The importance of well trained and stable neck flexors and extensors as well as trunk muscles for intentional headers in soccer is increasingly discussed. The neck flexors and extensors should ensure a coupling of trunk and head at the time of ball contact to increase the physical mass hitting the ball and reduce head acceleration. The aim of the study was to analyze the influence of a 6-week strength training program (neck flexors, neck extensors) on the acceleration of the head during standing, jumping and running headers as well as after fatigue of the trunk muscles on a pendulum header. A total of 33 active male soccer players (20.3 ± 3.6 years, 1.81 ± 0.07 m, 75.5 ± 8.3 kg) participated and formed two training intervention groups (IG1: independent adult team, IG2: independent youth team) and one control group (CG: players from different teams). The training intervention consisted of three exercises for the neck flexors and extensors. The training effects were verified by means of the isometric maximum voluntary contraction (IMVC) measured by a telemetric Noraxon DTS force sensor. The head acceleration during ball contact was determined using a telemetric Noraxon DTS 3D accelerometer. There was no significant change of the IMVC over time between the groups (F=2.265, p=.121). Head acceleration was not reduced significantly for standing (IG1 0.4 ± 2.0, IG2 0.1 ± 1.4, CG -0.4 ± 1.2; F = 0.796, p = 0.460), jumping (IG1-0.7 ± 1.4, IG2-0.2 ± 0.9, CG 0.1 ± 1.2; F = 1.272, p = 0.295) and running (IG1-1.0 ± 1.9, IG2-0.2 ± 1.4, CG -0.1 ± 1.6; F = 1.050, p = 0.362) headers as well as after fatigue of the trunk musculature for post-jumping (IG1-0.2 ± 2.1, IG2-0.6 ± 1.4; CG -0.6 ± 1.3; F = 0.184, p = 0.833) and post-running (IG1-0.3 ± 1.6, IG2-0.7 ± 1.2, CG 0.0 ± 1.4; F = 0.695, p = 0.507) headers over time between IG1, IG2 and CG. A 6-week strength training of the neck flexors and neck extensors could not show the presumed preventive benefit. Both the effects of a training intervention and the consequences of an effective intervention for the acceleration of the head while heading seem to be more complex than previously assumed and presumably only come into effect in case of strong impacts. Key words: Heading, kinetics, head-neck-torso-alignment, neck musculature, repetitive head impacts, concussion

The core muscles play a central role in stabilizing the head during headers in soccer. The objective of this study was to examine the influence of a fatigued core musculature on the acceleration of the head during jump headers and run headers. Acceleration of the head was measured in a pre-post-design in 68 soccer players (age: 21.5 ± 3.8 years, height: 180.0 ± 13.9 cm, weight: 76.9 ± 8.1 kg). Data were recorded by means of a telemetric 3D acceleration sensor and with a pendulum header. The treatment encompassed two exercises each for the ventral, lateral, and dorsal muscle chains. The acceleration of the head between pre- and post-test was reduced by 0.3 G (p = 0.011) in jump headers and by 0.2 G (p = 0.067) in run headers. An additional analysis of all pretests showed an increased acceleration in run headers when compared to stand headers (p < 0.001) and jump headers (p < 0.001). No differences were found in the sub-group comparisons: semi-professional vs. recreational players, offensive vs. defensive players. Based on the results, we conclude that the acceleration of the head after fatiguing the core muscles does not increase, which stands in contrast to postulated expectations. More tests with accelerated soccer balls are required for a conclusive statement.

Whole-body electromyostimulation (WB-EMS) is an extension of the EMS application known in physical therapy. In WB-EMS, body composition and skinfold thickness seem to play a decisive role in influencing the Ohmic resistance and therefore the maximum intensity tolerance. That is why the therapeutic success of (WB-)EMS may depend on individual anatomical parameters. The aim of the study was to find out whether gender, skinfold thickness and parameters of body composition have an influence on the maximum intensity tolerance in WB-EMS. [Participants and Methods] Fifty-two participants were included in the study. Body composition (body impedance, body fat, fat mass, fat-free mass) and skinfold thicknesses were measured and set into relation to the maximum intensity tolerance. [Results] No relationship between the different anthropometric parameters and the maximum intensity tolerance was detected for both genders. Considering the individual muscle groups, no similarities were found in the results. [Conclusion] Body composition or skinfold thickness do not seem to have any influence on the maximum intensity tolerance in WB-EMS training. For the application in physiotherapy this means that a dosage of the electrical voltage within the scope of a (WB-) EMS application is only possible via the subjective feedback (BORG Scale).

Many machine learning models show black box characteristics and, therefore, a lack of transparency, interpretability, and trustworthiness. This strongly limits their practical application in clinical contexts. For overcoming these limitations, Explainable Artificial Intelligence (XAI) has shown promising results. The current study examined the influence of different input representations on a trained model’s accuracy, interpretability, as well as clinical relevancy using XAI methods. The gait of 27 healthy subjects and 20 subjects after total hip arthroplasty (THA) was recorded with an inertial measurement unit (IMU)-based system. Three different input representations were used for classification. Local Interpretable Model-Agnostic Explanations (LIME) was used for model interpretation. The best accuracy was achieved with automatically extracted features (mean accuracy Macc = 100%), followed by features based on simple descriptive statistics (Macc = 97.38%) and waveform data (Macc = 95.88%). Globally seen, sagittal movement of the hip, knee, and pelvis as well as transversal movement of the ankle were especially important for this specific classification task. The current work shows that the type of input representation crucially determines interpretability as well as clinical relevance. A combined approach using different forms of representations seems advantageous. The results might assist physicians and therapists finding and addressing individual pathologic gait patterns

Strength training in youth soccer has both a preventive and a sports-specific component. Whole-body electromyostimulation (WB-EMS) could represent an interesting time-saving add-on to classical strength exercises in performance-oriented soccer. The objective of this study was to find out whether a 10-week superimposed WB-EMS training might have a more positive impact on strength parameters in male youth elite soccer players than regular athletic strength exercises alone. A total of 30 male youth soccer players from a youth academy aged 15 to 17 years participated in the study. Before and after the intervention, the isometric extension and flexion forces of trunk and knee, and the hip abduction and adduction forces were tested. Twelve players (control group) absolved a conventional 20-minute strength training once a week for a period of ten weeks. Eighteen players absolved the same exercises but with superimposed WB-EMS. Blood creatine kinase concentration was measured for training control. ANOVAs, Friedman tests and post hoc t-tests were calculated (p = 0.05) to examine the strength development during the training period between the groups. While we could not find significant strength increases in the leg, hip and trunk muscles in the control group (<4%), the strength of the WB-EMS group improved significantly in 4 of the 6 muscle groups tested. In this group, the strength of knee flexors increased significantly by 20.68 ± 21.55%, knee extensors by 31.43 ± 37.02%, hip adductors by 21.70 ± 12.86% and trunk flexors by 33.72 ± 27.43%. The rates of strength increase are partly in line with other studies, partly clearly higher, which might be explained by the athletically active target group. A 10-week superimposed WB-EMS training improves the strength of certain leg, hip and trunk muscles in male adolescent elite soccer players to a greater extent than a pure athletic strength training of the same duration.

In ihrem 50. Jubiläumsjahr lud die Technische Universität Kaiserslautern am 26. und 27. November 2020 zu einem Höhepunkt ein: dem Kongress #Sport #Gesundheit #Digital. Für zwei Tage wurden im Rahmen eines Online-Forums gemeinsam die Themenfelder Sport, Gesundheit und Digitalisierung diskutiert. Wir freuen uns sehr, dass die Techniker Krankenkasse die TUK als Ausrichter der Veranstaltung besonders unterstützt hat. #SGD – Der Kongress setzte an der Schnittstelle von Sport, Gesundheit und Digitalisierung an und beleuchtete Chancen und Möglichkeiten, die durch das Zusammenspiel dieser Disziplinen entstehen können. Gleichzeitig wurden Risiken und Herausforderungen der digitalen Entwicklungen in Sport und Gesundheit betrachtet und perspektivisch mit Blick in die Zukunft analysiert. Hochkarätige Beiträge aus Wissenschaft und Praxis aus allen für das Themenspektrum relevanten Fachrichtungen sorgten für ein hohes Maß an Abwechslung und Transfer. Der Kongress richtete sich dabei nicht nur an Personen aus Wissenschaft und Praxis der Bereiche Gesundheitswesen und -management, Medizin und Psychologie. Ebenso angesprochen wurden Übungsleitende und Angehörige aus Hochschulsport und Sportwissenschaft, Studierende und Mitarbeitende aller bezogenen Fachrichtungen sowie alle allgemein interessierten Personen. Der vorliegende Kongressband stellt die Sammlung der Kongressinhalte dar. Neben den schriftlichen Beiträgen lassen sich hier auch Impressionen der Kongresstage und die Vorträge als interaktiv eingebundene Videos finden.