scholarly journals A Comparison of Isometric Midthigh-Pull Strength, Vertical Jump, Sprint Speed, and Change-of-Direction Speed in Academy Netball Players

2017 ◽  
Vol 12 (7) ◽  
pp. 916-921 ◽  
Author(s):  
Christopher Thomas ◽  
Paul Comfort ◽  
Paul A. Jones ◽  
Thomas Dos’Santos
Keyword(s):  
High Performance ◽  
Vertical Jump ◽  
Young Female ◽  
Isometric Strength ◽  
Superior Performance ◽  
Strong Correlations ◽  
Sprint Speed ◽  
Change Of Direction ◽  
Body Strength ◽  
Squat Jumps

Purpose:To investigate the relationships between maximal isometric strength, vertical jump (VJ), sprint speed, and change-of-direction speed (CoDS) in academy netball players and determine whether players who have high performance in isometric strength testing would demonstrate superior performance in VJ, sprint speed, and CoDS measures.Method:Twenty-six young female netball players (age 16.1 ± 1.2 y, height 173.9 ± 5.7 cm, body mass 66.0 ± 7.2 kg) from a regional netball academy performed isometric midthigh pull (IMTP), squat jumps (SJs), countermovement jumps (CMJs), 10-m sprints, and CoDS (505).Results:IMTP measures displayed moderate to strong correlations with sprint and CoDS performance (r = –.41 to –.66). The VJs, which included SJs and CMJs, demonstrated strong correlations with 10-m sprint times (r = –.60 to –.65; P < .01) and CoDS (r = –.60 to –.71; P = .01). Stronger players displayed significantly faster sprint (ES = 1.1–1.2) and CoDS times (ES = 1.2–1.7) and greater VJ height (ES = 0.9–1.0) than weaker players.Conclusion:The results of this study illustrate the importance of developing high levels of lower-body strength to enhance VJ, sprint, and CoDS performance in youth netball players, with stronger athletes demonstrating superior VJ, sprint, and CoDS performances.

scholarly journals Physical Fitness Profiling of National Category Table Tennis Players: Implication for Health and Performance

2021 ◽  
Vol 18 (17) ◽  
pp. 9362
Author(s):  
Jon Mikel Picabea ◽  
Jesús Cámara ◽  
Javier Yanci
Keyword(s):  
Vertical Jump ◽  
Age Groups ◽  
Isometric Strength ◽  
Table Tennis ◽  
Arm Swing ◽  
Tennis Players ◽  
Change Of Direction ◽  
Counter Movement Jump ◽  
And Performance ◽  
Better Than

The aims of this study were to: (1) analyze table tennis players’ physical profiles considering and comparing players age categories (i.e., under U12, U14, U16, U20, Senior and Older); and (2) to quantify the correlations among the variables measured by each test. Seventy-one table tennis players (61 men and 10 women, 19.7 ± 11.23 years, 1.65 ± 0.13 m, 59.71 ± 17.72 kg and 21.60 ± 4.22 kg/m2) divided into six age groups, performed a sprint test, forearm isometric strength test, countermovement vertical test, countermovement horizontal test, change of direction ability (CODA) test and flexibility test. U14 players performed better than U12 in all tests (ES = −0.70 to 1.98, moderate to large) except in Sit and Reach (SAR) test (ES = 0.19, trivial). The U16 group also obtained better results than U14 in all tests (ES = 0.77 to −2.31, moderate to large) except for the SAR test (ES = 0.19, trivial). The U20 group performed better than U16 in all the tests (ES = 0.73 to −1.53, moderate to large) except for the 5 m sprint test (ES = −0.02, trivial), 10 m sprint test (ES = −0.51, moderate) and SAR (ES = 0.11, trivial). Differences between Senior and U20 were only found in the arm swing counter movement jump (CMJAS) (ES = −0.82, large) and modified agility test (MAT) (ES = 1.19, large), with the U20 group being better in both variables. The senior group performed better in the MAT test than the older group (ES = 0.94, large). The relation found between forearm isometric strength, vertical jump, horizontal jump, sprint and CODA ability (r = −0.53; ±0.14, 0/0/100, most likely to r = 0.83; ±0.06, 100/0/0, most likely) indicates that these capacities are related in table tennis players. Nevertheless, the lack of association between the sit and reach test with the other capacities may indicate that flexibility is an independent capacity.

scholarly journals The effects of cluster-set and traditional-set post activation potentiation protocols on vertical jump performance

2019 ◽  
Author(s):  
Antonio Dello Iacono ◽  
Marco Beato ◽  
Israel Halperin
Keyword(s):  
Vertical Jump ◽  
Muscular Fatigue ◽  
Superior Performance ◽  
Acute Effects ◽  
Countermovement Jump ◽  
Basketball Players ◽  
Jump Performance ◽  
Warm Up ◽  
Cluster Set ◽  
Squat Jumps

Purpose. To compare the acute effects of two post activation potentiation (PAP) protocols using traditional or cluster-set configurations on countermovement jump (CMJ) performance. Methods. Twenty-six male basketball players were evaluated on three occasions separated by 72 hours. On the first session, athletes performed barbell squat jumps with progressively heavier loads to determine their individual optimum power loads. On the second and third sessions, athletes completed two PAP protocols in a randomized, counterbalanced order: 3 sets of 6 repetitions of squat jumps using optimum power loads performed with either a traditional (no inter-repetition rest) or a cluster-set (20 s rest every 2 repetitions) configurations. After a comprehensive warm-up, CMJ height was measured using a force platform before, 30 s, 4 min, and 8 min after completing the PAP protocols. Results. While at post-30 s athletes jumped lower compared to baseline in both conditions, jump heights were 0.71 cm higher following the cluster-set compared to the traditional condition (95% CI: 0.37, 1.05 cm). While athletes jumped higher compared to baseline at post-4 and post-8 min in both conditioning, jump heights were higher following the cluster-set compared to the traditional condition in post-4 min by 1.33 cm (95% CI: 1.02, 1.65 cm) and in post-8 min by 1.64 cm (95% CI: 1.41, 1.88 cm). Conclusions. Both traditional and cluster-set configurations induced a PAP response in vertical jump performance using optimum power loaded squat jumps, but the cluster-set configuration led to superior performance likely due to the reduced accumulation of muscular fatigue.

scholarly journals Associations between Absolute and Relative Lower Body Strength to Measures of Power and Change of Direction Speed in Division II Female Volleyball Players

Sports ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 160 ◽  
Author(s):  
Whitney Tramel ◽  
Robert G. Lockie ◽  
Keston G. Lindsay ◽  
J. Jay Dawes
Keyword(s):  
Vertical Jump ◽  
Relative Strength ◽  
T Test ◽  
Lower Body ◽  
Strength And Conditioning ◽  
Change Of Direction ◽  
Jump Test ◽  
Body Strength ◽  
Volleyball Players ◽  
Lower Body Strength

Volleyball is a sport comprised of multiple explosive efforts and multidirectional change of direction speed (CODS) actions. Since strength underpins both of these abilities, it is important to explore the relationship between these variables in order to develop strength and conditioning programs to optimize performance. The purpose of this study is to determine if a relationship exists between absolute and relative strength and measures of power and CODS in collegiate volleyball players. Archived testing data from ten (n = 10, age: 19.1 ± 1.2 yrs, Ht: 173.1 ± 6.64 cm, Wt: 67 ± 7.04 kg) female DII collegiate volleyball players were analyzed. These data included: block vertical jump (Block VJ), approach vertical jump (Approach VJ), a repeat jump test (i.e., four consecutive VJs), modified T-test, 5-0-5 agility test, a single leg triple hop test, and a 1-3RM deadlift. Significant large correlations were observed between relative strength and the repeat jump test, modified T-test, and 5-0-5 agility test. Significant correlations were also observed between absolute strength and the modified T-test. These results indicate that strength and conditioning professionals should emphasize the development of both absolute and relative lower-body strength to improve measures of power and agility in collegiate volleyball players.

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.

Low ECD High Performance Invert Emulsion Drilling Fluids: Lab Development and Field Deployment

2021 ◽  
Author(s):  
Vikrant Wagle ◽  
Abdullah Yami ◽  
Michael Onoriode ◽  
Jacques Butcher ◽  
Nivika Gupta
Keyword(s):  
High Performance ◽  
Filter Cake ◽  
Drilling Fluid ◽  
Field Performance ◽  
Superior Performance ◽  
Core Material ◽  
Drilling Fluids ◽  
Invert Emulsion ◽  
Field Deployment ◽  
Permeability Studies

Abstract The present paper describes the results of the formulation of an acid-soluble low ECD organoclay-free invert emulsion drilling fluid formulated with acid soluble manganese tetroxide and a specially designed bridging package. The paper also presents a short summary of field applications to date. The novel, non-damaging fluid has superior rheology resulting in lower ECD, excellent suspension properties for effective hole cleaning and barite-sag resistance while also reducing the risk of stuck pipe in high over balance applications. 95pcf high performance invert emulsion fluid (HPIEF) was formulated using an engineered bridging package comprising of acid-soluble bridging agents and an acid-soluble weighting agent viz. manganese tetroxide. The paper describes the filtration and rheological properties of the HPIEF after hot rolling at 300oF. Different tests such as contamination testing, sag-factor analysis, high temperature-high pressure rheology measurements and filter-cake breaking studies at 300oF were performed on the HPIEF. The 95pcf fluid was also subjected to particle plugging experiments to determine the invasion characteristics and the non-damaging nature of the fluids. The 95pcf HPIEF exhibited optimal filtration properties at high overbalance conditions. The low PV values and rheological profile support low ECDs while drilling. The static aging tests performed on the 95pcf HPIEF resulted in a sag factor of less than 0.53, qualifying the inherent stability for expected downhole conditions. The HPIEF demonstrated resilience to contamination testing with negligible change in properties. Filter-cake breaking experiments performed using a specially designed breaker fluid system gave high filter-cake breaking efficiency. Return permeability studies were performed with the HPIEF against synthetic core material, results of which confirmed the non-damaging design of the fluid. The paper thus demonstrates the superior performance of the HPIEF in achieving the desired lab and field performance.

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.

scholarly journals Portable Force Plates: A Viable and Practical Alternative to Rapidly and Accurately Monitor Elite Sprint Performance

Sports ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 61 ◽  
Author(s):  
Irineu Loturco ◽  
Lucas Pereira ◽  
Ronaldo Kobal ◽  
Cesar Cal Abad ◽  
Victor Fernandes ◽  
...  
Keyword(s):  
Vertical Jump ◽  
Force Plate ◽  
Correlation Coefficients ◽  
Accurate Information ◽  
Strong Correlations ◽  
Regression Analyses ◽  
Actual Performance ◽  
Moment Coefficient ◽  
Competitive Athletes ◽  
Vertical Jumps

This study aimed to examine the associations between a series of mechanical variables automatically generated by a portable force plate (PFP) and the actual performance of professional sprinters over a 150 m course. To test these correlations, 12 top-level sprinters performed vertical jumps (squat and countermovement jumps; SJ and CMJ, respectively), a 60 m sprint test, and a 150 m sprint test. Pearson product-moment coefficient of correlation and multiple regression analyses were used to determine the relationships between the sprinting velocities and vertical jump outputs. The SJ parameters were moderately to near perfectly associated with the different sprint distances, and the SJ height presented the highest correlation scores (r = 0.90 with velocities over 10- and 20-m). The correlation coefficients between the CMJ outcomes and sprint results varied between moderate and very large (from 0.38 to 0.88). Finally, the coefficients of determination (R2) ranged from 0.71 to 0.85 for the different multiple regressions involving PFP automatic measures. The PFP can provide practitioners with quick and accurate information regarding competitive athletes. Due to the strong correlations observed, coaches are encouraged to frequently adjust and tailor the training strategies of their sprinters, using practical and timesaving PFP measurements.

scholarly journals Atomic Modulation of 3D Conductive Frameworks Boost Performance of MnO2 for Coaxial Fiber-Shaped Supercapacitors

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiaona Wang ◽  
Zhenyu Zhou ◽  
Zhijian Sun ◽  
Jinho Hah ◽  
Yagang Yao ◽  
...  
Keyword(s):  
Energy Density ◽  
Specific Capacitance ◽  
High Performance ◽  
High Specific Capacitance ◽  
Superior Performance ◽  
High Mass ◽  
Mass Loading ◽  
Energy Storage Devices ◽  
Free Standing ◽  
Cell Potential

Abstract Coaxial fiber-shaped supercapacitors are a promising class of energy storage devices requiring high performance for flexible and miniature electronic devices. Yet, they are still struggling from inferior energy density, which comes from the limited choices in materials and structure used. Here, Zn-doped CuO nanowires were designed as 3D framework for aligned distributing high mass loading of MnO2 nanosheets. Zn could be introduced into the CuO crystal lattice to tune the covalency character and thus improve charge transport. The Zn–CuO@MnO2 as positive electrode obtained superior performance without sacrificing its areal and gravimetric capacitances with the increasing of mass loading of MnO2 due to 3D Zn–CuO framework enabling efficient electron transport. A novel category of free-standing asymmetric coaxial fiber-shaped supercapacitor based on Zn0.11CuO@MnO2 core electrode possesses superior specific capacitance and enhanced cell potential window. This asymmetric coaxial structure provides superior performance including higher capacity and better stability under deformation because of sufficient contact between the electrodes and electrolyte. Based on these advantages, the as-prepared asymmetric coaxial fiber-shaped supercapacitor exhibits a high specific capacitance of 296.6 mF cm−2 and energy density of 133.47 μWh cm−2. In addition, its capacitance retention reaches 76.57% after bending 10,000 times, which demonstrates as-prepared device’s excellent flexibility and long-term cycling stability.

Reliability and Validity of a Novel Trunk-Strength Assessment for High-Performance Sprint Flat-Water Kayakers

2019 ◽  
Vol 14 (4) ◽  
pp. 486-492
Author(s):  
Darren Steeves ◽  
Leo J. Thornley ◽  
Joshua A. Goreham ◽  
Matthew J. Jordan ◽  
Scott C. Landry ◽  
...  
Keyword(s):  
High Performance ◽  
Isometric Force ◽  
Reliability And Validity ◽  
Small Degree ◽  
Strong Correlations ◽  
Strength Assessment ◽  
Performance Times ◽  
Voluntary Contractions ◽  
Pearson Correlations ◽  
Maximal Isometric Force

Purpose: To determine the reliability and validity of a novel trunk maximal isometric force assessment involving 7 different tasks with 200-m times for elite sprint flat-water kayakers. Methods: Ten elite sprint flat-water kayakers performed a series of maximal isometric voluntary contractions (MVCs) on 2 separate days to assess reliability. MVC force was assessed as the participants sat on a modified kayak ergometer and applied their maximal isometric force to a uniaxial load cell during 7 different tasks. The 7 tasks of interest were a seated trunk-forward flexion, bilateral (left and right) rotational pulls, bilateral rotational pushes, and a sport-specific bilateral kayak-stroke simulation. Twenty elite flat-water kayak athletes (10 male and 10 female) participated in the validity portion by completing the series of tasks in conjunction with a 200-m race. Results: MVC force values ranged from 84 to 800 N across all participants and all tasks. The average coefficient of variation of the 7 tasks ranged from 2.4% to 7.7%. Regression analysis showed Pearson correlations ranging from −.84 to −.22 for both absolute and relative values with 200-m performance times. Conclusions: MVC force measured in each task was considered reliable as a small degree of variance between trials was found. The summation of the 7 trunk scores showed very strong correlations with on-water performance, indicating that this assessment is valid for elite sprint kayakers.

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