Coordination of soccer players during preseason training

The effect of a 10-week TOCA Football System intervention program on sport-specific motor skills among junior footballers

Introduction

The objective of our study was to examine, in addition to using the TOCA Football System tool and training method, the effect of a 10-week intervention on elite youth athletes in terms of their sport-specific motor skills and anthropometric variables.

Methods

The study covered a group of 32 young players practicing football (U14) (13.45 ± 0.64 years). The junior U14 footballers were randomly assigned to an intervention or TOCA group (TG, N = 15, 13.25 ± 0.58 years) and a control group (CG, N = 17, 13.63 ± 0.66 years). Before starting the test, we performed full anthropometric measurements and assessed the sample's agility with and without the ball and their sport-specific endurance. The measurements were then repeated after the 10-week intervention.

Results

Within-group analysis showed significant improvements in muscle mass (p < 0.001), sport-specific endurance (p < 0.001), (p < 0.004) and agility (in TG) both with and without the ball (p = 0.002), (p = 0.004) however, we did not find a significant change in body fat percentage in either group (p = 0.988, p = 0.288). In the CG, "agility with the ball" changed significantly only (p = 0.023). In the between-group analysis with a repeated-measures analysis of variance (mixed-design ANOVA), there was no significant interaction in any performance variables. The main findings of this study indicate that a TOCA Football training program in addition to normal training during the in-season period does not produce additional effects in anthropometric factors, sport-specific endurance and agility performance with the ball (dribbling) and without the ball in comparison with the control condition.

Discussion

From a practical point of view, the presented anthropometric and physical profiles of players can be useful for football coaches in optimizing soccer training. Overall, it also can be concluded that the device can be safely used in the sensitive age group in terms of the development of motor skills since we did not find any negative effects during the use of the device in terms of the parameters we examined. In addition to the expansion of the number of elements and the inclusion of other age groups, it is advisable to carry out further complex tests, as the TOCA Football System offers many research opportunities.

Effects of plyometric training on technical skill performance among athletes: A systematic review and meta-analysis

BACKGROUND

The literature has proven that plyometric training (PT) improves various physical performance outcomes in sports. Even though PT is one of the most often employed strength training methods, a thorough analysis of PT and how it affects technical skill performance in sports needs to be improved.

METHODS

This study aimed to compile and synthesize the existing studies on the effects of PT on healthy athletes' technical skill performance. A comprehensive search of SCOPUS, PubMed, Web of Science Core Collection, and SPORTDiscus databases was performed on 3rd May 2023. PICOS was employed to establish the inclusion criteria: 1) healthy athletes; 2) a PT program; 3) compared a plyometric intervention to an active control group; 4) tested at least one measure of athletes' technical skill performance; and 5) randomized control designs. The methodological quality of each individual study was evaluated using the PEDro scale. The random-effects model was used to compute the meta-analyses. Subgroup analyses were performed (participant age, gender, PT length, session duration, frequency, and number of sessions). Certainty or confidence in the body of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE).

RESULTS

Thirty-two moderate-high-quality studies involving 1078 athletes aged 10-40 years met the inclusion criteria. The PT intervention lasted for 4 to 16 weeks, with one to three exercise sessions per week. Small-to-moderate effect sizes were found for performance of throwing velocity (i.e., handball, baseball, water polo) (ES = 0.78; p < 0.001), kicking velocity and distance (i.e., soccer) (ES = 0.37-0.44; all p < 0.005), and speed dribbling (i.e., handball, basketball, soccer) (ES = 0.85; p = 0.014), while no significant effects on stride rate (i.e., running) were noted (ES = 0.32; p = 0.137). Sub-analyses of moderator factors included 16 data sets. Only training length significantly modulated PT effects on throwing velocity (> 7 weeks, ES = 1.05; ≤ 7 weeks, ES = 0.29; p = 0.011). The level of certainty of the evidence for the meta-analyzed outcomes ranged from low to moderate.

CONCLUSION

Our findings have shown that PT can be effective in enhancing technical skills measures in youth and adult athletes. Sub-group analyses suggest that PT longer (> 7 weeks) lengths appear to be more effective for improving throwing velocity. However, to fully determine the effectiveness of PT in improving sport-specific technical skill outcomes and ultimately enhancing competition performance, further high-quality research covering a wider range of sports is required.

The Influence of Experience on Neuromuscular Control of the Body When Cutting at Different Angles

Cutting is an offensive technique commonly used in football and basketball to pass the opponent's defence by changing direction quickly in running. This paper aims to investigate the effect of experience and angle on the neuromuscular control strategies of the trunk and lower limbs during cutting. Non-negative matrix factorisation and K-means were used to extract muscle synergies (muscles that are activated in parallel) of 12 subjects with cut experience and 9 subjects without experience based on the sEMG signal collected from cutting at three cut angles (45°, 90°, and 135°), which was also mapped into the spinal motor output. Uncontrolled manifold analysis was used to establish the relationship between muscle synergies and COP. This study found that experienced subjects tended to use the lower limb muscles rather than the postural muscles as stabiliser muscles compared to novices. Experienced subjects can recruit an additional set of muscle synergy to cope with large-angle cuts. In addition, experienced subjects can activate the second muscle synergy, involving the hip and ankle stabilisation muscles, in advance to improve postural stability when cutting in large-angle. Synergy index of experienced subjects dropped rapidly before the quick stop and was relatively high during the change of direction. These results suggest that experience can modify the postural stabilisation mechanisms during cutting, and prompt the lower limb muscle synergy to produce anticipatory adjustment to improve postural stability in the anterior-posterior and internal-external directions.

High frequencies (HF) repetitive transcranial magnetic stimulation (rTMS) increase motor coordination performances in volleyball players

INTRODUCTION

It is widely demonstrated that high frequency (HF) repetitive transcranial magnetic stimulation (rTMS) has facilitative effects and is therefore capable to inducing changes in motor responses. One of the most investigated areas is the dorsolateral prefrontal cortex (DLPFC) as it plays a special executive attention role in actively preserving access to stimulus representations and objectives in environments with plenty of distraction such as those of team sports. Volleyball is a team sport in which the attention and coordination components are essential for achieving performance. Thus, the aim of this study was to investigate if HF rTMS at DLPFC in volleyball players can improve homolateral motor coordination and cortical excitability.

RESULTS

This study was a double-blinded (participant and evaluator) matched-pair experimental design. Twenty right-handed female volleyball players were recruited for the study and were randomly assigned either the active rTMS (n = 10) or the sham stimulation group (n = 10). The stimulation was performed in one session with 10 Hz, 80% of the resting motor threshold (RMT) of the right first dorsal interosseous muscle, 5 s of stimulation, and 15 s of rest, for a total of 1500 pulses. Before and after stimulation, the coordination and the cortical excitability were evaluated. The significant finding of this paper was that HF-rTMS of the DLPFC improved performance in terms of the homolateral interlimb coordination, with a significantly decreased in resting motor threshold and MEP latency of the ipsilateral motor cortex. It seem that HF-rTMS could increase coordination performances when the velocity of the execution is higher (120 bpm and 180 bpm).

CONCLUSION

Moreover, in active rTMS group significant differences emerged after stimulation in RMT and in MEP latency, while no differences emerged after stimulation in MEP amplitude. In conclusion we believe that these results may be of great interest to the scientific community and may also have practical implications in the future.

Supercompensation in Elite Water Polo: Heart Rate Variability and Perceived Recovery

We examined the association of heart rate variability assessed with the logarithm of the root mean square of successive differences (LnRMSSD) and perceived recovery status of nine elite water polo players with the fluctuations of the internal training load (ITL). ITL, post-wakening LnRMSSD, and measures of perceived recovery were obtained across one regeneration week, during two mesocycles of intensified preseason training (PR1, PR2) and during two mesocycles of in-season training (IN1, IN2). ITL at PR1 and PR2 was increased by 60–70% compared to regeneration week (p<0.01) and was reduced by 30% at IN1 and IN2 compared to PR1 and PR2 (p<0.01). Weekly averaged LnRMSSD (LnRMSSD _mean ) was higher in IN2 compared to regeneration week and PR2 (p<0.01 and p<0.05, respectively). Perceived recovery was higher at IN1 and IN2 compared to PR2 (p=0.01 and p<0.001, respectively). ITL correlated with LnRMSSD in the preseason (r=–0.26, p=0.03). Nonetheless, similar association was not apparent during the in-season period (r=0.02, p=0.88). Cardiac autonomic perturbations may not occur when an increment of internal training load is less than 60–70%. However, the reduction of training load in season by 30% improves both LnRMSSD _mean and perceived recovery status, implying that training periodization may lead players in supercompensation.

Psychometric Properties of the RESTQ-Sport-36 in a Collegiate Student-Athlete Population

The purpose of the current study was to examine the reliability and validity of the RESTQ-Sport-36 for use in the collegiate student-athlete population. A total of 494 collegiate student-athletes competing in National Collegiate Athletic Association Division I, II, or III sanctioned sport completed the RESTQ-Sport-36 and Brief Profile of Mood States (POMS). Structural equation modeling (SEM) procedures were used to compare first order to hierarchical model structures. Results of a confirmatory factor analysis (χ²[528] = 1129.941, p < 0.001; SRMR = 0.050; CFI = 0.929) and exploratory structural equation modeling analysis (χ²[264] = 575.424, p < 0.001; SRMR = 0.013; CFI = 0.963) indicated that the first order 12-factor structure demonstrated the best fit of all models tested. Support was not observed for the fit of any hierarchical model. Moderate to strong correlations were observed between stress and recovery subscales and mood states, thus supporting the construct validity of the abbreviated RESTQ measurement model. The current findings provide support for the measure's use in this population and give pause as it relates to the scoring and interpretation of hierarchical factors such as Total Stress and Total Recovery. Overall, the current results indicate that the RESTQ-Sport-36 may be a useful tool for collegiate student-athlete training load and competition monitoring.

Effects of Training with an Agility Ladder on Sprint, Agility, and Dribbling Performance in Youth Soccer Players

The aim of this study was to examine the effects of coordination training using an agility ladder compared with a control group on physical fitness and technical performance in youth soccer players. Eighteen male youth soccer players (age: 12.2 ± 0.4 years; body height: 158.3 ± 10.8 cm; body mass: 45.0 ± 8.0 kg) were randomly assigned to an agility ladder group (n = 10) or a control group (n = 8). The intervention program was carried out three times a week over six weeks. Before and after the training period, the 10 m sprint, 20 m sprint, dribbling speed test, agility test, and slalom dribbling test performances were assessed. Within-group analysis showed significant improvements (p < 0.005) in 10 m and 20 m sprint performance from the pre- to the post-test for the agility ladder group (-2.39% and -2.10%) and the control group (-2.54% and -1.44%). No significant differences (p > 0.005) were found from the pre- to the post-test in the dribbling speed test, agility test, slalom dribbling test, and skill index. In the between-group analysis, there were no differences between the agility ladder group and the control group in any variable. In conclusion, the findings of this study suggest coordination training with an agility ladder does not seem to be effective to improve physical fitness and dribbling. Therefore, this information could be beneficial to players and coaches for programming tasks during soccer training sessions.

Test-Retest Reliability of Skill Tests in the F-MARC Battery for Youth Soccer Players

This study aimed to evaluate the test-retest reliability of soccer skill tests belonging to the F-MARC test battery. To avoid bias during talent identification and development, coaches and scouts should be using reliable tests for assessing soccer-specific skills in young male players. Fifty-two U-14 outfield male soccer players performed F-MARC soccer skill tests on two occasions, separated by 7 days. After familiarization, we administered two trial sessions of five skill tests: speed dribbling, juggling, shooting, passing, and heading. We assessed absolute reliability by expressing the standard error of measurement as a coefficient of variation with 95% limits of agreement, and we assessed relative reliability with the intraclass correlation coefficient and with Pearson's correlation (r). The results demonstrated satisfactory relative and absolute reliability for speed dribbling, right foot juggling, short passing, shooting a dead ball right, shooting from a pass, heading in front, and heading right. However, reliability values for left foot juggling, chest-head-foot juggling, head-left-foot-right foot-chest-head juggling, long pass, and shooting a dead ball left tests were not strong enough to suggest their usage by coaches in training or sport scientists in research.

Effects of a 12-Month Complex Proprioceptive-Coordinative Training Program on Soccer Performance in Prepubertal Boys Aged 10-11 Years

Boraczyński, MT, Sozański, HA, and Boraczyński, TW. Effects of a 12-month complex proprioceptive-coordinative training program on soccer performance in prepubertal boys aged 10-11 years. J Strength Cond Res 33(5): 1380-1393, 2019-The aim was to examine the effects of a series of on-field proprioceptive-coordinative (P-C) exercises on motor performance (MP) in prepubertal soccer players. Fifty-three male soccer players aged 10.1-11.8 years were randomized among 2 experimental programs receiving P-C training (P-CT; n = 26) or regular training (RT; n = 27). A control group (C; n = 22) consisted of age-matched (10.3-11.9 years) cohorts not involved in any regular physical activity. Both experimental groups completed an identical 12-month comprehensive soccer program except training in P-CT was modified to substitute small-sided conditioning games with 24 multimode P-C exercises with modulated exercise intensity (every 8-9 weeks based on predicted maximal heart rate [HRmax]). Pre-, peri-, and posttraining measures included anthropometry and 5 tests assessing soccer-specific MP: movement rhythm (turning the ball backwards-T1), motor adaptation (running with the ball around poles-T2), spatial orientation (running to sequentially numbered balls-T3), balance (single-leg static balance-T4), and kinesthetic differentiation of movement (landing the ball on a 2 × 2 m sector-T5). Repeated-measures analysis of variance revealed no significance between-group differences for age, anthropometry, and body-fat percentage at baseline. Significant main effects for group (P-CT vs. RT) were found in all tests (T1-T5) and main effects for time (group P-CT) in T3-T5, whereas a significant group × time interaction was observed only in T4 (F = 2.98, p = 0.0204). Post hoc tests indicated that P-CT attained significantly better results than RT at peritraining (by 26.4%; p < 0.01) and posttraining (by 31.9%, p < 0.01). Modulated exercise intensity had little effect on soccer performance (T1-T3, T5). Based on the results, it is recommended that the training of young soccer players be supplemented with the bilateral balance exercises and games used in the study. Furthermore, the suitability of monitoring HR in P-C exercises targeting the analyzed MP skills is questionable.

Positional synchronization affects physical and physiological responses to preseason in professional football (soccer)

This study aimed to identify changes in tactical, physical and physiological performances in large-sided games during the preseason of elite footballers. Thirty professional football players participated in several GK+8vs.8+GK large-sided games across the first four weeks of the season. Players were monitored by GPS units and heart rate monitors to quantify physical, physiological and tactical performances. The variables were compared according to the preseason period, players' positioning and professional experience. The training situation promoted similar physiological responses during the first and the last training period. However, players were revealed to have higher levels of positional synchronization during the last preseason period, indicating an improved tactical performance. Tactical variables seem to reflect the improvement of players' performance during the preseason, measured in large-sided games situation, while affecting both physical and physiological demands. These results highlight the potential of positioning derived variables, concurrently to physical and physiological variables, for football training optimization.

Repeated Dribbling Ability in Young Soccer Players: Reproducibility and Variation by the Competitive Level

The intermittent nature of match performance in youth soccer supports relevance of ability to repeatedly produce high-intensity actions with short recovery periods. This study was aimed to examine the reproducibility of a repeated dribbling ability protocol and, additionally, to estimate the contribution of concurrent tests to explain inter-individual variability in repeated dribbling output. The total sample comprised 98 players who were assessed as two independent samples: 31 players were assessed twice to examine reliability of the protocol; and 67 juveniles aged 16.1 ± 0.6 years were compared by the competitive level (local, n = 34; national, n = 33) to examine construct validity. All single measurements appeared to be reasonably reliable: total (ICC = 0.924; 95%CI: 0.841 to 0.963); ideal (ICC = 0.913; 95%CI: 0.820 to 0.958); worst (ICC = 0.813; 95%CI: 0.611 to 0.910). In addition, the percentage of the coefficient of variation was below the critical value of 5% for total (%CV = 3.84; TEM = 2.51 s); ideal (%CV = 3.90, TEM = 2.48 s). Comparisons between local and national players suggested magnitude effects as follows: moderate (d-value ranged from 0.63 to 0.89) for all repeated sprint ability scores; large for total (d = 1.87), ideal (d = 1.72), worst (d = 1.28) and moderate for composite scores: the fatigue index (d = 0.69) and the decrement score (d = 0.67). In summary, the dribbling protocol presented reasonable reproducibility properties and output extracted from the protocol seemed to be independent from biological maturation.

Functional Assessment of Corticospinal System Excitability in Karate Athletes

Objectives

To investigate the involvement of the primary motor cortex (M1) in the coordination performance of karate athletes through transcranial magnetic stimulation (TMS).

Methods

Thirteen right-handed male karate athletes (25.0±5.0 years) and 13 matched non-athlete controls (26.7±6.2 years) were enrolled. A single-pulse TMS was applied using a figure-eight coil stimulator. Resting motor threshold (rMT) was determined. Surface electromyography was recorded from the first dorsal interosseous muscle. Motor evoked potential (MEP) latencies and amplitudes at rMT, 110%, and 120% of rMT were considered. Functional assessment of the coordination performance was assessed by in-phase (IP) and anti-phase (AP) homolateral hand and foot coordination tasks performed at 80, 120, and 180 bpm.

Results

Compared to controls, athletes showed lower rMT (p<0.01), shorter MEP latency (p<0.01) and higher MEP amplitude (p<0.01), with a significant correlation (r = 0.50, p<0.01) between rMT and MEP latency. Coordination decreased with increasing velocity, and better IP performances emerged compared to AP ones (p<0.001). In general, a high correlation between rMT and coordination tasks was found for both IP and AP conditions.

Conclusion

With respect to controls, karate athletes present a higher corticospinal excitability indicating the presence of an activity-dependent alteration in the balance and interactions between inhibitory and facilitatory circuits determining the final output from the M1. Furthermore, the high correlation between corticospinal excitability and coordination performance could support sport-specific neurophysiological arrangements.

Preseason Strategies of Italian First League Soccer Clubs in Relation to their Championship Ranking: A Five-Year Analysis

This study is focused on the strategies adopted by Italian ‘Serie A’ soccer clubs during the non-competitive period. Thus, duration (i.e., number of days) of the specific non-competitive periods (i.e., off- plus pre-season, off-season, pre-season, summer camp), the number of games (i.e., friendly, official and polled games) and days between games (i.e., ≤ 3, 4-5, or ≥ 6 days between two consecutive games) of the entire non-competitive period were recorded and compared by clubs participating in the European Championships (EU), only ‘Serie A’ (A) and promoted from ‘Serie B’ (B) during five and single seasons (i.e., 2009/10-2013/14). Due to the short B off-season duration (2009/10-2013/14, 2010/11, 2011/12, 2012/13, 2013/14, p≤.001), effects between clubs emerged also for the off- plus preseason (2009/10-2013/14, EU vs A, p≤.01, EU vs B, p≤.01, A vs B, p≤.001; 2011/12, 2012/13, 2013/14, p≤.001). Nevertheless, no difference between clubs resulted for the pre-season. Reduced duration of summer camps was reported by the EU (i.e., 2009/10-2013/14, 2009/10, 2013/14, p≤.001). A higher number of official games were played by EU than A (i.e., 2009/10-2013/14, p≤.001; 2010/11, p≤.01). No effect emerged for the days between games. Therefore, despite the longer ‘Serie B’ schedule and EU preliminary UEFA games that determined the off-season restriction, clubs demonstrated the tendency to guarantee satisfactory pre-season duration.

Short-term effects of complex training on agility with the ball, speed, efficiency of crossing and shooting in youth soccer players

Complex training (CXT) is the result of a combination of strength and plyometric exercises in the same session. This method has recently been used in the preparation of athletes of different sports. The aim of the present study was to observe the acute effects of a CXT program of 6 weeks: i) on agility with the ball, sprinting and the efficiency of crossing and shooting in youth soccer players; ii) and the influence of the number of CXT sessions per week (one vs. two). Sixteen youth male soccer players were randomly divided into three groups: a group that performed one weekly CXT session (GCT1, n = 5, age: 13.80 ± 0.45 years); or a group that performed two weekly CXT sessions (GCT2, n = 5, age: 14.20 ± 0.45 years); or a control group that did not perform the CTX (n = 6, age: 14.20 ± 0.84 years). All groups maintained their regular soccer training sessions. No significant interactions were found between GCT1 and GCT2 in all variables. Significant statistical differences were identified (F = 1139, p = 0.02, μ_p² = 0531) in the pre-test versus post-test, for both experimental groups, in shot effectiveness. In conclusion, the CXT program proved to be an effective method in boosting abilities and motor skills associated with soccer among young athletes, particularly in increasing shot effectiveness.

Changes in jump, sprint, and coordinative performances after a senior soccer match

This study aimed to verify the short-term after effects of a soccer match on senior players' all-out and interlimb coordination performances. Right before (prematch) and after (postmatch) a match, 10 senior (52.3 ± 10.2 years) male soccer players were administered jump (countermovement jump [CMJ]; repeated jump [RJ]), sprint (10 m and 10 m while dribbling the ball [10 mDB]), in-phase (IP) and antiphase (AP) interlimb coordination (synchronized hand and foot flexions and extensions at 80, 120, 180 bpm). Heart rate (HR) responses and subjective rating of perceived exertion (RPE) and rating of muscle pain (RMP) were used to evaluate the intensity of the friendly match. During the match, HR >85% of individual HRmax occurred for 50% of playing time. Subjective ratings at the end of the match were 12.9 ± 2.2 pt and 2.7 ± 2.2 pt for RPE and RMP, respectively. Postmatch CMJ, 10 m, 10 mDB, AP, IP 80 bpm, and IP 120 bpm performances did not show any difference with respect to prematch values, whereas improvements (p < 0.05) in RJ (prematch: 17.4 ± 3.9 cm; postmatch: 19.3 ± 4.8 cm) and IP 180 bpm (prematch: 30.4 ± 15.1 second; postmatch: 50.3 ± 18.9 second) emerged. These findings indicate that senior soccer players are able to cope with the high demands of match play and suggest that an acute bout of intense exercise has an arousing effect that counteracts fatigue effects and facilitates the performance of old trained individuals on complex motor behaviors relying on central executive control. In considering that players consider soccer as highly motivating, with advancing years this sport could help players in preserving high mental and physical functions and maintaining active engagement in life through social interactions.