On the origin of F-wave: involvement of central synaptic mechanisms.

Neurophysiological methods are used widely to gain information about motor neuron excitability and axon conduction in neurodegenerative diseases. The F-wave is a common biomarker used to test motor neuron properties in the diagnosis of neurological diseases. Although the origin of the F-wave is a subject of debate, the most widely accepted mechanism posits that the F-wave is generated by the backfiring of motor neurons stimulated antidromically from the periphery. In this study, we developed an ex vivo mouse sciatic nerve-attached spinal cord preparation with sensory axons severed. In this preparation, stimulation of the whole sciatic nerve or its tibial branch evoked responses with the electrophysiological signatures of F-waves. Manipulations of synaptic transmission by either removal of extracellular calcium or block of post-synaptic glutamate receptors abolished these responses. These results suggest that F-waves are mediated by spinal microcircuits activated by recurrent motor axon collaterals via glutamatergic synapses.

Endurance Performance Adaptations between SSG and HIIT in Soccer Players: A Meta-analysis.

The objective of this systematic review with meta-analysis was to compare the endurance performance chronic adaptations induced by running-based high-intensity interval training (HIIT), small-sided games (SSGs), and combined HIIT+SSGs in male and female youth and adult soccer players. The studies included in this review followed the PICOS criteria: (i) healthy soccer players; (ii) interventions based on SSGs; (iii) comparators exposed to only HIIT or combined SSGs+HIIT; (iv) endurance performance variables. Studies were searched for in the following databases: (i) PubMed; (ii) Scopus; (iii) SPORTDiscus; (iv) Web of Science. After conducting an initial database search that retrieved a total of 5,389 records, a thorough screening process resulted in the inclusion of 20 articles that met the eligibility criteria. Sixteen studies reported outcomes related to endurance performance measured through field-based tests, while five studies provided results from direct measurements of maximal oxygen uptake (VO2max). Results showed a non-significant small-magnitude favoring effect for the HIIT groups compared to the SSG groups (ES=0.37, p=0.074) for endurance, while a non-significant small-magnitude favoring SSGs was observed (ES=-0.20, p=0.303) for VO2max. Despite the very low certainty of evidence, the findings suggest similar effects induced by both SSG and HIIT on improving endurance performance and VO2max.

The Interunit Reliability of Global Navigation Satellite Systems Apex (STATSports) Metrics During a Standardized Intermittent Running Activity.

ABSTRACT: Beato, M, Wren, C, and de Keijzer, KL. The interunit reliability of global navigation satellite systems Apex (STATSports) metrics during a standardized intermittent running activity. J Strength Cond Res 38(2): e49-e55, 2024-This study aimed to evaluate the interunit reliability of global navigation satellite systems (GNSS) STATSports Apex metrics and to assess which metrics can be used by practitioners for the monitoring of short-distance intermittent running activities. Fifty-four male soccer players were enrolled (age = 20.7 ± 1.9 years, body mass = 73.2 ± 9.5 kg, and height = 1.76 ± 0.07 m) in this observational study. 10-Hz GNSS Apex (STATSports, Northern Ireland, Newry) units recorded total distance, high speed running (HSR), accelerations, decelerations, peak speed, average metabolic power, metabolic distance, dynamic stress load (DSL), relative distance, and speed intensity. The standardized intermitted running protocol used was a Yo-Yo intermittent recovery level 1. This study reported that Apex interunit analysis did not show any significant difference (delta difference and 95% confidence interval [CIs]) in total distance = 2.6 (-2.6; 7.9) m, HSR = 3.2 (-0.2; 6.8) m, accelerations = 0.09 (-0.9; 1.1), decelerations = 0.3 (-0.4; 1.1), peak speed = 0.02 (-0.03; 0.07) m·s -1 , average metabolic power = 0.01 (-0.02; 0.04) W·kg -1 , metabolic distance = 0.9 (-6.2; 8.0) m, DSL = 2.8 (-5.6; 10.7) au, relative distance = 0.14 (-0.19; 0.47) m·min -1 , and speed intensity = 0.21 (-0.21; 0.64) au. All metrics presented a delta d between trivial to small. The interunit intraclass correlation coefficient (ICC) was good or excellent for all metrics, with the exception of DSL, which was considered questionable . In conclusion, this study reports that all the metrics analysis in this study presents a low interunit bias and high reliability (ICC), with the exception of DSL.

The Analysis of Physical Performance During Official Competitions in Professional English Football: Do Positions, Game Locations, and Results Influence Players' Game Demands?

ABSTRACT: Beato, M, Youngs, A, and Costin, AJ. The analysis of physical performance during official competitions in professional English football: Do positions, game locations, and results influence players' game demands? J Strength Cond Res 38(5): e226-e234, 2024-This study aimed, first, to verify if physical parameters were different between players' positions during official matches in English professional football, and second, if the game location (H and A) or results (W, L, D) affected players' physical performance. Twenty-five male professional football players of the same team were included in this data analysis (age = 27 ± 9 years) during the 2022-23 season. Players were divided into positions: center backs, wide backs, center midfielders, attacking midfielders, and strikers. The external load parameters were distance covered, high-speed running (HSR), sprinting distance, accelerations, decelerations, and high metabolic load distance (HMLD, meters > 25.5 w·kg -1 ) that were monitored using global navigation satellite systems Apex (STATSports). Linear mixed models' analysis for positions reported a significant difference in total distance ( p = 0.011), HSR ( p < 0.001), sprinting distance ( p < 0.001), accelerations ( p = 0.003), decelerations ( p = 0.002), and HMLD ( p < 0.001). Centre backs showed the lowest physical performance in the metrics analyzed, whereas players in the other positions frequently displayed a similar physical performance. Regarding locations and results, differences were only found between locations for decelerations ( p = 0.041) and between results for HMLD ( p = 0.010). In conclusion, physical performance was influenced by players' positions, whereas game location or results seem to not affect physical performance during official competitions. Consequently, practitioners can physically prepare their players independently from the location of the match or of the possible game results, whereas specific positional training is requested to optimally prepare their players.

A Review of the Validity and Reliability of Accelerometer-Based Metrics From Upper Back-Mounted GNSS Player Tracking Systems for Athlete Training Load Monitoring.

ABSTRACT: Dawson, L, Beato, M, Devereux, G, and McErlain-Naylor, SA. A review of the validity and reliability of accelerometer-based metrics from upper back-mounted GNSS player tracking systems for athlete training load monitoring. J Strength Cond Res 38(8): e460-e475, 2024-Athlete load monitoring using upper back-mounted global navigation satellite system (GNSS) player tracking is common within many team sports. However, accelerometer-based load monitoring may provide information that cannot be achieved with GNSS alone. This review focuses on the accelerometer-based metrics quantifying the accumulation of accelerations as an estimation of athlete training load, appraising the validity and reliability of accelerometer use in upper back-mounted GNSS player tracking systems, the accelerometer-based metrics, and their potential for application within athlete monitoring. Reliability of GNSS-housed accelerometers and accelerometer-based metrics are dependent on the equipment model, signal processing methods, and the activity being monitored. Furthermore, GNSS unit placement on the upper back may be suboptimal for accelerometer-based estimation of mechanical load. Because there are currently no feasible gold standard comparisons for field-based whole-body biomechanical load, the validity of accelerometer-based load metrics has largely been considered in relation to other measures of training load and exercise intensity. In terms of convergent validity, accelerometer-based metrics (e.g., PlayerLoad, Dynamic Stress Load, Body Load) have correlated, albeit with varying magnitudes and certainty, with measures of internal physiological load, exercise intensity, total distance, collisions and impacts, fatigue, and injury risk and incidence. Currently, comparisons of these metrics should not be made between athletes because of mass or technique differences or between manufacturers because of processing variations. Notable areas for further study include the associations between accelerometer-based metrics and other parts of biomechanical load-adaptation pathways of interest, such as internal biomechanical loads or methods of manipulating these metrics through effective training design.

Practitioner Usage, Applications, and Understanding of Wearable GPS and Accelerometer Technology in Team Sports.

ABSTRACT: Dawson, L, McErlain-Naylor, SA, Devereux, G, and Beato, M. Practitioner usage, applications, and understanding of wearable GPS and accelerometer technology in team sports. J Strength Cond Res 38(7): e373-e382, 2024-Monitoring training load is essential for optimizing the performance of athletes, allowing practitioners to assess training programs, monitor athlete progress, and minimize the risk of injury and overtraining. However, there is no universal method for training load monitoring, and the adoption of wearable global positioning system (GPS) and accelerometer technology in team sports has increased the volume of data and, therefore, the number of possible approaches. This survey investigated the usage, applications, and understanding of this technology by team sports practitioners. Seventy-two practitioners involved in team and athlete performance monitoring using GPS and accelerometer technology completed the survey. All respondents reported supporting the use of GPS technology in their sport, with 70.8% feeling that GPS technology is important for success. Results showed that 87.5% of respondents use data from wearable technology to inform training prescription, although only 50% use the data to influence decisions in competition. In addition, results showed that GPS metrics are used more than accelerometer-derived metrics; however, both are used regularly. Discrepancies in accelerometer usage highlighted concerns about practitioners' understanding of accelerometer-derived metrics. This survey gained insight into usage, application, understanding, practitioner needs, and concerns and criticisms surrounding the use of GPS and accelerometer metrics for athlete load monitoring. Such information can be used to improve the implementation of this technology in team sport monitoring and highlight gaps in the literature that will help to design future studies to support practitioner needs.

Attentional Focus Effects on Lower-Limb Muscular Strength in Athletes: A Systematic Review.

ABSTRACT: Pompa, D, Carson, HJ, Beato, M, di Fronso, S, and Bertollo, M. Attentional focus effects on lower-limb muscular strength in athletes: A systematic review. J Strength Cond Res 38(2): 419-434, 2024-Evidence links an athlete's focus of attention to enhancing strength performance. However, additional research is needed to investigate the applicability of studies beyond the tasks and population currently examined. Therefore, we aimed to systematically review studies concerning attentional focus effects on strength characteristics on lower-limb tasks in athletes. Scopus, Web of Science, and EBSCO databases were searched using PRISMA PERSIST guidelines and keywords related to the focus of attention, force production processes, and athletes. Subjects were categorized: world class (tier 5); elite (tier 4); highly trained (tier 3); trained/developmental (tier 2); nonathletes (tiers 1-0); and mixed (different levels). Fifteen of 296 studies met the inclusion criteria. Included studies investigated the focus of attention effects on performance ( n = 6), between skill levels ( n = 2), and for learning ( n = 5), with respect to subject preference ( n = 1); one study did not state the aim. Studies achieved an average risk of bias score of "excellent"; however, findings suffered in the assessment of certainty. Only 2 studies reported an advantage for one type of attentional focus (external focus) across conditions ( g = 0.13-0.42) with tier 2 and mixed tier athletes. Research does not address the needs of elite athletes, and there is limited evidence on each type of strength characteristics and muscle action. There is also a need to incorporate methodological steps to promote task-relevant instructions. Research should focus on contextualized information within professional practice to offer stronger translational implications for athletes and coaches.

Analysis of Concentric and Eccentric Power in Flywheel Exercises Depending on the Subjects' Strength Level and Body Mass.

ABSTRACT: Asencio, P, García-Valverde, A, Albaladejo-García, C, Beato, M, Moreno-Hernández, FJ, and Sabido, R. Analysis of concentric and eccentric power in flywheel exercises depending on the subjects' strength level and body mass. J Strength Cond Res XX(X): 000-000, 2024-The objective of this study is to describe how flywheel exercise mechanical outputs are affected by the athletes' body mass (BM) and strength level and by the exercise type. Forty-six recreational athletes came to a laboratory 3 times. On the first day, descriptive data, squat (1 repetition maximum: 1RM) and flywheel familiarization were performed. After a second day of familiarization, subjects performed a randomized flywheel exercise-testing protocol of squat and split squat exercises. The variables used for data analysis were peak concentric power and peak eccentric power, eccentric/concentric ratio, and their relationship with 1RM/BM. Subjects were assigned to a stronger or weaker group according to their 1RM/BM ratio. Group differences were found in absolute values of eccentric overload (EOL) (p < 0.01; effect size [ES] = 0.51) and EOL/BM (p < 0.01; ES = 0.46) only in the split squat. Absolute power values in the concentric phase showed differences between inertial load (p < 0.01; ES = 0.41). The stronger group did not present significant differences between inertial loads during squat (p < 0.01; ES = 0.46), but they showed different ratios with light inertias in comparison with the weaker group (p < 0.01; ES = 0.46). There were significant differences between groups with light inertias in split squat (nondominant) and squat exercises (p < 0.05; ES = 0.29) in the eccentric and concentric phases (p < 0.116; ES = 0.20). Squat and split squat exercises present different profiles depending on the training level. In conclusion, it is recommended that practitioners perform a test to understand the inertial load-power profile (concentric, eccentric, and their ratio) for each exercise and also consider the user's strength level for selection of the inertial load and for the exercise to use in training.

Effects of Upper-Body and Lower-Body Conditioning Activities on Postactivation Performance Enhancement During Sprinting and Jumping Tasks in Female Soccer Players.

ABSTRACT: Santos da Silva, V, Nakamura, FY, Gantois, P, Nogueira Gouveia, JN, Peña, J, Beato, M, and Abade, E. Effects of upper-body and lower-body conditioning activities on postactivation performance enhancement during sprinting and jumping tasks in female soccer players. J Strength Cond Res 38(2): 342-349, 2024-This study aimed to investigate the postactivation performance enhancement (PAPE) effects of "specific" (half-back squat) and "nonspecific" (bench press) conditioning activities on sprinting and jumping performances in female soccer players. Fourteen players (mean ± SD : age = 22.3 ± 4.0 years; body mass = 60.2 ± 7.8 kg; height = 164.1 ± 4.2 cm) competing at national level (first League) participated in this within-subject crossover study. The players performed a warm-up protocol including 3 sets of 3 repetitions of half-back-squat or bench press exercises at 90% 1RM or a warm-up protocol without lifting weights (i.e., control condition). Forty-meter shuttle sprints (20 + 20 m with change of direction [COD-180°]), countermovement jump (CMJ), and horizontal jump (HJ) performances were recorded 6 minutes after the conditioning activities protocols or the control condition. Nonsignificant large positive effects were found for the HJ after the half-back-squat (ES = 1.68; p > 0.05) and bench press (ES = 1.68; p > 0.05) protocols. Although nonsignificant, HJ changes ( Δ = 0.07 m) were greater than the smallest worthwhile change (0.02 m) and standard error of measurement (0.03 m) after both conditioning activities. Moreover, no significant changes were found for sprint and CMJ performance after neither half-back-squat nor bench press protocols ( p > 0.05). In conclusion, both specific and nonspecific conditioning activities using heavy loads (i.e., 90% 1RM) may be suitable to enhance individual HJ. Finally, both conditioning activities are potentially ineffective for increasing sprint and CMJ performance in the context of this study.

Testing the peak running speed in analytical and contextual-based scenarios: Applied research in young adult soccer players.

The primary aim was to compare the peak running speed (PRS) attained in the 40-m linear sprint test, in an analytical-based soccer drill, in the 5-0-5 test, and a training match scenario. The secondary aim of the study was to evaluate the differences between the three assessment sessions and identify how the tests can vary from session to session. Additionally, we aimed to investigate the within-test variability to understand how consistent the performance is within each test format across the different sessions. Forty male under-19 players competing at the national level participated in this study. A training session was observed for each of the three study weeks in which the following tests/scenarios were monitored using a GPS. The 40-m linear sprint test and the analytical-based soccer drill presented the smallest within-subject coefficients of variation between the sessions. A large correlation (r = 0.742) was found between the PRS during the 40-m linear sprint test and the analytical-based soccer drill. The 40-m linear sprint test was the best method of those examined for measuring PRS. The analytical drill provides a reliable method for measuring PRS, although it differs from the 40-metre linear sprint test.

Seasonal Variation of Physical Performance, Bilateral Deficit, and Interlimb Asymmetry in Elite Academy Soccer Players: Which Metrics Are Sensitive to Change?

ABSTRACT: Bishop, C, Abbott, W, Brashill, C, Loturco, I, Beato, M, and Turner, A. Seasonal variation of physical performance, bilateral deficit, and interlimb asymmetry in elite academy soccer players: Which metrics are sensitive to change? J Strength Cond Res 37(2): 358-365, 2023-This study aimed to report seasonal variations for (a) physical performance, (b) interlimb asymmetry, and (c) bilateral deficit (BLD) data over the course of a competitive soccer season and determine which metrics are sensitive to change. This study used a repeated-measures observational design for 19 under-20, elite, academy, soccer players (age: 17.58 ± 0.61 years; height: 1.81 ± 0.09 m; body mass: 74.36 ± 7.58 kg), who conducted bilateral and single-leg countermovement jumps (CMJ and SLCMJ), linear speed (5, 10, 20, and 30-m) and 505 change of direction (COD) speed tests, at pre, mid, and end of season time points. For jump tests, jump height, reactive strength index modified, time to takeoff, and countermovement depth metrics were monitored, with interlimb asymmetry and the BLD also calculated for each. Significant improvements ( p < 0.05) in performance were evident in all fitness tests: CMJ (effect size [ES]: 0.61 to 1.03), SLCMJ (ES: 0.60 to 2.25), linear speed (ES: -0.54 to -1.96), and COD speed (ES: -0.68 to -1.14). Significant reductions in asymmetry (ES: -0.68 to -1.07) and significant increases in the BLD (ES: 1.15 to 1.57) were also evident throughout the season. Additionally, kappa coefficients were used to determine consistency in limb dominance throughout the season, but only poor to fair levels of agreement (kappa: -0.17 to 0.37) were evident, highlighting the fluctuating nature of limb dominance throughout the season. Despite all tests exhibiting meaningful change, the SLCMJ and linear speed showed the most frequent and largest differences in performance, highlighting their usefulness in the ongoing monitoring process of physical capacities in elite male academy players across a competitive soccer season.

A Comparison of Training and Match Play External Load During a Congested In-Season Period in English League 2 Football.

ABSTRACT: Fleming, A, Walker, M, Armitage, M, Connor, M, and Beato, M. A comparison of training and match play external load during a congested in-season period in English League 2 Football. J Strength Cond Res 37(9): e527-e534, 2023-This study aimed to investigate if external training load metrics differ between training days and match day (MD) during a period of fixture congestion and to verify if external load metrics vary based on playing positions. Training and MD data were collected in a part of the competition phase of the 2020-2021 season (6 weeks) in the English Football League 2 ( N = 20 players, mean ± SD s: age = 24.4 ± 4.7 years). Global Navigation Satellite System units (Catapult S7 Vector 10 Hz) were used to monitor external load metrics. The metrics were duration of training, total distance (TD), high-speed running distance (HSR), sprinting distance, relative intensity (m/min), total accelerations (TotAcc) (>3 m·s -2 ), and total decelerations (TotDec) (<-3 m·s -2 ). This study found that duration, TD, relative intensity, HSR distance, sprint distance, TotAcc, and TotDec were different ( p < 0.001, d = small to moderate ) between MD and match day minus two (MD-2) or match day minus one (MD-1); however, during match day minus four (MD-4), only relative intensity was significantly lower ( p < 0.001) compared with MD output. Therefore, MD-4 was the most demanding training session of the week (after the MD), and during MD-2 and MD-1, coaches decreased players' load to favor players' readiness. Moreover, this study found that MD and MD-1 resulted in statistically different values across several metrics between different playing positions (defenders < midfielders and strikers), whereas metrics in MD-4 and MD-2 were not statistically different, which highlights that in these sessions, players have similar external loads independently from their playing positions.

Rationale and Practical Recommendations for Testing Protocols in Female Soccer: A Narrative Review.

ABSTRACT: Beato, M, Datson, N, Anderson, L, Brownlee, T, Coates, A, and Hulton, A. Rationale and practical recommendations for testing protocols in female soccer: A narrative review. J Strength Cond Res 37(9): 1912-1922, 2023-The aim of this narrative review is to evaluate the presented literature on tests (aerobic, speed, changes of direction [COD], strength, power, jump, and anthropometry) of the varied components of female soccer and to draw attention to the most suitable protocols to allow practitioners to accurately track players' fitness status. The 2 most common field tests used to assess aerobic fitness are the Yo-Yo intermittent test (level 1 and level 2) and the 30-15 intermittent fitness test because of an ability to measure multiple players at once with a soccer-specific intermittent profile. The sprinting performance can be assessed on distances of <30 m; however, longer distances (e.g., 40 m) allow for achieving peak speed (flying sprint test), which can be assessed using global navigation satellite system. Changes-of-direction capacity has been found to be an important component of players testing and training programs, although there is no "gold standard" to assess COD or repeated sprint ability performance in female players. Lower-limb power can be assessed using jump tests that can use force platforms, jump mats, and optoelectronic devices, while maintaining a good reliability. Several in-direct tests are currently available for assessing anthropometry parameters, such as skinfold thickness, hydrodensitometry, and ultrasound. However, dual-energy x-ray absorptiometry is the most valid and reliable method for assessing body composition in team sport athletes, with the addition of bone health that is a key measure in female athletes. In conclusion, the evidence reported in this review will be able to aid practitioners, coaches, and researchers to decide which tests meet the requirements of their environment.

Measuring Interlimb Asymmetry for Strength and Power: A Brief Review of Assessment Methods, Data Analysis, Current Evidence, and Practical Recommendations.

ABSTRACT: Bishop, C, de Keijzer, KL, Turner, AN, and Beato, M. Measuring interlimb asymmetry for strength and power: A brief review of assessment methods, data analysis, current evidence, and practical recommendations. J Strength Cond Res 37(3): 745-750, 2023-The aim of this brief narrative review is to summarize the present evidence, provide recommendations for data analysis, and provide appropriate training methods to reduce strength and power asymmetries within athlete populations. Present evidence shows that a strong interest in the assessment of asymmetry exists. Despite the perceived associated relationship between asymmetry and injury and performance, a clear link is still missing. Practitioners need to be aware of this when they decide to assess asymmetries and later design training interventions. Several bilateral and unilateral tests could be used to assess asymmetries, such as isokinetic dynamometry, the isometric mid-thigh pull, squat, and Nordic hamstring exercise. Based on the current evidence, future investigations require further standardization of methodology and analysis to optimize interpretation (e.g., within session and between session), adoption, and implementation of interlimb asymmetry testing and appropriate interventions. In this review, 3 training interventions have been proposed to reduce existing lower limb asymmetries in sport populations: traditional resistance training, flywheel resistance training, and combined training interventions, with some evidence suggesting that such interventions can reduce lower limb asymmetries. Nonetheless, the number and quality of articles currently available are too limited to draw firm conclusions; therefore, further research is needed to verify whether training interventions can achieve these aims. To develop an understanding and application of interventions addressing interlimb asymmetries within the sport, greater methodological rigor should be applied toward study design, data analysis, and interpretation of future investigations and when appraising the current literature.

Eccentric overload differences between loads and training variables on flywheel training.

There is considerable debate about the existence of a real eccentric overload in flywheel exercises. This study aimed to analyse the differences in concentric: eccentric mechanical output ratios between different loads and variables in the flywheel squat exercise. Twenty physically active men (22.9 ± 2.2 years, height: 1.8 ± 0.1 m, weight: 79.6 ± 8.2 kg) performed a loading test using five moments of inertia. Angular speed was measured using a rotary encoder, while the vertical force was measured using force plates. For each variable (angular speed, angular acceleration, power, vertical force, and torque), mean and peak values were calculated for concentric and eccentric phases to allow comparisons across the loads. We tested the possible differences in Load × Phase (concentric and eccentric) and Load × Variable. The level of significance was established as p < 0.05. A significant Load × Phase interaction was found in mean angular speed, peak vertical force, peak angular acceleration, peak power and peak torque. Higher eccentric overload values were observed with speed-derived variables (angular speed, angular acceleration and power). In conclusion, speed-derived peak variables and lower loads are more likely to show an eccentric overload and can be used to monitor responses to flywheel training.

The effect of two sessions of combined jump and sprint training per week on fitness parameters in soccer players. A randomized controlled trial.

This study aimed to investigate the effect of a combined jump and sprint training program, two sessions a week for 6 weeks, on sprinting, change of directions (COD) and jumping performance in semi-professional soccer players. Twenty soccer players were enrolled in this randomized controlled trial (age 20 ± 2 years, body mass 74.3 ± 5.9 kg). Players were randomized into two groups such as training group (TG, n = 10 players) or control group (CG, n = 10 players). Physical tests were performed before and after 6 weeks of training such as sprint 10 m, sprint 30 m, 505-COD test and standing long jump (LJ). The two groups performed the same training except for the combined jump and sprint training performed twice a week by TG. After 6 weeks of training, between-group analysis reported statistical difference in favor of the TG in sprint 10 m (p = 0.015, η2 = 0.295, large), sprint 30 m (p < 0.001, η2 = 0.599, large), in 505-COD (p = 0.026, η2 = 0.154, large), and LJ (p = 0.025, η2 = 0.027, small). These data indicate that combined sprint and jump training, when performed twice a week, for the duration of 6 weeks, in addition to the regular team training, can improve specific physical performance in male soccer players. This study has shown that a volume increment of 10% after 3 weeks of training can be a suitable training dose progression and that a combination of 64-70 jumps and 675-738 m of sprinting training per session can yield benefits in sprint, COD and jump performance.

Arbitrary absolute vs. individualized running speed thresholds in team sports: A scoping review with evidence gap map.

The aims of this scoping review were (i) to characterize the main methodological approaches to assessing individualized running speed thresholds in team sports players; (ii) to assess the use of traditional arbitrary (absolute) thresholds compared to individualized running speed thresholds in team sports players; (iii) to provide an evidence gap map (EGM) about the approaches and study designs employed in investigations in team sports and (iv) to provide directions for future research and practical applications for the strength and conditioning field. Methods studies were searched for in the following databases: (i) PubMed; (ii) Scopus; (iii) SPORTDiscus and (iv) Web of Science. The search was conducted on 15/07/2022. Risk of bias was assessed using the Risk of Bias Assessment Tool for Nonrandomized Studies (RoBANS). From 3,195 potentially relevant articles, 36 were eligible for inclusion in this review. Of the 36 included articles, 27 (75%) focused on the use of arbitrary and individualized running speed thresholds to describe the locomotor demands (e.g., high intensity running) of players. Thirty-four articles used individualized speed running thresholds based on physical fitness assessments (e.g., 40-m linear sprint) or physical performance (e.g., maximal acceleration). This scoping review supported the need for a greater focus to be placed on improving the methodological aspects of using individualized speed running thresholds in team sports. More than just creating alternatives to arbitrary thresholds, it is essential to increase the replicability of methodological conditions whilst ensuring that research comparing the most adequate measures and approaches to individualization takes into consideration the population and context of each study.

Investigating the impact age has on within-over and death bowling performances in international level 50-over cricket.

The aims of this investigation were to determine if ageing effects were present in elite international level cricket. Ball-by-ball data were analysed for 96 bowlers in the 50-Over World Cup 2019. Bowlers were categorized into 1 of 3 age groups GROUP 1 (18-24), GROUP 2 (25-31) and GROUP 3 (32+). Ordinal Logistic Regressions (OLR) and Multinomial Logistic Regressions (MLR) were conducted to estimate the relationship between age and bowling performances. OLR Results revealed that younger bowlers were significantly more likely to concede a greater number of runs on the last ball of their overs than their older counterparts (p = 0.001). A separate MLR analysis was conducted for those bowlers entrusted to bowl during the "death" phase of an innings, and results revealed that GROUP 2 bowlers were significantly more likely to take wickets than either GROUP 1 (p = 0.021) or GROUP 3 (p = 0.022) bowlers. The evidence indicates that wicket taking "death bowlers" will likely perform at their peak between the ages of 25-31, which could inform the bowling strategy of team captains. Furthermore, there is evidence to suggest that younger bowlers are not as skilled as their older counterparts at restricting runs conceded.

The effects of training based on Nordic hamstring and sprint exercises on measures of physical fitness and hamstring injury prevention in U19 male soccer players.

This study analysed the effects of a training program based on Nordic hamstring and sprint exercises on physical performance and hamstring injuries in young male soccer players. Forty-nine U19 players were randomly assigned to a control (CG; n = 26) or experimental group (EG; n = 23). Linear sprint and with change of direction (COD) were assessed before and after a 14-week training period. Hamstring injuries were collected during the intervention period. Between-groups analysis revealed differences in linear sprint performance (p = 0.012-0.001) in favour of the EG. Pre-to-post performance increased significantly in the EG for 20 m (effect size [ES] = -0.56) and 30 m (ES = -0.62) sprints, but a significant reduction in some COD parameters was observed (ES = 0.45-0.57). In CG, only a significant reduction in COD with dominant leg was found (ES = 0.63). Significant differences in injury burden in favour of the EG was reported such as (27.87 [CG] vs. 3.82 [EG] absence days/1000 h of exposure, rate ratio = 7.30, 95% CI 3.34-15.99). While injury incidence was not different between the EG and CG. These findings suggest that the training program implemented can improve sprint performance and reduce injury burden.

Chronic effects of flywheel training on physical capacities in soccer players: a systematic review.

The aims of the current systematic review were to evaluate the current literature surrounding the chronic effect of flywheel training on the physical capacities of soccer players, and to identify areas for future research to establish guidelines for its use.Studies were identified following a search of electronic databases (PubMed and SPORTDiscus) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA).Eleven studies met the inclusion criteria and were included. The methodological quality of the included studies ranged between 10 and 18 with an average score of 15 points using the PEDro scale. The training duration ranged from 6 weeks to 27 weeks, with volume ranging from 1 to 6 sets and 6 to 10 repetitions, and frequency from 1 to 2 times a week. This systematic review reported that a diverse range of flywheel training interventions can effectively improve strength, power, jump, and changes of direction in male soccer players of varying levels.Flywheel training interventions improve the physical capacities of soccer players of varying levels. Nonetheless, the current literature suggests contrasting evidence regarding flywheel training induced changes in sprint speed and acceleration capacity of soccer players.