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.

Elbow Flexor Inhibition as a Function of Muscle Length

2002 ◽  
Vol 18 (1) ◽  
pp. 46-56 ◽  
Author(s):  
Luciana Brondino ◽  
Esther Suter ◽  
Hae-Dong Lee ◽  
Walter Herzog
Keyword(s):  
Isometric Force ◽  
Knee Extensor ◽  
Elbow Flexor ◽  
Peak Force ◽  
Knee Extensors ◽  
Emg Activity ◽  
Elbow Flexors ◽  
Muscle Inhibition ◽  
Voluntary Contractions ◽  
Maximal Isometric Force

Muscle inhibition (MI) in human knee extensors increases with increasing maximal voluntary force as a function of knee angle. It was speculated that this angle-dependent MI was modulated by force-dependent feedback, likely Golgi tendon organ pathways. Such angle-dependent MI is of clinical and theoretical importance. The purpose of this study was to determine MI in human elbow flexors for maximal voluntary contractions. Muscle inhibition, elbow flexor force, and electromyographic (EMG) activity were measured in 31 volunteers at elbow angles between 30º and 120º. MI and elbow flexor EMG were the same at all elbow angles. Maximal isometric forces were greatest at the 70º angle, and never fell below 70% of the peak force at any of the tested angles. From these results it is concluded that force-dependent modulation of MI did not occur in the elbow flexors, possibly because maximal isometric force remained relatively close (within 30%) to the peak force. In contrast, force-dependent modulation of MI occurred in the knee extensors at the most extended angles, when the average knee extensor force had dropped to 50% or less of the maximal knee extensor force. It is likely that human maximal voluntary contractions are not associated with a given activation. Rather, activation appears to be modulated by force-dependent feedback at force levels below 70% of the absolute peak force, which manifests itself in a change of MI that parallels the level of maximal isometric force in voluntary contractions.

Acute Physiological Response to Light- and Heavy-load Power-oriented Exercise in Older Adults

2021 ◽  
Author(s):  
Carlos Rodriguez-Lopez ◽  
Julian Alcazar ◽  
Jose Losa-Reyna ◽  
JuanManuel Carmona-Torres ◽  
Aurora Maria Cruz-Santaella ◽  
...  
Keyword(s):  
Older Adults ◽  
Creatine Kinase ◽  
Resistance Training ◽  
Isometric Force ◽  
Rate Of Force Development ◽  
Heavy Load ◽  
Force Development ◽  
Sit To Stand ◽  
Light Load ◽  
Maximal Isometric Force

AbstractThis study investigated the acute responses to volume-load-matched heavy-load (80% 1RM) versus light-load (40% 1RM) power-oriented resistance training sessions in well-functioning older adults. Using a randomized cross-over design, 15 volunteers completed each condition on a leg press. Neuromuscular (maximal isometric force and rate of force development) and functional performance (power during sit-to-stand test), lactate, and muscle damage biochemistry (creatine kinase, lactate dehydrogenase and C-reactive protein serum concentration) were assessed pre- and post-exercise. Performance declines were found after heavy-load (Cohen’s d effect size (d); maximal isometric force=0.95 d; rate of force development=1.17 d; sit-to-stand power =0.38 d, all p<0.05) and light-load (maximal isometric force=0.45 d; rate of force development=0.9 d; sit-to-stand power=1.17 d, all p<0.05), while lactate concentration increased only after light-load (1.7 d, p=0.001). However, no differences were found between conditions (all p>0.05). Both conditions increased creatine kinase the day after exercise (marginal effect=0.75 d, p<0.001), but no other blood markers increased (all, p>0.05). Irrespective of the load used, power training induced non-clinically significant decreases in sit-to-stand performance, moderate declines in maximal isometric force, but pronounced decreases in the rate of force development. Furthermore, the metabolic stress and muscle damage were minor; both sessions were generally well tolerated by well-functioning older adults without previous experience in resistance training.

Analyzing the Robustness of HPC Applications Using a Fine-Grained Soft Error Fault Injection Tool

2016 ◽  
pp. 277-305
Author(s):  
Qiang Guan ◽  
Nathan DeBardeleben ◽  
Sean Blanchard ◽  
Song Fu ◽  
Claude H. Davis IV ◽  
...  
Keyword(s):  
High Performance ◽  
Fault Injection ◽  
Soft Errors ◽  
Small Degree ◽  
Soft Error ◽  
Power Efficient ◽  
Fine Grained ◽  
Different Characteristics ◽  
The Impact ◽  
Performance Computing

As the high performance computing (HPC) community continues to push towards exascale computing, HPC applications of today are only affected by soft errors to a small degree but we expect that this will become a more serious issue as HPC systems grow. We propose F-SEFI, a Fine-grained Soft Error Fault Injector, as a tool for profiling software robustness against soft errors. We utilize soft error injection to mimic the impact of errors on logic circuit behavior. Leveraging the open source virtual machine hypervisor QEMU, F-SEFI enables users to modify emulated machine instructions to introduce soft errors. F-SEFI can control what application, which sub-function, when and how to inject soft errors with different granularities, without interference to other applications that share the same environment. We demonstrate use cases of F-SEFI on several benchmark applications with different characteristics to show how data corruption can propagate to incorrect results. The findings from the fault injection campaign can be used for designing robust software and power-efficient hardware.

scholarly journals Maximal isometric force exertion predicted by the force feasible set formalism: application to handbraking

Ergonomics ◽  
2019 ◽  
Vol 62 (12) ◽  
pp. 1551-1562
Author(s):  
Nasser Rezzoug ◽  
Xuguang Wang ◽  
Vincent Hernandez ◽  
Philippe Gorce
Keyword(s):  
Isometric Force ◽  
Feasible Set ◽  
Maximal Isometric Force

scholarly journals Psychometric Properties of the Polish Version of Task and Ego Orientation in Sport Questionnaire (TEOSQ)

2020 ◽  
Vol 17 (10) ◽  
pp. 3593 ◽  
Author(s):  
Maciej Tomczak ◽  
Małgorzata Walczak ◽  
Paweł Kleka ◽  
Aleksandra Walczak ◽  
Łukasz Bojkowski
Keyword(s):  
Psychometric Properties ◽  
High Performance ◽  
Factor Model ◽  
Intraclass Correlation ◽  
Reliability And Validity ◽  
Task Orientation ◽  
Correlated Errors ◽  
Polish Version ◽  
Ego Orientation ◽  
The Individual

The main aim of the study was to assess the psychometric properties of the Polish version of the task and ego orientation in sport questionnaire (TEOSQ). The study covered 651 athletes aged 19.2 years, SD (Standard deviation) = 2.21. The task and ego orientation in sport questionnaire (TEOSQ) and sport motivation scale (SMS-28) were used. Cronbach’s Alpha for the ego subscale was 0.84, and for the task subscale 0.81 (McDonald’s omega was 0.84, 0.82 respectively). The reliability of the test-retest with two weeks interval was ICC (Intraclass correlation coefficient) = 0.86 for ego and ICC = 0.86 for task. Initially, the two-factor model was not fully fitted (CFI (Comparative fit index) = 0.84), however the model with correlated errors for selected test items was well fitted to data (CFI = 0.95). Statistically significant, positive correlations between the task orientation and the intrinsic motivation components were obtained. Additionally, individual athletes had higher scores on the ego factor and lower scores on the task factor than the team athletes. These effects were moderated by the level of participation and occurred among high-performance athletes. Due to satisfactory reliability and validity indicators the Polish version of the task and ego orientation in sport questionnaire (TEOSQ) can be used both for scientific research and in the individual diagnostics of athletes.

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 Fatty Infiltration Is a Prognostic Marker of Muscle Function After Rotator Cuff Tear

2018 ◽  
Vol 46 (9) ◽  
pp. 2161-2169 ◽  
Author(s):  
Ana P. Valencia ◽  
Jim K. Lai ◽  
Shama R. Iyer ◽  
Katherine L. Mistretta ◽  
Espen E. Spangenburg ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Muscle Atrophy ◽  
Muscle Function ◽  
Contractile Function ◽  
Isometric Force ◽  
Fatty Infiltration ◽  
Collagen Content ◽  
Strongly Correlated ◽  
Computed Tomography Scanning ◽  
Maximal Isometric Force

Background: Massive rotator cuff tears (RCTs) begin as primary tendon injuries and cause a myriad of changes in the muscle, including atrophy, fatty infiltration (FI), and fibrosis. However, it is unclear which changes are most closely associated with muscle function. Purpose: To determine if FI of the supraspinatus muscle after acute RCT relates to short-term changes in muscle function. Study Design: Controlled laboratory study. Methods: Unilateral RCTs were induced in female rabbits via tenotomy of the supraspinatus and infraspinatus. Maximal isometric force and rate of fatigue were measured in the supraspinatus in vivo at 6 and 12 weeks after tenotomy. Computed tomography scanning was performed, followed by histologic analysis of myofiber size, FI, and fibrosis. Results: Tenotomy resulted in supraspinatus weakness, reduced myofiber size, FI, and fibrosis, but no differences were evident between 6 and 12 weeks after tenotomy except for increased collagen content at 12 weeks. FI was a predictor of supraspinatus weakness and was strongly correlated to force, even after accounting for muscle cross-sectional area. While muscle atrophy accounted for the loss in force in tenotomized muscles with minimal FI, it did not account for the greater loss in force in tenotomized muscles with the most FI. Collagen content was not strongly correlated with maximal isometric force, even when normalized to muscle size. Conclusion: After RCT, muscle atrophy results in the loss of contractile force from the supraspinatus, but exacerbated weakness is observed with increased FI. Therefore, the level of FI can help predict contractile function of torn rotator cuff muscles. Clinical Relevance: Markers to predict contractile function of RCTs will help determine the appropriate treatment to improve functional recovery after RCTs.

scholarly journals Measurement of Multiple Intelligences among Sample of Students with Autism, and Intellectual Disability Using Teacher Estimation and Its Relationship with the Variables: The Type and Severity of Disability, Gender, Age, Type of Center

2016 ◽  
Vol 8 (1) ◽  
pp. 107 ◽  
Author(s):  
Sabah Hasan Al-Onizat
Keyword(s):  
Multiple Intelligences ◽  
High Performance ◽  
Assessment Tool ◽  
Reliability And Validity ◽  
Multiple Intelligence ◽  
Mental Disability ◽  
Validity And Reliability ◽  
Musical Intelligence ◽  
Severity Of Disability ◽  
Students With Autism

<p>This study aims to measure the multiple intelligence among sample of student with autism<br />disorder and Mental disability by using teacher estimation in multiple intelligence scale and<br />its relationship with the variables: type and severity of disability, gender, and the type of<br />center, the study sample consisted of (81) student with autism and (85) student with mental<br />disability, male and female, who enrolled in private and governmental situations in Amman.<br />And for achieving the goals of the study the researcher developed the multiple intelligences<br />assessment tool consists of (56) items, were verified validity and reliability of the tool where<br />it was found that with acceptable degrees of reliability and validity.<br />After processing the data statistically and analyzed, the results indicated that the most visible<br />intelligence in mental disability is of musical intelligence, and in autism student is the<br />kinesthetic intelligence, And Autistic children also showed superiority in arithmetic and<br />kinesthetic intelligence compared with mental disability. Also children with mild disabilities<br />have high performance in all type intelligences.<br />And there are no differences in type of intelligence according to the gender and this proves<br />that disability affects the brain regardless of the gender. While the adolescents have<br />superiority in each of the linguistic, social and musical intelligence, there are no differences<br />in the multiple intelligences depending on the type of center which the student attends in it.</p><p> </p>

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