Karen Zentgraf

• PhD
• Head of Department at Goethe University Frankfurt

Speed is a key component of football performance. An individualized approach may be necessary to achieve optimal speed development. Force-velocity profiling breaks down linear sprint performance into force, velocity, and mechanical effectiveness on an individual basis. In young footballers, these factors are related to maturation and have a strong...

Introduction Dropout, a premature end of a sporting career, is considered a major problem for the elite sports system. This paper examines factors that contribute to elite athletes’ considerations regarding dropout. Drawing on key theorizing from the sociology of work and organizations, we conceptualize dropout as the result of a reflexive process...

Purpose This study investigated elite German athletes to (1) assess their serum 25(OH)D levels and the prevalence of insufficiency, (2) identify key factors influencing serum 25(OH)D levels, and (3) analyze the association between serum 25(OH)D levels and handgrip strength. Methods In this cross-sectional study, a total of 474 athletes (231 female...

Introduction More and more studies recommend combining holistic coaches’ assessments (CA) with multidimensional measurements for selection decisions to enhance predictive value for talent development. The so-called coach’s eye is one of the most used criteria for talent selection, especially in sports games. Few studies have analyzed predictors for...

The role of power performance in elite athletes has been enriched by identifying associations between specific single nucleotide polymorphisms (SNPs) and power performance. To deepen our understanding of this association, the objective of this study was to explore the relationship between the genotype and the phenotype in elite athletes. A total of...

Background It is commonly assumed that it is mainly older, pregnant, and postnatal women who suffer from urinary incontinence. However, young and healthy women who are active in sports are also affected, and research suggests that women practicing high-impact sports are more prone to incontinence than their nonathletic peers. This review evaluates...

Elite athletes are high-performance outliers within their specific sports. Even though science seeks to understand the nature of expertise and elite performance, much knowledge remains compartmentalized within subdisciplines. Despite this multidimensionality being acknowledged, an interdisciplinary approach to understanding elite athletes is still...

A competitive trampoline routine consists of ten scored jumps on which trampoline gymnasts need to exhibit an adequate strength endurance performance of their lower extremities. These strength endurance requirements are assessed with “Repeated Jump Tests” (RJT). However, existing tests are not designed for trampolining, but rather for game sports....

Functional cognition is relevant for athletic success and interdependent with physical exercise, yet despite repeatedly demonstrated inflammatory responses to physical training, there are no studies addressing the relationship between cognition and inflammation in athletes. The aim of this study was to investigate the relationship between cognitive...

Introduction 3 × 3 basketball is becoming more and more professionalized, which is leading to a growing interest in talent development and talent selection. Different studies have demonstrated relevant factors in the talent selection process of 5v5 basketball but not in 3 × 3 basketball. Therefore, this study investigated the main predictors in the...

Introduction Basketball, introduced by Naismith as a contactless and indoor alternative to sports such as American football, now frequently involves physical contact among players, challenging the traditional notion. Up to date, a thorough understanding of these contacts and their implications remains limited. This study aims to analyze player cont...

Introduction Ice hockey is a high pace sports game that requires players to integrate multiple skills. Players face perceptive, cognitive, and motor tasks concurrently; hence, players are regularly exposed to dual- or multi-task demands. Dual-tasking has been shown to lead to decreased performance in one or both performed tasks. The degree of perfo...

Introduction The menstrual cycle may affect well-being and physical performance of elite female athletes by interfering with the function of multiple physiological systems. The aim of this study was to characterize the symptoms of the menstrual cycle and their frequency in elite female volleyball players. Methods Twenty professional female volleyb...

Drawing on theories from the sociology of work and organizations, such as Leiter and Maslach's concept of burnout and Siegrist's model of effort–reward imbalance, this paper argues that burnout symptoms in elite sport are related to a mismatch of investment and gratification. Building on data from a sample of German elite athletes ( N = 312), findi...

Simple Summary The gut microbiota is fundamental for human health. This complex health construct is a pivotal part of performance development in athletes. The gut microbiota plays its role in the physiology of the athlete by influencing immune function, gut barrier integrity, macro- and micronutrient absorption, muscular efficiency, and the gut-bra...

Research has improved the understanding of sports related concussion (SRC), and several classification systems and guidelines are available in the literature. The exact timing and clearing of athletes for return-to-play (RTP) is still based primarily on subjective reports of concussion symptoms, however symptoms link poorly to objective recovery. C...

Purpose: The aim of this study was to investigate the dynamics of external training load (eTL), internal training load (iTL), and well-being status, during a regular season week with one game, and to examine the differential workloads of players depending on their distance from game day during a competitive season. Method: Subjects were 10 full-tim...

Imagine blocking the opposing defense linemen in American football to protect your quarterback or creating gaps in the opponents' defense by setting blocks as a pivot player in handball. Such movements require a pushing action away from the body with the arms and stabilizing the whole body in different postural positions. Upper-body strength obviou...

Introduction The dynamic structure of sport games forces players to make time-sensitive decisions and to initiate actions that may then have to be canceled in response to sudden changes in the game situation. Whether and up to which time already initiated movements can still be inhibited is an important criterion for game performance in elite sport...

Purpose 3 × 3 is a variation of classic basketball (BB) that imposes new demands on both athletes and coaches. The objective of this study was to comprehensively describe similarities and differences in load structures between 3 × 3 and BB. Method Between January 2020 and July 2021, internal and external load parameters of 90 elite BB and 3 × 3 at...

Cuts and changes of direction (COD) are frequent movements during games in team sports. Since those movements are seen as a key performance variable, COD assessments are included in performance diagnostics. However, some tests are criticized as they seem to be confounded by variables such as linear sprinting. Therefore, it is suggested that not onl...

Background Studies on motor imagery (MI) practice based on different designs and training protocols have reported changes in maximal voluntary contraction (MVC) strength. However, to date, there is a lack of information on the effects of MI training on contractile properties of the trained muscle. Methods Forty-five physically active sport science...

This study investigated acute effects of real and imagined endurance exercise on sustained attention performance in healthy young adults in order to shed light on the action mechanisms underlying changes in cognitive functioning. The neural similarities between both imagined and physically performed movements reveal that imagery induces transient h...

Beach handball athletes experience an overlap during their preparation phase for the beach and the indoor season for several weeks. This transition phase from playing on an indoor surface to a sand surface is crucial for players’ performance levels both on the sand and indoor surfaces, but coaches and athletes alike are concerned about possible per...

Purpose: 3 × 3 basketball games are characterized by high-intensity accelerations and decelerations, and a high number of changes of direction and jumps. It is played in tournament form with multiple games per day. Therefore, optimal regeneration is crucial for maintaining a high performance level over the course of the tournament. To elucidate how...

Beach handball is a young discipline that is characterized by numerous high-intensity actions. By following up on previous work, the objective was to perform in-depth analyses evaluating external load (e.g., distance traveled, velocity, changes in direction, etc.) in beach handball players. In cross-sectional analyses, data of 69 players belonging...

Background: 3x3 basketball games are characterized by high-intensity accelerations and decelerations, and a high number of changes of direction and jumps. It is played in tournament form with multiple games per day. Therefore, optimal regeneration is crucial for maintaining a high performance level over the course of the tournament. To elucidate ho...

Many studies have investigated the activation of cortical areas and corticospinal excitability during motor imagery (MI) in relation to motor execution. Similar activation of cortical areas during imagined and executed bodily movements and increased corticospinal excitability while imagining movements has been demonstrated. Despite these similariti...

Muscular fatigue can affect postural control processes by impacting on the neuromuscular and somatosensory system. It is assumed that this leads to an increased risk of injury, especially in sports such as alpine skiing that expose the body to strong and rapidly changing external forces. In this context, posture constraints and contraction-related...

Auditory and visual percepts are integrated even when they are not perfectly temporally aligned with each other, especially when the visual signal precedes the auditory signal. This window of temporal integration for asynchronous audiovisual stimuli is relatively well examined in the case of speech, while other natural action-induced sounds have be...

The aim of this systematic review was to assess the effects of genetic variations and polymorphisms on endurance performance, muscle strength and injury susceptibility in competitive sports. The electronic databases PubMed and Web of Science were searched for eligible studies. The study quality was assessed using the RoBANS tool. Studies were inclu...

The influence of delayed auditory feedback on action evaluation and execution of real-life action-induced sounds apart from language and music is still poorly understood. Here, we examined how a temporal delay impacted the behavioral evaluation and neural representation of hurdling and tap-dancing actions in a functional magnetic resonance imaging...

Motor imagery is conceptualized as an internal simulation that uses motor-related parts of the brain as its substrate. Many studies have investigated this sharing of common neural resources between the two modalities of motor imagery and motor execution. They have shown overlapping but not identical activation patterns that thereby result in a moda...

Müller, C and Zentgraf, K. Neck and trunk strength training to mitigate head acceleration in youth soccer players. J Strength Cond Res XX(X): 000-000, 2020-Heading in soccer involves repetitive head accelerations that may be detrimental for brain health. One way to mitigate adverse effects may be to increase head-neck stabilization and thus reduce...

The float serve is an effective weapon to impede the attack of the opposing team. Because of its great importance in indoor and beach volleyball, we measured and quantified the float effect. We recorded 24 float serves of 12 top athletes in beach volleyball and indoor volleyball, respectively, and analyzed them using video analysis. We determined t...

The final result in competitive trampoline gymnastics is composed of different subscores. These contribute differentially to the final score and result in a gymnast's ranking. The present study was designed to investigate the impact that alternative score calculations of the horizontal displacement of the landing positions on the trampoline's cloth...

Many studies have investigated the activation of cortical areas and corticospinal excitability during motor imagery (MI) in relation to motor execution. Similar activation of cortical areas during imagined and executed bodily movements as well as increased corticospinal excitability while MI has been demonstrated. Despite these similarities on the...

Specific Neck and Trunk Strength Training to Mitigate Head Acceleration in Youth Soccer Players A Practical Guide Recommended application: Exercises can be continuously integrated into the athletic training with ...

This chapter looks at the neurobiological aspects of how physical activity (PA) and physical exercise (PEx) change the human brain in its structure and functionality on a short‐ and long‐term level. It reviews findings related to brain structure, connectivity, blood perfusion, as well as results on growth factors and metabolic changes that occur in...

Most human actions produce concomitant sounds. Action sounds can be either part of the action goal (GAS, goal-related action sounds), as for instance in tap dancing, or a mere by-product of the action (BAS, by-product action sounds), as for instance in hurdling. It is currently unclear whether these two types of action sounds—incidental or intentio...

The role of attentional focusing in motor tasks has been highlighted frequently. The “internal–external” dimension has emerged, but also the spatial distance between body and attended location. In two experiments, an extended attentional focus paradigm was introduced to investigate distality effects of attentional foci on balance performance. First...

A new measurement system (HDTS - horizontal displacement, time of flight, synchronicity) was investigated regarding the latest changes to the international evaluation rules in trampoline gymnastics. It allows for the real-time measurement of objective criteria, such as flight time and landing position, without affecting the gymnast. The aim of this...

Background: The nature of perceptual-cognitive expertise in interactive sports has gained more and more scientific interest over the last two decades. Research to understand how this expertise can be developed has not been addressed profoundly yet. In approaches to study this with interventional designs, only few studies have scrutinized several le...

Inhibition is a central component of human behavior. It enables flexible and adaptive behavior by suppressing prepotent motor responses. In former studies, it has been shown that sport athletes acting in dynamic environments exhibit superior motor inhibitory control based on sensory stimuli. So far, existing studies have corroborated this in manual...

Motor imagery (MI) is the process in which subjects imagine executing a body movement with a strong kinesthetic component from a first-person perspective. The individual capacity to elicit such mental images is not universal but varies within and between subjects. Neuroimaging studies have shown that these inter- as well as intra-individual differe...

Background: One key issue in elite interactive team sports is the simultaneous execution of motor actions (e.g., dribbling a ball) and perceptual-cognitive tasks (e.g., visually scanning the environment for action choices). In volleyball, one typical situation is to prepare and execute maximal block jumps after multiple-options decision-making and...

ECSS CONFERENCE ABSTRACT: INTRODUCTION: Plyometric training has demonstrated to be efficient in improving power-related measurements in athletic performance and muscle-tendon behaviour during stretch shortening cycle (SSC) exercise (Markovic, 2007; Hirayama et al., 2017). In handball, many actions require such attributes. Recently, beach handball...

In daily life, we are asked to adapt our motor behavior to the constantly changing conditions in our environment. This adaptation can be influenced by the perceptual processing of observed actions. Since many years, it is suggested that both action and perception are represented on a higher processing level that shares a common code (Prinz, 1997)....

Recent studies suggest that in addition to movements between ankle and hip joints, movements of the upper body, in particular of the arms, also significantly contribute to postural control. In line with these suggestions, we analyzed regulatory movements of upper and lower body joints supporting dynamic balance regulation during challenged locomoti...

One major characteristic of autism spectrum disorder (ASD) is problems with social interaction and communication. The present study explored ASD-related alterations in perceiving emotions expressed via body movements. 16 participants with ASD and 16 healthy controls observed video scenes of human interactions conveyed by point–light displays. They...

Analysing some behavioural data during physical and mental practice of an arm sequence movement.

The use of wearable devices during running has become commonplace. Although there is ongoing research on interaction techniques for use while running, the effects of the resulting interactions on the natural movement patterns have received little attention so far. While previous studies on pedestrians reported increased task load and reduced walkin...

When two or more people aim to produce joint action outcomes they need to coordinate their individual actions in space and time. Successful joint action performance has been reported to depend, among others, on visual and somatosensory information provided to the joint actors. This study investigated whether and how the systematic manipulation of v...

Although practical guidelines refer to core stability as a necessity for agility performance, it is not explicitly considered a prerequisite for agility performance development. Therefore, we assume an essential role of the core regarding the development of agility performance.

The general purpose of this systematic review was to study the effectiveness of off-court perceptual–cognitive training interventions in nonnovice, interactive sport athletes. We looked at task-specific practice effects and, more importantly, the transfer of effects. Databases used for the literature search were PubMed, Web of Science, and PsycINFO...

With a growing body of research devoted to uncovering regions of the brain implicated in action observation following various action-related experiences, including sport, we ask what we know from this research, and what we still need to know, as it pertains to sport and the brain. To do this, we review and integrate knowledge garnered from developm...

Simulation theory proposes motor imagery (MI) to be a simulation based on representations also used for motor execution (ME). Nonetheless, it is unclear how far they use the same neural code. We use multivariate pattern analysis (MVPA) and representational similarity analysis (RSA) to describe the neural representations associated with MI and ME wi...

The Movement Assessment Battery for Children (MABC-2) is a functional test for identifying deficits in the motor performance of children. The test contains a ball-catching task that requires the children to catch a self-thrown ball with one hand. As the task can be executed with a variety of different catching strategies, it is assumed that the tas...

Previous research has shown that focus of attention affects movement economy in endurance tasks. This experimental study was designed to take a closer look at how focusing attention on special characteristics of endurance cycling actions can influence metabolic energy costs. Twenty-five trained cyclists completed 4 × 6 min time trials at submaximal...

Facilitation of the primary motor cortex (M1) during the mere observation of an action is highly congruent with the observed action itself. This congruency comprises several features of the executed action such as somatotopy and temporal coding. Studies using reach-grasp-lift paradigms showed that the muscle-specific facilitation of the observer's...

Team sports place high demands on visuospatial and other cognitive skills. However, there is a lack of research on visuospatial skills of elite athletes and there are heterogeneous results on basic cognitive skills of this population. Therefore, this series of studies tested different cognitive skills in elite team sports athletes. In Experiment 1,...

While the benefits of both an external focus of attention (FOA) and of a longer quiet eye (QE) duration have been well researched in a wide range of sporting activities, little is known about the interaction of these two phenomena and how a potential interaction might influence performance. It was this study’s aim to investigate the interaction and...

Supporting Information

How motor maps are organized while imagining actions is an intensely debated issue. It is particularly unclear whether motor imagery relies on action-specific representations in premotor and posterior parietal cortices. This study tackled this issue by attempting to decode the content of motor imagery from spatial patterns of Blood Oxygen Level Dep...

Aktuelle Studien haben gezeigt, dass starke Assoziationen zwischen der koordinativen und schulischen Leistungsfähigkeit von Kindern bestehen. Trotz dieser Erkenntnisse mangelt es an schulbasierten Interventionsstudien, die sich mit dem möglichen Einfluss eines gezielten koordinativ ausgelegten Bewegungsprogramms auf die schulischen Leistungen von S...

Anticipation is informed by experience. Having focused on action effects in the past will lead to differences when the focus is now on the effector. Boules-type throwing movements were presented as point-light displays of shoulder and arm-markers. Activation in motor-related areas measured with functional magnetic resonance imaging was compared bet...

When table tennis players anticipate the course of the ball while preparing their motor responses, they not only observe their opponents striking the ball but also listen to events such as the sound of racket–ball contact. Because visual stimuli can be detected more easily when accompanied by a sound, we assumed that complementary sensory audiovisu...

Much recent research has shown that personality disorders are associated with an altered emotion perception. Whereas most of this research was conducted with stimuli such as faces, the present study examined possible differences in the perception of emotions expressed via body language and body movements. 30 patients with borderline personality dis...

The action observation network (AON) is supposed to play a crucial role when athletes anticipate the effect of others' actions in sports such as tennis. We used functional magnetic resonance imaging to explore whether motor expertise leads to a differential activation pattern within the AON during effect anticipation and whether spatial and motor a...

In many daily activities, and especially in sport, it is necessary to predict the effects of others' actions in order to initiate appropriate responses. Recently, researchers have suggested that the action–observation network (AON) including the cerebellum plays an essential role during such anticipation, particularly in sport expert performers. In...

This study addresses the controversy over how motor maps are organized during action simulation by examining whether action simulation states, that is, motor imagery and action observation, run on either effector-specific and/or action-specific motor maps. Subjects had to observe or imagine three types of movements effected by the right hand or the...

Much recent research has shown an association between mood disorders and an altered emotion perception. However, these studies were conducted mainly with stimuli such as faces. This is the first study to examine possible differences in how people with major depressive disorder (MDD) and healthy controls perceive emotions expressed via body movement...

Research on motor-related attentional foci suggests that switching from an internal to an external focus of attention has advantageous effects on motor performance whereas switching from an external to an internal focus has disadvantageous effects. We used functional magnetic resonance imaging to investigate the neural correlates of switching the f...

Jeannerod (2001) hypothesized that action execution, imagery, and observation are functionally equivalent. This led to the major prediction that these motor states are based on the same action-specific and even effector-specific motor representations. The present study examined whether hand and foot movements are represented in a somatotopic manner...

One central issue in social cognitive neuroscience is that perceiving emotions in others relates to activating the same emotion in oneself. In this study we sought to examine how the ability to perceive own emotions assessed with the Toronto Alexithymia Scale related to both the ability to perceive emotions depicted in point-light displays and the...