Kinematic Profile of Visually Impaired Football Players During Specific Sports Actions

Characterization of the External Load of Soccer Goalkeepers Depending on the Category and Sports Context

BACKGROUND/OBJECTIVES

Studies focused on the soccer goalkeeper position in training and official matches are scarce. The present study aimed to analyze the external load during training sessions and official matches in semi-professional goalkeepers.

METHODS

Data from goalkeepers (n = 6) from the youth ranks of a professional team belonging to the first Spanish soccer league have been used. The sample is made up of a total of 758 data collected during all the training and competitions carried out by the analyzed teams that made up the squad during the 2021/2022 and 2022/2023 seasons. A descriptive and inferential analysis was carried out based on the category (Youth B or Youth C) and the sports context (training or competition).

RESULTS

The results showed significant differences depending on the category (average time to feet left, average time to feet right, total jumps, total dives, total left dives, total right dives, high metabolic load distance (HMLD), and high metabolic power efforts (HMPE)), and the sport context (average time to feet right, total jumps, total dives, total left dives, total right dives, total distance, distance 18-21 km/h, distance 21-24 km/h, Dec 2-3, efforts, and HMLD).

CONCLUSIONS

The EL of the GKs shows differences regarding the category and the context. Therefore, it is necessary to analyze and determine the threshold of each player considering different variables related to the external and internal load to individualize the training tasks and prevent injuries due to overload.

Head movements affect skill acquisition for ball trapping in blind football

Blind football players use head movements to accurately identify sound location when trapping a ball. Accurate sound localization is likely important for motor learning of ball trapping in blind football. However, whether head movements affect the acquisition of ball-trapping skills remains unclear. Therefore, this study examined the effect of head movements on skill acquisition during ball trapping. Overall, 20 sighted male college students were recruited and assigned to one of the following two groups: the conventional training group, where they were instructed to move leftward and rightward to align their body with the ball's trajectory, and the head-movement-focused group, where they were instructed to follow the ball with their faces until the ball touched their feet, in addition to the conventional training instructions. Both groups underwent a 2-day training for ball trapping according to the specific instructions. The head-movement-focused group showed a decrease in errors in ball trapping at near distances and with larger downward head rotations in the sagittal plane compared to the conventional training group, indicating that during the skill acquisition training for ball trapping, the sound source can be localized more accurately using larger head rotations toward the ball. These results may help beginner-level players acquire better precision in their movements while playing blind football.

Reliability and validity of My Jump 2® app to measure the vertical jump in visually impaired five-a-side soccer athletes

Background

Although My Jump 2 ® consistently presented excellent values of reliability and validity when compared to force platforms (FPs) and contact mats, to date no scientific investigation assessed the validity and reliability of My Jump 2 ® to measure jump height in visually impaired five-a-side soccer athletes. Thus, the study aimed at analyzing the validity and reliability of the My Jump 2® to measure the vertical jump of five-a-side soccer athletes.

Methods

Twelve visually impaired five-a-side soccer athletes, volunteered for this study. Each player performed five countermovement jumps (CMJs) and squat jumps (SJs) on a contact platform (CP) while they were simultaneously recorded using My Jump 2 ®.

Results

There was almost perfect agreement between the My Jump 2® and the contact platform measurements of CMJ (intraclass correlation coefficient = 0.99; p < 0.001) and SJ (intraclass correlation coefficient = 0.99; p < 0.001), heights for athletes during the first and second measurement days. Bland-Altman analysis showed a bias of 0.25 ± 0.5 cm; maximum SD = 1.3; minimum SD = -0.88 for CMJ, while that Bland-Altman analysis showed bias 0.18 ± 0.5 cm; maximum SD = 1.3; minimum SD = -0.96, for SJ.

Conclusion

We can conclude that the My Jump 2® is a valid and reliable method to measure CMJ and SJ in visually impaired five-a-side soccer athletes.

Reactive Agility and Pitching Performance Improvement in Visually Impaired Competitive Italian Baseball Players: An Innovative Training and Evaluation Proposal

Visual input significantly affects kinesthesis skills and, hence, visually impaired individuals show less developed sensorimotor control, especially in an unfamiliar outdoor environment. Regular blind baseball practice can counteract such a deficit but, given the complex kinetic chain model required, a targeted workout proposal is needed to improve the main athletic gesture performance. On these premises, we investigated, for the first time, the running and pitching performance of a competitive Italian blind baseball team through quantitative tools and parameters such as Libra Easytech sensorized proprioceptive board, goniometric active range of motion, chronometric speed, and pitching linear length. Moreover, the perceived physical exertion was assessed by the Borg CR10 scale. Consequently, an adapted athletic training protocol was designed and tested on the field during the competitive season, with the aim to strengthen sport specific-gesture coordination and efficacy as well as to prevent injuries. Quantitative assessments showed an improvement in ankle stability index, bilateral upper limb and hip mobility, reactive agility, running braking phase control during second base approaching, and auditory target-related pitching accuracy along with a decrease in perceived physical exertion. This protocol might therefore represent an effective and easily reproducible training and evaluation approach to tailor management of visually impaired baseball players, and safely improve their athletic performance under the supervision of an adapted exercise specialist.

INTERLEAVED TACTICAL TRAINING OF BIG FOOTBALL TEAMS

ABSTRACT Introduction Tactical football training is significant in teaching great football teams. Analyzing and discussing existing problems and proposals for corresponding countermeasures should be carried out periodically. Objective Investigate and understand the main factors that affect the development of tactical training activities of big football teams. Methods Large-scale soccer match tactics at the 2018 World Cup are evaluated and treated statistically by dividing the defensive behaviors in the game between individual defensive tactics and collective defensive tactics. Results The primary means of launching a fast defensive attack is a medium to long pass across the court. Launching a fast attack requires combining a pass with a sudden attack. Conclusion Attackers often take the initiative in their confrontation tactics. The aggressive style of the players excels in the initiative and midfield advantage. Evidence level II; Therapeutic Studies - Investigating the results.

Analysis of Injuries and Wellness in Blind Athletes during an International Football Competition

Five-a-side football for blind people is the only adapted football modality present at the Paralympic games. Fa5 is a collaborative-opposition sport in which its participants play with no vision, which causes numerous impacts. At the London 2012 Paralympic Games, it was the sport with the highest incidence of sports injuries. The main objective of this work is to analyse the association between pain perception; spatio-temporal, mechanical, and metabolic workload with injuries; and wellness in players during an international Fa5 competition. The following variables, monitored during an International Fa5 Tournament, were analysed: general well-being, perception of pain and injuries, and the spatio-temporal and metabolic workload. The results show that the incidence of injuries increases as the tournament progresses, where injured players reported greater muscle pain and stress before the matches started. Besides, the players’ internal and external load did not explain the incidence of injury. Still, the values obtained in the wellness questionnaire, the perception of pain, and stress suggested they contributed to the incidence of injury.

A database of physical therapy exercises with variability of execution collected by wearable sensors

This document introduces the PHYTMO database, which contains data from physical therapies recorded with inertial sensors, including information from an optical reference system. PHYTMO includes the recording of 30 volunteers, aged between 20 and 70 years old. A total amount of 6 exercises and 3 gait variations were recorded. The volunteers performed two series with a minimum of 8 repetitions in each one. PHYTMO includes magneto-inertial data, together with a highly accurate location and orientation in the 3D space provided by the optical system. The files were stored in CSV format to ensure its usability. The aim of this dataset is the availability of data for two main purposes: the analysis of techniques for the identification and evaluation of exercises using inertial sensors and the validation of inertial sensor-based algorithms for human motion monitoring. Furthermore, the database stores enough data to apply Machine Learning-based algorithms. The participants' age range is large enough to establish age-based metrics for the exercises evaluation or the study of differences in motions between different groups.

5-A-SIDE SOCCER: PREVALENCE OF SPORTS INJURIES IN BRAZILIAN TEAM PLAYERS

ABSTRACT Introduction: 5-a-side soccer is a sports modality exclusively for athletes with vision impairment (VI) classified as blind - B1 (Blind 1) by the visual classification process. Type of impairment and high-performance training are factors that contribute to the development of sports injuries. Objective: The purpose of this study was to characterize the prevalence of sports-related injuries in visually disabled athletes of the Brazilian 5-a-side soccer team. Methods: The method was defined as a descriptive, longitudinal, epidemiological study. The sample was composed of ten male athletes, members of the Brazilian 5-a-side soccer team, including two athletes without VI and eight athletes with the B1 visual classification, who participated in competitions in 2014. The questionnaire for the data collection was based on the Sport Injuries Protocol for Paralympic Sports (PLEEP), expressing quantitative data analyzed by descriptive statistics. Results: The results showed that, in 2014, five athletes with VI had seven sports injuries, with a prevalence of 62.5%, clinical incidence of 0.87 injuries per athlete per year, and 1.4 injuries per injured athlete. The main sports injuries were muscle strain (28.6%), groin pull (athletic pubalgia) (28.6%), and shin splints (periostitis) (28.6%). All sports injuries occurred in the lower limbs, affecting legs (71.4%) and hips (28.6%). Overload was the most frequent mechanism (57%), reported after the technical kick movement and linked to the muscle imbalance between dominant and supporting lower limbs, in addition to the postural misalignment typical of people with visual impairments. Conclusions: In summary, the Brazilian 5-a-side soccer athletes presented a pattern of overload injuries resulting from the repetition of the technical kick movement, occurring predominantly in sports competitions. Epidemiological data can contribute to the development of strategies to prevent injuries in this sport. Level of evidence II, Progressive prognostic study.

Psychometric Suitability of Adaptations to the Special Judo Fitness Test for Athletes With Visual Impairment

This study aimed to test the reliability, sensitivity, construct and logical validity of an adapted Special Judo Fitness Test (SJFT) for judo athletes with visual impairment . Twenty judo athletes with visual impairments performed both the adapted SJFT with tactile and sonorous stimuli (experimental conditions) and the typically administered SJFT (standard condition). We used analyses of variance (ANOVAs) with repeated-measures to compare the groups' SJFT performances, and one-way ANOVAs to compare different visual ability classes of athletes (B1, B2 and B3). We used t-tests to compare SJFT variables between elite and sub-elite groups. We set statistical significance for all tests at p < 0.05. The standard SJFT showed excellent test-retest reliability for number of throws and overall index (ICC = 0.91-0.95), and both sonorous and tactile sensitivity adaptations of the SJFT showed medium sensitivity for detecting performance changes. The number of throws and SJFT index were higher with the sonorous adaptation of the test, compared to the tactile and standard versions (p < 0.001). Athletes who were blind (B1) presented similar performances to athletes who were partially sighted (B2 and B3) only on the SJFT with the sonorous stimulus. Moreover, only the sonorous SJFT adaptation discriminated between the performances of elite and sub-elite athletes (p < 0.001). In conclusion, both SJFT adaptations showed excellent reliability and medium sensitivity on test-retest, but, only the SJFT with the sonorous stimulus seemed valid for assessing judo athletes with varying degrees of visual impairment, and only the sonorous stimulus SJFT discriminated elite from sub-elite athletes.

Data Mining to Select Relevant Variables Influencing External and Internal Workload of Elite Blind 5-a-Side Soccer

(1) Background: Data mining has turned essential when exploring a large amount of information in performance analysis in sports. This study aimed to select the most relevant variables influencing the external and internal load in top-elite 5-a-side soccer (Sa5) using a data mining model considering some contextual indicators as match result, body mass index (BMI), scoring rate and age. (2) Methods: A total of 50 top-elite visually impaired soccer players (age 30.86 ± 11.2 years, weight 77.64 ± 9.78 kg, height 178.48 ± 7.9 cm) were monitored using magnetic, angular and rate gyroscope (MARG) sensors during an international Sa5 congested fixture tournament.; (3) Results: Fifteen external and internal load variables were extracted from a total of 49 time-related and peak variables derived from the MARG sensors using a principal component analysis as the most used data mining technique. The principal component analysis (PCA) model explained 80% of total variance using seven principal components. In contrast, the first principal component of the match was defined by jumps, take off by 24.8% of the total variance. Blind players usually performed a higher number of accelerations per min when losing a match. Scoring players execute higher DistanceExplosive and Distance21-24 km/h. And the younger players presented higher HRAVG and AccMax. (4) Conclusions: The influence of some contextual variables on external and internal load during top elite Sa5 official matches should be addressed by coaches, athletes, and medical staff. The PCA seems to be a useful statistical technique to select those relevant variables representing the team's external and internal load. Besides, as a data reduction method, PCA allows administrating individualized training loads considering those relevant variables defining team load behavior.

Optical motion capture dataset of selected techniques in beginner and advanced Kyokushin karate athletes

Human motion capture is commonly used in various fields, including sport, to analyze, understand, and synthesize kinematic and kinetic data. Specialized computer vision and marker-based optical motion capture techniques constitute the gold-standard for accurate and robust human motion capture. The dataset presented consists of recordings of 37 Kyokushin karate athletes of different ages (children, young people, and adults) and skill levels (from 4th dan to 9th kyu) executing the following techniques: reverse lunge punch (Gyaku-Zuki), front kick (Mae-Geri), roundhouse kick (Mawashi-Geri), and spinning back kick (Ushiro-Mawashi-Geri). Each technique was performed approximately three times per recording (i.e., to create a single data file), and under three conditions where participants kicked or punched (i) in the air, (ii) a training shield, or (iii) an opponent. Each participant undertook a minimum of two trials per condition. The data presented was captured using a Vicon optical motion capture system with Plug-In Gait software. Three dimensional trajectories of 39 reflective markers were recorded. The resultant dataset contains a total of 1,411 recordings, with 3,229 single kicks and punches. The recordings are available in C3D file format. The dataset provides the opportunity for kinematic analysis of different combat sport techniques in attacking and defensive situations.

Blind footballers direct their head towards an approaching ball during ball trapping

In blind football, players predict the sound location of a ball to underpin the success of ball trapping. It is currently unknown whether blind footballers use head movements as a strategy for trapping a moving ball. This study investigated characteristics of head rotations in blind footballers during ball trapping compared to sighted nonathletes. Participants performed trapping an approaching ball using their right foot. Head and trunk rotation angles in the sagittal plane, and head rotation angles in the horizontal plane were measured during ball trapping. The blind footballers showed a larger downward head rotation angle, as well as higher performance at the time of ball trapping than did the sighted nonathletes. However, no significant differences between the groups were found with regards to the horizontal head rotation angle and the downward trunk rotation angle. The blind footballers consistently showed a larger relative angle of downward head rotation from an early time point after ball launching to the moment of ball trapping. These results suggest that blind footballers couple downward head rotation with the movement of an approaching ball, to ensure that the ball is kept in a consistent egocentric direction relative to the head throughout ball trapping.