scholarly journals Sprint Mechanical Characteristics of Female Soccer Players: A Retrospective Pilot Study to Examine a Novel Approach for Correction of Timing Gate Starts

2021 ◽  
Vol 3 ◽  
Author(s):  
Jason D. Vescovi ◽  
Mladen Jovanović
Keyword(s):  
Pilot Study ◽  
Repeated Measures ◽  
Mechanical Characteristics ◽  
Soccer Players ◽  
Parameter Estimates ◽  
Novel Approach ◽  
Start Line ◽  
Time Correction ◽  
Timing Gate ◽  
High Level

The purpose of this study was to compare model estimates of linear sprint mechanical characteristics using timing gates with and without time correction. High-level female soccer players (n = 116) were evaluated on a 35-m linear sprint with splits at 5, 10, 20, 30, and 35 m. A mono-exponential function was used to model sprint mechanical metrics in three ways: without a time correction, with a fixed (+0.3 s) time correction, and with an estimated time correction. Separate repeated-measures ANOVAs compared the sprint parameter estimates between models and also the residuals between models. Differences were identified between all modeled sprint mechanical metrics; however, comparable estimates to the literature occurred when either time correction was used. Bias for both time-corrected models was reduced across all sprint distances compared to the uncorrected model. This study confirms that a time correction is warranted when using timing gates at the start line to model sprint mechanical metrics. However, determining whether fixed or estimated time corrections provide greater accuracy requires further investigation.

scholarly journals Comportamento tático de atletas sub-15 no futebol: avaliação das alterações ao longo de uma temporada esportiva

2017 ◽  
Vol 19 (2) ◽  
pp. 251
Author(s):  
Gibson Moreira Praça ◽  
Raphael Brito e Sousa ◽  
Jorge Victor De Oliveira Silva ◽  
Frederico Gonçalves Constantino ◽  
Pedro Emílio Drumond Moreira ◽  
...  
Keyword(s):  
Field Test ◽  
Repeated Measures ◽  
Soccer Players ◽  
Significance Level ◽  
Friedman's Test ◽  
Belo Horizonte ◽  
High Level ◽  
The City ◽  
One Way Anova

DOI: http://dx.doi.org/10.5007/1980-0037.2017v19n2p251 This study aimed to compare the tactical behavior of U-15 soccer players over a season. Sixteen high-level athletes (mean age 14.5 years) from the city of Belo Horizonte participated in the study. Athletes were monthly evaluated by means of the field test using the System of Tactical Assessment in Soccer – FUTSAT, which allowed the characterization of the incidence of tactical principles and place of action in the game field, as well as the percentage of positive offensive and defensive tactical principles. Data were analyzed by Friedman’s test (incidence of tactical principles and place of the action) and one-way ANOVA for repeated measures (percentage of positive tactical principles), adopting significance level of p<0.05. Results showed differences in the incidence of offensive and defensive units tactical principle, as well as the place of actions in the game field. An improvement in offensive and defensive tactical behavior was also observed throughout the season.

Power of Modified Brown-Forsythe and Mixed-Model Approaches in Split-Plot Designs

Methodology ◽  
2017 ◽  
Vol 13 (1) ◽  
pp. 9-22 ◽  
Author(s):  
Pablo Livacic-Rojas ◽  
Guillermo Vallejo ◽  
Paula Fernández ◽  
Ellián Tuero-Herrero
Keyword(s):  
Repeated Measures ◽  
Statistical Power ◽  
Mixed Model ◽  
Covariance Structure ◽  
Simulation Method ◽  
Future Research ◽  
Repeated Measures Design ◽  
Fixed And Random Effects ◽  
Split Plot ◽  
High Level

Abstract. Low precision of the inferences of data analyzed with univariate or multivariate models of the Analysis of Variance (ANOVA) in repeated-measures design is associated to the absence of normality distribution of data, nonspherical covariance structures and free variation of the variance and covariance, the lack of knowledge of the error structure underlying the data, and the wrong choice of covariance structure from different selectors. In this study, levels of statistical power presented the Modified Brown Forsythe (MBF) and two procedures with the Mixed-Model Approaches (the Akaike’s Criterion, the Correctly Identified Model [CIM]) are compared. The data were analyzed using Monte Carlo simulation method with the statistical package SAS 9.2, a split-plot design, and considering six manipulated variables. The results show that the procedures exhibit high statistical power levels for within and interactional effects, and moderate and low levels for the between-groups effects under the different conditions analyzed. For the latter, only the Modified Brown Forsythe shows high level of power mainly for groups with 30 cases and Unstructured (UN) and Autoregressive Heterogeneity (ARH) matrices. For this reason, we recommend using this procedure since it exhibits higher levels of power for all effects and does not require a matrix type that underlies the structure of the data. Future research needs to be done in order to compare the power with corrected selectors using single-level and multilevel designs for fixed and random effects.

A pilot study of the Spanish adaptation of MSCI for its use in young soccer players

2007 ◽  
Author(s):  
Eva M. Garcia-Quinteiro ◽  
Elena M. Andrade ◽  
Rodriguez Mauro
Keyword(s):  
Pilot Study ◽  
Soccer Players

scholarly journals Effectiveness of Abdominal and Gluteus Medius Training in Lumbo-Pelvic Stability and Adductor Strength in Female Soccer Players. A Randomized Controlled Study

2021 ◽  
Vol 18 (4) ◽  
pp. 1528
Author(s):  
Héctor Guerrero-Tapia ◽  
Rodrigo Martín-Baeza ◽  
Rubén Cuesta-Barriuso
Keyword(s):  
Repeated Measures ◽  
Gluteus Medius ◽  
Soccer Players ◽  
Controlled Study ◽  
Control Group ◽  
Extrinsic Factors ◽  
Randomized Controlled ◽  
Limb Injuries ◽  
Experimental Group

Background. Abdominal and lumbo-pelvic stability alterations may be the origin of lower limb injuries, such as adductor pathology in soccer players. Imbalance can be caused by both intrinsic and extrinsic factors. Methods: In this randomized controlled trial over 8 weeks, 25 female footballers were randomly allocated to an experimental group (isometric abdominal training and gluteus medius-specific training) or a control group (isometric abdominal training). Evaluations were performed at baseline, at the end of the intervention and after a 4-week follow-up period. The exercise protocol in common for both groups included three exercises: Plank, Lateral plank and Bird dog. Specific exercises for the gluteus medius were: Pelvic drop and Stabilization of the gluteus medius in knee valgus. Outcome measures were lumbar-pelvic stability and adductor strength. Results: After the intervention, there was an increase in lumbo-pelvic stability in both groups, being greater in the control group than in the experimental group (mean differences [MD]: 4.84 vs. MD: 9.58; p < 0.01) with differences in the analysis of repeated measures (p < 0.001), but not in group interaction (p = 0.26). Changes were found in adductor strength in the experimental group (MD: −2.48; p < 0.001 in the left adductor; MD: −1.48; p < 0.01 in right adductor) and control group (MD: −1.68; p < 0.001 in the left adductor; MD: −2.05; p < 0.001 in the right adductor) after the intervention, with differences in the analysis of repeated measures in left (p < 0.001) and right (p < 0.001) adductor strength. Conclusions: An abdominal and gluteal training protocol shows no advantage over a protocol of abdominal training alone for lumbo-pelvic stability and adductor strength, while improvements in both variables are maintained at four weeks follow-up.

scholarly journals Towards a contemporary player learning in development framework for sports practitioners

2021 ◽  
pp. 174795412110023
Author(s):  
Mark O Sullivan ◽  
Carl T Woods ◽  
James Vaughan ◽  
Keith Davids
Keyword(s):  
Linear Process ◽  
Task Environment ◽  
Coach Education ◽  
Development Framework ◽  
Novel Approach ◽  
Non Linear ◽  
And Performance ◽  
Learning Development ◽  
High Level ◽  
User Friendly

As it is appreciated that learning is a non-linear process – implying that coaching methodologies in sport should be accommodative – it is reasonable to suggest that player development pathways should also account for this non-linearity. A constraints-led approach (CLA), predicated on the theory of ecological dynamics, has been suggested as a viable framework for capturing the non-linearity of learning, development and performance in sport. The CLA articulates how skills emerge through the interaction of different constraints (task-environment-performer). However, despite its well-established theoretical roots, there are challenges to implementing it in practice. Accordingly, to help practitioners navigate such challenges, this paper proposes a user-friendly framework that demonstrates the benefits of a CLA. Specifically, to conceptualize the non-linear and individualized nature of learning, and how it can inform player development, we apply Adolph’s notion of learning IN development to explain the fundamental ideas of a CLA. We then exemplify a learning IN development framework, based on a CLA, brought to life in a high-level youth football organization. We contend that this framework can provide a novel approach for presenting the key ideas of a CLA and its powerful pedagogic concepts to practitioners at all levels, informing coach education programs, player development frameworks and learning environment designs in sport.

scholarly journals Dietary and Ergogenic Supplementation to Improve Elite Soccer Players’ Performance

2021 ◽  
pp. 1-7
Author(s):  
Haniel Fernandes
Keyword(s):  
Dietary Supplements ◽  
High Performance ◽  
Scientific Literature ◽  
Soccer Players ◽  
Competitive Sport ◽  
Beetroot Juice ◽  
Improve Performance ◽  
Sustained Release Tablets ◽  
High Level ◽  
Ergogenic Supplements

<b><i>Background:</i></b> Soccer is an extremely competitive sport, where the most match important moments can be defined in detail. Use of ergogenic supplements can be crucial to improve the performance of a high-performance athlete. Therefore, knowing which ergogenic supplements are important for soccer players can be an interesting strategy to maintain high level in this sport until final and decisive moments of the match. In addition, other supplements, such as dietary supplements, have been studied and increasingly referenced in the scientific literature. But, what if ergogenic supplements were combined with dietary supplements? This review brings some recommendations to improve performance of soccer athletes on the field through dietary and/or ergogenic supplements that can be used simultaneously. <b><i>Summary:</i></b> Soccer is a competitive sport, where the match important moments can be defined in detail. Thus, use of ergogenic supplements covered in this review can improve performance of elite soccer players maintaining high level in the match until final moments, such as creatine 3–5 g day<sup>−1</sup>, caffeine 3–6 mg kg<sup>−1</sup> BW around 60 min before the match, sodium bicarbonate 0.1–0.4 g kg<sup>−1</sup> BW starting from 30 to 180 min before the match, β-alanine 3.2 and 6.4 g day<sup>−1</sup> provided in the sustained-release tablets divided into 4 times a day, and nitrate-rich beetroot juice 60 g in 200 mL of water (6 mmol of NO3<sup>−</sup> L) around 120 min before match or training, including a combination possible with taurine 50 mg kg<sup>−1</sup> BW day<sup>−1</sup>, citrulline 1.2–3.4 g day<sup>−1</sup>, and arginine 1.2–6 g day<sup>−1</sup>. <b><i>Key Messages:</i></b> Soccer athletes can combine ergogenic and dietary supplements to improve their performance on the field. The ergogenic and dietary supplements used in a scientifically recommended dose did not demonstrate relevant side effects. The use of various evidence-based supplements can add up to further improvement in the performance of the elite soccer players.

Does transcranial direct current stimulation affect selective visual attention in children with left-sided infantile hemiplegia? A randomized, controlled pilot study

2020 ◽  
pp. 1-13
Author(s):  
Raed A. Alharbi ◽  
Saleh A. Aloyuni ◽  
Faizan Kashoo ◽  
Mohamed I. Waly ◽  
Harpreet Singh ◽  
...  
Keyword(s):  
Pilot Study ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Repeated Measures ◽  
Sham Group ◽  
Time Points ◽  
Selective Visual Attention ◽  
Subject Factor ◽  
And Control

Abstract Objective: Infantile hemiplegia due to brain injury is associated with poor attention span, which critically affects the learning and acquisition of new skills, especially among children with left-sided infantile hemiplegia (LSIH). This study aimed to improve the selective visual attention (SVA) of children with LSIH through transcranial direct current stimulation (tDCS). Methods: A total of 15 children participated in this randomized, double-blinded, pilot study; of them, 10 experienced LSIH, and the remaining 5 were healthy age-matched controls. All the children performed the Computerized Stroop Color-Word Test (CSCWT) at baseline, during the 5th and 10th treatment sessions, and at follow-up. The experimental (n = 5) and control groups (n = 5) received tDCS, while the sham group (n = 5) received placebo tDCS. All three groups received cognitive training on alternate days, for 3 weeks, with the aim to improve SVA. Results: Two-way repeated measures analysis of variance (ANOVA) showed a statistically significant change in the mean scores of CSCWT between time points (baseline, 5th and 10th sessions, and follow-up) within-subject factor, group (experimental, sham) between-subject factor and interaction (time points X group) (p < 0.005). Furthermore, a one-way repeated measures ANOVA showed significant differences between time point (p < 0.005) for the experimental and control group but not the sham group. Conclusion: These pilot results suggest that future research should be conducted with adequate samples to enable conclusions to be drawn.

scholarly journals A Novel Approach for Comparison of Reception Performance in a Technique Test and Small-Sided Games

Sports ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 66
Author(s):  
Arne Sørensen ◽  
Vidar Sørensen ◽  
Terje Dalen
Keyword(s):  
Correlation Coefficient ◽  
Rank Order ◽  
Technical Skills ◽  
Quality Score ◽  
Soccer Players ◽  
Moderate Correlation ◽  
Technical Aspects ◽  
Youth Soccer ◽  
Novel Approach

The purpose of this study was to evaluate the correlation between soccer players’ performance of receptions of passes in tests of both isolated technical skills and more match-realistic situations in small-sided games (SSGs). In addition, this study investigated whether the involvement in SSGs (number of receptions) correlated with the quality of receptions in the respective SSGs. The participants were 13 male outfield youth soccer players from teams in the first division of the regional U18 league. The quality of receptions was scored by educated coaches according to set criteria of performance. Statistical analyses of correlations were determined using Spearman’s rank-order correlation coefficient (rs). The main results were (1) a significant correlation in the quality of ball reception between 4vs1 SSGs and 5vs5 SSGs (rs = −0.61, p < 0.01) and (2) a trend towards moderate correlation between the quality of ball reception using a ball projection machine and 5vs5 SSGs (rs = −0.48, p = 0.10). (3) A significant correlation was found between the number of receptions in 5vs5 SSGs and the quality score of receptions in 5vs5 SSGs (rs = −0.70, p < 0.01). The trend towards moderate correlations between 5vs5 SSGs and the isolated technical reception test could imply the importance of training in the technical aspects of ball reception. Moreover, it seems as though the players with the best reception performance are the players who are most involved in SSGs, that is, having the most receptions.

The Effects of the BAILAMOSTM Dance Program on Physical Activity Levels and Cognition of Older Latino Adults: A Pilot Study

2021 ◽  
pp. 089826432110209
Author(s):  
Guilherme M. Balbim ◽  
Susan Aguiñaga ◽  
Olusola A. Ajilore ◽  
Eduardo E. Bustamante ◽  
Kirk I. Erickson ◽  
...  
Keyword(s):  
Physical Activity ◽  
Pilot Study ◽  
Health Education ◽  
Repeated Measures ◽  
Activity Levels ◽  
Cognitive Health ◽  
Physical Activity Levels ◽  
Global Cognition ◽  
Latino Adults ◽  
And Performance

Objective: To investigate the effects of the BAILAMOSTM dance program on physical activity (PA), cardiorespiratory, and cognitive health. Methods: A parallel, two-armed pilot study was conducted with 57 older Latinos randomized to the BAILAMOSTM dance program ( n = 28) or health education (HE) ( n = 29). We conducted two- and three-way repeated-measures ANOVAs. Results: BAILAMOSTM participants increased participation in leisure moderate-to-vigorous PA (LMVPA) ( F[1,53] = 3.17, p = .048, η2 G = .01) and performance in global cognition relative to HE participants ( F[1,52] = 4.19, p = .045, η2 G = .01). Attendance moderated increases in moderate PA, MVPA, LMVPA, and total PA ( p < .05). Participants of both groups with ≥75% attendance increased participation in PA. Among participants with <75% attendance, BAILAMOSTM participants increased PA relative to HE. Discussion: BAILAMOSTM positively impacted self-reported PA and global cognition in older Latinos. Even smaller doses of dance appear to impact self-reported PA levels.

scholarly journals Deep Reinforcement Learning for End-to-End Local Motion Planning of Autonomous Aerial Robots in Unknown Outdoor Environments: Real-Time Flight Experiments

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2534
Author(s):  
Oualid Doukhi ◽  
Deok-Jin Lee
Keyword(s):  
Reinforcement Learning ◽  
Real Time ◽  
Autonomous Navigation ◽  
Control Technique ◽  
Local Motion ◽  
Aerial Robots ◽  
Novel Approach ◽  
Outdoor Environments ◽  
Aerial Vehicle ◽  
High Level

Autonomous navigation and collision avoidance missions represent a significant challenge for robotics systems as they generally operate in dynamic environments that require a high level of autonomy and flexible decision-making capabilities. This challenge becomes more applicable in micro aerial vehicles (MAVs) due to their limited size and computational power. This paper presents a novel approach for enabling a micro aerial vehicle system equipped with a laser range finder to autonomously navigate among obstacles and achieve a user-specified goal location in a GPS-denied environment, without the need for mapping or path planning. The proposed system uses an actor–critic-based reinforcement learning technique to train the aerial robot in a Gazebo simulator to perform a point-goal navigation task by directly mapping the noisy MAV’s state and laser scan measurements to continuous motion control. The obtained policy can perform collision-free flight in the real world while being trained entirely on a 3D simulator. Intensive simulations and real-time experiments were conducted and compared with a nonlinear model predictive control technique to show the generalization capabilities to new unseen environments, and robustness against localization noise. The obtained results demonstrate our system’s effectiveness in flying safely and reaching the desired points by planning smooth forward linear velocity and heading rates.

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