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1.
J Appl Microbiol ; 135(4)2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38565314

RESUMO

AIMS: Ethyl hexanoate, one of the key flavor compounds in strong-flavor Baijiu. To improve the content of ethyl hexanoate in strong-flavor Baijiu, a functional strain with high yield of ethyl hexanoate was screened and its ester-producing performance was studied. METHODS AND RESULTS: Upon identification, the strain was classified as Candida sp. and designated as ZY002. Under optimal fermentation conditions, the content of ethyl hexanoate synthesized by ZY002 can be as high as 170.56 mg L-1. A fermentation test was carried out using the ZY002 strain bioaugmented Daqu to verify the role of the strain applied to Baijiu brewing. It was found that strain ZY002 could not only improve the moisture and alcohol contents of fermented grains but also diminish the presence of reducing sugar and crude starch. Furthermore, it notably amplified the abundance of flavor compounds. CONCLUSION: In this study, Candida sp. ZY002 with a high yield of ethyl hexanoate provided high-quality strain resources for the actual industrial production of Baijiu.


Assuntos
Candida , Caproatos , Ésteres , Fermentação , Alimentos Fermentados , Caproatos/metabolismo , Ésteres/metabolismo , Ésteres/análise , Alimentos Fermentados/microbiologia , Alimentos Fermentados/análise , Candida/metabolismo , Aromatizantes/metabolismo , Microbiologia de Alimentos , Bebidas Alcoólicas/microbiologia , Bebidas Alcoólicas/análise
2.
Eur J Appl Physiol ; 124(2): 417-431, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37535141

RESUMO

PURPOSE: This manuscript is devoted to discuss the interplay between velocity and acceleration in setting metabolic and mechanical power in team sports. METHODS: To this aim, an essential step is to assess the individual Acceleration-Speed Profile (ASP) by appropriately analysing training sessions or matches. This allows one to estimate maximal mechanical and metabolic power, including that for running at constant speed, and hence to determine individual thresholds thereof. RESULTS: Several approaches are described and the results, as obtained from 38 official matches of one team (Italian Serie B, season 2020-2021), are reported and discussed. The number of events in which the external mechanical power exceeded 80% of that estimated from the subject's ASP ([Formula: see text]) was 1.61 times larger than the number of accelerations above 2.5 m s-2 ([Formula: see text]). The difference was largest for midfielders and smallest for attackers (2.30 and 1.36 times, respectively) due to (i) a higher starting velocity for midfielders and (ii) a higher external peak power for attackers in performing [Formula: see text]. From the energetic perspective, the duration and the corresponding metabolic power of high-demanding phases ([Formula: see text]) were essentially constant (6 s and 22 W  kg-1, respectively) from the beginning to the end of the match, even if their number decreased from 28 in the first to 21 in the last 15-min period, as a consequence of the increased recovery time between [Formula: see text] from 26 s in the first to 37 s in the last 15-min period. CONCLUSION: These data underline the flaws of acceleration counting above fixed thresholds.


Assuntos
Desempenho Atlético , Futebol Americano , Corrida , Humanos , Esportes de Equipe , Metabolismo Energético , Aceleração
3.
Pediatr Exerc Sci ; 36(4): 233-239, 2024 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-39117310

RESUMO

This study critically examines the suitability of using a single drop height to assess the reaction strength index in trained and active participants, a key component of athletic performance. Using a cross-sectional design, 377 trained (n = 163) and active (n = 214) participants aged 14-18 years performing drop jumps from 4 different heights (24, 32, 40, and 48 cm) were studied. The primary aim was to explore the individual differences in reaction strength index at these heights and to assess whether a single height can reliably represent stretch-shortening cycle capabilities. While the repeated measures analysis of variance did not reveal any significant differences, the Bland-Altmann analysis revealed significant individual discrepancies between the performance of the drop heights, resulting in a mean absolute error of 32.1 and a mean absolute percentage error of 20.6%. These results strongly suggest that a single drop height is not sufficient to determine performance in the stretch-shortening cycle. This has important practical implications as it can lead to underestimates of performance trends. The study advocates the inclusion of a range of drop heights in routine testing to accurately measure reactive power and thus improve the effectiveness of individualized training programs for young athletes/active youth.


Assuntos
Desempenho Atlético , Força Muscular , Humanos , Adolescente , Estudos Transversais , Masculino , Desempenho Atlético/fisiologia , Feminino , Força Muscular/fisiologia , Teste de Esforço , Exercício Pliométrico
4.
J Sports Sci ; 42(12): 1164-1172, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-39101451

RESUMO

Wearables quantify the activity in team sports and indicate that players experience peak physical loads during competitions. Accordingly, players with limited court time in competitions will miss important training stimuli. The present study aimed to quantify these gaps in physical load in professional handball players. Activity of all players competing in the 2021/2022 Bundesliga (Germany) was tracked using Kinexon LPS sensors. Gaps in physical load were quantified comparing the 25% of appearances with the highest (HIGH; 51.8 ± 5.2 mins) and lowest court times (LOW; 10.1 ± 4.3 mins). Distances, accumulated acceleration, jumps, sprints, impacts, accelerations, and decelerations were analysed as absolute and relative (per minute) outcomes. Players were grouped into wings, backcourts, and pivots. Unpaired t-tests between HIGH and LOW were performed (p < .05), and effect sizes were calculated (Cohen´s d). Analyses revealed significant effects of court time on activity. While absolute activity increased for HIGH, relative activity increased for LOW (p < .05). In addition, effect sizes revealed position-specific gaps in physical load, particularly for acyclic activities (jumps, accelerations). Gaps in physical load resulting from limited court time are highly position-specific. Our observations may provide benchmarks for the position-specific calibration of compensatory training.


Assuntos
Aceleração , Desempenho Atlético , Comportamento Competitivo , Humanos , Desempenho Atlético/fisiologia , Comportamento Competitivo/fisiologia , Esportes/fisiologia , Estudos de Tempo e Movimento , Masculino , Esportes de Equipe , Fatores de Tempo , Adulto Jovem , Condicionamento Físico Humano , Adulto
5.
J Sports Sci ; 42(1): 3-8, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38369857

RESUMO

A handball is one of two technical skills used to dispose of the ball in Australian Football. Previous research has only considered handball effectiveness in the analysis of team performance and there is a need to understand whether there are other more important characteristics of handball execution that explain effectiveness (i.e., performance). 1342 handballs from Australian Football League matches were analysed. Ten characteristic variables were created that represent the context and execution of each handball included in the analysis. A mixed effects generalised linear model was used to evaluate the effect of the (ten) characteristics on handball outcome. Three out of ten characteristics were associated with handball outcome, and these related to the posture of the handballer and the type of defensive pressure applied to the handballer and the receiver of the handball. These findings explain both how to increase handball effectiveness and how to reduce the handball effectiveness of an opposition team. Given the important role of handballing in passing sequences and maintaining ball possession, the practical application of these findings could enhance overall team performance.


Assuntos
Desempenho Atlético , Humanos , Austrália , Modelos Lineares , Esportes de Equipe
6.
J Sports Sci ; : 1-10, 2024 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-39422215

RESUMO

The concept of space has been successfully modelled in football using spatiotemporal player data and Voronoi diagrams. Current approaches, however, are narrow in scope by focusing on an inter-team allocation of space to measure space control. The present work extends this widespread perspective with an intra-team application of the Voronoi diagram and its dual Delaunay triangulation to measure space management. Both models are leveraged to derive novel performance metrics, which assess how teams use triangular positioning and how players tie up defenders during attacks. The outcome of N = 128,187 attacking sequences from 306 elite men's football matches is analysed using linear mixed-effects models to validate the proposed performance metrics. Results show that attacking success is characterized by player positioning which promotes forming of large triangles especially in ball proximity, whereas the overall number of triangles is of no relevance. Furthermore, players tie up more defenders and thus create free teammates more often during successful attacks. The results demonstrate that a new perspective on space is helpful to better quantify and understand the effect of space management and player positioning on attacking performance in football.

7.
J Sports Sci ; 42(18): 1759-1766, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39356869

RESUMO

This study examined the effects of game schedule, travel demands and contextual factors on team game-related statistics during a full season. The top 10 teams competing in the 2020-2021 Euroleague basketball season were included where game-related statistics from their respective national competitions and the Euroleague competition were retrieved (761 games). Hierarchical linear regression models were computed to evaluate the effects of distance travelled, game schedule and contextual factors for the previous and current games (league, season phase, opponent level, game outcome, score differential) on key performance indicators (points, shooting, rebounds, assists, turnovers, fouls). Several significant models (p < 0.05) yielded R2 values ranging from 0.05 to 0.22 with small-to-medium effect magnitudes. Analyses revealed significant associations between longer durations separating games and less free-throws being made and between further distances travelled and worse 3-point shooting, more offensive rebounds and more fouls. Regarding contextual factors, favourable outcomes for shooting, assists, steals, fouling and turnovers were significantly associated with team success. Playing higher-level teams and competing in playoffs or finals was associated with several diminished outcomes. These results emphasize the multi-factorial nature of performance in elite European basketball, with game schedule, travel and various contextual factors requiring consideration in developing holistic operational plans for teams.


Assuntos
Desempenho Atlético , Basquetebol , Comportamento Competitivo , Basquetebol/estatística & dados numéricos , Humanos , Masculino , Comportamento Competitivo/fisiologia , Europa (Continente) , Viagem/estatística & dados numéricos , Esportes de Equipe , Fatores de Tempo , Modelos Lineares
8.
J Sports Sci ; 42(2): 160-168, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38477311

RESUMO

This study presents a method for analysing badminton matches based on the concept of perturbations. We transfer this principle to a badminton rally and describe the decisive shot, which turns a balanced situation into an advantage for one team or one player. Our paper proposes an observational system, which models the decisive shots by using four consecutive actions: impulse (the perturbation), follow-up, survival, and convert. To test the objectivity of the operationalization, independent raters analysed six matches in the singles disciplines of the 2022 World Championships. To evaluate rater agreement, Jaccard coefficient and Cohen's kappa were used. Results show an agreement in identifying impulses of J(R1, R2) = .80, while the agreement in classifying the impulse type (positive/negative) reached κ = .70. A comparison of this perturbation-based analysis and last shot analyses shows significantly different results. Direct errors usually occur in the midcourt (56.4%), whereas most negative perturbations originate from the backcourt (40.0%). In contrast to direct winners, mostly originating from a smash (45.5%), most positive perturbations are created by net shots (30.1%). We argue that our method can be complementary to common last shot analyses and provides a possibility to describe players' strengths and weaknesses in more detail.


Assuntos
Esportes com Raquete , Humanos , Projetos de Pesquisa
9.
J Sports Sci ; : 1-9, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38916261

RESUMO

Despite the growing popularity of women's rugby, there is a lack of research understanding the contribution of place-kicking to match outcomes. This study aims to establish the characteristics and contribution of place-kicking to women's international Rugby Union and evaluate the performance of place-kickers while accounting for factors that contribute to kick difficulty. Data from 674 place-kicks across 80 matches were analysed. A binomial generalised linear mixed model (GLMM) was used to predict the probability of kick success. 60.5% of place-kicks were successful, and they contributed 23.9% of all points scored; conversions accounted for 16.8% and penalties 7.1%. Kick success percentages for conversions (56.9%) and penalties (78.3%) significantly differed (p < 0.01). Kick distance and angle were significant (p < 0.01) predictors of kick success and the GLMM had a prediction accuracy of 73.6%. The performance rankings of kickers changed when comparing observed and expected success, highlighting the need to consider contextual factors contributing to kick difficulty when evaluating performance. The GLMM results provide valuable insights for coaches and players to make informed decisions, for example, whether to attempt a place-kick when a penalty is awarded, by enabling predictions of place-kick success. This could enhance a team's chances of winning matches.

10.
Sensors (Basel) ; 24(13)2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-39000933

RESUMO

The galvanic dissolved oxygen sensor finds widespread applications in multiple critical fields due to its high precision and excellent stability. As its core sensing components, the oxygen-permeable membrane, electrode, and electrolyte significantly impact the sensor's performance. To systematically investigate the comprehensive effects of these core sensing components on the performance of galvanic dissolved oxygen sensors, this study selected six types of oxygen-permeable membranes made from two materials (Perfluoroalkoxy Polymer (PFA) and Fluorinated Ethylene Propylene Copolymer (FEP)) with three thicknesses (0.015 mm, 0.03 mm, and 0.05 mm). Additionally, five concentrations of KCl electrolyte were configured, and four different proportions of lead-tin alloy electrodes were chosen. Single-factor and crossover experiments were conducted using the OxyGuard dissolved oxygen sensor as the experimental platform. The experimental results indicate that under the same membrane thickness conditions, PFA membranes provide a higher output voltage compared to FEP membranes. Moreover, the oxygen permeability of FEP membranes is more significantly affected by temperature. Furthermore, the oxygen permeability of the membrane is inversely proportional to its thickness; the thinner the membrane, the better the oxygen permeability, resulting in a corresponding increase in sensor output voltage. When the membrane thickness is reduced from 0.05 mm to 0.015 mm, the sensor output voltage for PFA and FEP membranes increases by 86% and 74.91%, respectively. However, this study also observed that excessively thin membranes might compromise measurement accuracy. In a saturated, dissolved oxygen environment, the sensor output voltage corresponding to the six oxygen-permeable membranes used in the experiment exhibits a highly linear inverse relationship with temperature (correlation coefficient ≥ 98%). Meanwhile, the lead-tin ratio of the electrode and electrolyte concentration have a relatively minor impact on the sensor output voltage, demonstrating good stability at different temperatures (coefficient of variation ≤ 0.78%). In terms of response time, it is directly proportional to the thickness of the oxygen-permeable membrane, especially for PFA membranes. When the thickness increases from 0.015 mm to 0.05 mm, the response time extends by up to 2033.33%. In contrast, the electrode material and electrolyte concentration have a less significant effect on response time. To further validate the practical value of the experimental results, the best-performing combination of core sensing components from the experiments was selected to construct a new dissolved oxygen sensor. A performance comparison test was conducted between this new sensor and the OxyGuard dissolved oxygen sensor. The results showed that both sensors had the same response time (49 s). However, in an anaerobic environment, the OxyGuard sensor demonstrated slightly higher accuracy by 2.44%. This study not only provides a deep analysis of the combined effects of oxygen-permeable membranes, electrodes, and electrolytes on the performance of galvanic dissolved oxygen sensors but also offers scientific evidence and practical guidance for optimizing sensor design.

11.
Sensors (Basel) ; 24(4)2024 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-38400458

RESUMO

This paper studies the security and reliability of the power splitting (PS)-based relaying in the Internet of Things (IoT) networks with the help of a jammer. Based on the considered system model, we derive outage probability (OP) and intercept probability (IP) under two distinguished schemes, namely, the static PS relaying (SPSR) scheme and the dynamic PS relaying (DPSR) scheme. More precisely, the PS ratio of the former is a constant number, while the latter is optimally adjusted in order to minimize the OP and counts only on the channel gain of the second hop. Numerical results are provided to not only verify the accuracy of the proposed mathematical framework but also identify the trends of both OP and IP with respect to several important parameters. Our findings unveil that the OP and IP have contradictory behavior with respect to the transmit power and number of sources. Moreover, the performance of the DPSR scheme is superior to that of the SPSR scheme.

12.
Sensors (Basel) ; 24(6)2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38544064

RESUMO

Vehicular wireless networks are one of the most valuable tools for monitoring platforms in the automotive domain. At the same time, Internet of Things (IoT) solutions are playing a crucial role in the same framework, allowing users to connect to vehicles in order to gather data related to their working cycle. Such tasks can be accomplished by resorting to either cellular or non-cellular wireless technologies. While the former can ensure low latency but require high running costs, the latter can be employed in quasi-real-time applications but definitely reduce costs. To this end, this paper proposes the results of two measurement campaigns aimed at assessing the performance of the long-range wide-area network (LoRaWAN) protocol when it is exploited as an enabling technology to provide vehicles with connectivity. Performances are evaluated in terms of packet loss (PL) and received signal strength indicator (RSSI) in wireless links. The two testing scenarios consisted of a transmitter installed on a motorbike running on an elliptical track and a receiver placed in the centre of the track, and a transmitter installed on the roof of a car and a receiver placed next to a straight road. Several speeds were tested, and all the spreading factors (SFs) foreseen by the protocol were examined, showing that the Doppler effect has a marginal influence on the receiving performance of the technology, and that, on the whole, performance is not significantly affected by the speed. Such results prove the feasibility of LoRaWAN links for vehicular network purposes.

13.
Sensors (Basel) ; 24(3)2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38339486

RESUMO

This paper begins by exploring the challenge of event-triggered state estimations in nonlinear systems, grappling with packet dropout and correlated noise. A communication mechanism is introduced that determines whether to transmit measurement values based on whether event-triggered conditions are violated, thereby minimizing redundant communication data. In designing the filter, noise decorrelation is initially conducted, followed by the integration of the event-triggered mechanism and the unreliable network transmission system for state estimator development. Subsequently, by combining the three-degree spherical-radial cubature rule, the numerical implementation steps of the proposed state estimation framework are outlined. The performance estimation analysis highlights that by adjusting the event-triggered threshold appropriately, the estimation performance and transmission rate can be effectively balanced. It is established that when there is a lower bound on the packet dropout rate, the covariance matrix of the state estimation error remains bounded, and the stochastic stability of the state estimation error is also confirmed. Ultimately, the algorithm and conclusions that are proposed in this paper are validated through a simulation example of a target tracking system.

14.
Molecules ; 29(19)2024 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-39407577

RESUMO

Extensive data on the characteristics and performance of the catalysts synthesized and tested for methane oxidative coupling (OCM) is available in thousands of reports published during the last four decades. Revisiting and analyzing the general trends recognizable in those data could improve the current understanding of the catalyst functionality under different reaction conditions. This is instrumental in determining the direction of future research aiming for more efficient OCM catalysts and reactors. These are the subjects of the comprehensive analysis reported in this paper, which covers the main aspects associated with the analysis of the OCM catalytic performance, including the catalyst characteristics, reaction mechanism, and reactor operation. Special attention was devoted to analyzing these aspects in the framework of thermal-reaction engineering and, accordingly, critically reviewing the reported catalytic performances in the literature.

15.
BMC Nurs ; 23(1): 302, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38724959

RESUMO

OBJECTIVE: To identify critical satisfaction gaps in a home nursing mobile application (APP) using a systematic decision-making model. METHODS: Initially, the decision-making trial and evaluation laboratory method was used to analyze the relationship structure and corresponding weights among the indicators. The Importance-Performance Analysis (IPA) method was used to identify the categories of all indicators and their corresponding strategic directions. Twenty-six home nursing specialists currently providing home nursing services were recruited for this study. RESULTS: The IPA results revealed that "Assurance," "Reliability," and "Personal security protection" are critical satisfaction gaps. From the influence network and weight results, "information quality" and "system quality" were the critical quality factors in the home nursing mobile APP. The influence of the network relationship structure and weight demonstrated a 98.12% significance level, indicating good stability. CONCLUSION: Continuous improvement in information and system quality is recommended to optimize the overall quality of the home nursing mobile APP. Additionally, user demands should be considered, and personal safety guarantee functions should be developed and integrated into the system to ensure the safety of home nursing workers.

16.
Entropy (Basel) ; 26(10)2024 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-39451926

RESUMO

Due to the inherent broadcasting nature and openness of wireless transmission channels, wireless communication systems are vulnerable to the eavesdropping of malicious attackers and usually encounter undesirable situations of information leakage. The problem may be more serious when a passive eavesdropping device is directly connected to the transmitter of a single-input single-output (SISO) system. To deal with this urgent situation, a novel IRS-assisted physical-layer secure transmission scheme based on joint transmitter perturbation and IRS reflection (JPR) is proposed, such that the secrecy of wireless SISO systems can be comprehensively guaranteed regardless of whether the reflection-based jamming from the IRS to the eavesdropper is blocked or not. Moreover, to develop a trade-off between the achievable performance and implementation complexity, we propose both element-wise and group-wise reflected perturbation alignment (ERPA/GRPA)-based IRS reflection strategies, respectively. In order to evaluate the achievable performance, we analyze the ergodic secrecy rate (ESR) and secrecy outage probability (SOP) of the SISO secure systems with the ERPA/GRPA-based JPRs, respectively. Finally, by characterizing the simulated and numerical ESR and SOP performance results, our proposed scheme is compared with the benchmark scheme of random phase-based reflection, which strongly demonstrates the effectiveness of our proposed scheme.

17.
Minim Invasive Ther Allied Technol ; 33(2): 90-101, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38109095

RESUMO

BACKGROUND: The objective of this study was to evaluate the novices' learning curves and proficiency level reached in laparoendoscopic single-site (LESS) surgery using three surgical training programs. MATERIAL AND METHODS: Participants were randomly divided into three groups, who trained in a specific practice regimen for 12 days using a laparoscopic box simulator and three tasks. Group A trained in three stages using conventional laparoscopic surgery (CLS) with straight instruments, and LESS with straight and articulating instruments for four days each. Group B trained in two stages in LESS with straight and articulating instruments for six days each. Group C trained only in LESS with articulating instruments exclusively for all 12 days. Performance was registered daily during the 12 days to evaluate the participants' progress. RESULTS: Pre- and post-training analysis of the three groups showed significant differences in performance, denoting the significant improvement in their LESS skills, with no difference between the groups. Group C reached a high level of technical competence with their specific training program in LESS, obtaining a lower asymptote and slow learning rate. CONCLUSION: Specific training programs in LESS settings using articulated instruments showed a slower learning rate than the other programs but better proficiency in the technique with the best surgical performance.


Assuntos
Laparoscopia , Treinamento por Simulação , Humanos , Curva de Aprendizado , Competência Clínica , Laparoscopia/métodos , Treinamento por Simulação/métodos
18.
Biol Sport ; 41(4): 3-9, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39416504

RESUMO

The aims were to I. assess the differences in unforced errors between men's and women's professional padel players, II. assess the differences in unforced errors between winners and losers of the set in professional padel players, III. analyse the evolution of unforced errors in professional padel. To do this, the unforced errors (which are provided by World Padel Tour (WPT)) were collected from 2,567 sets (1,476 men's sets and 1,091 women's sets) corresponding to matches from the final draw (round of 32, round of 16, quarterfinals, semi-finals and finals) of tournaments on the WPT men's and women's circuits during 2016 to 2022 seasons, which are available on the WPT YouTube channel and on the WPT TV website. The results with respect to the first aim indicate that the number of unforced errors was higher in women's padel than in men's, regardless of the set number, tournament round, season and court. With respect to the second aim, not committing unforced errors is a fundamental factor in professional padel to win the sets. Finally, regarding the third aim, the number of unforced errors decreased as the seasons progressed; therefore, to win, players should not only have to pass the ball without missing, but they might have to hit winners or generate forced errors of the opponent.

19.
Biol Sport ; 41(1): 95-106, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38188112

RESUMO

The aim of the study was to determine whether the physical performance of young soccer player during various small sided games (SSGs) underloads, replicates or overloads the requirements of the worst-case scenarios (WCS) during match play. A total of 521 SSGs' individual observations and 15 different formats of SSGs with different areas per player (ApP) (ApP100: < 100; ApP200: ranged from 101 to 200; ApP300: > 201, all in m2 · player-1) were taken into consideration. Whole (90-min average; OM) and 15-, 5- and 1-min worst-case scenarios (WCS15, WCS5 and WCS1, respectively) were analysed. Total distance covered relative (m · min-1) (TDCR), high-speed distance relative (m · min-1) (HSDR), very high-speed distance relative (m · min-1) (VHSDR) and sprint distance relative (m · min-1) (SDR), player load relative (PLR) and both total (ACCR) and high intensity relative accelerations (n · min-1) (ACCHR) were collected. All external load measures analysed were significantly higher in WCS1 compared to WCS of longer duration and SSGs with different ApP (p < 0.001). The analysis demonstrated interactions between game type and player positions (p < 0.001) for TDCR, VHSDR, PLR and ACCHR. The SSG formats did not sufficiently stimulate the WCS for locomotor demands (VHSDR and SDR). SSGs played on an ApP100 overestimated the mechanical values compared to WCS15 and WCS5. The analysed SSG formats did not sufficiently stimulate players to cope with all external load demands that occurred during WCS1. This study provides useful information for practitioners on the heightened impact of different SSG formats on external load in relation to the WCS of competitive match play.

20.
Biol Sport ; 41(3): 267-274, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38952903

RESUMO

Substitutions play a key role in modern football and can substantially affect the physical and overall performance of a team, and the recent substitution rule changes are worth investigating. This study explored the characteristics of substitutions, including different substitution rules, game results, sex, competition stages, tournaments and penalty shoot-outs success rates. We analysed data from a total of 3,738 substitutions from the last 10 years (2013-2023) of European Championships and World Cups, both men's and women's games. Non-parametric tests and chi-square tests were used for statistical analysis with the significance level set at p < 0.05. With the 5-substitution rule, 48% more substitutions occurred compared to the 3-substitution rule (4.26 ± 1.07 vs. 2.87 ± 0.43, p < 0.05) with a slight increase in the average substitution time (70.6 ± 14.3 vs. 69.2 ± 14.6 min, p < 0.05), and 10% more substitutions in the men's game compared to the women's game (p < 0.05). The timing of the first substitution was slightly different in the knock-out stage compared to group stage (59.8 ± 14.7 vs. 57.2 ± 13.3 min, p < 0.05), and the timing for the winning team and drawing team was later than for the losing team (p < 0.05). A total of 13.2% goals were scored by substitutes, with no significant difference between the 5-substitution rule (15.9%) vs the 3-substition rule (12.5%) (p > 0.05). Interestingly, substitute players had a lower success rate in penalty shoot-out compared to starters (61 vs. 74%, p < 0.05). Additionally, substitute player goal scorers entered the pitch later (p < 0.05) in male games compared to female games and in knock-out stage games compared to group games. This study highlights the importance of substitution rules and timing in modern elite football matches. The timing of the first substitution, introduction of substitutes in knock-out stages, and a lower success rate of substitute players in penalty shoot-outs are crucial factors to consider. Coaches can use this information to make strategic substitution decisions to improve team performance.

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