scholarly journals Relación entre el CMJ y cambios de dirección en deportes colectivos / Relationship between CMJ and change of direction in collective sports

2016 ◽  
Vol 2 (1) ◽  
pp. 30
Author(s):  
J. Ferrando Fenoll ◽  
JL. Schneider Tirado
Keyword(s):  
Performance Level ◽  
Countermovement Jump ◽  
Change Of Direction ◽  
Full Speed ◽  
Force Components ◽  
Para Determinar ◽  
The Relationship ◽  
Highly Involved

RESUMENEn la ejecución de una carrera a máxima velocidad con cambio de dirección observamos una alta participación de componentes de fuerza. Dichos componentes vienen siendo entrenados de forma específica, como por ejemplo a través de la pliometría. Pocos estudios valoran la fuerza explosiva y reactiva de forma unilateral (1,2) y su correlación con las carreras cortas de aceleración con cambios de dirección. Según los resultados de los trabajos revisados, (3,4,5,6,7) nuestro propósito es conocer la relación entre medidas de fuerza-explosiva y fuerza reactiva, con carreras cortas de aceleración con cambios de dirección, para determinar si la manifestación de fuerza con un salto con contramovimiento (CMJ) predice el rendimiento en carreras cortas de aceleración con cambios de dirección de 90º.ABSTRACTWhen executing a race at full speed with change-of-direction force components are highly involved. These components are being specifically trained through plyometric exercises, among others. Few studies evaluate on one side explosive and reactive strength (1,2) and their correlation with short change-of-direction sprints.Once analysed the evidences showed in some studies reviewed (3,4,5,6,7), our purpose is to determine the relationship between both explosive and reactive strength measures and short change-ofdirection sprints in order to find whether the countermovement jump (CMJ) force manifestation helps predicting the performance level during change-of-direction 90º acceleration sprints.

scholarly journals Assessing the Magnitude and Direction of Asymmetry in Unilateral Jump and Change of Direction Speed Tasks in Youth Female Team-Sport Athletes

2021 ◽  
Vol 79 (1) ◽  
pp. 15-27
Author(s):  
Jordi Arboix-Alió ◽  
Chris Bishop ◽  
Ariadna Benet ◽  
Bernat Buscà ◽  
Joan Aguilera-Castells ◽  
...  
Keyword(s):  
Team Sports ◽  
Team Sport ◽  
Kappa Coefficient ◽  
Fitness Testing ◽  
Countermovement Jump ◽  
Linear Speed ◽  
Female Youth ◽  
Change Of Direction ◽  
Time Performance ◽  
The Relationship

Abstract The direction of inter-limb asymmetries and the change of direction (COD) deficit are two aspects that have increased in recent years. The main objective of the present study was to assess the magnitude of neuromuscular asymmetries in an elite youth female team-sports sample and determine its directionality. Secondary objectives were to evaluate the relationship between COD deficit, linear speed and COD time performance. Elite female youth basketball and handball players (n = 33, age = 16 ± 1.17 y) performed the Single Leg Countermovement Jump in vertical (SLCJ-V), horizontal (SLCJ-H), and lateral (SLCJ-L) directions, the COD and the 10-m sprint. Results showed statistical differences between limbs in all the neuromuscular tests (p < 0.001). The Kappa coefficient showed poor to fair levels of agreement between tasks (K range = -0.087 to 0.233), indicating that asymmetries rarely favoured the same limb between skills. Additionally, small and non-significant correlations were found between the linear sprint capacity and the COD ability. The findings of the present study highlight the independent directionality of asymmetries across tests. The COD deficit does not appear to be much more advantageous than COD total time to measure asymmetry. Practitioners are encouraged to use a fitness testing battery to detect existing side differences and each ability should be specifically trained with functional tasks.

scholarly journals Relationship of Performance Measures and Muscle Activity between a 180° Change of Direction Task and Different Countermovement Jumps

Sports ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 47 ◽  
Author(s):  
Hallvard Nygaard Falch ◽  
Håvard Guldteig Rædergård ◽  
Roland Van den Tillaar
Keyword(s):  
Performance Measures ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Biceps Femoris ◽  
Soccer Players ◽  
Countermovement Jump ◽  
Change Of Direction ◽  
Relationship Of ◽  
The Relationship ◽  
Adductor Longus

The ability to rapidly perform change of direction (COD) is crucial for performance in Soccer. COD speed is thought to share similarities with countermovement jumps in kinematics and muscle activation. Thus, the objective of the current study was to investigate the relationship between muscle activities in performance measures of a modified 505-agility test and different countermovement jumps. Twenty-one experienced soccer players performed a COD test including the 505-agility test and uni- and bi-lateral horizontal and vertical countermovement jumps. The main findings were that the vertical bilateral and horizontal unilateral countermovement jump were able to predict total time to complete the COD, but not 505-agility time. Muscle activity in the COD and countermovement jumps was only distinguished by a higher peak muscle activity for the adductor longus, semitendinosus and biceps femoris in the COD to stabilize the hip and decelerate knee joint movements when turning compared with the jumps. Conclusively, the relationship between performance in countermovement jumps and total time to complete the COD test was due to longer sprint distances, which makes the distinction between performances bigger. Peak muscle activity of most muscles is similar between the jumps and the COD step, indicating similar muscular demands between these activities.

scholarly journals Analyzing the Magnitude of Interlimb Asymmetries in Young Female Soccer Players: A Preliminary Study

2021 ◽  
Vol 18 (2) ◽  
pp. 475
Author(s):  
Javier Raya-González ◽  
Filipe Manuel Clemente ◽  
Daniel Castillo
Keyword(s):  
Range Of Motion ◽  
Muscle Mass ◽  
Injury Risk ◽  
Young Female ◽  
Asymmetry Index ◽  
Lower Limbs ◽  
Soccer Players ◽  
Countermovement Jump ◽  
Change Of Direction ◽  
Jump Ability

Although asymmetries in lower limbs have been linked with players’ performance in male soccer players, literature that has been published addressing female soccer is scarce. Thus, the aim of this study was twofold: (i) describe the asymmetries of women soccer players during jumping, change-of-direction and range-of-motion tests; and (ii) test possible relationships between asymmetries and injury risk in female soccer players. Sixteen female players (15.5 ± 1.5 years) performed a battery of fitness tests (i.e., jump ability, change-of-direction ability and passive range-of-motion) and muscle mass analysis via dual-energy X-ray absorptiometry, through which the specific asymmetry index and the related injury risk were calculated. Significant (p < 0.05) lower asymmetries in the change-of-direction test were observed in comparison to those observed in jumping and range-of-motion tests; significant (p < 0.05) lower asymmetries in muscle mass were also reported compared to those found in the change-of-direction and countermovement jump tests. Additionally, increased injury risk for countermovement jump and hip flexion with extended knee range-of-motion (relating to asymmetry values) and for ankle flexion with flexed knee range-of-motion in both legs (relating to reference range-of-motion values), as well as increased individual injury risk values, were observed across all tests. These findings suggest the necessity to implement individual approaches for asymmetry and injury risk analyses.

Changes in selected locomotor skills of young runners after one athletic season: Influence of sex and age

2021 ◽  
pp. 174795412110066
Author(s):  
Josune Rodriguez-Negro ◽  
Iñaki Llodio ◽  
Daniel Castillo ◽  
Estibaliz Romaratezabala ◽  
Javier Yanci
Keyword(s):  
Athletic Training ◽  
Countermovement Jump ◽  
Training School ◽  
Change Of Direction ◽  
Age And Sex

The aim of the present research was to describe the changes in the locomotor competence [i.e. sprint, change of direction ability (CODA) and jump capacity] of young runners from an athletic training school after one season, according to runners’ sex and age. Two hundred and forty-one young runners from an athletic training school were divided by sex (boys, n = 107, and girls, n = 134) and age [under 8 years old (U8, n = 70), under 10 years old (U10, n = 68), under 12 years old (U12, n = 45), under 14 years old (U14, n = 39) and under 16 years old (U16, n = 19)]. At the start of the training season (PRE) and at the end of the season (POST), the runners performed different tests in order to assess their locomotor competence. The results showed that boys and girls improved their performance during the season in the 5 m sprint ( p = 0.000, ES = -0.58 to -0.74) and horizontal countermovement jump (HCMJ) ( p = 0.000, ES = 0.51 to 1.02), and decreased it in the 15 m sprint test ( p = 0.011 or p = 0.006, ES = 0.27 to 0.31), and only girls improved in change of direction ability (CODA) ( p = 0.000, ES = -0.22 to -0.27). In addition, with respect to age categories, all groups improved their performance in the HCMJ ( p = 0.000 - 0.005, ES > 0.40) and the 5 m sprint tests ( p = 0.000 - 0.002, ES = -0.68 to -1.24). Although in the 505 test no group improved its result ( p = 0.184 - 0.314, ES = -0.25 to 0.01), the U8 and U10 groups improved in the modified agility test (MAT) ( p = 0.000 or p = 0.003, ES = -0.38 to -0.41). In conclusion, there are differences in the changes in the locomotor competence according to runners’ sex and age, so perhaps age- and sex-dependent specialization in training is necessary.

scholarly journals Associations between Inter-Limb Asymmetries in Jump and Change of Direction Speed Tests and Physical Performance in Adolescent Female Soccer Players

2021 ◽  
Vol 18 (7) ◽  
pp. 3474
Author(s):  
Elena Pardos-Mainer ◽  
Chris Bishop ◽  
Oliver Gonzalo-Skok ◽  
Hadi Nobari ◽  
Jorge Pérez-Gómez ◽  
...  
Keyword(s):  
Physical Performance ◽  
Age Groups ◽  
Soccer Players ◽  
Adolescent Female ◽  
Specific Training ◽  
Countermovement Jump ◽  
Change Of Direction ◽  
Percentage Difference ◽  
Hop Test ◽  
Physical Tests

The association between asymmetries in jump and change of direction (COD) with physical performance in several sports show inconclusive results. The purposes of this study were to: (1) measure inter-limb asymmetries in three distinct groups in adolescent female soccer players and, (2) to determine the association between inter-limb asymmetries and physical performance in different age groups. Fifty-four players were distributed in three age groups: U-18, U-16 and U-14. All of them performed a series of jumps, sprints and change of direction speed tests. Asymmetries were assessed as the percentage difference between limbs, with the equation: 100/Max value (right and left) * in value (right and left) * −1 + 100. Mean inter-limb asymmetries were 2.91%, 4.82% and 11.6% for 180° COD, single leg hop and single leg countermovement jump tests respectively, but higher percentages of asymmetries were observed in many players individually. U-18 and U-16 showed significant differences on 180° left COD compared to U-14. Effect size (ES): 0.80 and 0.74, respectively; U-18 presented differences on single left leg hop test compared to U-14, ES: −0.72; U-16 also showed differences on 40 m speed compared to U-14, ES 0.87 (All p < 0.05). Jumping and COD physical tests show asymmetries in adolescent female soccer players, but these asymmetries do not interfere with physical performance. The largest asymmetry was observed in the single leg countermovement jump, and no asymmetries between groups were found. Due to the high variability in the direction of asymmetries, it is recommended to consider players’ individual asymmetries for designing specific training programs.

scholarly journals CAD-Based 3D-FE Modelling of AISI-D3 Turning with Ceramic Tooling

Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 4
Author(s):  
Panagiotis Kyratsis ◽  
Anastasios Tzotzis ◽  
Angelos Markopoulos ◽  
Nikolaos Tapoglou
Keyword(s):  
Statistical Model ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Fe Model ◽  
Fe Modelling ◽  
3D Finite Element ◽  
Force Components ◽  
Four Levels ◽  
The Relationship ◽  
Strong Agreement

In this study, the development of a 3D Finite Element (FE) model for the turning of AISI-D3 with ceramic tooling is presented, with respect to four levels of cutting speed, feed, and depth of cut. The Taguchi method was employed in order to create the orthogonal array according to the variables involved in the study, reducing this way the number of the required simulation runs. Moreover, the possibility of developing a prediction model based on well-established statistical tools such as the Response Surface Methodology (RSM) and the Analysis of Variance (ANOVA) was examined, in order to further investigate the relationship between the cutting speed, feed, and depth of cut, as well as their influence on the produced force components. The findings of this study point out an increased correlation between the experimental results and the simulated ones, with a relative error below 10% for most tests. Similarly, the values derived from the developed statistical model indicate a strong agreement with the equivalent numerical values due to the verified adequacy of the statistical model.

scholarly journals The Influence of Countermovement Jump Protocol on Reactive Strength Index Modified and Flight Time: Contraction Time in Collegiate Basketball Players

Sports ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 37 ◽  
Author(s):  
Aaron Heishman ◽  
Brady Brown ◽  
Bryce Daub ◽  
Ryan Miller ◽  
Eduardo Freitas ◽  
...  
Keyword(s):  
Force Plate ◽  
Flight Time ◽  
Contraction Time ◽  
Strength Index ◽  
Countermovement Jump ◽  
Basketball Players ◽  
Arm Swing ◽  
Collegiate Basketball ◽  
Positive Correlations ◽  
The Relationship

The purpose of the present investigation was to evaluate differences in Reactive Strength Index Modified (RSIMod) and Flight Time to Contraction Time Ratio (FT:CT) during the countermovement jump (CMJ) performed without the arm swing (CMJNAS) compared to the CMJ with the arm swing (CMJAS), while exploring the relationship within each variable between jump protocols. A secondary purpose sought to explore the relationship between RSIMod and FT:CT during both jump protocols. Twenty-two collegiate basketball players performed both three CMJNAS and three CMJAS on a force plate, during two separate testing sessions. RSIMod was calculated by the flight-time (RSIModFT) and impulse-momentum methods (RSIModIMP). CMJ variables were significantly greater during the CMJAS compared to CMJNAS (p < 0.001). There were large to very large correlations within each variable between the CMJAS and CMJNAS. There were significant positive correlations among RSIModFT, RSIModIMP, and FT:CT during both the CMJAS (r ≥ 0.864, p < 0.001) and CMJNAS (r ≥ 0.960, p < 0.001). These findings identify an increase in RSIMod or FT:CT during the CMJAS, that may provide independent information from the CMJNAS. In addition, either RSIMod or FT:CT may be utilized to monitor changes in performance, but simultaneous inclusion may be unnecessary.

Effects of complex strength training with elastic band program on repeated change of direction in young female handball players: Randomized control trial

2021 ◽  
pp. 174795412110621
Author(s):  
Mehrez Hammami ◽  
Nawel Gaamouri ◽  
Yosser Cherni ◽  
Sabri Gaied ◽  
Mohamed Souhaiel Chelly ◽  
...  
Keyword(s):  
Strength Training ◽  
Young Female ◽  
Control Group ◽  
Countermovement Jump ◽  
Elastic Band ◽  
Squat Jump ◽  
Change Of Direction ◽  
Jump Test ◽  
Back Extensor ◽  
Experimental Group

This study examined the effect of 10-week complex strength training with elastic band program on fitness components in young female handball players. Thirty-eight handball players aged 15.8 ± 0.2 years were randomly assigned to an experimental group or control group. The experimental group performed complex strength training with elastic band twice a week over 10 weeks, which included 8 workshops of progressing set length (number of sets) and band resistance for each specific exercise. Sessions were lasted approximately 35 min. The control group maintained regular in-season training. Tests included handgrip; back extensor; medicine ball throw; 30 m sprint times; Modified Illinois change-of-direction (Illinois-MT); four jump tests (squat jump, countermovement jump, countermovement jump with arms and five jump test; static (stork test) and dynamic (Y balance test) balance; and repeated sprint T-test. The experimental group enhanced all strength performance (handgrip right ( p < 0.001), handgrip left ( p < 0.001), back extensor strength ( p < 0.001) and medicine ball throw ( p < 0.001) compared to the controls); sprint performance (5 m ( p<0.001), 10 m ( p < 0.001), 20 m ( p < 0.001), and 30 m ( p < 0.001)); the change of direction (Illinois-MT ( p < 0.001)); jump performance (squat jump ( p < 0.001), countermovement jump ( p < 0.001), countermovement jump with arms ( p < 0.001), and five jump test ( p < 0.01)); and the repeated sprint T-test scores ( p<0.001in all scores). In contrast, no significant difference in both static and dynamic balance performance between experimental group and control group. Ten weeks of complex strength training with elastic band improve fitness components measures in young female handball players then habitual training.

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