scholarly journals The reliability and validity of a video-based method for assessing hamstring strength in football players

2017 ◽  
Vol 15 (1) ◽  
pp. 18-21 ◽  
Author(s):  
Justin W.Y. Lee ◽  
Cheng Li ◽  
Patrick S.H. Yung ◽  
Kai-Ming Chan
Author(s):  
Nikola Foretic ◽  
Barbara Gilic ◽  
Damir Sekulic

Purpose: Agility is an important determinant of success in football (soccer), but there is a lack of reliable and valid tests applicable in the evaluation of different agility components in youth football players. In this study we evaluated the reliability and factorial validity of the two newly developed tests of agility in male youth football players. Methods: The sample comprised 44 youth football players (all males, 14–15 years of age) who were tested on anthropometrics (body height and mass), newly developed tests of foot-ball specific reactive agility (FS-RAG) and change of direction speed (FS-CODS), one stand-ard test of CODS (20-yards), and sprinting over 20-m distance (S20M). The relative reliability is evaluated by calculation of Intra-Class-Correlation coeficients (ICC), while the absolute reliability was evaluated by calculation of the coeficient of variation (CV). Further, systematic bias was checked by analysis of variance for repeated measurements (ANOVA). The asso-ciations between studied variables were evidenced by Pearson’s correlation. Finally, factor analysis was calculated to define the factorial validity of agility tests (FS-RAG, FS-CODS, 20-yards). Results: The newly developed football-specific tests were found to be reliable, with better re-liability of FS-CODS (ICC: 0.81, CV: 6%), than of FS-RAG (ICC: 0.76, CV: 9%). The ANOVA evidenced significant (p < 0.05) learning effects for FS-RAG, but post-hoc analysis indicated stabilization of the results until the third testing trial. Factor analysis extracted one significant factor under the Guttmann-Kaiser criterion (Explained Variance: 1.67), showing the appro-priate factorial validity of newly developed tests in comparison to standard agility indicator 20-yards. Meanwhile, the significant correlations between all agility performances with S20M (Pearson’s R: 0.52–0.63; all p < 0.01) revealed that sprinting capacity significantly influence agility performances and that conditioning capacities of youth football players are not yet discriminated. Conclusion: Results showed appropriate reliability and validity of the newly developed tests of football specific change of direction speed and reactive agility. Therefore, here proposed FS-CODS and FS-RAG can be used as reliable and valid measures of agility components in youth football players. Further studies should evaluate the discriminative validity of the here proposed tests (i.e. identification of position-specific or performance-related differences), as well as reliability in younger players than those studied herein.


2018 ◽  
Vol 13 (5) ◽  
pp. 597-603 ◽  
Author(s):  
Raúl Reina ◽  
Aitor Iturricastillo ◽  
Rafael Sabido ◽  
Maria Campayo-Piernas ◽  
Javier Yanci

Purpose: To evaluate the reliability and validity of vertical and horizontal jump tests in football players with cerebral palsy (FPCP) and to analyze the jump performance differences between current International Federation for Cerebral Palsy Football functional classes (ie, FT5–FT8). Methods: A total of 132 international parafootballers (25.8 [6.7] y; 70.0 [9.1] kg; 175.7 [7.3] cm; 22.8 [2.8] kg·m−2; and 10.7 [7.5] y training experience) participated in the study. The participants were classified according to the International Federation for Cerebral Palsy Football classification rules, and a group of 39 players without cerebral palsy was included in the study as a control group. Football players’ vertical and horizontal jump performance was assessed. Results: All the tests showed good to excellent relative intrasession reliability scores, both in FPCP and in the control group (intraclass correlation = .78–.97, SEM < 10.5%). Significant between-groups differences (P < .001) were obtained in the countermovement jump, standing broad jump, 4 bounds for distance, and triple hop for distance dominant leg and nondominant leg. The control group performed higher/farther jumps with regard to all the FPCP classes, obtaining significant differences and moderate to large effect sizes (ESs) (.85 < ES < 5.54, P < .01). Players in FT8 class (less severe impairments) had significantly higher scores in all the jump tests than players in the lower classes (ES = moderate to large, P < .01). Conclusions: The vertical and horizontal jump tests performed in this study could be applied to the classification procedures and protocols for FPCP.


2015 ◽  
Vol 16 (7) ◽  
pp. 755-763 ◽  
Author(s):  
Susana C. A. Póvoas ◽  
Carlo Castagna ◽  
José M. C. Soares ◽  
Pedro M. R. Silva ◽  
Mariana V. M. F. Lopes ◽  
...  

Author(s):  
Ling-Yu Guo ◽  
Phyllis Schneider ◽  
William Harrison

Purpose This study provided reference data and examined psychometric properties for clausal density (CD; i.e., number of clauses per utterance) in children between ages 4 and 9 years from the database of the Edmonton Narrative Norms Instrument (ENNI). Method Participants in the ENNI database included 300 children with typical language (TL) and 77 children with language impairment (LI) between the ages of 4;0 (years;months) and 9;11. Narrative samples were collected using a story generation task, in which children were asked to tell stories based on six picture sequences. CD was computed from the narrative samples. The split-half reliability, concurrent criterion validity, and diagnostic accuracy were evaluated for CD by age. Results CD scores increased significantly between ages 4 and 9 years in children with TL and those with LI. Children with TL produced higher CD scores than those with LI at each age level. In addition, the correlation coefficients for the split-half reliability and concurrent criterion validity of CD scores were all significant at each age level, with the magnitude ranging from small to large. The diagnostic accuracy of CD scores, as revealed by sensitivity, specificity, and likelihood ratios, was poor. Conclusions The finding on diagnostic accuracy did not support the use of CD for identifying children with LI between ages 4 and 9 years. However, given the attested reliability and validity for CD, reference data of CD from the ENNI database can be used for evaluating children's difficulties with complex syntax and monitoring their change over time. Supplemental Material https://doi.org/10.23641/asha.13172129


2017 ◽  
Vol 76 (3) ◽  
pp. 91-105 ◽  
Author(s):  
Vera Hagemann

Abstract. The individual attitudes of every single team member are important for team performance. Studies show that each team member’s collective orientation – that is, propensity to work in a collective manner in team settings – enhances the team’s interdependent teamwork. In the German-speaking countries, there was previously no instrument to measure collective orientation. So, I developed and validated a German-language instrument to measure collective orientation. In three studies (N = 1028), I tested the validity of the instrument in terms of its internal structure and relationships with other variables. The results confirm the reliability and validity of the instrument. The instrument also predicts team performance in terms of interdependent teamwork. I discuss differences in established individual variables in team research and the role of collective orientation in teams. In future research, the instrument can be applied to diagnose teamwork deficiencies and evaluate interventions for developing team members’ collective orientation.


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