Latest research in football - week 50 - 2023

#1 Cognition in soccer and futsal: evidence of validity of a 4-instrument protocol to assess executive functioning among women athletes

Reference: BMC Psychol. 2023 Dec 9;11(1):436. doi: 10.1186/s40359-023-01464-0.

Authors: Alberto Filgueiras, Matthew Stults-Kolehmainen, Gislane Melo, Richard Keegan 

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10709850/pdf/40359_2023_Article_1464.pdf

Summary: Evidence suggests that success in sports, especially soccer and futsal are linked to higher levels of executive functioning. Still, the literature does not present a homogeneous set of instruments to measure executive functions, which leads to large variability in results. In this paper, we assembled four already recognised measures to propose a valid 4-instrument protocol to assess executive functions among soccer and futsal athletes. We conducted two studies to validate the proposed protocol. We addressed known-groups validity and latent structure in Study 1 for data collected on 105 female soccer and futsal athletes from elite and lower-division clubs. Findings pointed to partial validity of the protocol - with working memory and inhibition showing the best results. For Study 2, we used performance data from 51 elite female soccer players collected throughout a season of the first division league to assess predictive validity. Our protocol was able to partially replicate previous findings and added new insights on how working memory, processing speed and higher-level executive functions might play different roles for goalscoring and assist-making skills. Specifically, study 1 did not find a significant difference between elite and lower-division athletes in higher-order executive functions as in previous studies, but it did find on visual working memory and inhibitory control which weights towards higher demands of core executive functions. On the other hand, study 2 yielded significant results for processing speed and visual working memory to predict assists among elite soccer players, but not inhibitory control as previous findings suggested. Regardless, the proposed 4-instrument protocol showed adequate criterion and structural validity in both studies.

 

 

#2 Soccer Ball-like Assembly of Edge-to-edge Oriented 2D-silica Nanosheets: A Promising Catalyst Support for High-Temperature Reforming

Reference: Angew Chem Int Ed Engl. 2023 Dec 8:e202316630. doi: 10.1002/anie.202316630.

Authors: Sun Woo Jang, Nitee Kumari, Eonu Nam, Yun Kyung Lee, Yunmi Cha, Kwangjin An, In Su Lee

Summary: Controlled assembly of nanoparticles into well-defined assembled architectures through precise manipulation of spatial arrangement and interactions allows the development of advanced mesoscale materials with tailored structures, hierarchical functionalities, and enhanced properties. Despite remarkable advancements, the controlled assembly of highly anisotropic 2Dnanosheets is significantly challenging, primarily due to the limited availability of selective edge-to-edge connectivity compared to the abundant large faces. Innovative strategies are needed to unlock the full potential of 2D-nanomaterialsin self-assembled structures with distinct and desirable properties. This research unveils the discovery of controlled self-assembly of 2D-silica nanosheets (2D-SiNSs) into hollow micron-sized soccer ball-like shells (SA-SiMS). The assembly is driven by the physical flexibility of the 2D-SiNSs and the differential electricdouble-layer charge gradient creating electrostatic bias on the edge and face regions. The resulting SA-SiMS structures exhibit high mechanical stability, even at high-temperatures, and exhibit excellent performance as catalyst support in the dry reforming of methane. The SA-SiMS structures facilitate improved mass transport, leading to enhanced reaction rates, while the thin silica shell prevents sintering of small catalyst nanocrystals, thereby preventing coke formation. This discovery sheds light on the controllable self-assembly of 2D nanomaterials and provides insights into the design and synthesis of advanced mesoscale materials with tailored properties.

 

 

#3 Different effects of four rest periods after the last weekly training session on young male professional soccer players' physical performance

Reference: PLoS One. 2023 Dec 7;18(12):e0294867. doi: 10.1371/journal.pone.0294867. eCollection 2023.

Authors: Mehdi Ben Brahim, Alejandro Sal-de-Rellán, Hussain Yasin, Ariadna Hernaiz-Sánchez

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10703244/pdf/pone.0294867.pdf

Summary: The main aim of this study was to analyze the optimal pre-competitive recovery period for young male professional soccer players to be in the best conditions to achieve a higher physical performance. Seventeen young male professional soccer players (age: 20.7 ± 1.0 years) who participated in the Tunisian soccer league participated in this study. Players underwent a fitness test battery after four different recovery periods: 12, 24, 36, and 48h following their last training session. The battery fitness test included a linear sprint test (i.e., 5 and 20m distances), squat jumps (SJ), countermovement jumps (CMJ), ball shooting test, a Yo-yo endurance intermittent test (YYIRT-1) and a 15-m ball dribbling agility test (Ag). The main findings indicated that the 12h recovery period resulted in better performance in the 5m sprint test compared to 36h, as well as in the SJs and CMJs as compared to the 48h recovery period. Additionally, the 24h recovery period showed significantly better results in the 20-m sprint test compared to all other recovery periods, as well as in the SJ and Ag tests compared to the 48h recovery period. In practical terms, these findings suggest that coaches should consider scheduling the last training session for soccer players 12-24h before the match to enhance their physical performance, particularly in linear sprinting, vertical jumps, and agility variables. However, in situations where it is not possible to adjust the timing of the last training session, an alternative approach is to incorporate "priming-day" exercises on the match day, around 6-8h prior to the competition.

 

 

#4 Discriminative validity of summarized hip and knee angular accelerations for lower extremity training load quantification in male soccer players during a standardised training drill

Reference: Sci Med Footb. 2023 Dec 7:1-9. doi: 10.1080/24733938.2023.2290083. Online ahead of print.

Authors: Bram J C Bastiaansen, Riemer J K Vegter, Erik Wilmes, Edwin Goedhart, Koen A P M Lemmink, Michel S Brink

Summary: This study assessed the discriminative validity of summarized hip and knee angular accelerations during a standardized training drill. Twenty-eight soccer players performed a standardized training drill that mimics game demands. Discriminative validity was examined by assessment of between-group differences of summarized preferred kicking leg hip and knee angular accelerations, and Playerload between national and regional soccer players for the full training drill, and parts based on locomotor intensity, or additional pass and jumping header activities. Furthermore, relationships were assessed between the summarized hip and knee angular accelerations and conventional load indicators derived from a local positioning measurement system, such as high-intensity running distance and Playerload. National players had higher summarized hip (Mean difference: 62.7 A.U. ES = 0.77, p = 0.049) and knee (Mean difference: 137.1 A.U. ES = 1.06, p = 0.008) angular accelerations. Significant interaction effects were observed during high-intensity running (Hip: 0.2 A.U./m, ES = 0.98, p = 0.005; Knee: 0.61 A.U./m, ES = 1.52, p < 0.001), and sprinting (Hip: 0.3 A.U./m, ES = 1.01, p < 0.02; Knee: 0.56 A.U./m, ES = 1.57, p < 0.001). Between-group differences were not present for additional passing or jumping header activities. Compared to summarized hip and knee angular accelerations, Playerload had less ability to discriminate between players and activities. Moreover, the lower extremity training load indicators were unrelated to conventional load indicators. Together these results confirm discriminative validity of summarized hip and knee angular acceleration training load indicators during a standardised training drill.

 

 

#5 Evidence for a new model of the complex interrelationship of ball possession, physical intensity and performance in elite soccer

Reference: Scand J Med Sci Sports. 2023 Dec 7. doi: 10.1111/sms.14546. Online ahead of print.

Authors: Benjamin W C Jerome, Michael Stoeckl, Ben Mackriell, Christian W Dawson, Daniel T P Fong, Jonathan P Folland

Download link: https://onlinelibrary.wiley.com/doi/epdf/10.1111/sms.14546

Summary: How the physical metrics, especially physical intensity, and possession interact with each other, and subsequently combine to influence performance remains opaque. Therefore, we investigated the interrelationship of possession, physical metrics, and team performance in elite soccer. Four seasons of a top European league were used to derive 80 team league performances (points), together with possession and physical data. Physical metrics were absolute distances (m) during the whole match and ball-in-play, and rates of distance covered (m⋅min-1 ) as the index of physical intensity, notably when in-possession/out-of-possession, in total and within five speed categories. Interrelationships of possession, physical metrics, possession, and performance were assessed with Pearson's correlations and mediation analysis. Overall possession (r = 0.794) and time out-of-possession within the defensive third (r = -0.797) were most strongly correlated with performance. The strong relationships between in-possession distances and performance appeared coincidental due to greater time in-possession. Physical intensity had a complex relationship with possession and performance, with opposite relationships according to possession status: lower physical intensity when in-possession and higher physical intensity when out-of-possession were associated with possession and performance. Mediation analysis revealed the direct, independent importance of possession for team performance; however, the association of physical intensity with performance was largely (>79%) mediated by possession. Based on these findings, we propose a novel model of the interrelationships between possession, physical intensity, and performance, whereby higher possession is the largest, direct contributor toward enhanced team performance, with lower physical intensity in-possession a consequence of higher possession, but greater physical intensity when out-of-possession a cause of increased possession.

 

 

#6 Is there a relationship between static postural control and core stability? A cross-sectional study in soccer players with groin pain

Reference: J Orthop. 2023 Nov 17:48:1-5. doi: 10.1016/j.jor.2023.11.036. eCollection 2024 Feb.

Authors: Fatma Chaari, Abderrahmane Rahmani, Haithem Rebai, Thouraya Fendri, Sébastien Boyas, Sonia Sahli

Summary: Static postural control disorders have been documented in soccer players suffering from groin pain (GP). Understanding the mechanisms of these disorders is crucial in designing rehabilitation programs. The aim was to (i) assess static postural control and core stability in soccer players suffering from GP compared to their peers and (ii) explore the relationship between these two parameters. This cross-sectional study involved 42 male soccer players suffering from GP (GP group: GPG) and 42 healthy players (control group: CG). Static postural control (stabilometric platform) and core stability (core endurance tests) were assessed. Center of pressure velocity in the GPG was significantly higher compared to the CG during bipedal stance on the firm surface with eyes closed (2.66 [95 % CI: 0.86-3.67]; p < 0.01) and on the foam one (p < 0.001) in both conditions; eyes opened (2.88 [95 % CI: 1.42-4.43]) and closed (5.88 [95 % CI: 2.66-9.10]), and on the IL in eyes closed (12.54 [95 % CI: 4.27-20.80]; p < 0.01). Besides, GPG revealed significant (p < 0.001) lower core stability measures compared to CG. No significant associations (p > 0.05) were observed between static postural control and core stability in GPG. Soccer players suffering from GP showed static disorders of postural control compared with their peers. These impairments were not associated with measures of core stability. These findings provide insight into the direction of future research exploring the mechanisms underlying deficits in static postural control in soccer players suffering from GP.

 

 

#7 Cause-Effect: The Relationship between Role and Experience with Psychological and Physical Responses in the Competition Context in Soccer Referees

Reference: J Hum Kinet. 2023 Jul 25:89:289-300. doi: 10.5114/jhk/169174. eCollection 2023 Oct.

Authors: Alfonso Castillo-Rodríguez, Jesús Lorenzo Rodríguez Caparrós, Antonio Figueiredo, Francisco Tomás González-Fernández, Wanesa Onetti-Onetti

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10694706/pdf/JHK-89-169174.pdf

Summary: This study analyzed the effects of psychological responses (impulsivity, self-esteem, self-confidence, and anxiety) in baseline and pre-competitive contexts of national soccer referees (SRs), their control of the game (yellow and red cards), and physical performance (PP) according to the role (assistant or main referee), and experience in the category. Twenty-seven national SRs from Spain participated in this study. Baseline and pre-competitive psychological data were collected through the Competitive State Anxiety Inventory-2 (CSAI-2 test), Urgency, Premeditation (lack of), Perseverance (lack of), Sensation Seeking, Positive Urgency, Impulsive Behavior Scale (UPPS-P test), and Rosenberg tests. Furthermore, WIMU PRO™ inertial devices were used to monitor PP. The results indicated that a lack of perseverance and self-esteem were higher in the main SRs and somatic anxiety in assistant SRs. Experience of SRs was related to anxiety, self-confidence, self-esteem, impulsivity dimensions, and PP metrics (p < 0.05). Finally, red cards were related to positive and negative urgency (r = 0.38 and r = 0.35, p < 0.05, respectively). In conclusion, the main SRs and SRs with more experience had better psychological characteristics and PP in a competitive context. However, yellow and red cards were not associated with these factors, although red cards were related with urgency. Based on these data, specific training programs could be incorporated to enhance emotional control in SRs with less experience to achieve greater performance and professional development.

 

 

#8 Differences in Situational Patterns During Change of Direction Movements Greater than 90° in Youth Male and Female Soccer Players

Reference: J Hum Kinet. 2023 Sep 5:89:149-160. doi: 10.5114/jhk/169524. eCollection 2023 Oct.

Authors: Aki-Matti Alanen, Eric S Gibson, Meghan Critchley, Lauren C Benson, Matthew J Jordan, Reed Ferber, Kati Pasanen

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10694721/pdf/JHK-89-169524.pdf

Summary: Change of direction (COD) maneuvers in soccer create tactical advantages, but also expose the player to an increased risk of injury. COD ability is commonly tested with pre-planned drills including cuts greater than 90°. These tests do not take into consideration positional differences players encounter during games. This case-series study used principal component analysis (PCA) to examine situational differences during COD movements between playing positions in youth soccer games. For each of the four teams included (26 females, 27 males), one game was analyzed using video-analysis. Two independent reviewers identified situational patterns and a PCA was used to examine differences between playing positions. Three principal components explained 89% of the variation in the data and were categorized as the total quantity of CODs, attacking/goal-scoring and defensive reacting types of CODs. One-way ANOVA on the individual principal component (PC) scores showed significant differences (p < 0.05) between centre midfielders, goalkeepers, and centrebacks in the quantity of CODs (PC1), and between wingers and fullbacks and centre backs in attacking/goal-scoring CODs (PC2), whereas PC3 was not different between playing positions. Differences between playing positions suggest that training and testing protocols in soccer could be enhanced to better match the individual and playing position-based needs.

 

 

#9 Physical predictors for retention and dismissal of professional soccer head coaches: an analysis of locomotor variables using logistic regression pipeline

Reference: Front Sports Act Living. 2023 Nov 20:5:1301845. doi: 10.3389/fspor.2023.1301845. eCollection 2023.

Authors: Honorato Sousa, Rabiu Muazu Musa, Filipe Manuel Clemente, Hugo Sarmento, Élvio R Gouveia

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10694450/pdf/fspor-05-1301845.pdf

Summary: Soccer has enormous global popularity, increasing pressure on clubs to optimize performance. In failure, the tendency is to replace the Head coach (HC). This study aimed to check the physical effects of mid-season replacements of HCs, investigating which external load variables can predict retention or dismissal. The data was collected in training and matches of a professional adult male soccer team during three complete seasons (2020/21-2022/2023). The sample included 6 different HCs (48.8 ± 7.4 years of age; 11.2 ± 3.9 years as a HC). The 4 weeks and 4 games before and after the replacement of HCs were analysed. External load variables were collected with Global Positioning System (GPS) devices. A logistic regression (LR) model was developed to classify the HCs' retention or dismissal. A sensitivity analysis was also conducted to determine the specific locomotive variables that could predict the likelihood of HC retention or dismissal. In competition, locomotor performance was better under the dismissed HCs, whereas the new HC had better values during training. The LR model demonstrated a good prediction accuracy of 80% with a recall and precision of 85% and 78%, respectively, amongst other model performance indicators. Meters per minute in games was the only significant variable that could serve as a potential physical marker to signal performance decline and predict the potential dismissal of an HC with an odd ratio of 32.4%. An in-depth analysis and further studies are needed to understand other factors' effects on HC replacement or retention.

 

 

#10 Training Load and Current Soreness Predict Future Delayed Onset Muscle Soreness in Collegiate Female Soccer Athletes

Reference: Int J Sports Phys Ther. 2023 Dec 1;18(6):1271-1282. doi: 10.26603/001c.89890. eCollection 2023.

Authors: Brett S Pexa, Christopher J Johnston, Jeffrey B Taylor, Kevin R Ford

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10693489/pdf/ijspt_2023_18_6_89890.pdf

Summary: Delayed onset muscles soreness (DOMS) is an indication of muscle stress and trauma that develops from excessive musculoskeletal loads. Musculoskeletal loads can be measured with wearable devices, but there is limited research on specific training load metrics that most correlate with DOMS after activity. The aim was to determine the predictive capabilities of training load variables on the development of lower extremity DOMS in female collegiate soccer athletes throughout an entire season. Twenty-seven collegiate female soccer athletes reported their lower extremity DOMS each day prior to all soccer activity. Participants wore Polar heart rate and global positioning monitors to capture training load measures. Pearson correlation coefficients were used to assess the relationships between the training load variables and change in DOMS when collapsed across dates. Separate linear mixed models were performed with the following day's DOMS as the outcome variable, training load and the current day's DOMS as predictor variables, and participants serving as random intercepts. All training load variables significantly predicted change in DOMS, with number of decelerations (ρ=0.72, p <0.001), minutes spent at greater than 80% of maximum heart rate (HRmax) (ρ=0.71 , p <0.001), and distance (ρ=0.70 , p <0.001) best correlating with change in DOMS. Linear mixed models revealed a significant interaction of all training load and current day's DOMS on the following day's DOMS (p<0.001), but number of decelerations, HRmax, and total number of accelerations demonstrated the highest coefficient of determination (R2 marginal=33.2% - 29.2% , R2 conditional= 46.9% - 44.8%). Training load variables paired with the current day's DOMS significantly predict lower extremity DOMS in the future, with number of decelerations, accelerations, and HRmax best predicting future DOMS. Although this demonstrates that training load variables predict lower extremity DOMS, future research should incorporate objective measures of strength or jump kinetics to identify if similar relationships exist.

 

 

#11 Examining the relationship between sleep quality and depressive symptoms in Korean women engaged in soccer during the coronavirus pandemic

Reference: Front Public Health. 2023 Nov 17:11:1282887. doi: 10.3389/fpubh.2023.1282887. eCollection 2023.

Authors: Young-Jae Kim, Da-Som Lee, E-Sack Kim

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10691262/pdf/fpubh-11-1282887.pdf

Summary: The COVID-19 pandemic has caused sudden changes to daily lives, such as self-isolation and social distancing, and has negatively affected sleep quality and patterns. The resulting psychological discomfort has caused many Korean women to experience depressive moods. Vigorous physical activity is considered effective in improving sleep quality and alleviating depressive symptoms. As a form of vigorous physical activity, soccer could be used to improve women's mental health. This study aimed to ascertain the effects of playing soccer on sleep quality and depressive symptoms in women. Non-face-to-face questionnaires were administered using Pittsburgh Sleep Quality Index to measure sleep quality and Patient Health Questionnaire-9 to measure depressive symptoms, targeting 200 of 297 soccer-playing Korean women aged 20-50 years, from October 13, 2022, to January 15, 2023. A total of 172 questionnaires administered to soccer participants were used, while 28 with insincere and double or no-responses were excluded. Additionally, 124 samples of non-exercise participants were collected, with the help of "EMBRAIN," a Korean research and survey company. This study analyzed differences in sleep quality and depressive symptoms, and correlations and multiple regression analysis were performed. The soccer group was shown to have a high quality of sleep. In relation to the effect of sleep quality on depressive symptoms, subjective sleep quality, sleep latency, sleep disturbance, use of sleeping pills, and daytime functional disorder had a significant effect. In the relation to the effect of sleep quality on depressive symptoms, significant effect was found in subjective sleep quality, sleep latency, sleep disturbance, and daytime functional disorder of soccer participants, and non-exercise participants displayed significant effect in subjective sleep quality, sleep disturbance, and the use of sleeping pills. This study examined the effect of soccer participation on sleep quality and depressive symptoms among women. Soccer, which requires high activity and teamwork levels, improves sociability in women by enhancing their sense of belonging, self-confidence, and team spirit.

 

 

#12 The Success Factors of Rest Defense in Soccer - A Mixed-Methods Approach of Expert Interviews, Tracking Data, and Machine Learning

Reference: J Sports Sci Med. 2023 Dec 1;22(4):707-725. doi: 10.52082/jssm.2023.707. eCollection 2023 Dec.

Authors: Leander Forcher, Leon Forcher, Stefan Altmann, Darko Jekauc, Matthias Kempe

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10690503/pdf/jssm-22-707.pdf

Summary: While the tactical behavior of soccer players differs between specific phases of play (offense, defense, offensive transition, defensive transition), little is known about successful behavior of players during defensive transition (switching behavior from offense to defense). Therefore, this study aims to analyze the group tactic of rest defense (despite in ball possession, certain players safeguard quick counterattacks in case of ball loss) in defensive transition. A mixed-methods approach was used, involving both qualitative and quantitative analysis. Semi-structured expert interviews with seven professional soccer coaches were conducted to define rest defense. In the quantitative analysis, several KPIs were calculated, based on tracking and event data of 153 games of the 2020/21 German Bundesliga season, to predict the success of rest defense situations in a machine learning approach. The qualitative interviews indicated that rest defense can be defined as the positioning of the deepest defenders during ball possession to prevent an opposing counterattack after a ball loss. For instance, the rest defending players created a numerical superiority of 1.69 ± 1.00 and allowed a space control of the attacking team of 11.51 ± 9.82 [%] in the area of rest defense. The final machine learning model showed satisfactory prediction performance of the success of rest defense (Accuracy: 0.97, Precision: 0.73, f1-Score: 0.64, AUC: 0.60). Analysis of the individual KPIs revealed insights into successful behavior of players in rest defense, including controlling deep spaces and dangerous counterattackers. The study concludes regaining possession as fast as possible after a ball loss is the most important success factor in defensive transition.

 

 

#13 Adequate Interval between Matches in Elite Female Soccer Players

Reference: J Sports Sci Med. 2023 Dec 1;22(4):614-625. doi: 10.52082/jssm.2023.614. eCollection 2023 Dec.

Authors: Trevor C Chen, Tai-Ying Chou, Kazunori Nosaka

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10690515/pdf/jssm-22-614.pdf

Summary: The present study compared four different intervals between three simulated soccer matches for changes in muscle damage and performance parameters. Thirteen well-trained female university soccer players performed three bouts of 90-min Loughborough Intermittent Shuttle Test (LIST) with four different intervals between bouts; one (1d), two (2d), three (3d) and four days (4d), with >12-weeks between conditions in a counterbalanced order. Heart rate, blood lactate, rating of perceived exertion and distance covered in each LIST were measured. Changes in several muscle damage markers (e.g., maximal voluntary isometric torque of the knee extensors: MVC-KE, muscle soreness), performance parameters (e.g., Yo-Yo intermittent recovery test level 1: Yo-Yo IR1), and blood measures (e.g., osmolality, high sensitivity cardiac troponin T) before the first LIST, 1 h after each LIST, and one to five days after the third LIST were compared among the conditions. The total distance covered during the first two LISTs was not different among the conditions, but that during the third LIST was shorter (P < 0.05) for the 1d (9,416 ± 885 m) and 2d conditions (9,737 ± 246 m) than the 3d (10,052 ± 490 m) and 4d conditions (10,432 ± 538 m). Changes in all measures were smaller (P < 0.05) in the 3d and 4d conditions (e.g., the decrease in MVC-KE at one day after the third LIST was -13 ± 4% and -10 ± 3%, respectively) when compared with the 1d and 2d conditions (-20 ± 7%, -18 ± 5%). Performance parameters showed smaller (P < 0.05) changes in the 4d (e.g., the decrease in Yo-Yo IR1 at one day after the third LIST was -9 ± 3%) and 3d (-13 ± 6%) conditions when compared with the 1d (-19 ± 4%) and 2d (-20 ± 8%) conditions. These results suggest that muscle damage and fatigue accumulate when soccer matches are performed three consecutive days or every other day, but if more than three days are inserted between matches, this could be minimized.

 

 

#14 Adaptations to Optimized Interval Training in Soccer Players: A Comparative Analysis of Standardized Methods for Individualizing Interval Interventions

Reference: J Sports Sci Med. 2023 Dec 1;22(4):760-768. doi: 10.52082/jssm.2023.760. eCollection 2023 Dec.

Authors: Lu Dai, Bixia Xie

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10690519/pdf/jssm-22-760.pdf

Summary: Accurately prescribing supramaximal interval training facilitates targeting desired physiological adaptations. This study compared the homogeneity of adaptations in cardiorespiratory parameters to supramaximal [i.e., intensities beyond maximal aerobic speed (MAS)] interval interventions prescribed using anaerobic speed reserve (ASR), the speed attained at the end of 30-15 Intermittent Fitness Test (VIFT), and MAS. Using repeated-measures factorial design, and during the off-season phase of the athletes' yearly training cycle, thirty national-level soccer players (age = 19 ± 1.6 years; body mass = 78.9 ± 1.6 kg; height = 179 ± 4.7 cm; Body fat = 11 ± 0.9%) were randomized to interventions consisting of 2 sets of 6, 7, 8, 7, 8, and 9-min intervals (from 1st to 6th week), including 15 s running at Δ%20ASR (MAS + 0.2 × ASR), 120%MAS, or 95%VIFT followed by 15 s passive recovery. All ASR, VIFT, and MAS programs sufficiently stimulated adaptive mechanisms, improving relative maximal oxygen uptake [V̇O2max (p < 0.05; ES = 1.6, 1.2, and 1.1, respectively)], absolute V̇O2max (p < 0.05; ES = 1.5, 1.1, and 0.7), ventilation [V̇E (p < 0.05; ES = 1.6, 1.1, and 1.1)], O2 pulse [V̇O2/HR (p < 0.05; ES = 1.4, 1.1, and 0.6)], first and second ventilatory threshold [VT1 (p < 0.05; ES = 0.7, 0.8, and 0.7) and VT2 (p < 0.05; ES = 1.1, 1.1, and 0.8)], cardiac output [Q̇max (p = 1.5, 1.0, and 0.7)], and stroke volume [SVmax (p < 0.05; ES = 0.9, 0.7, and 0.5)]. Although there was no between-group difference for the change in the abovementioned variables over time, supramaximal interval training prescribed using ASR and VIFT resulted in a lower coefficient of variation [CV (inter-individual variability)] in physiological adaptations compared to exercise intensity determined as a proportion of MAS. Expressing the intensity of supramaximal interval programs according to the athlete's ASR and VIFT would assist in accurately prescribing interventions and facilitate imposing mechanical and related physiological stimulus according to the athletes' physiological ceiling. Such an approach leads to identical stimulation across athletes with differing profiles and potentially facilitates more homogenized adaptations.

 

 

#15 The Effect of a Balance Training Program on the Balance and Technical Skills of Adolescent Soccer Players

Reference: J Sports Sci Med. 2023 Dec 1;22(4):645-657. doi: 10.52082/jssm.2023.645. eCollection 2023 Dec.

Authors: Ioannis Mitrousis, Dimitrios I Bourdas, Stylianos Kounalakis, Evangelos Bekris, Michael Mitrotasios, Νikolaos Kostopoulos, Ioannis E Ktistakis, Emmanouil Zacharakis

Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10690516/pdf/jssm-22-645.pdf

Summary: Soccer is a complex sport, and balance appears to play a crucial role in the quality execution of technical skills, which are mostly performed while standing on one foot. Nevertheless, in younger ages, when learning still affects soccer performance, the effect of a balance-training program on the player's balance and technical skills remains unexplored. This research examined the effect of a balance-training program (BTP) on balance and technical skills of adolescent soccer players. Τhe participating volunteers were thirty-two soccer players (12-13 years old with 3.84 ± 0.95 years of practice), randomly separated into two groups: an experimental (EXP, n1 = 17) and a control group (CON, n2 = 15). Both groups were evaluated in static and dynamic balance and in technical skills (dribbling, passing, juggling, and shooting with dominant and non-dominant legs) before (Pre-condition) and after the intervention (Post-condition) which was an eight-week BTP for the EXP group and a placebo-training program for the CON group. Α 2 by 2 (groups×condition) mixed analysis of variance (ANOVA) with repeated measures on the condition factor was used to assess possible differences between groups. A significant groups × condition interaction effect was found in dynamic balance (p = 0.008), static (p = 0.042), and shooting (p = 0.022) with dominant leg performance. The EXP group improved (p = 0.007) its static balance by 37.82% and also significantly improved its dynamic balance and shooting accuracy with dominant leg in Post condition by 24.98% (p = 0.006) and 83.84% (p = 0.006) respectively. No significant improvement of other variables was detected in the EXP group Post condition. Dynamic and static balance, and shooting with dominant leg skills can be improved in adolescent soccer players through a specialized 8-week BTP. Balance-training program may contribute to technical skill improvement in soccer training.