Elite Soccer Players' Weekly Workload Assessment Through a New Training Load and Performance Score.

Purpose: Monitoring players' training load allows practitioners to enhance physical performance while reducing injury risk. The aim of this study was to identify the key external load indicators in professional U19 soccer. Methods: Twenty-four-professional Italian young (U19) soccer players were monitored by using the rating of perceived exertion (CR-10 RPE scale) and a wearable inertial sensor during the competitive season. Three main components were detected by a Principal Component Analysis (PCA): i) volume metabolic related component, ii) intensity mechanical stimuli component, and iii) intensity metabolic/mechanical component. We hence computed two scores (i.e. Performance [PERF] and total workload [WORK]) permitting to investigate the weekly microcycle. Results: Correlation analysis showed that scores (i.e. PERF and WORK) are low correlated (r = -0.20) suggesting that they were independent. Autocorrelation analysis showed that a weekly microcycle is detectable in all the scores. Two-way ANOVA RM showed a statistical difference between match day (MD) and playing position for the three PCA components and PERF score. Conclusion: We proposed an innovative approach to assess both the players' physical performance and training load by using a machine learning approach allowing reducing a large dataset in an objective way. This approach may help practitioners to prescribe the training in the microcycle based on the two scores.

Association between match-related physical activity profiles and playing positions in different tasks: A data driven approach.

Assessing the intensity characteristics of specific soccer drills (matches, small-side game, and match-based exercises) could help practitioners to plan training sessions by providing the optimal stimulus for every player. In this paper, we propose a data analytics framework to assess the neuromuscular or metabolic characteristics of a soccer-specific exercise in relation with the expected match intensity. GPS data describing the physical tasks' external intensity during an entire season of twenty-eight semi-professional soccer players competing at the fourth Italian division were used in this study. A supervised machine-learning approach was tested in order to detect difference in playing positions in different sport-specific drills. Moreover, a non-supervised machine-learning model was used to profile the match neuromuscular and metabolic characteristics. Players' playing positions during matches and match-based exercises are characterised by specific metabolic and neuromuscular characteristics related to tactical demands, while in the small-side game these differences are not detected. Additionally, our framework permits to evaluate if the match performance request is mirrored during training drills. Practitioners could evaluate the type of stimulus performed by a player in a specific training drill in order to assess if they reflect the matches characteristics of their specific playing position.

Relationship between external and internal load indicators and injury using machine learning in professional soccer: a systematic review and meta-analysis.

This study verified the relationship between internal load (IL) and external load (EL) and their association on injury risk (IR) prediction considering machine learning (ML) approaches. Studies were included if: (1) participants were male professional soccer players; (2) carried out for at least 2 sessions, exercises, or competitions; (3) correlated training load (TL) with non-contact injuries; (4) applied ML approaches to predict TL and non-contact injuries. TL included: IL indicators (Rating of Perceived Exertion, RPE; Session-RPE, Heart Rate, HR) and EL indicators (Global Positioning System, GPS variables); the relationship between EL and IL through index, ratio, formula; ML indicators included performance measures, predictive performance of ML methods, measure of feature importance, relevant predictors, outcome variable, predictor variable, data pre-processing, features selection, ML methods. Twenty-five studies were included. Eleven addressed the relationship between EL and IL. Five used EL/IL indexes. Five studies predicted IL indicators. Three studies investigated the association between EL and IL with IR. One study predicted IR using ML. Significant positive correlations were found between S-RPE and total distance (TD) (r = 0.73; 95% CI (0.64 to 0.82)) as well as between S-RPE and player load (PL) (r = 0.76; 95% CI (0.68 to 0.84)). Association between IL and EL and their relationship with injuries were found. RPE, S-RPE, and HR were associated with different EL indicators. A positive relationship between EL and IL indicators and IR was also observed. Moreover, new indexes or ratios (integrating EL and IL) to improve knowledge regarding TL and fitness status were also applied. ML can predict IL indicators (HR and RPE), and IR. The present systematic review was registered in PROSPERO (CRD42021245312).

Toward a New Conceptual Approach to "Intensity" in Soccer Player's Monitoring: A Narrative Review.

ABSTRACT: Pillitteri, G, Clemente, FM, Petrucci, M, Rossi, A, Bellafiore, M, Bianco, A, Palma, A, and Battaglia, G. Toward a new conceptual approach to "intensity" in soccer player's monitoring: A narrative review. J Strength Cond Res 37(9): 1896-1911, 2023-In the last decade, monitoring physiological and match-related demands in soccer has become an increasingly common practice in sports sciences. One of the great challenges during monitoring process is the identification of key indicators that permit to generalize evidence and sustain decision-making process during training prescription. Actually, one of the major debates in the scientific community and among practitioners is the identification of the "intensity" concept. Defining a given training session or exercise based on "intensity" is difficult due to the fact that a huge amount of indicators are available (related both to the performed activities and to the athletes' psychophysiological responses). These indicators can lead to specific outcomes with different interpretations. The current narrative review aims to discuss the different measures approaches used in soccer to describe the intensity for both internal and external demands. In addition, a second purpose of this review is to propose general recommendations for combining intensity indicators with the aim of defining an overall intensity score of a training session or drill.

External load profile during different sport-specific activities in semi-professional soccer players.

BACKGROUND: Global Positioning System (GPS) devices are widely used in soccer for monitoring external load (EL) indicators with the aim of maximizing sports performance.The aim of this study was to investigate the EL indicators differences in players of different playing positions (i.e., central backs, external strikers, fullbacks, midfielders, strikers, wide midfielder) between and within different sport-specific tasks and official matches. METHODS: 1932 observations from 28 semi-professional soccer players (age: 25 ± 6 years, height: 183 ± 6 cm, weight: 75.2 ± 7 kg) were collected through GPS devices (Qstarz BT-Q1000EX, 10 Hz) during the season 2019-2020. Participants were monitored during Official Match (OM), Friendly Matches (FM), Small Sided Games (SSG), and Match-Based Exercises (MBE). Metabolic (i.e., metabolic power, percentage of metabolic power > 35w, number of intense actions per minute, distance per minute, passive recovery time per minute) and neuromuscular indicators (i.e., percentage of intense accelerations, percentage of intense decelerations, change of direction per min > 30°) were recorded during each task. RESULTS: Statistically significant differences were detected in EL indicators between playing positions within each task and between tasks. In particular, results from the two-way ANOVA tests showed significant interaction, but with small effect size, in all the EL indicators between playing positions for each task and within tasks. Moreover, statistical differences, but with small effect size, between playing positions were detected in each task and for each EL indicator. Finally, the strongest statistical differences (with large effect size) were detected between tasks for each EL indicator. Details of the Tukey post-hoc analysis reporting the pairwise comparisons within and between tasks with playing positions are also provided. CONCLUSION: In semi-professional soccer players, different metabolic and neuromuscular performance were detected in different playing position between and within different tasks and official matches. Coaches should consider the different physical responses related to different physical tasks and playing position to design the most appropriate training program.

Match Load Physical Demands in U-19 Professional Soccer Players Assessed by a Wearable Inertial Sensor.

BACKGROUND: Wearable inertial sensors are poorly used in soccer to monitor external load (EL) indicators. However, these devices could be useful for improving sports performance and potentially reducing the risk of injury. The aim of this study was to investigate the EL indicators (i.e., cinematic, mechanical, and metabolic) differences between playing positions (i.e., central backs, external strikers, fullbacks, midfielders, and wide midfielder) during the first half time of four official matches (OMs). METHODS: 13 young professional soccer players (Under-19; age: 18.5 ± 0.4 years; height: 177 ± 6 cm; weight: 67 ± 4.8 kg) were monitored through a wearable inertial sensor (TalentPlayers TPDev, firmware version 1.3) during the season 2021-2022. Participants' EL indicators were recorded during the first half time of four OMs. RESULTS: significant differences were detected in all the EL indicators between playing positions except for two of them (i.e., distance traveled in the various metabolic power zones (<10 w) and the number of direction changes to the right >30° and with speed >2 m). Pairwise comparisons showed differences in EL indicators between playing positions. CONCLUSIONS: Young professional soccer players showed different loads and performances during OMs in relation to playing positions. Coaches should consider the different physical demands related to playing positions in order to design the most appropriate training program.

Comparison of external load indicators between official matches and sport-specific training in semi-professional soccer players: focus on intensity and strength.

BACKGROUND: The aim of this study was to investigate any differences in external load indicators (ELi) between official matches (OM) and sport-specific tasks in semi-professional soccer players. METHODS: Among 28 semi-professional soccer players, 1932 observations (age: 25±6 years, height: 183±6 cm, weight: 75.2±7 kg; FC Palermo, Palermo, Italy) were collected through GPS devices (Qstarz BT-Q1000EX, 10 Hz; Qstarz International Co., Ltd., Taipei, Taiwan) and the related software (LaGalaColli V: 8.6.4.3; Spinitalia Srl, Rome, Italy) during the season 2019-2020. Participants were monitored during OM, friendly matches (FM), small sided games (SSG), and match-based exercises (MBE), considering the percentage of intense accelerations (%int. acc.), percentage of intense decelerations (%int. dec.), and passive recovery time /min (PrT/m) as Eli. RESULTS: We detected the highest mean value for PrT/m in OM and the lowest in MBE and SSG (18.36±4.38 and 13.4±5.26 and 13.4±4.29 (s/min), respectively). The lowest mean values of %int. acc. and %int. dec. were found in OM and the highest in SSG (8.64±1.52 vs. 13.02±3.14 and 9.25±1.56 vs. 15.68±3.14, for %int. acc. and %int. dec., respectively). Significant differences between the four tasks for all the ELi considered (P<0.001). The post-hoc pairwise comparisons revealed significant differences for all the ELi between all tasks (P<0.001) except for the %int. acc. between MBE vs. FM (P=0.003). No significant difference was found in PrT/m between MBE vs. FM and SSG vs. FM. CONCLUSIONS: ELi are in accordance with the performance model by achieving better values in training than OM, suggesting the fundamental role of GPS for monitoring external load in soccer.

Effects of osteopathic manipulative treatment of the pivots on lower limb function in young professional football players.

INTRODUCTION: The most frequent injuries in professional soccer players are those pertinent to the lower limbs. In particular, strains of the hamstrings and ligamentous injuries of the knee. Therefore, preventive measures are aimed to reduce such events. We aimed to investigate if an osteopathic manipulative treatment (OMT) of the pivots could improve lower limb function in young professional football players. METHODS: Thirty-eight young male professional football players were recruited (mean age 17.8 ± 0.44 years). These were randomly assigned to an OMT or control group (n = 20 and 18, respectively). Both groups underwent osteopathic evaluation. A sit-and-reach test, a vertical jump test, a hand-grip strength test, a cervical ROM test and a balance evaluation were also performed. RESULTS: A significant improvement (p < 0.01) was observed between pre and post measures in the OMT for dysfunctional assessment of the pivots. However, only L3 and C2 also differed from the control group post evaluation (p < 0.0001). No differences were present for any functional measure in the control group. Only the sit-&-reach of the OMT increased significantly (p < 0.001). Static balance with open eyes in the OMT, but not in the control group, improved during post evaluation (p < 0.01). CONCLUSION: The OMT of the pivots was able to increase the sit-and-reach measure, improve postural control with open eyes and improve dysfunctional patterns of the lumbosacral and upper cervical spine in young professional football players.

The influence of soccer shoes on plantar distribution in young players in a static condition: a pilot study.

BACKGROUND: Injuries are a serious problem in soccer for the player but also for the society. It has been noted most of the injuries occurs during non-contact situations and, the soccer shoes have an important role. Unfortunately, few studies investigated the plantar distribution, argument that could help to deeply understand the causes behind the injuries. The objective was to evaluate the influence of the soccer shoes on plantar distribution in young players in a static condition. METHODS: Young soccer players (range 11-18) were recruited and performed two tests on a baropodometric platform, one barefoot and one with technical soccer shoes. A student's t-test was performed to evaluate the differences between the conditions. RESULTS: Significative results were between the left plantar surface (P<0.05) and in the total surface anterior (P<0.05) with and without the soccer shoe. Related to the pressure values, soccer shoes resulted higher than barefoot condition. Statistical significance has been found also between the forefoot and the rearfoot in the left foot, in barefoot condition (P<0.05). CONCLUSIONS: Soccer shoes generally produce a reduction in the contact plantar surface, especially in the anterior zone and the foot load is higher in the forefoot zone.

The Case of Insertional Adductor Tendinopathy of an International-Level 3,000-m Steeplechase Runner.

Background: Groin pain is a frequent condition among athletes. One of the causes of groin pain is tendinopathy, a frequently diagnosed medical condition, which can also occur in the adductor muscles. Despite the high prevalence of this medical condition among athletes, it is infrequent to observe tendinopathic groin pain in steeplechase runners. The aim of this case study is to describe the case of an international-level 3,000-m steeplechase runner with groin pain, who was subsequently diagnosed with adductor insertional tendinopathy. Case Presentation: We present the case of an Italian 3,000-m steeplechase and long distance runner, Ala Zoghlami (180 cm, 57 kg), with groin pain, diagnosed as insertional adductor tendinopathy. The runner, after manifesting the painful symptomatology, underwent medical screening (ultrasound and MRI). The radiological investigations highlighted adductor tendinopathy. After refraining from training, the runner underwent medical and physical therapy which, in the first phase, did not improve the painful symptomatology. Further evaluation, after 6 months from the initial training cessation, highlighted a case of malocclusion. Such was treated from a dentistry perspective with the creation of a personalized dental bite. Results: A multidisciplinary approach which included medical and physical therapy, osteopathy, and dentistry, in adjunct with refraining from training, was able to reduce the symptomatology and allowed a correct return to run (after 9 months from the first painful manifestation) of the steeplechase runner. To date, Ala Zoghlami has fully recovered and was able to win the 3,000-m steeplechase race during the 2021 national Italian competition.

A Prospective Analysis of the Injury Incidence of Young Male Professional Football Players on Artificial Turf.

BACKGROUND: The effects of synthetic surfaces on the risk of injuries is still debated in literature and the majority of published data seems to be contradictory. For such reasons the understanding of injury incidence on such surfaces, especially in youth sport, is fundamental for injury prevention. OBJECTIVES: The aim of this study was to prospectively report the epidemiology of injuries in young football players, playing on artificial turfs, during a one sports season. PATIENTS AND METHODS: 80 young male football players (age 16.1 ± 3.7 years; height 174 ± 6.6 cm; weight 64.2 ± 6.3 kg) were enrolled in a prospective cohort study. The participants were then divided in two groups; the first included players age ranging from 17 to 19 (OP) whereas the second included players age ranging from 13 to 16 (YP). Injury incidence was recorded prospectively, according to the consensus statement for soccer. RESULTS: A total of 107 injuries (35 from the OP and 72 from the YP) were recorded during an exposure time of 83.760 hours (incidence 1.28/1000 per player hours); 22 during matches (incidence 2.84/1000 per player hours, 20.5%) and 85 during training (incidence 1.15/1000 per player hours, 79.5%). Thigh and groin were the most common injury locations (33.6% and 21.5%, respectively) while muscle injuries such as contractures and strains were the most common injury typologies (68.23%). No statistical differences between groups were displayed, except for the rate of severe injuries during matches, with the OP displaying slightly higher rates compared to the YP. Severe injuries accounted for 10.28% of the total injuries reported. The average time lost due to injuries was 14 days. Re-injuries accounted for 4.67% of all injuries sustained during the season. CONCLUSIONS: In professional youth soccer injury rates are reasonably low. Muscle injuries are the most common type of injuries while groin and thigh the most common locations. Artificial turf pitches don't seem to contribute to injury incidence in young football players.

Motor and cognitive growth following a Football Training Program.

Motor and cognitive growth in children may be influenced by football practice. Therefore the aim of this study was to assess whether a Football Training Program taken over 6 months would improve motor and cognitive performances in children. Motor skills concerned coordinative skills, running, and explosive legs strength. Cognitive abilities involved visual discrimination times and visual selective attention times. Forty-six children with chronological age of ∼9.10 years, were divided into two groups: Group 1 (n = 24) attended a Football Exercise Program and Group 2 (n = 22) was composed of sedentary children. Their abilities were measured by a battery of tests including motor and cognitive tasks. Football Exercise Program resulted in improved running, coordination, and explosive leg strength performances as well as shorter visual discrimination times in children regularly attending football courses compared with their sedentary peers. On the whole these results support the thesis that the improvement of motor and cognitive abilities is related not only to general physical activity but also to specific ability related to the ball. Football Exercise Programs is assumed to be a "natural and enjoyable tool" to enhance cognitive resources as well as promoting and encouraging the participation in sport activities from early development.

Motor and cognitive development: the role of karate.

BACKGROUND: regular physical activity has an effect on biological responses in both muscles and organs that, in turn, alter the structure and functions of the brain. Therefore, this study aims at comparing motor (sprint, coordination ability and explosive legs strength skills) and cognitive abilities (working memory, attention, executive functioning) in children. METHODS: 39 children with average chronological age of 9 years were divided in: Karatekas (n=19) and Sedentary (n=20) groups. Their abilities were measured by motor and cognitive tests. Motor skills were assessed through a battery composed by the 20 mt Sprint test, the Agility test and the Standing board jump Test. Cognitive profile was assessed by a battery of tests derived from BVN 5-11, "Batteria di Valutazione Neuropsicologica per l'Et à Evolutiva": Visual discrimination test, Reaction time test, Forwards and Backwards Digit Span Tests, Corsi Block-Tapping test and Tower of London. RESULTS: our results reveal significant differences between two groups (p < 0.05). Karate children show better speed times, explosive legs strength and coordination skills. They scored better on working memory, visual selective attention and executive functions. CONCLUSION: karate exercise training shows global benefits resulting in physiological and psychological gains in children.

The surprising influence of family history to type 2 diabetes on anaerobic performance of young male élite athletes.

AIMS/HYPOTHESIS: It is known that family history to type 2 diabetes induces anthropometric changes in various populations. Regular physical activity can induce adaptations in these subjects regularizing body composition and anthropometric parameters. The aim of this study is therefore to understand if family history to type 2 diabetes affects anaerobic performance in young male élite athletes. METHODS: Forty six young male élite athletes were tested. Thirty three without family history to type 2 diabetes (FH-) and thirteen with family history to type 2 diabetes (FH+). Anthropometric parameters, body composition, physiological parameters and athletic performance were assessed. RESULTS: Weight (p 0,0050), BMI (p 0,0019), waist circumference (p 0,0090), hips circumference (p 0,0490) and WHR (p 0,0339) were different between the two groups, showing greater values for the FH + subjects. Body composition showed lower FM and higher FFM percentages for the FH + group compared to the FH-. Anaerobic performance tests showed differences between the groups highlighting that the FH + group had higher anaerobic performance values (Wingate test for FH + 512,77 ± 107,93 W vs Wingate test for FH- 447,94 ± 56,95 W). CONCLUSIONS/INTERPRETATION: The élite athletes with FH + showed better anaerobic performances and a higher body mass. At this stage we cannot generalise, but in a sample of athletes we tested, all who were with FH + showed both interesting and unexpected results; if confirmed, this evidence may represent a remarkable knowledge for fitness coaches and professionals who are daily dealing with track and field athletes and their performances.

Postural stability in subjects with whiplash injury symptoms: results of a pilot study.

CONCLUSIONS: Posturographic tests can be used to assess and confirm the body's imbalance in subjects with whiplash injury. Further studies with larger cohorts are necessary to confirm this pilot study. OBJECTIVES: To verify through a posturographic exam the qualitative and quantitative alterations of postural stability in subjects with previous cervical trauma in comparison with healthy subjects. METHODS: A total of 42 subjects were analysed for the study; 22 as the control group (NM) and 20 (WM) with a positive anamnesis of whiplash injury from 3 to 12 month from diagnosis through a force platform. Centre of pressure (CoP) movements of the two groups with their eyes open and closed were recorded. RESULTS: During the closed eye test, the subjects with cervical injuries displayed a significant increase in the anterior-posterior oscillation velocity (p < 0.05) compared with the control group, with a significant reduction (p < 0.01) of the ratio between the shifting length (SL) of CoP on the polygon support and the total envelope area (EA, mm(2)) of CoP movements in the polygon support (SL/EA-ratio, mm(-1)).

Type 2 diabetes family histories, body composition and fasting glucose levels: a cross-section analysis in healthy sedentary male and female.

BACKGROUND: Diabetes type 2 is a world wide spread disease with a multifactorial pathogenetic evolution. Various factors like obesity, physical inactivity and poor lifestyle habits contribute to its development. The aim of this study was to verify if in young healthy sedentary male and female there is positive correlation between family history to type 2 diabetes and an increase in body weight and fat mass, or alterations in basal glycemia values. METHODS: Totally183 male and 237 female healthy sedentary subjects were analysed in 2012, in Italy. They were divided in three groups: FH(+) with first degree family history, FH(++) with second degree family history and FH(-) with no family history. Anthropometrics, body composition and blood parameters were assessed. RESULTS: Male had the highest BMI values (P<0.01). FH(+) and FH(++) had increased waist and hip circumferences and body weight (P<0.005 for men, P<0.0001 for women), body mass index (P< 0.0001 in both sexes), waist-hip ratio (P< 0.05 for men and women) and triceps skinfold (P< 0.0005 for both sexes). Obesity incidence was higher in FH(+) and FH(++) compared to control groups. CONCLUSIONS: The study confirms family history to diabetes type 2 as a risk factor for the development of the illness, mainly in a case of first degree of FH. Preventive interventions are necessary to promote significant life-style changes, such as increased physical activity and controlled quantity and quality of food intake.

Patient satisfaction in pediatric outpatient settings from the parents' perspective - the Child ZAP: a psychometrically validated standardized questionnaire.

BACKGROUND: Patient surveys constitute a valuable source of information in patient-focused health care. The objective of this study was to develop and validate a standardized, patient centered, quantitative instrument to assess parent satisfaction in ambulatory pediatric care to be used in quality management and benchmarking activities, the Child-ZAP. METHODS: A preliminary version of the survey (38 items) was conducted in n = 19 pediatric practices. After psychometric testing a modified Child-ZAP was tested in a second survey (n = 20 new pediatric practices). Data from n = 979 patients were available for analysis. RESULTS: The final version of the Child-ZAP contains eight dimensions, three "Child-Scales" and five "Parent-Scales". Confirmatory factor analysis confirms the three hypothesized child dimensions as well as the five parent dimensions. The factorial structure is confirmed in subgroups of younger and older children. CONCLUSIONS: With satisfactory to good results for validity and reliability testing, the final Child-ZAP is applicable in pediatric ambulatory care for children of all age groups.

A comparison of conventional and retrospective measures of change in symptoms after elective surgery.

BACKGROUND: Measuring change is fundamental to evaluations, health services research and quality management. To date, the Gold-Standard is the prospective assessment of pre- to postoperative change. However, this is not always possible (e.g. in emergencies). Instead a retrospective approach to the measurement of change is one alternative of potential validity. In this study, the Gold-Standard 'conventional' method was compared with two variations of the retrospective approach: a perceived-change design (model A) and a design that featured observed follow-up minus baseline recall (model B). METHODS: In a prospective longitudinal observational study of 185 hernia patients and 130 laparoscopic cholecystectomy patients (T0: 7-8 days pre-operative; T1: 14 days post-operative and T2: 6 months post-operative) changes in symptoms (Hernia: 9 Items, Cholecystectomy: 8 Items) were assessed at the three time points by patients and the conventional method was compared to the two alternatives. Comparisons were made regarding the percentage of missing values per questionnaire item, correlation between conventional and retrospective measurements, and the degree to which retrospective measures either over- or underestimated changes and time-dependent effects. RESULTS: Single item missing values in model A were more frequent than in model B (e.g. Hernia repair at T1: model A: 23.5%, model B: 7.9%. In all items and at both postoperative points of measurement, correlation of change between the conventional method and model B was higher than between the conventional method and model A. For both models A and B, correlation with the change calculated with the conventional method was higher at T1 than at T2. Compared to the conventional model both models A and B also overestimated symptom-change (i.e. improvement) with similar frequency, but the overestimation was higher in model A than in model B. In both models, overestimation was lower at T1 than at T2 and lower after hernia repair than after cholecystectomy. CONCLUSIONS: The retrospective method of measuring change was associated with a larger improvement in symptoms than was the conventional method. Retrospective assessment of change results in a more optimistic evaluation of improvement by patients than does the conventional method (at least for hernia repair and laparoscopic cholecystectomy).