Relationship between explosive strength characteristics with change of direction speed in junior and cadet karate athletes

2021 ◽  
pp. 1-10
Author(s):  
Alex Ojeda-Aravena ◽  
Tomás Herrera-Valenzuela ◽  
Pablo Valdés-Badilla ◽  
Jairo Azócar-Gallardo ◽  
Victor Campos-Uribe ◽  
...  
Keyword(s):  
Multiple Regression Model ◽  
Superior Performance ◽  
Percentage Increase ◽  
Strength Index ◽  
Squat Jump ◽  
Change Of Direction ◽  
Explosive Strength ◽  
Physical Abilities ◽  
The Relationship ◽  
Karate Athletes

BACKGROUND: Explosive strength and change of direction speed (CODS) are relevant physical abilities in karate. OBJECTIVE: To examine the relationship between the characteristics of explosive strength and the 5-m linear sprint (5M) with CODS performance and ii) to examine the influential characteristics of explosive strength on CODS performance. METHODS: Eighteen cadet and junior karate athletes, eight females and ten males were evaluated. The physical abilities assessments included: squat jump (SJ), countermovement jump (CMJ), 5M and CODS. Also, pre-stretch percentage increase (PSA), eccentric utilization index (EUR) reactive strength index (RSI) were calculated. RESULTS: Superior performance (p< 0.05) was documented in SJ, CMJ and CODS in male vs. female. Also, significant correlations between CODS with SJ and CMJ (r=-0.70 to -0.80; R2=-0.51 to -0.73; p< 0.05, respectively) and correlations (r=-0.14 to -0.22; R2= 0.01 to 0.04; p> 0.05) between CODS with RSI, EUR and PSA. Multiple regression model documented that only SJ significantly influenced CODS performance in male (R2= 60%; p= 0.009) and female (R2= 71%; p= 0.001). CONCLUSION: CODS correlate with SJ and CMJ. In particular, SJ influence CODS independently of gender.

scholarly journals Relación de la Asimetría Bilateral y el Déficit Bilateral con la Velocidad del Cambio de Dirección en Atletas Cadetes de Karate: Un estudio Piloto (Relationship of Bilateral Asymmetry and Bilateral Deficit with the Change of Direction Speed in Cadet Kara

Retos ◽  
2021 ◽  
Vol 42 ◽  
pp. 100-108
Author(s):  
Alex Ojeda-Aravena ◽  
Jairo Azócar-Gallardo ◽  
Tomás Herrera-Valenzuela ◽  
José Manuel García-García
Keyword(s):  
Negative Relationship ◽  
Bilateral Asymmetry ◽  
Bilateral Deficit ◽  
Change Of Direction ◽  
Explosive Strength ◽  
P 16 ◽  
Physical Abilities ◽  
Relationship Of ◽  
The Relationship ◽  
Karate Athletes

  Antecedentes: La Asimetría Bilateral (AB) y el Déficit Bilateral (DBL) y su potencial relación negativa con el rendimiento físico es actualmente estudiada, aunque la relación con la velocidad del cambio de dirección (CODS) y el sprint lineal (5-M) en atletas de karate se desconoce. Objetivo: Examinar las correlaciones entre la AB y el DBL con el CODS y 5-M, así como entre el salto horizontal con el CODS y 5-M. Métodos: Diez atletas hombres de categoría cadetes participaron voluntariamente de este estudio. Entre las habilidades físicas evaluadas se incluyeron: salto horizontal bilateral (SBJ), salto horizontal unilateral derecho (RSBJ), salto horizontal unilateral izquierdo (LSBJ), CODS y 5-M. Posteriormente, la AB y el DBL fueron calculados. Resultados: Se reportó una baja AB (5.17 ± 3.61%) y presencia de DBL (-36.9 ± 6.2 %). Correlaciones moderadas entre la AB con CODS (r = -.38; R2 = .15%; p = .30) y 5-M (r = -.47; R2 = .22%; p = .19) y entre DBL con 5-M (r = .51; R2 = .26%; p = .16) y bajas con CODS (r = .20; R2 = .04%; p = .60). Correlaciones significativas (p < .05) entre CODS con RSBJ (r = -.92; R2 = .85%; p = .00), SBJ (r = -.87; R2 = .75%; p = .00) y LSBJ (r = -.82; R2 = .67%; p = .00). Conclusiones: La AB y el DBL se relacionarían negativamente con el CODS y 5-M. Aunque, el CODS se relaciona con la fuerza explosiva horizontal bilateral y unilateral. Abstract. Background: Bilateral asymmetry (AB) and Bilateral Deficit (DBL) and their potential negative relationship with physical performance is currently studied, although the relationship with change of direction speed (CODS) and linear sprint (5-M) in karate athletes is unknown. Aim: To examine correlations between AB and DBL with CODS and 5-M, as well as between horizontal jump with CODS and 5-M. Methods: Ten male cadet athletes voluntarily participated in this study. The physical abilities assessed included: bilateral horizontal jump (SBJ), right unilateral horizontal jump (RSBJ), left unilateral horizontal jump (LSBJ), CODS and 5-M. Subsequently, AB and DBL were calculated. Results: Low AB (5.17 ± 3.61%) and presence of DBL (-36.9 ± 6.2 %) were reported. Moderate correlations between AB with CODS (r = -.38; R2 = .15%; p = .30) and 5-M (r = -.47; R2 = .22%; p = .19) and between DBL with 5-M (r = .51; R2 = .26%; p = .16) and low with CODS (r = .20; R2 = .04%; p = .60). Significant correlations (p < .05) between CODS with RSBJ (r = -.92; R2 = .85%; p = .00), SBJ (r = -.87; R2 = .75%; p = .00) and LSBJ (r = -.82; R2 = .67%; p = .00). Conclusions: AB and DBL would be negatively related to CODS and 5-M. However, CODS is related to bilateral and unilateral horizontal explosive strength.

Interrelationship between specific high-intensity intermittent efforts ability with aerobic capacity and slow stretch-shortening cycle utilization in taekwondo athletes

2021 ◽  
pp. 1-10
Author(s):  
Alex Ojeda-Aravena ◽  
Tomás Herrera-Valenzuela ◽  
Pablo Valdés-Badilla ◽  
Eduardo Baez-San Martín ◽  
José Zapata-Bastías ◽  
...  
Keyword(s):  
Aerobic Capacity ◽  
High Intensity ◽  
Dynamic Strength ◽  
Multiple Regression Model ◽  
Strength Index ◽  
Male Athletes ◽  
Squat Jump ◽  
Stretch Shortening Cycle ◽  
The Relationship ◽  
Shuttle Run

BACKGROUND: Repeat high-intensity intermittent efforts is a taekwondo-specific ability but the influence of aerobic capacity and dynamic strength characteristics on this ability has received relatively little attention in the literature. OBJECTIVE: To examine the relationship between specific high-intensity intermittent efforts with aerobic capacity and slow stretch-shortening cycle utilization in taekwondo athletes. METHODS: Nineteen taekwondo male athletes were assessed by squat jump (SJ), countermovement jump (CMJ), 20-meter shuttle run (20MSR), and frequency speed of kick test multiple (FSKTMULT). From the FSKTMULT, total kicks and kick decrement index [KDI] were calculated. Additionally, from both jump tests, the slow stretch-shortening cycle utilization (Slow SSC Utilization) was determined from the eccentric utilization ratio [EUR], pre-stretch augmentation [PSA], and reactive strength index [RSI]. RESULTS: There were positive and significant correlations between total kicks with 20MSR (r= 0.85; p= 0.00) and SJ (r= 0.66; p< 0.05). The multiple regression model demonstrated that total kicks where significantly influenced by 20MSR (R2= 71%; p= 0.00). Additionally, only EUR and RSI explained total kicks performance to a greater proportion (R2= 76%). CONCLUSIONS: The FSKTMULT total kicks performance is positively correlated and influenced by aerobic capacity and slow SSC utilization.

scholarly journals The relationship between lower limb maximal and explosive strength and change of direction ability: Comparison of basketball and tennis players, and long-distance runners

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256347
Author(s):  
Žiga Kozinc ◽  
Darjan Smajla ◽  
Nejc Šarabon
Keyword(s):  
Muscle Strength ◽  
Lower Limb ◽  
Trunk Muscles ◽  
Distance Runners ◽  
Long Distance ◽  
Basketball Players ◽  
Tennis Players ◽  
Change Of Direction ◽  
Explosive Strength ◽  
The Relationship

Change-of-direction (CoD) ability is an important determinant of athletic performance. Muscle strength is among the most important determinants of CoD ability. However, previous studies investigating the relationship between CoD ability and muscle strength focused mostly on flexor and extensor muscle groups, or used multi-joint exercises, such as jumps, squats or mid-thigh pull. The purpose of the present study was to investigate the relationship between CoD ability and strength of ankle, knee, hip and trunk maximal and explosive strength. The participants (n = 327), consisting of male and female basketball players, tennis players and long-distance runners completed isometric strength assessments and CoD testing (90° and 180° turn tests). The times of both CoD tests were associated with muscle strength (peak torques and the rate of torque development variables), with correlation coefficients being mostly weak to moderate (r = 0.2–0.6). Strength variables explained 33%, 62% and 48% of the variance in the 90° turn task, and 42%, 36% and 59% of the variance in the 180° turn task, in basketball players, long-distance runners and tennis players, respectively. Hip and trunk muscle strength variables were the most prevalent in the regression models, especially hip adduction and abduction strength. Our results suggest that the strength of several lower limb muscles, in particular of the hip abductors and adductors, and trunk muscles, but also hip rotators, extensors and flexors, as well as knee and ankle flexors and extensors should be considered when aiming to improve CoD performance.

scholarly journals The Relationship between Change of Direction Tests in Elite Youth Soccer Players

Sports ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 111 ◽  
Author(s):  
Björn Kadlubowski ◽  
Michael Keiner ◽  
Hagen Hartmann ◽  
Klaus Wirth ◽  
Ulrich Frick
Keyword(s):  
Pearson Correlation ◽  
Team Sports ◽  
Soccer Players ◽  
Limiting Factor ◽  
Youth Soccer ◽  
Change Of Direction ◽  
False Discovery ◽  
Physical Abilities ◽  
Pearson Correlation Analysis ◽  
The Relationship

Change of direction (COD) is a performance-limiting factor in team sports. However, there are no exact definitions describing which physical abilities limit COD performance in soccer. Nevertheless, different COD tests are used or have been recommended as being equally effective in the professional practice of measuring COD performance. Therefore, the aim of this study was to evaluate the relationship between different COD tests, and to test the independence and generalizability of these COD tests in soccer. As such, 27 elite youth soccer players were randomly recruited and were tested in different COD tests (i.e., Illinois agility test (IAT), T agility test (TT), 505 agility test (505), Gewandtheitslauf (GewT), triangle test (Tri-t), and square test (SQT)). Bivariate Pearson correlation analysis was used to assess the relationships between the COD tests. The Benjamini–Hochberg method was used to control for the false discovery rate of the study at 0.05. This investigation calculated explained variances of 10% to 55% between performances in the different COD tests. This suggested that the tests covered different aspects or task-specific characteristics of the COD. Therefore, coaches and sport scientists should review and select different tests with a logical validity, based on the requirement profiles of the corresponding sport.

scholarly journals Empirical Examination of the Relationship Between Venture Capital Financing and the Profitability of the Portfolio Companies in Uganda

2021 ◽  
Author(s):  
Ahmed Idi Kato ◽  
Chiloane-Phetla E Germinah
Keyword(s):  
Venture Capital ◽  
Positive Impact ◽  
Early Stage ◽  
Multiple Regression Model ◽  
Superior Performance ◽  
Empirical Examination ◽  
Capital Financing ◽  
Value Add ◽  
Enterprise Success ◽  
The Relationship

Abstract PurposeThis paper empirically examined the relationship between Venture capital Financing and the profitability of portfolio companies in Uganda. Several empirical works paint an intriguing picture that VC financing is a reality in fostering economic growth of the early-stage enterprisesDesign/methodology/approachThe paper embraced a mixed-method wherein quantitative data were collected from 68 key VC stakeholders and statistical data was analysed using a multiple regression model by generating the results from the SPSS. This was supplemented by 16 semi-structured face-to-face interviews. Qualitative data were transcribed and analysed using Altas-ti.Findings The key findings from this study suggest superior performance of VC-financed enterprises following VC financing when compared to non-VC financed enterprises. The VC-financed enterprises realised tremendous growth in terms of: Return on Equity - 42.3%; profitability - 30% - 50%; Return on Assets - 44.5%. In addition, 63% of the respondents confirmed a positive impact of government regulatory policy in enhancing the development of the early-stage firms. The higher the percentage of growth the better for the growth of the company. Research limitations/implicationsThis study may assist the policymakers and business fraternity to develop policy frameworks tailored to enhancing a vibrant venture capital market in Uganda. Contribution/value-addThis study makes a vital contribution to knowledge by offering a diversified framework for enterprise success, to benefit the VC stakeholders in customizing funding programs that can propel the early-stage enterprise success in Uganda and similar emerging economies.

scholarly journals The prediction of swim start performance based on squat jump force-time characteristics

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9208
Author(s):  
Shiqi Thng ◽  
Simon Pearson ◽  
Evelyne Rathbone ◽  
Justin W.L. Keogh
Keyword(s):  
Body Mass ◽  
National Level ◽  
Multiple Regression Model ◽  
Lower Body ◽  
Strength Index ◽  
Mean Power ◽  
Front Crawl ◽  
Jump Performance ◽  
Squat Jump ◽  
Force Time

Background Depending on the stroke and distances of the events, swim starts have been estimated to account for 0.8% to 26.1% of the overall race time, with the latter representing the percentage in a 50 m sprint front crawl event (Cossor & Mason, 2001). However, it is still somewhat unclear what are the key physiological characteristics underpinning swim start performance. The primary aim of this study was to develop a multiple regression model to determine key lower body force-time predictors using the squat jump for swim start performance as assessed by time to 5 m and 15 m in national and international level swimmers. A secondary aim was to determine if any differences exist between males and females in jump performance predictors for swim start performance. Methods A total of 38 males (age 21 ±  3.1 years, height 1.83 ±  0.08 m, body mass 76.7 ±  10.2 kg) and 34 females (age 20.1 ±  3.2 years, height 1.73 ±  0.06 m, body mass 64.8 ±  8.4 kg) who had competed at either an elite (n = 31) or national level (n = 41) participated in this study. All tests were performed on the same day, with participants performing three bodyweight squat jumps on a force platform, followed by three swim starts using their main swimming stroke. Swim start performance was quantified via time to 5 m and 15 m using an instrumented starting block. Results Stepwise multiple linear regression with quadratic fitting identified concentric impulse and concentric impulse2 as statistically significant predictors for time to 5 m (R2 = 0.659) in males. With time to 15 m, concentric impulse, age and concentric impulse2 were statistically significant predictors for males (R2 = 0.807). A minimum concentric impulse of 200–230 N.s appears required for faster times to 5 m and 15 m, with any additional impulse production not being associated with a reduction in swim start times for most male swimmers. Concentric impulse, Reactive strength index modified and concentric mean power were identified as statistically significant predictors for female swimmers to time to 5 m (R2 = 0.689). Variables that were statistically significant predictors of time to 15 m in females were concentric impulse, body mass, concentric rate of power development and Reactive strength index modified (R2 = 0.841). Discussion The results of this study highlight the importance of lower body power and strength for swim start performance, although being able to produce greater than 200 or 230 N.s concentric impulse in squat jump did not necessarily increase swim start performance over 5 m and 15 m, respectively. Swimmers who can already generate greater levels of concentric impulse may benefit more from improving their rate of force development and/or technical aspects of the swim start performance. The sex-related differences in key force-time predictors suggest that male and female swimmers may require individualised strength and conditioning programs and regular monitoring of performance.

scholarly journals Relación entre el Movement change in karate position Test con el rendimiento neuromuscular en atletas de karate: Un estudio piloto (Relationship between Movement change in karate position Test and neuromuscular performance in karate athletes: A pilot stud

Retos ◽  
2020 ◽  
pp. 505-508
Author(s):  
Tomas Herrera-Valenzuela ◽  
Gricelle Miccono-González ◽  
Margaret Fazekas-Molina ◽  
Gonzalo Astorga-Rojas ◽  
Pablo Valdés-Badilla ◽  
...  
Keyword(s):  
Body Mass ◽  
Countermovement Jump ◽  
Squat Jump ◽  
Neuromuscular Performance ◽  
Long Jump ◽  
Physical Abilities ◽  
High Intensity Interval ◽  
Relationship Of ◽  
Movement Change ◽  
Karate Athletes

Resumen. Antecedentes: El karate es un deporte intervalado de alta-intensidad con características aeróbicas y anaeróbicas, la velocidad y la fuerza explosiva son habilidades físicas determinantes para los atletas de karate durante el combate. Problema y objetivo: El principal objetivo de este estudio fue examinar la relación del Movement change in karate position Test “MKUKS” con el rendimiento neuromuscular medido a través de pruebas de salto en atletas de karate categoría junior. Métodos: Una muestra de 10 atletas de karate, distribuidos en 4 hombres (edad:17.3 ± 2.1 años; masa corporal: 69.0 ± 15.8 kg; talla: 1.74 ± 0.04 m) y 6 mujeres (edad: 17.3 ± 1.6 años; masa corporal: 57.9 ± 2.5 kg; talla: 1.59 ± 0.04 m), pertenecientes a la selección chilena categoría junior fue evaluada. Resultados: Observamos una correlación entre el MKUKS con el salto largo bilateral (r = -.68, p = .03), squat jump (r = -.65, p = .04), el salto contramovimiento (r = -.70, p = .02), y salto contramovimiento con brazos (r = -.68, p = .03). Conclusiones: La prueba MKUKS se relaciona significativamente con el rendimiento neuromuscular en atletas de karate. Abstract. Background: Karate is a high intensity interval sport with aerobic and anaerobic characteristics, velocity and explosive strength are crucial physical abilities for karate athletes during the combat. Problem and Aim: The main objective of this study was to examine the relationship of the Movement change in karate position Test “MKUKS” with the neuromuscular performance measured through jump tests in karate athletes junior category Methods: A team of 10 karate athletes, distributed in 4 men (age: 17.3 ± 2.1 years; body mass: 69.0 ± 15.8 kg; height: 1.74 ± 0.04 m) and 6 women (age: 17.3 ± 1.6 years; body mass: 57.9 ± 2.5 kg; height: 1.59 ± 0.04 m), belonging to the Chilean national junior team was evaluated. Results: We observed a correlation between the MKUKS with the bilateral long jump (r = -.68, p = .03), squat jump (r = -.65, p = .04), countermovement jump (r = -. 70, p = .02), and countermovement jump with arms (r = -.68, p = .03). Conclusions: MKUKS is significantly related to neuromuscular performance in karate athletes.

Clinical Update: Functional Capacity Evaluations and Disability

1998 ◽  
Vol 3 (2) ◽  
pp. 4-5
Author(s):  
Glenn Pransky
Keyword(s):  
Direct Observation ◽  
Functional Capacity ◽  
Work Capacity ◽  
Functional Capacity Evaluation ◽  
Whole Body ◽  
Validity Of Results ◽  
Job Tasks ◽  
Capacity Evaluation ◽  
Physical Abilities ◽  
The Relationship

Abstract According to the AMA Guides to the Evaluation of Permanent Impairment, a functional capacity evaluation (FCE) measures an individual's physical abilities via a set of activities in a structured setting and provides objective data about the relationship between an impairment and maximal ability to perform work activities. A key distinction between FCEs and self-reported activities of daily living is that the former involve direct observation by professional evaluators. Numerous devices can quantify the physical function of a specific part of the musculoskeletal system but do not address the performance of whole body tasks in the workplace, and these devices have not been shown to predict accurately the ability to perform all but the simplest job tasks. Information about reliability has been proposed as a way to identify magnification and malingering, but variability due to pain and poor comprehension of instructions may cause variations in assessments. Structured work capacity evaluations involve a set of activities but likely underestimate the individual's ability to do jobs that involve complex or varying activities. Job simulations involve direct observation of an individual performing actual job tasks, require a skilled and experienced evaluator, and raise questions about expense, time, objectivity and validity of results, and interpretation of results in terms of the ability to perform specific jobs. To understand the barriers to return to work, examiners must supplement FCEs with information regarding workplace environment, accommodations, and demotivators.

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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