth and a higher downward movement velocity (CMJPR). Jump height, time, force, velocity and center of mass displacement were measured during the countermovement and the propulsion phase. Results. No differences in jump height were found between the three types of jump. CMJPR showed a substantial increase in maximum force and initial force in comparison with the CMJ. CMJP force variables were lower than the values obtained during the CMJ. The time of the countermovement phase was lower in the CMJ in comparison with the CMJP, and no differences were found between the CMJ and the CMJPR. The time of the propulsion phase was lower than the other countermovement jumps performed. Conclusion. Increases in the countermovement depth of the CMJ through a simple instruction did not increase the vertical jump performance in the present investigation.

Pelvic Kinematic Method for Determining Vertical Jump Height

2010 ◽  
Vol 26 (4) ◽  
pp. 508-511 ◽  
Author(s):  
Loren Z.F. Chiu ◽  
George J. Salem
Keyword(s):  
Vertical Jump ◽  
Center Of Mass ◽  
Reaction Force ◽  
Jump Height ◽  
Impulse Method ◽  
Vertical Jump Height ◽  
Reconstruction Methods ◽  
Kinematic Method ◽  
Mass Displacement ◽  
Vertical Jumps

Sacral marker and pelvis reconstruction methods have been proposed to approximate total body center of mass during relatively low intensity gait and hopping tasks, but not during a maximum effort vertical jumping task. In this study, center of mass displacement was calculated using the pelvic kinematic method and compared with center of mass displacement using the ground-reaction force-impulse method, in experienced athletes (n= 13) performing restricted countermovement vertical jumps. Maximal vertical jumps were performed in a biomechanics laboratory, with data collected using an 8-camera motion analysis system and two force platforms. The pelvis center of mass was reconstructed from retro-reflective markers placed on the pelvis. Jump height was determined from the peak height of the pelvis center of mass minus the standing height. Strong linear relationships were observed between the pelvic kinematic and impulse methods (R2= .86;p< .01). The pelvic kinematic method underestimated jump height versus the impulse method, however, the difference was small (CV = 4.34%). This investigation demonstrates concurrent validity for the pelvic kinematic method to determine vertical jump height.

scholarly journals Larger Countermovement Increases the Jump Height of Countermovement Jump

Sports ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 131 ◽  
Author(s):  
Alberto Sánchez-Sixto ◽  
Andrew Harrison ◽  
Pablo Floría
Keyword(s):  
Center Of Mass ◽  
The Self ◽  
Jump Height ◽  
Simulation Studies ◽  
Countermovement Jump ◽  
Jump Performance ◽  
Force Application ◽  
Mass Displacement ◽  
Biomechanical Parameters

Simulation studies show that jump performance can be improved by increasing the depth of countermovement. The purpose of this study was to determine how modifications to the depth of countermovement lead to changes in jump height and the biomechanical parameters related to center of mass displacement and force application. Twenty-nine competitive males participated in this investigation, performing nine countermovement jumps using a self-selected, a deep, and a shallow crouch position. Jump height and relative net vertical impulse were greater when using a deeper crouch position, compared to the self-selected position. Force application variables did not report differences, when the deeper countermovement was compared to the self-selected countermovement; although, the shallower countermovement showed higher values in force application parameters. The deeper countermovement jumps achieved higher velocities of the center of mass than the self-selected jumps, while shallower jumps produced lower velocities than the self-selected jumps. The results of this investigation were consistent with simulation studies, showing that deep countermovements increase net vertical impulse, leading to a higher jump height. In addition, the maximum downward velocity was higher, when the crouch position was deeper. Conversely, force-applied variables did not change when jump performance was increased.

scholarly journals Effects of Plyometric vs. Combined Plyometric Training on Vertical Jump Biomechanics in Female Basketball Players

2021 ◽  
Vol 77 (1) ◽  
pp. 25-35
Author(s):  
Alberto Sánchez-Sixto ◽  
Andrew J Harrison ◽  
Pablo Floría
Keyword(s):  
Vertical Velocity ◽  
Vertical Jump ◽  
Center Of Mass ◽  
Height Velocity ◽  
Moderate Increase ◽  
Training Methods ◽  
Plyometric Training ◽  
Basketball Players ◽  
Jump Performance ◽  
Combined Training

Abstract The purpose of this study was to assess and compare the effects of plyometric training and combined training programs on vertical jump kinematics and kinetics of female basketball players. Thirty-six female basketball players were included in the study and further divided into three groups: plyometric training, n = 11; combined training n =13; and a control group, n =12. Combined training comprised full squat exercise with low resistance (50-65% 1RM) and low volume (3-6 repetitions/set) combined with repeated jumps. Plyometric training included drop jumps and repeated jumps. Both training methods showed a moderate increase in jump performance, although combined training achieved substantially higher values than plyometric training alone. After plyometric training, the vertical velocity and displacement of the center of mass of the countermovement jump increased, while force variables decreased. Combined training increased power, vertical velocity and displacement of the center of mass, but force variables remained unchanged. Both training methods improved jump height, velocity and displacement of the center of mass. Combined training maintained force measures while plyometric training decreased them. These results indicate that combined training might provide better outcomes on jump performance than plyometric training alone. It also appears important to measure biomechanical variables to appropriately interpret the effects of different training methods.

Variability in the Application of Force During the Vertical Jump in Children and Adults

2014 ◽  
Vol 30 (6) ◽  
pp. 679-684 ◽  
Author(s):  
Pablo Floria ◽  
Luis A. Gómez-Landero ◽  
Andrew J. Harrison
Keyword(s):  
Coefficient Of Variation ◽  
Development Time ◽  
Task Complexity ◽  
Vertical Jump ◽  
Center Of Mass ◽  
Mass Movement ◽  
Rate Of Force Development ◽  
Force Development ◽  
Velocity Relationship ◽  
Force Velocity

The purpose of this study was to determine if children exhibit greater variability in center of mass movement and kinetics compared with adults in vertical jumping. Countermovement jumps with arms (CMJA) and without arms (CMJ) performed by 20 female children and 20 female adults were examined using force platform. The data were analyzed using continuous methods to determine differences in variability between groups and between types of jump. Jumping variability was measured by using the average coefficient of variation of the force-, velocity-, displacement-, and rate of force development-time curves across the jump. The analysis indicated that children and adults had similar levels of variability in the CMJ but different levels in the CMJA. In the CMJA, the children had a greater coefficient of variation than adults in force- (20 ± 7% and 12 ± 6%), velocity- (41 ± 14% and 22 ± 9%), displacement- (8 ± 16% and 23 ± 11%) and rate of force development-time (103 ± 46% and 75 ± 42%) curves, as well as in force-velocity relationship (6 ± 2% and 4 ± 2%). The results of analysis suggest that the variability depends on both the level of maturation of the participants as well as the task complexity.

scholarly journals Assessing the Validity of the MyJump2 App for Measuring Different Jumps in Professional Cerebral Palsy Football Players: An Experimental Study (Preprint)

2018 ◽  
Author(s):  
Victor Coswig ◽  
Anselmo De Athayde Costa E Silva ◽  
Matheus Barbalho ◽  
Fernando Rosch De Faria ◽  
Claudio D Nogueira ◽  
...  
Keyword(s):  
Cerebral Palsy ◽  
Injury Risk ◽  
Mobile Apps ◽  
Vertical Jump ◽  
Field Evaluation ◽  
Flight Time ◽  
Jump Height ◽  
Validity And Reliability ◽  
Jump Performance ◽  
P 16

BACKGROUND Vertical jumps can be used to assess neuromuscular status in sports performance. This is particularly important in Cerebral Palsy Football (CP Football) because players are exposed to high injury risk, but it may be complicated because the gold standard for assessing jump performance is scarce in field evaluation. Thus, field techniques, such as mobile apps, have been proposed as an alternative method for solving this problem. OBJECTIVE This study aims to evaluate the reliability of the measures of the MyJump2 app to assess vertical jump performance in professional CP Football. METHODS We assessed 40 male CP Football athletes (age 28.1 [SD 1.4] years, weight 72.5 [SD 6.2] kg, and height 176 [SD 4.2] cm) through the countermovement jump (CMJ) and squat jump (SJ) using a contact mat. At the same time, we assessed the athletes using the MyJump2 app. RESULTS There were no significant differences between the instruments in SJ height (P=.12) and flight time (P=.15). Additionally, there were no significant differences between the instruments for CMJ in jump height (P=.16) and flight time (P=.13). In addition, it was observed that there were significant and strong intraclass correlations in all SJ variables varying from 0.86 to 0.89 (both P<.001), which was classified as “almost perfect.” Similar results were observed in all variables from the CMJ, varying from 0.92 to 0.96 (both P ≤.001). CONCLUSIONS We conclude that the MyJump2 app presents high validity and reliability for measuring jump height and flight time of the SJ and CMJ in CP Football athletes.

scholarly journals Concurrent validity, inter-, and intrarater reliabilities of smart device based application for measuring vertical jump performance

2020 ◽  
Vol 12 (3) ◽  
pp. 35-46
Author(s):  
DONG-SIK OH ◽  
YOON-HEE CHOI ◽  
YU-JIN SHIM ◽  
SAM-HO PARK ◽  
MYUNG-MO LEE
Keyword(s):  
Concurrent Validity ◽  
Vertical Jump ◽  
Flight Time ◽  
Smart Device ◽  
Portable Devices ◽  
Jump Height ◽  
Post Injury ◽  
Jump Performance ◽  
Injury Rehabilitation ◽  
Vertical Jumps

Background: The aim of this study was to examine the concurrent validity and inter-and intra-rater reliabilities of smart device based application, against force platform-based portable device Wii balance board (WBB) measurements for the flight time and jump height during the vertical jump. Material and methods: Thirty participants (23.8 ±3.41 years) completed three vertical jumps, which were evaluated using WBB and application for smart device. To assess the concurrent validity, jump height and flight times were obtained from each device. Inter-and intra-rater reliabilities were determined by replicating data analysis of smart device based application recordings. Results: Flight time and jump height collected from smart device based application showed excellent agreement level with WBB (flight time and jump height: ICC [2,1]=0.972). However mean flight time and jump height from the smart device based application was significantly higher than WBB (mean difference: 0.006 sec, 0.745 cm, p < 0.05). Intra-rater sessions showed good level of agreement (flight time: ICC [2,1] = 0.967, jump height: ICC [2,1] = 0.974), and inter-rater session showed almost perfect reliability (flight time: ICC [2,1] = 0.985, jump height: ICC [2,1] = 0.987). Conclusions: Smart device-based applications could be used to replace pressure-based portable devices for clinical evaluations in post-injury rehabilitation as well as evaluating sports performance.

Kinetic and Electromyographic Subphase Characteristics With Relation to Countermovement Vertical Jump Performance

2018 ◽  
Vol 34 (4) ◽  
pp. 291-297 ◽  
Author(s):  
John R. Harry ◽  
Max R. Paquette ◽  
Brian K. Schilling ◽  
Leland A. Barker ◽  
C. Roger James ◽  
...  
Keyword(s):  
Vertical Jump ◽  
Effect Sizes ◽  
Jump Height ◽  
Strength Index ◽  
Jump Performance ◽  
Force Development ◽  
The Poor ◽  
Large Jump ◽  
Jump Time ◽  
Vertical Jumps

This study sought to identify kinetic and electromyographic subphase characteristics distinguishing good from poor jumpers during countermovement vertical jumps (CMVJs), as defined by the reactive strength index (RSI, CMVJ displacement divided by jump time; cutoff = 0.46 m·s−1). A total of 15 men (1.8 [0.6] m, 84.5 [8.5] kg, 24 [2] y) were stratified by RSI into good (n = 6; RSI = 0.57 [0.07] m·s−1) and poor (n = 9; RSI = 0.39 [0.06] m·s−1) performance groups. The following variables were compared between groups using independentttests (α = .05) and Cohen’sdeffect sizes (d ≥ 0.8, large): jump height, propulsive impulse, eccentric rate of force development, and jump time, unloading, eccentric, and concentric subphase times, and average electromyographic amplitudes of 8 lower extremity muscles. Compared with the poor RSI group, the good RSI group exhibited a greater, though not statistically different CMVJ displacement (d = 1.07,P = .06). In addition, the good RSI group exhibited a significantly greater propulsive impulse (P = .04,d = 1.27) and a significantly more rapid unloading subphase (P = .04,d = 1.08). No other significant or noteworthy differences were detected. Enhanced RSI appears related to a quicker unloading phase, allowing a greater portion of the total jumping phase to be utilized generating positive net force. Poor jumpers should aim to use unloading strategies that emphasize quickness to enhance RSI during CMVJ.

scholarly journals Stretch-Shortening Cycle in Countermovement Jump: Exclusive Review of Force-Time Curve Variables in Eccentric and Concentric Phases

2017 ◽  
Author(s):  
Mahdi Cheraghi ◽  
Javad Sarvestan ◽  
Masoud Sebyani ◽  
Elham Shirzad
Keyword(s):  
Peak Power ◽  
Vertical Jump ◽  
Average Power ◽  
Peak Force ◽  
Jump Height ◽  
Time Curve ◽  
Jump Performance ◽  
Volleyball Players ◽  
Time Variables ◽  
Force Time

The importance of vertical jump in sport fields and rehabilitation is widely recognized. Furthermore, Force-Time variables of vertical jump are factors affecting jumping height. Exclusive review of each of this variables, in eccentric and concentric phases, can lead to a specific focus on them during jumping exercises. So, the aims of his study were to a) reviewing the relationship between force-time curve variables of eccentric and concentric phases with jump height and b) description of this variables in Iran national youth volleyball players society. This is an observational study. 12 elite volleyball player (Male, Iran national youth volleyball players, 17&plusmn;0.7 years) have participated in this study. Correlation between Force-Time variables - included peak force (PF), relative peak force (RPP), peak power (PP), average power (AP), relative peak power (RPP), and Modified Reactive Strength Index (MRSI) - in eccentric and concentric phases and ultimate jump height has been studied. Results showed that the average power (r=0.7) and relative peak force (r=0.75) of concentric phase and MRSI (r=0.83) have significant correlation with ultimate jump height (JH). Relative peak power and average power of concentric phase can massively effect Jump Height in sports like volleyball, which vertical jump is an integral part of them. Focus on both of these factors, which has been studied in this research, in training programs, can improve athlete jump performance significantly.

Kinematic Analysis of Vertical Jump Performances Before and After Fatigue in Basketball Players

2021 ◽  
Vol 15 (7) ◽  
pp. 2226-2228
Author(s):  
Ahmet Atli ◽  
Ali Furkan Yarar
Keyword(s):  
Kinematic Analysis ◽  
Vertical Jump ◽  
Biomechanical Analysis ◽  
Jump Height ◽  
Basketball Players ◽  
Jump Performance ◽  
Joint Injury ◽  
Before And After ◽  
Parameter Values ◽  
Vertical Jumps

Background and Study Aim: This single group pre- and post-test study aimed to examine kinematic changes in vertical jump performances before and after fatigue in basketball players. Material and Method: Ten male university student (age 23.28±1.31 years, height 181.17±6.87 cm, body weight 74.53±9.27 kg) basketball players voluntarily participated in the study. Vertical jump test was performed twice, once before fatigue and again after fatigue, and jump measurements were recorded with 2 cameras capable of shooting 240 frames per second. The vertical jumps were measured using a Smart Speed device. The recorded measurements were analyzed using a biomechanical analysis program, and the results were analyzed statistically. Each participant performed 5 resting jumps on the jump mat after warm-up, and the highest height reached was determined as the jump height. Next, the protocol for inducing fatigue was initiated without a period of rest, and the participants were asked to sprint 6x10 m, following which vertical jumps were performed 5 times without any break. The maximum value of each parameter obtained from among the 5 vertical jumps was used for analysis. The protocol for inducing fatigue was followed until the post-fatigue vertical jump parameter values were below 70% of the maximum values recorded before fatigue. Pre- and post-fatigue jump parameter values were statistically analyzed using the paired samples t-test. Results and Conclusion: Statistically significant differences were observed in knee flexion angle measurements before and after fatigue as well as in jump height measurements before and after fatigue (p<0.05). Therefore, it is believed that fatigue may be associated with a risk of knee joint injury in basketball players. Keywords: Kinematic Analysis, Vertical Jump, Performance, Fatigue, Basketball Players

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