Search

Purpose: The aim of the present study was to investigate the influence of players' relative age, maturation-related characteristics, and motor performance tests on two different stages of talent selection (regional and national level) in youth elite basketball. Methods: Relative age, maturation-related variables (height, weight, maturity offset, maturity timing) and motor performance (Countermovement jump, Standing long jump, Modified agility T-test, Linear sprint 20 m) of N = 68 male youth basketball players (Mage = 14.39 ± 0.28 years) were assessed during the initial selection tournament for the German U15 national team. Pre-selection biases regarding relative age and maturity timing on the regional level were investigated utilizing one-sample t-tests. Differences in relative age, maturation-related characteristics and motor performance between players selected (n = 27) and non-selected (n = 41) for the youth national team were examined via independent samples' t-tests and logistic regression analyses. Results: Strong pre-selection biases toward early-born and early-maturing players were confirmed on the regional level. Significant advantages in height and weight and higher values in maturity offset and maturity timing were found for selected players. Among the motor variables, only Countermovement jump performance was significantly better in selected players. When controlling for relative age and biological maturation regression models including motor performance variables did not significantly discriminate players' selection status. Conclusion: Coaches working in national, but also preceding selection stages (regional and club level) should raise their awareness to relative age and biological maturation when evaluating players' potential and current (motor) performance. [ABSTRACT FROM AUTHOR]

In soccer substantial work has been invested to identify factors predicting future performance and success. As it concerns psychological characteristics, quantitatively and qualitatively limited research restricts insights on potential differences due to moderating variables such as players' age and developmental stage within the talent pathway. Thus, the purpose of this study was to extend the empirical evidence on psychological characteristics by (a) validating the prognostic power of potential talent predictors for adult success in U17 "elite promotion" stage players and by (b) comparing these results to the group of U12 "talent development" stage players of the former study by Höner and Feichtinger using the same methodological approach. For both, an online survey was utilized to assess psychological variables across the domains of motivation, volition, self-concept, and emotions. Further, players' performance level was determined four years after the assessment (i.e., U12 success criteria: admission to youth academy; U17 success criteria: achieving professional status). The statistical analyses revealed notable differences in the expression and prognostic value of psychological characteristics between the two samples. Among U17 players, dysfunctional (e.g., fear of failure, competitive anxiety) and functional attributes (e.g., hope for success, ego-orientation, competitiveness) significantly predicted individuals' professional status. The results are discussed within the light of potential environmental demands which may influence the role of psychological dispositions and skills throughout talent development. Additionally, the significance of reliable assessments for applied practice is highlighted regarding sport psychological diagnostics and interventions. Lay summary: To optimally support talent development in soccer, researchers and practitioners seek to understand factors which facilitate players' successful progression through talent pathways up to a professional level. The current study highlights psychological characteristics (e.g., hope for success, competitiveness) which predict future performance and should thus be nourished in young players. The results highlight distinct psychological characteristics which seem to be relevant for a successful progression through the talent development pathway of the German FA and should therefore be facilitated within sport psychological service delivery. The results further suggest age/developmental stage dependent differences in the expression functional and dysfunctional psychological attributes and their potential relevance for performance development mid-term. Such moderators need to be considered when planning to implement sport psychological diagnostics and interventions. Long-term monitoring of youth athletes in institutionalized talent pathways (e.g., FAs) can contribute to an optimization of talent development on a local level (e.g., youth academies). [ABSTRACT FROM AUTHOR]

While sporting research has focussed on the performance factors and activities contributing to elite performance, there is still limited acknowledgement of the athlete's voice on the specific experiences and milestones that shaped their development into elite athletes. Therefore, the current study, used qualitative first-hand experiences of international level players to understand their developmental stories. In total, 17 players who represented the Australian National Soccer team during the "Golden Generation" Australian soccer (i.e. represented the Australian National Soccer Team during the Qualification period and subsequent 2006 and 2010 FIFA World Cup competitions) participated in the study. Semi-structured interviews were conducted with all participants, with the analysis identifying six key themes which described the developmental story of players. The themes included, Passion; Family; Mentality; Environment; Practice; and Pathway. The findings provide a detailed description of the environmental and socio-cultural factors the players perceived as critical in their journey to representing their nation. [ABSTRACT FROM AUTHOR]

Exploratory factor analysis is a widely used framework in the social and behavioral sciences. Since measurement errors are always present in human behavior data, latent factors, generating the observed data, are important to identify. While most factor analysis methods rely on linear relationships in the data‐generating process, deep learning models can provide more flexible modeling approaches. However, two problems need to be addressed. First, for interpretation, scaling assumptions are required, which can be (at least) cumbersome for deep generative models. Second, deep generative models are typically not identifiable, which is required in order to identify the underlying latent constructs. We developed a model that uses a variational autoencoder as an estimator for a complex factor analysis model based on importance‐weighted variational inference. In order to receive interpretable results and an identified model, we use a linear factor model with identification constraints in the measurement model. To maintain the flexibility of the model, we use normalizing flow latent priors. Within the evaluation of performance measures in a talent development program in soccer, we found more clarity in the separation of the identified underlying latent dimensions with our models compared to traditional PCA analyses. [ABSTRACT FROM AUTHOR]

Researchers consider motivation a key determinant of physical activity. In physical education (PE) and youth sport, the more children and adolescents evaluate their teachers and coaches to be autonomy supportive, as opposed to controlling, the more self-determined they are in their motivation. Therefore, it appears valuable to help PE teachers and youth sport coaches optimize their interactions with the individuals they work with. This study was designed to systematically review the literature related to autonomy support interventions with PE teachers and youth sport coaches. After relevant databases were searched and duplicates were removed, 1,523 potentially pertinent articles were found. These were subsequently screened based on specific inclusion criteria. This systematic review process helped identify 21 studies that were included for further analyses. Overall, the interventions were frequently successful in enhancing PE teachers' and youth sport coaches' behavior. Additional research appears justified to foster self-determined motivation among children and adolescence. [ABSTRACT FROM AUTHOR]

The importance of considering information related to athletes' biological maturation within talent identification and development processes is frequently emphasized by both sport scientists and practitioners. Although there is evidence for the use of objective diagnostics for assessing biological maturation, little is known about its subjective determinations by coaches. Such approaches are particularly relevant when scientific support is limited. Therefore, the current study aimed to compare a practical subjective approach (coaches' eye) to assess biological maturity timing (BMT) with objective reference diagnostics (MRI). For this purpose, data were collected from 63 male elite soccer players of the U12 and U14 age group who were part of the German talent promotion program. Players' BMT (i.e., skeletal – chronological age) was assessed by MRI and a subjective rating of two coaches. Data analyses revealed high-rank correlations (rs =.55; p <.001) for the total sample as well as for U14 players (rs =.65; p <.001) and moderate rank correlations for U12 players (rs =.42; p <.05). Single case analyses showed substantial agreements between the diagnostics. However, particularly for U12 players, judgements did not always correspond with the MRI rankings. Although coaches seem to have the ability for recognizing the earliest and latest maturing players in the sample, inconsistencies exist in single cases, especially for players that were identified on-time by objective MRI diagnostics. Although utilizing subjective coach assessments as an alone-standing tool to assess a player's BMT is not recommended in applied practice, its use can be beneficial when applied in addition to common objective diagnostics or in circumstances where objective data are not available. [ABSTRACT FROM AUTHOR]

In species with separate sexes, females and males often differ in their morphology, physiology and behaviour. Such sex‐specific traits are functionally linked to variation in reproductive competition, mate choice and parental care, which have all been linked to sex roles. At the 150th anniversary of Darwin's theory on sexual selection, the question of why patterns of sex roles vary within and across species remains a key topic in behavioural and evolutionary ecology. New theoretical, experimental and comparative evidence suggests that variation in the adult sex ratio (ASR) is a key driver of variation in sex roles. Here, we first define and discuss the historical emergence of the sex role concept, including recent criticisms and rebuttals. Second, we review the various sex ratios with a focus on ASR, and explore its theoretical links to sex roles. Third, we explore the causes, and especially the consequences, of biased ASRs, focusing on the results of correlational and experimental studies of the effect of ASR variation on mate choice, sexual conflict, parental care and mating systems, social behaviour, hormone physiology and fitness. We present evidence that animals in diverse societies are sensitive to variation in local ASR, even on short timescales, and propose explanations for conflicting results. We conclude with an overview of open questions in this field integrating demography, life history and behaviour. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Animal Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Coaches are among the most important agents for young football talents' development. Their coaching style may impact not only players' skill acquisition but also their motivation to meet their full potential. This study begins by presenting an intervention promoting need-supportive coaching to facilitate holistic talent development within the German Football Association (Deutscher Fußball-Bund [DFB]). The intervention was grounded in Deci and Ryan's self-determination theory and designed as a hybrid model of coach education (i.e., online and in-present elements). In addition, DFB competence center coordinators were utilized as multipliers to reach a large population of approximately 1,300 coaches across Germany. The specific aim of this paper is to examine how these coordinators experienced the development and implementation process of the intervention. Utilizing a mixed-methods approach, coordinators' satisfaction and experiences with the intervention were evaluated via a quantitative online survey (n = 23) and qualitative follow-up interviews (n = 8). Overall, the findings suggest that the presented approach may be suitable to address potential barriers in coach education, such as gaining coaches' buy-in, transferring scientific knowledge into practice, and supporting long-term behavioral modifications in coaches. Specific recommendations (e.g., knowledge translation, gaining buy-in) for designing future interventions are highlighted. [ABSTRACT FROM AUTHOR]

Soccer requires athletes to make quick decisions in dynamic environments. Several off-court technology-based interventions have been developed to train these perceptual cognitive skills. However, the evidence for training transfer using technologies to athletic performance has been sparse. Previous research found 3-dimensional multiple object tracking (3D MOT) training to cause a significant increase in quality of passing decision-making. Limitations to the research warrant further investigation of this association. To re-examine the effectiveness of 3D MOT on training decision-making. Thirty-one NCAA Division III soccer players (female n = 16) were randomized to 3D MOT training or a control task. The experimental group received 10 training sessions over a span of 4 weeks. The manipulation check indicated a significant training effect in 3D MOT performance for the intervention but not the control group (F(1,29) = 21.46, p <.001, np2 =.43). Non-significant changes with small effect sizes (np2 =.01-.03) in decision-making and measures of near-transfer were found. The findings challenge the association between 3D MOT training and increased quality of decision-making in soccer. [ABSTRACT FROM AUTHOR]

The Basketball Learning and Performance Assessment Instrument (BALPAI) has been initially developed and evaluated to assess the performance of students or youth basketball players on the entry level. As it is currently the only observational instrument that allows an overall assessment of players' in-game performance, it might represent a valuable tool for talent identification and development purposes. To investigate this potential field of application, this study aimed to evaluate the BALPAI regarding reliability and diagnostic validity when assessing youth basketball players within a competitive setting. The study sample comprised N = 54 male youth players (M age = 14.36 ± 0.33 years) of five regional selection teams (Point Guards, PG: n = 19; Shooting Guards and Small Forwards, SG/SF: n = 21; and Power Forwards and Centers, PF/C: n = 14) that competed at the annual U15 national selection tournament of the German Basketball Federation (n = 24 selected; n = 30 non-selected). A total of 1997 ball-bound actions from five games were evaluated with BALPAI. The inter-rater reliability was assessed for technical execution, decision making, and final efficacy. The diagnostic validity of the instrument was examined via mean group comparisons of the players' offensive game involvement and performance regarding both selection-dependent and position-dependent differences. The inter-rater reliability was confirmed for all performance-related components (κ adj ≥ 0.51) while diagnostic validity was established only for specific the BALPAI variables. The selection-dependent analysis demonstrated higher offensive game involvement of selected players in all categories (p < 0.05, 0.27 ≤ Φ ≤ 0.40) as well as better performance in shooting and receiving (p < 0.05, 0.23 ≤ Φ ≤ 0.24). Within the positional groups, the strongest effects were demonstrated among PG (p < 0.05, 0.46 ≤ Φ ≤ 0.60). The position-dependent analysis revealed that PG are more involved in total ball-bound actions (p < 0.05; 0.34 ≤ Φ ≤ 0.53), passing (p < 0.001; 0.55 ≤ Φ ≤ 0.67), and dribbling (p < 0.05, 0.45 ≤ Φ ≤ 0.69) compared to players in other positions. Further differences between players according to selection status and playing position were not detected. The results of this evaluation indicate that the instrument, in its current form, is not yet applicable in competitive youth basketball. The findings highlight the importance of optimizing BALPAI for reliable and valid performance assessments in this context. Future studies should investigate the application of stricter and position-specific criteria to use the observational tool for talent identification and development purposes. [ABSTRACT FROM AUTHOR]

Fostering health-related fitness knowledge is a common goal across physical education curricula. However, carefully developed knowledge tests that satisfy the psychometric criteria of educational assessment are lacking. Therefore, two studies were conducted to evaluate a newly developed health-related fitness knowledge test within the framework of classical test and item response theory regarding item quality, test reliability, construct validity, and dimensionality. Overall, 794 ninth graders (Mage = 14.3 years, 50.6% girls) took part in Study 1. They differed in the type of physical education classes (minor or major subject) and school (lower or higher educational level) they attended. Study 2 incorporated 834 ninth graders at the same educational level (Mage = 14.2 years, 52.5% girls). Item–test correlation, test reliability, and validity were examined. In addition, item and test quality were investigated using unidimensional two-parameter logistic item response models. In Study 1, pupils at the same educational level with physical education as a major achieved higher knowledge scores than pupils with physical education as a minor (t = −5.99, p < 0.001; d = 0.58), which confirmed the test's construct validity. In Study 2, the weighted likelihood estimate reliability of the final 27 items was 0.65, and the test–retest reliability reached rtt = 0.70. The items satisfied the assumption of local independence. The final test fulfilled the psychometric criteria of reliability and construct validity to assess health-related fitness knowledge in cross-sectional and interventional studies. This test extends the possibilities of research on health-related fitness knowledge in physical education. [ABSTRACT FROM AUTHOR]

A central goal of physical education (PE) is to empower students to be physically active in a health-enhancing way. Therefore, using a competence-based approach, the objective of the health- and fitness-related PE intervention 'Promotion of physical activity-related health competence in PE' (GEKOS) was to address practical and theoretical content regarding training, fitness, and health. The aim of this person-oriented study was to examine differential effects of the GEKOS intervention on control competence and related knowledge, skills, abilities, and motivation. A total of 860 ninth graders were randomly assigned to an intervention or control group. Intervention group students received six PE lessons that combined practical and theoretical content regarding training, fitness, and health. Measurements were taken before, directly after, and with a follow-up after 8–12 weeks. Students completed a knowledge test and a fitness test, and filled out scales considering motivation and perceived control competence. Latent profile analysis and multinomial logistic regression were estimated. Five patterns of outcome measures were found. Intervention group students transitioned significantly more often to patterns with improved outcome values. The intervention was especially effective for a subgroup of students who initially had rather low outcome values. For a small proportion of students, the intervention entailed a loss of health-related motivation. The study indicated that students with low control competence and related knowledge, skills, abilities, and motivation can benefit from the GEKOS intervention. Future studies should investigate modes of actions and interventions that explicitly address motivation and vary the content and methods used in PE. [ABSTRACT FROM AUTHOR]

Facilitating players' skill acquisition is a major challenge within sport coaches' work which should be supported by evidence-based recommendations outlining the most effective practice and coaching methods. This systematic review aimed at accumulating empirical knowledge on the influence of practice design and coaching behavior on perceptual-motor and perceptual-cognitive skill acquisition in soccer. A systematic search was carried out according to the PRISMA guidelines across the databases SPORTDiscus, PsycInfo, MEDLINE, and Web of Science to identify soccer-specific intervention studies conducted in applied experimental settings (search date: 22nd November 2020). The systematic search yielded 8,295 distinct hits which underwent an independent screening process. Finally, 34 eligible articles, comprising of 35 individual studies, were identified and reviewed regarding their theoretical frameworks, methodological approaches and quality, as well as the interventions' effectiveness. These studies were classified into the following two groups: Eighteen studies investigated the theory-driven instructional approaches Differential Learning, Teaching Games for Understanding, and Non-linear Pedagogy. Another seventeen studies, most of them not grounded within a theoretical framework, examined specific aspects of practice task design or coaches' instructions. The Downs and Black checklist and the Template for Intervention Description and Replication were applied to assess the quality in reporting, risk of bias, and the quality of interventions' description. Based on these assessments, the included research was of moderate quality, however, with large differences across individual studies. The quantitative synthesis of results revealed empirical support for the effectiveness of coaching methodologies aiming at encouraging players' self-exploration within representative scenarios to promote technical and tactical skills. Nevertheless, "traditional" repetition-based approaches also achieved improvements with respect to players' technical outcomes, yet, their impact on match-play performance remains widely unexplored. In the light of the large methodological heterogeneity of the included studies (e.g., outcomes or control groups' practice activities), the presented results need to be interpreted by taking the respective intervention characteristics into account. Overall, the current evidence needs to be extended by theory-driven, high-quality studies within controlled experimental designs to allow more consolidated and evidence-based recommendations for coaches' work. [ABSTRACT FROM AUTHOR]

By focusing on high experimental control and realistic presentation, the latest research in expertise assessment of soccer players demonstrates the importance of perceptual skills, especially in decision making. Our work captured omnidirectional in-field scenes displayed through virtual reality glasses to 12 expert players (picked by DFB), 10 regional league intermediate players, and13 novice soccer goalkeepers in order to assess the perceptual skills of athletes in an optimized manner. All scenes were shown from the perspective of the same natural goalkeeper and ended after the return pass to that goalkeeper. Based on the gaze behavior of each player, we classified their expertise with common machine learning techniques. Our results show that eye movements contain highly informative features and thus enable a classification of goalkeepers between three stages of expertise, namely elite youth player, regional league player, and novice, at a high accuracy of 78.2%. This research underscores the importance of eye tracking and machine learning in perceptual expertise research and paves the way for perceptual-cognitive diagnosis as well as future training systems. [ABSTRACT FROM AUTHOR]

In many animal societies, dominant males have a higher reproductive success than subordinate males. The proximate mechanisms by which social rank influences reproductive success are poorly understood. One prominent hypothesis posits that rank‐related male attributes of attractiveness and fighting ability are the main mediators of reproductive skew. Yet, empirical evidence in support of this hypothesis is limited. An alternative hypothesis emphasises the inherent social dimension of dominance relationships and posits that the relationship between male social rank and reproductive success is mediated by the physiological costs of male–male competition. This has not been tested in systems in which the two hypotheses can be disentangled.We investigated the interplay between male social rank, physiological costs and male investment in social and sexual activities. We used measurements of faecal glucocorticoid metabolite concentrations (fGMC) as biomarkers of physiological costs and long‐term behavioural data of 319 males in free‐ranging spotted hyenas Crocuta crocuta, a species in which male access to females and reproductive success do not depend on physical attributes.When males courted females and interacted with male competitors, low‐ranking males had higher fGMC than high‐ranking males. In contrast, fGMC did not vary with social rank when males were alone or when they courted females and competitors were absent. Low‐ranking males minimised their exposure to physiologically costly intrasexual competition; they spent more time alone and less time engaging in social and sexual activities than did high‐ranking males. They also invested less than high‐ranking males in courting the most contested and highest‐quality females.Our findings demonstrate that the physiological costs of intrasexual competition in male spotted hyenas vary with social rank and shape behavioural trade‐offs between the allocation of time and physiological resources to social integration, reproduction and self‐maintenance. Our study suggests that physiological and social constraints play a pivotal role in the emergence of rank‐related male reproductive success. The study provides insights into how the social organisation and breeding system shape physiological constraints and patterns of reproductive skew within and between species. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to develop a valid video-based diagnostic instrument that assesses decision-making with a sport-specific motor response. Methods: A total of 86 German youth academy players (16.7 ± 0.9 years) viewed game situations projected on a large video screen and were required to make a decision by dribbling and passing to one of three targets (representing different decision options). The test included 48 clips separated into two categories: build-up (bu) and offensive decisions (off). Criterion-related validity was tested based on age (i.e., U16, U17, and U19), playing status (i.e., minutes played in official matches of the current season) and in a prospective approach relating to future youth national team status (i.e., selected or nonselected). Finally, it was investigated whether decision-making competence was influenced by playing position (i.e., defenders vs. midfielders vs. forwards). Results: Instrumental reliability demonstrated satisfactory values for SCbu (r = 0.72), and lower for SCoff (r = 0.56). Results showed the diagnostic instrument is suitable for discriminating between playing status (SCbu: Φ = 0.22, p < 0.01; SCoff: Φ = 0.14, p < 0.05) and between younger (U16) and older players (U17 > U16 in SCbu: Φ = 0.24 and SCoff: Φ = 0.39, p < 0.01; U19 > U16 in SCbu: Φ = 0.41 and SCoff: Φ = 0.46, p < 0.01); however, there was no difference between U17 and U19 players. Furthermore, the predictive value of the test indicates that future youth national team players make better decisions with respect to the build-up category (SCbu: Φ = 0.20; p < 0.05), whereas playing position did not significantly influence decision-making competence. Conclusion: Results indicate the video-based decision-making diagnostic instrument can discriminate decision-making competence within a high-performance youth group. The outcomes associated with national youth team participation demonstrate the predictive value of the diagnostic instrument. This study provides initial evidence to suggest a new video-based diagnostic instrument with a soccer-specific motor response can be used within a talent identification process to assist with assessment of decision-making performance. [ABSTRACT FROM AUTHOR]

Copyright of German Journal of Exercise & Sport Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Considering the scarce empirical evidence regarding talent predictors in female youth soccer, the present study aimed to investigate the long-term prognostic validity of elite female soccer players' adolescent motor performance for future success in adulthood. Additionally, the three-year development of highly talented girls' motor performance and the predictive value of this motor development for reaching a professional adult performance level (APL) was analysed. Overall, N = 737 female players participated in nationwide motor diagnostics (sprinting, agility, dribbling, ball control, shooting) within the German Soccer Association's talent identification and development programme at least twice between the age groups Under-12 (U12) and U15. Based on their APL at least four years later, participants were assigned to a professional (first German division, 6.2%) or non-professional group (lower divisions, 93.8%). Multilevel regression analyses revealed a general prognostic relevance for the investigated parameters with respect to players' APL. In addition, there was a non-linear improvement in participants' motor performance across all variables from U12 to U15. However, non-significant interactions between APL and these improvements indicate motor performance development itself cannot adequately predict players' future success in adulthood. Findings provide insightful information that can help coaches foster optimal support for young female soccer players' development. [ABSTRACT FROM AUTHOR]

Introduction: While research has provided valuable information about talent predictors, there is a gap regarding female soccer. This study analyzed the prognostic relevance of motor tests for players' future selection level in female soccer and assessed the role of sex as a moderator variable. Methods: Within the German talent promotion program, N = 499 U12 girls participated in motor diagnostics (sprint, agility, dribbling, ball control, shooting). Five years later, 14.2% of them made the youth national team (NT), 18.8% the regional association team (RA), and 66.9% were not further selected (NS). The tests' predictive validity for achieving one of these levels was analyzed using ANOVAs with post-hoc tests and logistic regressions. Subsequently, results were compared to data from previous research with N = 22,843 male U12 players. Results: Girls' performances in the motor diagnostics significantly discriminated between all three selection levels. Future NT players outperformed NS (d = 1.04) and RA players (d = 0.55), who, in turn, performed better than NS players (d = 0.47). Exception for dribbling, the motor tests demonstrated predictive validity independent of sex. Discussion: Although diagnostics are not sensitive enough to determine individual decisions for talent selection, they provide objective information to supplement coaches' work. [ABSTRACT FROM AUTHOR]

Within the multidimensional nature of soccer talent, recently there has been an increasing interest in psychological characteristics. The aim of this present research was to systematically review the predictive value of psychological talent predictors and provide better comprehension of the researchers’ methodological approaches and the empirical evidence for individual factors (i.e., psychomotor, perceptual-cognitive and personality-related). Results highlighted heterogeneous study designs (e.g., participants, measurement methods, statistical analyses) which may limit the comparability of studies’ findings. Analyzing the number of included studies, psychomotor (n = 10) and personality-related factors (n = 8) received more consideration within the literature than perceptual-cognitive factors (n = 4). In regard to empirical evidence, dribbling (0.47 ≤ d ≤ 1.24), ball control (0.57 ≤ d ≤ 1.28) and decision-making (d = 0.81) demonstrated good predictive values as well as the achievement motives hope for success (0.27 ≤ d ≤ 0.74) and fear of failure (0.21 ≤ d ≤ 0.30). In conclusion, there is growing acceptance of the need for more complex statistical analyses to predict future superior performance based on measures of current talent. New research addresses the necessity for large-scale studies that employ multidisciplinary test batteries to assess youth athletes at different age groups prospectively. [ABSTRACT FROM AUTHOR]

Individuals of many species rely on odors to communicate, find breeding partners, locate resources and sense dangers. In vertebrates, odorants are detected by chemosensory receptors of the olfactory system. One class of these receptors, the trace amine-associated receptors (TAARs), was recently suggested to mediate male sexual interest and mate choice. Here we tested this hypothesis in mice by generating a cluster deletion mouse (Taar2-9 −/−) lacking all TAARs expressed in the olfactory epithelium, and evaluating transduction pathways from odorants to TAARs, neural activity and behaviors reflecting sexual interest. We found that a urinary volatile amine, isobutylamine (IBA), was a potent ligand for TAAR3 (but not TAAR1, 4, 5, and 6). When males were exposed to IBA, brain regions associated with sexual behaviors were less active in Taar2-9 −/− than in wild type males. Accordingly, Taar2-9 −/− males spent less time sniffing both the urine of females and pure IBA than wild type males. This is the first demonstration of a comprehensive transduction pathway linking odorants to TAARs and male sexual interest. Interestingly, the concentration of IBA in female urine varied across the estrus cycle with a peak during estrus. This variation in IBA concentration may represent a simple olfactory cue for males to recognize receptive females. Our results are consistent with the hypothesis that IBA and TAARs play an important role in the recognition of breeding partners and mate choice. [ABSTRACT FROM AUTHOR]

Several talent identification and development (TID) programs in soccer have implemented diagnostics to measure players’ motor performance. Yet, there is a lack of research investigating the relationship between motor development in adolescence and future, adult performance. This longitudinal study analyzed the three-year development of highly talented young soccer players’ speed abilities and technical skills and examined the relevance of this development to their adult success. The current research sample consisted of N = 1,134 players born between 1993 and 1995 who were selected for the German Soccer Association’s TID program and participated in nationwide motor diagnostics (sprinting, agility, dribbling, ball control, shooting) four times between the Under 12 (U12) and Under 15 (U15) age class. Relative age (RA) was assessed for all players, and a total motor score was calculated based on performances in the individual tests. In order to investigate players’ future success, participants were divided into two groups according to their adult performance level (APL) in the 2014/2015 season: Elite (1st-5th German division; N = 145, 12.8%) and non-elite players (lower divisions; N = 989, 87.2%). Using multilevel regression analyses each motor performance was predicted by Time, Time2 (level-1 predictors), APL, and RA (level-2 covariates) with simultaneous consideration for interaction effects between the respective variables. Time and Time2 were significant predictors for each test performance. A predictive value for RA was confirmed for sprinting and the total motor score. A significant relationship between APL and the motor score as well as between APL and agility, dribbling, ball control, and shooting emerged. Interaction effects distinctly failed to reach significance. The study found a non-linear improvement in players’ performance for all considered motor performance factors over a three-year period from early to middle adolescence. While their predictive value for future success was confirmed by a significant relationship between APL and most of the considered factors, there was no significant interaction between APL and Time. These findings indicate that future elite players had already been better at the beginning of the TID program and maintained this high level throughout their promotion from U12 to U15. [ABSTRACT FROM AUTHOR]

Talent identification and selection in soccer is typically based on subjective evaluations of experienced coaches. Recently, there has been a trend to complement these subjective assessments with objective tests. However, there is currently no comprehensive overview of the prognostic relevance of objective measurements in youth soccer. Therefore, the primary purpose of the current study was to systematically review published empirical studies related to the prognostic relevance of physiological (e.g. endurance and speed) and physical characteristics (i.e. height and weight). Of 6876 initially identified studies, nine articles were included. In those studies, endurance (nine studies), change of direction (seven), height (seven), and weight (seven) received the most meaningful consideration within the literature. In regard to physiological predictors, between 16 and 29 effect sizes were tested for endurance, sprint, and change of direction, and about half of them were found to be significant with small to moderate effects (0.37 ≤ Mdn(d) ≤ 0.57). In addition, while only investigated in two studies all tested effect sizes for repeated sprint ability were found to be significant. Despite their frequent consideration in the literature, low numbers of significant effect sizes (≤ 26%) and magnitude (0.23 ≤ Mdn(d) ≤ 0.29) were found for the physical predictors height and weight. Overall, results appear to be dependent on the respective study design and, in particular, moderator variables (i.e. soccer development stage, performance level T1/T2, prognostic period, and sample size). Consequently, additional research seems warranted to more comprehensively investigate the predictive relevance of the individual characteristics using more homogeneous study designs.   [ABSTRACT FROM PUBLISHER]

Copyright of German Journal of Exercise & Sport Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Several talent development programs in youth soccer have implemented motor diagnostics measuring performance factors. However, the predictive value of such tests for adult success is a controversial topic in talent research. This prospective cohort study evaluated the long-term predictive value of 1) motor tests and 2) players’ speed abilities (SA) and technical skills (TS) in early adolescence. The sample consisted of 14,178 U12 players from the German talent development program. Five tests (sprint, agility, dribbling, ball control, shooting) were conducted and players’ height, weight as well as relative age were assessed at nationwide diagnostics between 2004 and 2006. In the 2014/15 season, the players were then categorized as professional (n = 89), semi-professional (n = 913), or non-professional players (n = 13,176), indicating their adult performance level (APL). The motor tests’ prognostic relevance was determined using ANOVAs. Players’ future success was predicted by a logistic regression threshold model. This structural equation model comprised a measurement model with the motor tests and two correlated latent factors, SA and TS, with simultaneous consideration for the manifest covariates height, weight and relative age. Each motor predictor and anthropometric characteristic discriminated significantly between the APL (p < .001; η2 ≤ .02). The threshold model significantly predicted the APL (R2 = 24.8%), and in early adolescence the factor TS (p < .001) seems to have a stronger effect on adult performance than SA (p < .05). Both approaches (ANOVA, SEM) verified the diagnostics’ predictive validity over a long-term period (≈ 9 years). However, because of the limited effect sizes, the motor tests’ prognostic relevance remains ambiguous. A challenge for future research lies in the integration of different (e.g., person-oriented or multilevel) multivariate approaches that expand beyond the “traditional” topic of single tests’ predictive validity and toward more theoretically founded issues. [ABSTRACT FROM AUTHOR]

In the debate about the usefulness of motor diagnostics in the talent identification process, the prognostic validity for tests conducted in early adolescence is of critical interest. Using a group- and individual-based statistical approach, this prospective cohort study evaluated a nationwide assessment of speed abilities and technical skills regarding its relevance for future achievement levels. The sample consisted of 22,843 U12-players belonging to the top 4% in German football. The U12-results in five tests served as predictors for players’ selection levels in U16-U19 (youth national team, regional association, youth academy, not selected). Group-mean differences proved the prognostic relevance for all predictors. Low individual selection probabilities demonstrated limited predictive values, while excellent test results proved their particular prognostic relevance. Players scoring percentile ranks (PRs) ≥ 99 had a 12 times higher chance to become youth national team players than players scoring PR < 99. Simulating increasing score cut-off values not only enhanced specificity (correctly identified non-talents) but also led to lower sensitivity (loss of talents). Extending the current research, these different approaches revealed the ambiguity of the diagnostics’ prognostic relevance, representing both the usefulness and several pitfalls of nationwide diagnostics. Therefore, the present diagnostics can support but not substitute for coaches’ subjective decisions for talent identification, and multidisciplinary designs are required. [ABSTRACT FROM PUBLISHER]

Adolescence is regarded as a key developmental phase in the course of talented football players' careers. The present study focuses on early adolescent players' development of achievement motives, volitional components, and self-referential cognitions. Based on the multidimensional and dynamic nature of talent, the development of multifaceted personality characteristics is an important issue in the context of sports talent research. According to previous findings in psychology, personality characteristics' development is defined by both stability and change, and the current study analyses four different types: differential stability (I), mean-level change (II), individual-level change (III), and structural stability (IV). The sample consists of 151 male players in the talent development programme of the German Football Association. Psychological diagnostics of the personality characteristics are implemented across longitudinal sections over a time period of three seasons, from the U12 to U14 age classes. The results reveal that the personality characteristics show (I) moderate test–retest correlations over one-year intervals (.43 ≤ rtt ≤ .62), and lower coefficients for a two-year period (.26 ≤ rtt ≤ .53). (II) Most of the personality characteristics' mean values differ significantly across the age classes with small effect sizes (.01 ≤  ≤ .03). (III) Only minor individual-level changes in the football players' development are found. (IV) The personality characteristics' associations within a two-factor structure do not stay invariant over time. From the results of the present study, conclusions are drawn regarding the talent identification and development process. [ABSTRACT FROM AUTHOR]

Enzyme immunoassays ( EIAs) are widely used to quantify concentrations of hormone metabolites. Modifications in laboratory conditions may affect the accuracy of metabolite concentration measurements and lead to misinterpretations when results of different accuracy are combined for a statistical analysis. This issue is of great relevance to studies in behavioural and evolutionary ecology because these usually aim at understanding how hormone concentrations vary between individuals, environments or experimental conditions., We present a method based on re-assaying a subset of samples to standardize hormone metabolite concentrations when changes in EIA accuracy occur. We used glucocorticoid metabolite concentrations ( fGMCs) measured in faeces of spotted hyaenas ( Crocuta crocuta) between 2011 and 2013 with a previously validated EIA. Changes in accuracy were assessed by monitoring the metabolite concentration of faecal control 'pools' that were systematically assayed with faecal samples. A cluster analysis on these pools identified two distinct sample sets with different EIA accuracy; 'Cluster 1' and 'Cluster 2'. We then re-assayed all samples of Cluster 1 ( n = 138) with an EIA accuracy similar to that of Cluster 2 and fitted a linear regression to the remeasured fGMCs against the initial fGMCs to predict fGMCs in Cluster 2. To determine the minimum number of samples to re-assay that allows reliable predictions, we assessed the variation in the quality of model predictions by fitting linear regressions on decreasing numbers of re-assayed samples. This revealed that re-assaying 27 samples would be sufficient to generate reliable predictions considering our data set., To test the robustness of our method, we fitted a new linear regression to 27 randomly chosen samples and used its equation to standardize all fGMCs of Cluster 1. The standardized fGMCs were similar to the remeasured fGMCs, and the regression on 27 samples was as effective at standardizing fGMCs as the regression fitted on the complete data set., Our standardization method permits the combination of results of different accuracy. It is a simple and reliable alternative to the costly, time-consuming and often impractical re-assaying of complete sample sets that can be applied to a wide variety of species and sample types. [ABSTRACT FROM AUTHOR]

The utilisation of motor performance tests for talent identification in youth sports is discussed intensively in talent research. This article examines the reliability, differential stability and validity of the motor diagnostics conducted nationwide by the German football talent identification and development programme and provides reference values for a standardised interpretation of the diagnostics results. Highly selected players (the top 4% of their age groups, U12–U15) took part in the diagnostics at 17 measurement points between spring 2004 and spring 2012 (N = 68,158). The heterogeneous test battery measured speed abilities and football-specific technical skills (sprint, agility, dribbling, ball control, shooting, juggling). For all measurement points, the overall score and the speed tests showed high internal consistency, high test–retest reliability and satisfying differential stability. The diagnostics demonstrated satisfying factorial-related validity with plausible and stable loadings on the two empirical factors “speed” and “technical skills”. The score, and the technical skills dribbling and juggling, differentiated the most among players of different performance levels and thus showed the highest criterion-related validity. Satisfactory psychometric properties for the diagnostics are an important prerequisite for a scientifically sound rating of players’ actual motor performance and for the future examination of the prognostic validity for success in adulthood. [ABSTRACT FROM AUTHOR]

Copyright of Sportwissenschaft is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study examined the disturbing effects of relative age on the talent identification process in the talent development programme of the German Football Association. The bias in the selection rate was examined via the extent of relative age effects. The bias in motor performance diagnostics was analysed by comparing the motor performance of selected players with normal motor development. The mechanisms underlying the relative age biases in motor performance were examined by modelling the direct and indirect effects of relative age on single motor performance tests for sprint, running agility, dribbling and ball passing and control. Data from 10,130 selected football players from the U12 to U15 age groups were collected in autumn 2010. The birth distribution differed significantly from the reference population with approximately 61% of the players born in the first half of the year. The selection probability was approximately two times higher for players born in the first quarter of the year than for players born in the last quarter. Revised motor performance diagnostics showed better results on average for relatively younger players. Path analysis revealed significant direct and indirect relative age effects for physiologically demanding tests and almost no effects for technically demanding tests. Large sample sizes allowed high resolution in relative age with additional informational content and multivariate modelling of the complex relationships among relative age, physical development and motor performance. The results are discussed on how relative age affects the effectiveness and fairness of talent identification and development processes. [ABSTRACT FROM PUBLISHER]

Copyright of Sportwissenschaft is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Spotted hyenas live in social groups of up to 100 members. In these complex societies, a strikingly simple behavioural pattern has evolved that efficiently prevents inbreeding: females are very picky when it comes to choosing a father for their young and as a result, most sexually mature males disperse from the group. The results of pioneering studies in Tanzania's Ngorongoro Crater. [ABSTRACT FROM AUTHOR]

Copyright of Forschung is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: The diet of free-ranging carnivores is an important part of their ecology. It is often determined from prey remains in scats. In many cases, scat analyses are the most efficient method but they require correction for potential biases. When the diet is expressed as proportions of consumed mass of each prey species, the consumed prey mass to excrete one scat needs to be determined and corrected for prey body mass because the proportion of digestible to indigestible matter increases with prey body mass. Prey body mass can be corrected for by conducting feeding experiments using prey of various body masses and fitting a regression between consumed prey mass to excrete one scat and prey body mass (correction factor 1). When the diet is expressed as proportions of consumed individuals of each prey species and includes prey animals not completely consumed, the actual mass of each prey consumed by the carnivore needs to be controlled for (correction factor 2). No previous study controlled for this second bias. Methodology/Principal Findings: Here we use an extended series of feeding experiments on a large carnivore, the cheetah (Acinonyx jubatus), to establish both correction factors. In contrast to previous studies which fitted a linear regression for correction factor 1, we fitted a biologically more meaningful exponential regression model where the consumed prey mass to excrete one scat reaches an asymptote at large prey sizes. Using our protocol, we also derive correction factor 1 and 2 for other carnivore species and apply them to published studies. We show that the new method increases the number and proportion of consumed individuals in the diet for large prey animals compared to the conventional method. Conclusion/Significance: Our results have important implications for the interpretation of scat-based studies in feeding ecology and the resolution of human-wildlife conflicts for the conservation of large carnivores. [ABSTRACT FROM AUTHOR]

Summary 1. The long-term ecological impact of pathogens on group-living, large mammal populations is largely unknown. We evaluated the impact of a pathogenic bacterium, Streptococcus equi ruminatorum, and other key ecological factors on the dynamics of the spotted hyena Crocuta crocuta population in the Ngorongoro Crater, Tanzania. 2. We compared key demographic parameters during two years when external signs of bacterial infection were prevalent ('outbreak') and periods of five years before and after the outbreak when such signs were absent or rare. We also tested for density dependence and calculated the basic reproductive rate R0 of the bacterium. 3. During the five pre-outbreak years, the mean annual hyena mortality rate was 0·088, and annual population growth was relatively high (13·6%). During the outbreak, mortality increased by 78% to a rate of 0·156, resulting in an annual population decline of 4·3%. After the outbreak, population size increased moderately (5·1%) during the first three post-outbreak years before resuming a growth similar to pre-outbreak levels (13·9%). We found no evidence that these demographic changes were driven by density dependence or other ecological factors. 4. Most hyenas showed signs of infection when prey abundance in their territory was low. During the outbreak, mortality increased among adult males and yearlings, but not among adult females - the socially dominant group members. These results suggest that infection and mortality were modulated by factors linked to low social status and poor nutrition. During the outbreak, we estimated R0 for the bacterium to be 2·7, indicating relatively fast transmission. 5. Our results suggest that the short-term 'top-down' impact of S. equi ruminatorum during the outbreak was driven by 'bottom-up' effects on nutritionally disadvantaged age-sex classes, whereas the longer-term post-outbreak reduction in population growth was caused by poor survival of juveniles during the outbreak and subsequent poor recruitment of breeding females. These results suggest synergistic effects of 'bottom-up' and 'top-down' processes on host population dynamics. [ABSTRACT FROM AUTHOR]

Objectives: The present study tested the effectiveness of a theory-based intervention (VIN-CET) aimed to promote physical activity and to improve health-related quality of life in cardiac rehabilitation. Design: Program effectiveness was evaluated by means of a quasi-experiment with a longitudinal sample of 485 individuals with cardiovascular diseases participating in a 3-week inpatient rehabilitation program (phase II). The VIN-CET intervention was integrated into the exercise therapy of the standard program ( n = 300). Standard program participants were used as comparison group ( n = 185). Follow-ups were conducted at 3 and 12 months after the intervention. Method: Physical exercise and leisure-time physical activity were assessed by standardised self-report measures. Physical and mental health status was measured with the SF-12 and physical functioning was assessed with a sub-scale of the SF-36. Results: One year after the intervention, group comparisons showed small intervention effects ( ps < .05) for physical exercise (Standardised Mean Difference, SMD = 0.22), physical health status (SMD = 0.20) and physical functioning (SMD = 0.17). Conclusion: The VIN-CET intervention seems to be an effective and efficient way of promoting physical exercise in cardiac rehabilitation. Practical significance is reinforced by effects on physical aspects of health-related quality of life. [ABSTRACT FROM AUTHOR]

GLO:W52/01dec21:fee2441-fig-0001.jpg PHOTO (COLOR): . gl The society of spotted hyenas ( I Crocuta crocuta i ) is often depicted as a textbook example of uncontested female supremacy. Hyena mothers are the fiercest and most reliable allies; they support their young - daughters and sons - against members of lower-ranking matrilines and thereby ensure they hold the social rank right below their own. Male hyenas are portrayed as pushovers that must show deference to hyper-aggressive females if they wish to mate or feed. [Extracted from the article]

We used naturally occurring spatial and temporal changes in prey abundance to investigate whether the foraging behavior of a social, territorial carnivore, the spotted hyena (Crocuta crocuta), conformed to predictions derived from the ideal free distribution. We demonstrate that hyenas in the Ngorongoro Crater, Tanzania, redistributed themselves from less profitable to more profitable areas, even when this required them to undertake foraging trips to areas beyond their clan territory boundary, or required normally philopatric females to emigrate. As expected for a system with rank related access to food resources in the territory, females of low social status foraged more often outside their territory and were more likely to emigrate than dominant females. Probably because Crater hyenas regularly foraged outside their territories, there was no correlation between clan size and prey density within territories, suggesting that clan sizes may have exceeded the carrying capacity of territories. A substantial decline of the hyena population in the Crater from 385 adults in the mid 1960s to 117 in 1996 was most likely due to a substantial decline of their main prey. The decline in the hyena population was associated with a decline in the size of clans but not in the number of clans. The number of clans probably remained constant due to emigration by females from large clans into vacant areas or clans with no adult females, and because hyenas regularly fed in areas containing concentrations of prey beyond their territory boundary. Between 1996 and 2003 annual recruitment rates of Crater hyenas consistently exceeded annual mortality rates, resulting in an almost doubling of the adult population. This increase was most likely due to an increase in prey abundance, a relatively low level of predation on hyenas by lions (Panthera leo), and an absence of high levels of disease related mortality. [ABSTRACT FROM AUTHOR]

Avian models of facultative siblicide predict that rates of sibling aggression and the incidence of siblicide should be lower in prey-rich than prey-poor environments, and that siblicide should only occur when fitness benefits outweigh costs. We tested these predictions by comparing data from spotted hyena ( Crocuta crocuta) twin litters in the Ngorongoro Crater, Tanzania, a habitat with a high density of resident prey (176 animals/km2) with similar data from the adjacent Serengeti National Park where density of resident prey is low (3.3 animals/km2). As predicted, rates of sibling aggression in Crater twin litters were substantially lower than those among twin siblings in the Serengeti. There was no evidence of siblicide in the Crater, in contrast to the Serengeti, where facultative siblicide occurs frequently. The growth rate of Crater cubs in singleton litters was similar to that of cubs in twin litters, whereas the growth rate of Serengeti singletons was higher than that of cubs in twin litters. Thus despotic behavior by dominant Crater cubs was unlikely to provide fitness benefits, while dominant Serengeti cubs that eliminated their sibling benefited from increased growth and enhanced survival. Previous studies have demonstrated biases in the sex-composition of hyena litters due to facultative siblicide. No such biases were apparent in Crater litters. Our results provide strong evidence that levels of sibling aggression in spotted hyenas are adjusted in an adaptive manner, and that siblicide is facultative and resource dependent. Our results do not support the idea of pre-natal manipulation of offspring sex by female spotted hyenas in response to changes in resource abundance. [ABSTRACT FROM AUTHOR]

Summary 1.Over the last three decades the main prey species (wildebeest Connochaetes taurinus , zebra Equus burchelli , Thomson’s gazelle Gazella thomsoni , and Grant’s gazelle Gazella granti ) of spotted hyaenas Crocuta crocuta in the Ngorongoro Crater, Tanzania, substantially declined in numbers, whereas buffalo Syncerus caffer numbers increased strongly. This provided a ‘natural experiment’ to investigate how a generalist predator such as the spotted hyaena responds to long-term changes in prey populations. Here we compare data on the feeding ecology of Crater hyaenas from the late 1990s (period II) with equivalent data from the late 1960s (period I). 2.Hyaenas showed strong hunting preferences for wildebeest calves and gazelle fawns during both periods I and II. Adult buffaloes, prey difficult to hunt for hyaenas, were rarely hunted in either period despite a large increase in buffalo numbers from period I to II. 3.Hyaenas exhibited a functional response to the changes in prey populations by killing more buffalo calves and adult wildebeest during period II, relatively easy prey categories for hyaenas to hunt. 4.The proportion of carcasses scavenged and acquired by kleptoparasitizing other predators increased from period I to II. This was facilitated by an increase in the relative number of lion kills available to hyaenas during the same period. 5.Hyaenas defended a similar proportion of their kills against kleptoparasitic attempts by lions during both periods. Since the ratio of kills hyaenas kleptoparasitized from lions in relation to kills lost to lions increased from period I to period II, hyaenas obtained more food resources from lions during period II than I. 6.The success of hyaenas kleptoparasitizing lions was influenced by the presence of male lions and the ability of hyaenas to recruit sufficient clan members to appropriate carcasses from lions. 7.This study is the first to demonstrate both a functional response of a... [ABSTRACT FROM AUTHOR]

Members of the genus Colobus have been observed to associate frequently with Cercopithecus monkeys in several African sites. In the Taï National Park, Ivory Coast, one group of western red colobus was found to be in association with one particular group of diana monkeys more than could be expected by chance ( Holenweg et al., 1996). We show that dyadic association is not an idiosyncrasy of these two groups, but rather a pattern that is general for our study site. All five red colobus groups we studied were closely associated with diana monkeys during more than 60% of the time. Four groups had one particular diana partner group, the fifth two different partners. Apart from the red colobus, three more primate species, the olive colobus, Campbell's monkey, and the lesser spot-nosed monkey, were also strongly attracted to diana monkeys. [ABSTRACT FROM AUTHOR]