Analyzing dependence matrices to investigate relationships between national football league combine event performances

2018 ◽  
Vol 14 (4) ◽  
pp. 201-212
Author(s):  
Brook T. Russell ◽  
Paul Hogan
Keyword(s):  
National Football League ◽  
The Other ◽  
Dependence Structure ◽  
Elite Level ◽  
Multivariate Dependence ◽  
Physical Tests ◽  
Pairwise Dependence

Abstract The National Football League (NFL) Scouting Combine takes place annually for the purpose of allowing NFL teams to evaluate prospects. The battery of six physical tests receives a great deal of attention, and are a focus of team personnel as well as fans of NFL teams. Recently, some have suggested that the current battery of tests should be modified. This work aims to characterize the multivariate dependence structure between tests for Combine prospects, for both typical and elite-level performers, for the purpose of better understanding the current battery of tests before making modifications. Through analysis of two pairwise dependence matrices, one quantifying dependence in the center of the distribution and the other quantifying dependence in the tails of the distribution, this analysis finds that several events show differing levels of association, and that fewer Combine events may be sufficient going forward.

The Coach-Athlete Relationship: A Tripartite Efficacy Perspective

2009 ◽  
Vol 23 (2) ◽  
pp. 203-232 ◽  
Author(s):  
Ben Jackson ◽  
Peter Knapp ◽  
Mark R. Beauchamp
Keyword(s):  
Self Efficacy ◽  
Efficacy Beliefs ◽  
The Other ◽  
International Level ◽  
Dyad Member ◽  
Semistructured Interviews ◽  
Elite Level ◽  
Antecedents And Consequences

The purpose of the current study was to identify putative antecedents and consequences associated with self-efficacy, other-efficacy, and relation-inferred self-efficacy, within the context of elite coach-athlete dyads. Semistructured interviews were conducted with each member of six international-level coach-athlete partnerships, and data were analyzed using inductive and deductive content analytic techniques. Results for both athletes and coaches demonstrated that the above ‘tripartite efficacy beliefs’ (cf. Lent & Lopez, 2002) were identified as originating from perceptions regarding oneself, inferences regarding the ‘other’ dyad member (e.g., the athlete’s coach), as well as the dyad as a whole. Results also revealed that the tripartite efficacy constructs were interrelated, and independently associated with a number of positive task-related and relationship-oriented consequences. Findings are considered in relation to developing and sustaining effective coach-athlete relationships at the elite level.

scholarly journals Streamflow estimation at partially gaged sites using multiple dependence conditions via vine copulas

2020 ◽  
Author(s):  
Kuk-Hyun Ahn
Keyword(s):  
Missing Values ◽  
The Other ◽  
Dependence Structure ◽  
Proposed Model ◽  
Pee Dee ◽  
Streamflow Estimation ◽  
Vine Copula ◽  
Bivariate Copula ◽  
Pee Dee River ◽  
Vine Copulas

Abstract. Reliable estimates of missing streamflow values are relevant for water resources planning and management. This study proposes a multiple dependence condition model via vine copulas for the purpose of estimating streamflow at partially gaged sites. The proposed model is attractive in modeling the high dimensional joint distribution by building a hierarchy of conditional bivariate copulas when provided a complex streamflow gage network. The usefulness of the proposed model is firstly highlighted using a synthetic streamflow scenario. In this analysis, the bivariate copula model and a variant of the vine copulas are also employed to show the ability of the multiple dependence structure adopted in the proposed model. Furthermore, the evaluations are extended to a case study of 54 gages located within the Yadkin-Pee Dee River Basin, the eastern U. S. Both results inform that the proposed model is better suited for infilling missing values. After that, the performance of the vine copula is compared with six other infilling approaches to confirm its applicability. Results demonstrate that the proposed model produces more reliable streamflow estimates than the other approaches. In particular, when applied to partially gaged sites with sufficient available data, the proposed model clearly outperforms the other models. Even though the model is illustrated by a specific case, it can be extended to other regions with diverse hydro-climatological variables for the objective of infilling.

Performance-Based Outcomes After Anterior Cruciate Ligament Reconstruction in Professional Athletes Differ Between Sports

2017 ◽  
Vol 45 (10) ◽  
pp. 2226-2232 ◽  
Author(s):  
Harry T. Mai ◽  
Danielle S. Chun ◽  
Andrew D. Schneider ◽  
Brandon J. Erickson ◽  
Ryan D. Freshman ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
National Football League ◽  
Cruciate Ligament ◽  
Survival Rates ◽  
The Other ◽  
Return To Play ◽  
Professional Athletes ◽  
Level Of Evidence ◽  
Performance Statistics ◽  
Anterior Cruciate

Background: Excellent outcomes have been reported for anterior cruciate ligament (ACL) reconstruction (ACLR) in professional athletes in a number of different sports. However, no study has directly compared these outcomes between sports. Purpose: To determine if differences in performance-based outcomes exist after ACLR between professional athletes of each sport. Study Design: Cohort study; Level of evidence, 3. Methods: National Football League (NFL), National Basketball Association (NBA), National Hockey League (NHL), and Major League Baseball (MLB) athletes undergoing primary ACLR for an acute rupture were identified through an established protocol of injury reports and public archives. Sport-specific performance statistics were collected before and after surgery for each athlete. Return to play (RTP) was defined as a successful return to the active roster for at least 1 regular-season game after ACLR. Results: Of 344 professional athletes who met the inclusion criteria, a total of 298 (86.6%) returned to play. NHL players had a significantly higher rate of RTP (95.8% vs 83.4%, respectively; P = .04) and a shorter recovery time (258 ± 110 days vs 367 ± 268 days, respectively; P < .001) than athletes in all the other sports. NFL athletes experienced significantly shorter careers postoperatively than players in all the other sports (2.1 vs 3.2 years, respectively; P < .001). All athletes played fewer games ( P ≤ .02) 1 season postoperatively, while those in the NFL had the lowest rate of active players 2 and 3 seasons postoperatively (60%; P = .002). NBA and NFL players showed decreased performance at season 1 after ACLR ( P ≤ .001). NFL players continued to have lower performance at seasons 2 and 3 ( P = .002), while NBA players recovered to baseline performance. Conclusion: The data indicate that NFL athletes fare the worst after ACLR with the lowest survival rate, shortest postoperative career length, and sustained decreases in performance. NHL athletes fare the best with the highest rates of RTP, highest survival rates, longest postoperative career lengths, and no significant changes in performance. The unique physical demand that each sport requires is likely one of the explanations for these differences in outcomes.

ON A MULTIVARIATE GENERALIZED POLYA PROCESS WITHOUT REGULARITY PROPERTY

2019 ◽  
Vol 34 (4) ◽  
pp. 484-506
Author(s):  
Ji Hwan Cha ◽  
F.G. Badía
Keyword(s):  
Regularity Property ◽  
Dependence Structure ◽  
Counting Processes ◽  
Multiple Events ◽  
New Class ◽  
Different Types ◽  
Polya Process ◽  
Multivariate Dependence ◽  
Pólya Process ◽  
Stochastic Properties

Most of the multivariate counting processes studied in the literature are regular processes, which implies, ignoring the types of the events, the non-occurrence of multiple events. However, in practice, several different types of events may occur simultaneously. In this paper, a new class of multivariate counting processes which allow simultaneous occurrences of multiple types of events is suggested and its stochastic properties are studied. For the modeling of such kind of process, we rely on the tool of superposition of seed counting processes. It will be shown that the stochastic properties of the proposed class of multivariate counting processes are explicitly expressed. Furthermore, the marginal processes are also explicitly obtained. We analyze the multivariate dependence structure of the proposed class of counting processes.

scholarly journals The effect of univariate bias adjustment on multivariate hazard estimates

2019 ◽  
Vol 10 (1) ◽  
pp. 31-43 ◽  
Author(s):  
Jakob Zscheischler ◽  
Erich M. Fischer ◽  
Stefan Lange
Keyword(s):  
Heat Stress ◽  
Climate Model ◽  
Internal Variability ◽  
Climate Impacts ◽  
Dependence Structure ◽  
Risk Indicator ◽  
Statistical Bias ◽  
Bias Adjustment ◽  
Multivariate Dependence ◽  
Impact Models

Abstract. Bias adjustment is often a necessity in estimating climate impacts because impact models usually rely on unbiased climate information, a requirement that climate model outputs rarely fulfil. Most currently used statistical bias-adjustment methods adjust each climate variable separately, even though impacts usually depend on multiple potentially dependent variables. Human heat stress, for instance, depends on temperature and relative humidity, two variables that are often strongly correlated. Whether univariate bias-adjustment methods effectively improve estimates of impacts that depend on multiple drivers is largely unknown, and the lack of long-term impact data prevents a direct comparison between model outputs and observations for many climate-related impacts. Here we use two hazard indicators, heat stress and a simple fire risk indicator, as proxies for more sophisticated impact models. We show that univariate bias-adjustment methods such as univariate quantile mapping often cannot effectively reduce biases in multivariate hazard estimates. In some cases, it even increases biases. These cases typically occur (i) when hazards depend equally strongly on more than one climatic driver, (ii) when models exhibit biases in the dependence structure of drivers and (iii) when univariate biases are relatively small. Using a perfect model approach, we further quantify the uncertainty in bias-adjusted hazard indicators due to internal variability and show how imperfect bias adjustment can amplify this uncertainty. Both issues can be addressed successfully with a statistical bias adjustment that corrects the multivariate dependence structure in addition to the marginal distributions of the climate drivers. Our results suggest that currently many modeled climate impacts are associated with uncertainties related to the choice of bias adjustment. We conclude that in cases where impacts depend on multiple dependent climate variables these uncertainties can be reduced using statistical bias-adjustment approaches that correct the variables' multivariate dependence structure.

Developments in elite level Thai boxing in Belgium: has there been a civilising influence?

2019 ◽  
Vol 41 (2) ◽  
pp. 32-54
Author(s):  
Joannes Van Gestel
Keyword(s):  
Physical Characteristics ◽  
International Federation ◽  
The Other ◽  
Combat Sports ◽  
The Public ◽  
Other Hand ◽  
Elite Level ◽  
The One

This paper analyses the changes in the elite level of Thai Boxing in Belgium from the mid-1980s by employing the concept of ‘sportization’. This analysis demonstrates that there has been a small development towards the condemnation of violence and an increase in the number of weight categories which support an argument in favour of the sportization process, while a reduction of the minimum participation age suggests a counter trend. Although clear changes have been identified for other combat sports, the relative immobility of Thai Boxing is due to the diversified figurational network involving the Belgian Thai Boxing Federation. On the one hand, the federation seeks recognition from the public and the international federations representing the official sports organisations, which requires a visually attractive and safe sport. On the other hand, it also attracts those interested and inspired by its more dangerous physical characteristics. Despite the ambiguity of these findings it is argued that Thai Boxing has undergone a slight sportization process. As the rules and regulations applied in Belgium have always adhered to those of the international federation, it is likely that the results can be seen as reflecting the sport’s development in other nations.

Assessment of the presence of independent flexor digitorum superficialis function in the small fingers of professional string players: Is this an example of natural selection?

2013 ◽  
Vol 39 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Y. Godwin ◽  
G. A. C. Wheble ◽  
C. Feig
Keyword(s):  
Natural Selection ◽  
Meta Analysis ◽  
Ring Finger ◽  
Control Group ◽  
Finger Movement ◽  
Flexor Digitorum Superficialis ◽  
Professional Musicians ◽  
Elite Level ◽  
Physical Tests ◽  
Flexor Digitorum

This study estimated the prevalence of independent flexor digitorum superficialis function in the small fingers of 90 violin and viola players. The hypothesis tested was that the independent digital movements required in this population would select out those with absent flexor digitorum superficialis function. Professional string players were tested clinically, using standard and modified tests, for flexor digitorum superficialis function. Two additional physical tests were applied: the gap and stretch tests. These tests assess ring finger movement once the small finger is placed and the instrument is held in the chin-hold position. A statistically significant reduction in the prevalence of absent flexor digitorum superficialis function was confirmed in the musicians compared with a control group and published meta-analysis. This suggests that independent flexor digitorum superficialis function is important for professional musicians playing at an elite level.

296. The effect of varying pitching point and rate of scald on the physical properties and general quality of cheese made from milk of varying acidity and from pasteurized milk

1942 ◽  
Vol 13 (1) ◽  
pp. 73-84 ◽  
Author(s):  
G. W. Scott Blair ◽  
F. M. V. Coppen ◽  
D. V. Dearden
Keyword(s):  
Physical Properties ◽  
Rank Order ◽  
The Other ◽  
Physical Test ◽  
Ripening Process ◽  
Subjective Judgement ◽  
General Quality ◽  
Physical Tests ◽  
Self Consistency

1. Following the experiences gained from an earlier experiment, cheese were made at varying controlled pitching points and rates of scald, the experiment being done both with sweet milk and comparatively acid milk.2. One of the two cheese made from each vat was submitted to physical tests at regular intervals during the ripening process and the other cheese, when ripe, were judged by a panel of experts who also, together with non-experts and routine analysts, gave judgements of firmness and ‘spring’.3. Tables were drawn up in which the rank orders of the cheese for each objective physical test and subjective judgement are compared with one another.4. With the possible exception of vapour pressure and ‘spring’, the effect of pitching consistency was much more marked than that of the differences in rate of scald although the latter were considerable. Many physical properties were well correlated with pitching consistency.5. The cheese makers are shown to have a greater self-consistency as individuals in picking out replicates and as a group in their decisions as to the rank order, by comparison with the other categories.

scholarly journals ASSESSMENT OF THE REGIONAL FREQUENCY ANALYSIS TO THE ESTIMATION OF EXTREME STORM SURGES

2012 ◽  
Vol 1 (33) ◽  
pp. 27 ◽  
Author(s):  
Jérôme Weiss ◽  
Pietro Bernardara ◽  
Michel Benoit
Keyword(s):  
Frequency Analysis ◽  
Storm Surges ◽  
Regional Frequency Analysis ◽  
Dependence Structure ◽  
The North ◽  
Extreme Storm ◽  
Physically Based ◽  
Pairwise Dependence ◽  
Homogeneous Regions ◽  
Regional Frequency

Regional frequency analysis (RFA) is performed to estimate extreme storm surges along the French coasts of the Atlantic Ocean, the English Channel and the Southern part of the North Sea. An insight on the formation of physically homogeneous regions from a criterion of propagation of storms is provided. The treatment of the pairwise dependence structure within a given region through a spatial extreme value copula is also considered, leading to a model coupling physically-based RFA and spatial dependence to describe the probabilistic behavior of extreme storm surges.

Sign in / Sign up

Export Citation Format

Share Document