Towards a Grand Unified Theory of sports performance

Inconsistencies in the perceived impact of the menstrual cycle on sport performance and in the prevalence of menstrual cycle symptoms: A scoping review of the literature

OBJECTIVES

This scoping review aimed to summarize the findings of studies regarding the perceived impact of the menstrual cycle on athletic performance, as well as the prevalence of negative menstrual cycle symptoms.

DESIGN

Scoping review.

METHODS

Three databases were searched and the Preferred Reporting Items for Systematic reviews and Meta Analyses extension for Scoping Reviews (PRISMA-ScR) was used as guidance.

RESULTS

A total of 39 studies were included in the final analysis. Between 2.8 and 100 % of athletes reported their performance being negatively impacted by their menstrual cycle, and the main reason was the occurrence of menstrual cycle symptoms. Additionally, a large variability in the prevalence of menstrual cycle symptoms was reported in the different studies mainly due to methodological differences and recall biases.

CONCLUSIONS

Similarly, as to what has been reported in reviews summarizing performance outcomes during different menstrual cycle phases, this review highlights the high degree of variability between how athletes perceive to be impacted by their menstrual/hormonal contraceptive cycle.

REGISTRATION

The protocol of this scoping review was registered at the Open Science Framework on 14 September 2023 (osf.io/efu9x).

Assessing the individual relationships between physical test improvements and external load match parameters in male professional football players-a brief report

Purpose

This study aimed to explore whether a meaningful improvement in physical performance following an in-season strength training intervention can be related to external load match parameters at an individual level in professional male football players.

Methods

Eight male professional football players (25.4 ± 3.1 years, 184.1 ± 3.4 cm, 79.3 ± 2.2 kg) completed a 10-week strength intervention period in addition to football-specific training and matches. Commonly used physical and external load measures were assessed before and after intervention. Physical performance improvements had to exceed the measurement's typical error and the smallest worthwhile difference (SWD) to be considered meaningful. External load match parameters were assessed before and after the intervention period using SWD and non-overlap of all pairs (NAP) analysis. A Bayesian pairwise correlation analysis was performed to evaluate relationships between changes in physical performance and external load match parameters.

Results

Three players displayed meaningful improvements in two to five physical performance measures. However, positive changes exceeding the SWD and positive effects in NAP results were observed for all players in external load match parameters. Kendall's tau correlation analysis showed evidence (base factor >3) for only one correlation (maximum speed - decelerations, τ = -0.62) between the changes in physical performance and external load measures, while the remaining comparisons exhibited no relation.

Conclusions

The findings suggest that improvements in physical performance may not necessarily translate to improvements in external load match parameters. Further research, with larger sample sizes, is needed to understand potential mechanisms between acute and chronic physical performance changes and football external load parameters during training and matches.

Understanding the effects of a sudden directional shift in somatosensory feedback and increasing task complexity on postural adaptation in individuals with and without chronic ankle instability

BACKGROUND

Individuals with chronic ankle instability (CAI) present somatosensory dysfunction following an initial ankle sprain. However, little is known about how individuals with CAI adapt to a sudden sensory perturbation of instability with increasing task and environmental constraints to maintain postural stability.

METHODS

Forty-four individuals with and without unilateral CAI performed the Adaptation Test to a sudden somatosensory inversion and plantarflexion perturbations (environment) in double-, injured-, and uninjured- limbs. Mean sway energy scores were analyzed using 2 (group) × 2 (somatosensory perturbations) × 3 (task) repeated measures analysis of variance.

RESULTS

There were significant interactions between the group, environment, and task (P=.025). The CAI group adapted faster than healthy controls to a sudden somatosensory inversion perturbation in the uninjured- (P=.002) and injured- (P<.001) limbs, as well as a sudden somatosensory plantarflexion perturbation in the double- (P=.033) and uninjured- (P=.035) limbs. The CAI and healthy groups presented slower postural adaptation to a sudden inversion perturbation than a sudden somatosensory plantarflexion perturbation in double-limb (P<.001). Whereas both groups demonstrated faster postural adaptation to a sudden somatosensory inversion perturbation compared to somatosensory plantarflexion perturbation while maintaining posture in the injured- (P<.001) and uninjured- (P<.001) limbs. The CAI and healthy groups adapted faster to a sudden somatosensory inversion perturbation in the injured- (P<.001) and uninjured- (P<.001) limbs than in double-limb, respectively.

DISCUSSION

Postural adaptation in individuals with and without CAI depended on environmental (somatosensory perturbations) and task constraints. The CAI group displayed comparable and faster postural adaptation to a sudden somatosensory inversion and plantarflexion in double-, injured-, and uninjured- limbs, which may reflect a centrally mediated alteration in neuromuscular control in CAI.

The Influence of Contextual and Theoretical Expertise on Generic and Occupation-Specific Lifting Strategy

OBJECTIVE

To determine whether (i) low back loads and/or (ii) kinematic coordination patterns differed across theoretical expert, contextual expert and novice groups when completing both generic and occupation-specific lifts.

BACKGROUND

Experience has been proposed as a factor that could reduce biomechanical exposures in lifting, but the literature reports mixed effects. The inconsistent relationship between experience and exposures may be partially attributable to the broad classification of experience and experimental lifting protocols not replicating the environment where experience was gained.

METHODS

Purposive sampling was used to recruit 72 participants including theoretical experts (formal training on lifting mechanics), contextual experts (paramedics), and novices. Participants performed 10 barbell and crate (generic) lifts, as well as backboard and stretcher (occupation-specific) lifts while whole-body kinematics and ground reaction forces were collected. Peak low back compression and anteroposterior shear loads normalized to body mass, as well as kinematic coordination patterns, were calculated as dependent variables.

RESULTS

No significant differences in low back loads were observed across expertise groups. However, significant differences were seen in kinematic coordination patterns across expertise groups in occupation-specific lifts, but not in generic lifts.

CONCLUSION

Increasing expertise is unlikely to minimize low back loads in lifting. However, contextual expertise did influence lifting kinematics, but only when performing occupationally specific lifts.

APPLICATION

Contextual expertise may help lifters adopt lifting kinematics that enhance the tolerance of their musculoskeletal system to withstand applied loads, but does not seem to reduce the applied low back loads relative to noncontextual expert groups.

Contextualizing Evaluation of Performance in Volleyball: Introducing Contextual Individual Contribution Coefficients to Assess Technical Actions

In this study, we proposed novel metrics for evaluating volleyball technical performance in relation to the action context. To assess each player's relative participation, we also introduced relative contextual coefficients. We analyzed 20 games played by the world's top eight teams during the 2019 FIVB Women's Club World Championship, using Data Volley software and Python programming. We evaluated inter- and intra-observer reliability and used binomial logistic regression models to estimate each variable's probability of having contributed to the team's set win. We calculated estimated confidence intervals, standard errors, and Wald values; and we employed Akaike's and Bayesian criteria to evaluate the model's goodness of fit. We identified optimal cut-off points using receiver operating characteristic curves, and we found that the proposed contextual evaluation coefficients prevented overestimation of a player's technical performance in uneven situations. We addressed the issue in which the winning team may be the one that scored the fewest points, and we were able to predict a team's victory with confidence. The proposed coefficients made multiple technical and contextual aspects of the game easily accessible and comprehensible, offering significant beneficial implications for coaches and players.

Biomechanical role can vary depending on the conditions of the motor task

Expert players in throwing sports may reduce the variability of projectile arrival position by systematically relating release parameters (e.g., release position, velocity, and angular velocity of the projectile). Reducing the variability of the projectile arrival position is often believed to increase the success rate of throwing task, but it may not be always true. Here, we experimentally illustrate that the systematic relationship between release parameters that reduce the variability of the ball arrival position may not increase the number of hitting trials during a throwing task. Furthermore, we demonstrate that the role of the release parameters in increasing successful trials can vary depending on the target size. Each participant threw balls at two different-sized targets (small and large target conditions). Additionally, they alternately threw balls with overhead and sidearm throwing for both the small and large targets. Our results showed that the release position and velocity in the left-right direction reduced the variability of the ball arrival position and increased the successful trials in the small target condition. In the large target condition, the two release parameters reduced the variability of the ball arrival position, but they did not increase the successful trials. Consequently, reducing the variability of the ball arrival position did not always equate to an increase in successful trials, as it depended on the target size. These findings indicate that the role of the release parameters in increasing hitting trials is not constant but varies depending on the condition of the motor task.

Can we enable individuals to reach further down without rounding their backs before beginning a lift? Examining the influence of starting foot and trunk position on reach depth

There is disagreement regarding the efficacy of 'safe' lifting recommendations for reducing low back disorder risk. These recommendations commonly focus on minimising lumbar spine flexion, which limits the range of allowable starting lift positions for that person. This study evaluated whether starting postural adaptations could allow a person to reach down further without rounding their lumbar spine before beginning a lift. Reach displacement was measured as participants performed a series of maximal reach tasks under different combinations of stance width, foot orientation and trunk inclination, with their lumbar spine motion restricted. There were no interactions between any of the three postural adaptations or any effect of stance width or trunk inclination. Seventy-nine percent of participants achieved their greatest reach displacement with their feet externally rotated, which contributed to a 4 cm greater reach displacement compared to a neutral foot orientation (p < 0.001).Practitioner summary: This study examined whether aspects of initial posture could influence the ability to adhere to 'safe' lifting recommendations across a range of lift heights. As a component of lifting (re)training interventions, practitioners should consider starting lift posture adaptations (e.g. manipulating foot external rotation) to improve capacity to adhere to recommendations.

Quantifying how functional and structural personal factors influence biomechanical exposures in paramedic lifting tasks

It is unknown how structural (sex, stature, body mass) and functional (strength, flexibility) personal factors influence lifting strategy in paramedic work. We explored whether variance in peak low back forces and kinematic coordination patterns could be explained by structural and functional personal factors in paramedic lifting tasks. Seventy-two participants performed backboard and stretcher lifts. Peak low back forces normalised to body mass, as well as kinematic coordination patterns, were calculated as dependent variables. Being female, stronger, shorter, having higher body mass, and/or having greater lower body range of motion (ROM) were all independently associated with lower normalised low back forces across backboard and stretcher lifting. Females and stronger individuals seemed to define a movement objective to consistently minimise compressive forces, while individuals with greater hip ROM consistently minimised anteroposterior shear forces. The efficacy of improving strength and hip ROM to reduce low back forces in paramedic lifting should be investigated.Practitioner summary: Females, stronger individuals, and individuals with greater hip range of motion consistently exhibited lower normalised low back forces in paramedic lifting. Improving strength and hip range of motion via training is a potential proactive ergonomics approach to reduce peak low back forces in paramedic lifting tasks.

Beyond the border of the athlete-centered approach: a model to understand runners' performance

Our purpose is to move beyond the borders of the athlete-centered approach by examining the runners' environment interplay as a key factor for performance. Based on the ecological systems theory, the micro-level (intrapersonal, interpersonal, and training characteristics), meso-level (a direct association with athletes is not observed, but the environment plays an influence on the relationships built at the micro-level), and macro-level (contextual features that influence athletic systems) were theorized and contextualized as important factors for the expression of different outcomes, including performance and participation. We also conceptualized the microtime, mesotime, and macrotime as a constraint. Through this model, we aimed to provide applications and conclusions about how this conceptual model provides advances in the scientific research field. By understanding how environmental factors influence their performance, runners can make informed decisions about where and how to train and compete. Furthermore, by recognizing the role of culture and social context in shaping runners' experiences and outcomes, we can work toward creating a more equitable and supportive running culture for all.

Joint Coordination With a Change in Task Constraint During Accurate Overhead Throwing

In sports situations, players may be required to throw at different speeds. The question of how skilled players throw the ball accurately to the desired location under different speed conditions is of interest to biomechanics researchers. Previous research suggested that throwers use different types of joint coordination. However, joint coordination with a change in throwing speed has not been studied. Here, we show the effects of changes in throwing speed on joint coordination during accurate overhead throwing. Participants were seated on a low chair with their trunk fixed and threw a baseball aimed at a target under 2 different speed conditions (slow and fast). In the slow condition, the elbow flexion/extension angle coordinated with other joint angles and angular velocities to reduce the variability of the vertical hand velocity. In the fast condition, the shoulder internal/external rotation angle and the shoulder horizontal flexion/extension angular velocity coordinated with other joint angles and angular velocities to reduce the variability of the vertical hand velocity. These results showed that joint coordination differed with changes in throwing speed, indicating that joint coordination is not always fixed, but may differ depending on the task constraints, such as throwing speed.

Walking Endurance and Oxygen Uptake On-Kinetics in Individuals With Parkinson Disease Following Overground Locomotor Training

BACKGROUND AND PURPOSE

Poor walking endurance in Parkinson disease (PD) may be attributable to both bioenergetic and biomechanical factors, but locomotor training methods addressing both these factors simultaneously are understudied. Our objective was to examine the effects of overground locomotor training (OLT) on walking endurance in individuals with mild-to-moderate PD, and to further explore potential cardiorespiratory contributions.

METHODS

A single-arm, longitudinal design was used to examine the effects of 24 biweekly sessions of OLT in people with mild-to-moderate PD (n = 12). Walking endurance was measured as total distance walked during a 10-minute walk test (10minWT). Oxygen uptake (V˙ o2 ) on-kinetic profiles were determined using a monoexponential function. Perceived fatigability was assessed following the 10minWT using a self-report scale. Magnitude of change in primary outcomes was assessed using Cohen's d and adjusted for sample size (Cohen's d(unbiased) ).

RESULTS

Participants executed 3036 (297) steps and maintained 65.5% (8%) age-predicted heart rate maximum in a typical session lasting 56.9 (2.5) minutes. Medium effects in total distance walked-885.9 (157.2) versus 969.5 (140.9); Cohen's d(unbiased) = 0.54-and phase II time constant of the V˙ o2 on-kinetic profile-33.7 (12.3) versus 25.9 (15.3); Cohen's d(unbiased) = 0.54-were observed alongside trivial effects for perceived fatigability-4.7 (1.4) versus 4.8 (1.5); Cohen's d(unbiased) = 0.11-following OLT.

DISCUSSION AND CONCLUSIONS

These preliminary findings may demonstrate the potential for moderate-intensity OLT to improve walking endurance and enhance cardiorespiratory adjustments to walking activity in adults with mild-to-moderate PD.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A407 ).

Which Factors Influence Running Gait in Children and Adolescents? A Narrative Review

In recent years, running has dramatically increased in children and adolescents, creating a need for a better understanding of running gait in this population; however, research on this topic is still limited. During childhood and adolescence multiple factors exist that likely influence and shape a child's running mechanics and contribute to the high variability in running patterns. The aim of this narrative review was to gather together and assess the current evidence on the different factors that influence running gait throughout youth development. Factors were classified as organismic, environmental, or task-related. Age, body mass and composition, and leg length were the most researched factors, and all evidence was in favour of an impact on running gait. Sex, training, and footwear were also extensively researched; however, whereas the findings concerning footwear were all in support of an impact on running gait, those concerning sex and training were inconsistent. The remaining factors were moderately researched with the exception of strength, perceived exertion, and running history for which evidence was particularly limited. Nevertheless, all were in support of an impact on running gait. Running gait is multifactorial and many of the factors discussed are likely interdependent. Caution should therefore be taken when interpreting the effects of different factors in isolation.

Evaluating the influence of a constraint manipulation on technical, tactical and physical athlete behaviour

Evaluating practice design is an important component of supporting skill acquisition and improving team-sport performance. Constraint manipulations, including creating a numerical advantage or disadvantage during training, may be implemented by coaches to influence aspects of player or team behaviour. This study presents methods to evaluate the interaction between technical, tactical and physical behaviours of professional Australian Football players during numerical advantage and disadvantage conditions within a small-sided game. During each repetition of the game, team behaviour was manually annotated to determine: repetition duration, disposal speed, total disposals, efficiency, and disposal type. Global Positioning System devices were used to quantify tactical (surface area) and physical (velocity and high intensity running) variables. A rule association and classification tree analysis were undertaken. The top five rules for each constraint manipulation had confidence levels between 73.3% and 100%, which identified the most frequent behaviour interactions. Specifically, four advantage rules involved high surface area and medium high intensity running indicating the attacking team's frequent movement solution within this constraint. The classification tree included three behaviour metrics: surface area, velocity 1SD and repetition duration, and identified two unique movement solutions for each constraint manipulation. These results may inform if player behaviour is achieving the desired outcomes of a constraint manipulation, which could help practitioners determine the efficacy of a training task. Further, critical constraint values provided by the models may guide practitioners in their ongoing constraint manipulations to facilitate skill acquisition. Sport practitioners can adapt these methods to evaluate constraint manipulations and inform practice design.

Match Analysis in Team Ball Sports: An Umbrella Review of Systematic Reviews and Meta-Analyses

Background

Match analysis has evolved exponentially over the past decades in team sports resulting in a significant number of published systematic reviews and meta-analyses. An umbrella review of the available literature is needed to provide an integrated overview of current knowledge and contribute to more robust theoretical explanations of team performance.

Methods

The Web of Science (all databases), PubMed, Cochrane Library (Cochrane Database of Systematic Reviews), Scopus, and SPORTDiscus databases were searched for relevant publications prior to 19 February 2021. Appraisal of the methodological quality of included articles was undertaken using the tool for Assessing the Methodological Quality of Systematic Reviews (AMSTAR-2). Twenty-four studies were reviewed that met the following criteria: (1) contained relevant data from match analyses in team ball sports; (2) were defined as systematic reviews or/and meta-analyses; and (3) were written in the English language.

Results

The overall methodological quality of the 24 included reviews, obtained through the AMSTAR-2, revealed very low confidence ratings (Critically Low, n = 12) for the results of most systematic reviews of match analyses in team ball sports. Additionally, the results showed that research is focused mainly on four levels of analysis: (1) dyadic (microlevel); (2) individual (molecular level; predominant); (3) group (mesolevel), and (4) team dynamics (macrolevel). These levels of analysis included tactical, technical, physical, and psychosocial variables. Team performance was contextualized at two levels, with reference to: (1) match context (e.g. match status, match location, match period, quality of opposition) and (2) sociodemographic and environmental constraints (sex, age groups, competitive level, altitude, temperature, pitch surface).

Conclusions

The evolution of methods for match analysis in team ball sports indicates that: (1) an individual-level performance analysis was predominant; (2) the focus on intermediate levels of analysis, observing performance in dyadic and group interactions, has received less attention from researchers; (3) neglected areas of research include psychosocial aspects of team sports and women’s performance; and (4) analyses of match contexts need greater depth.

Registration: The protocol was registered in the International Platform of Registered Systematic Review and Meta-Analysis Protocols with the number 202080067 and the DOI number https://doi.org/10.37766/inplasy2020.8.0067.

In the Opinion of Elite Volleyball Coaches, How Do Contextual Variables Influence Individual Volleyball Performance in Competitions?

The main objective was to know the elite coaches’ opinions regarding the relevance, definition, and importance of volleyball contextual variables to measure individual performance in competition. After performing a literature review, an instrument to gather the opinion of the world’s elite volleyball coaches was elaborated by four volleyball specialists. The sample of experts consisted in 20 world’s elite volleyball coaches who met at least three experience years in first division or national teams. The instrument collected experts’ information on the contextual variables in relation to relevance, definition, and importance. Cronbach’s α and Aiken’s V coefficient were used to test the reliability and content validity of the contextual variables, respectively. To compare the importance of the contextual variables U de Mann-Whitney and Kruskal-Wallis tests were used. Results showed that opposition level, set period, score difference, results of the previous set, competitive load variables, high level, final periods ≥20, and high load categories were relevant (Aikens V > 0.70). In addition, high level, final period ≥20 and ≥+10, and high load categories were significantly more important (p < 0.05). We conclude that, according to the elite coaches, the contextual variables should not be analyzed separately. Future studies should consider contextual variables dynamically.

Predicting Perceived Sport Performance via Self-Determination Theory

Sport performance depends in part on psychological factors. Self-determination theory emphasizes that the satisfisfaction of basic psychological needs and autonomous motivation may be linked to positive behavioral results and positive perceptions of performance. Our main objective in this study was to analyze the predictive power of such variables as perceived autonomy support, the satisfaction of psychological needs, and autonomous motivation on perceived sport performance. We recruited 447 young Portuguese athletes/participants (340 males, 107 females; Mage = 15.72 years, SD = 1.8). We had participants complete Portuguese sport versions of the Perceived Autonomy Support Exercise Climate Questionnaire, the Basic Psychological Needs in Exercise Scale, the Behavior Regulation Sport Questionnaire and the Perceived Performance in Sport Questionnaire. A gender invariant structural equation model showed that the coach's autonomy support significantly predicted the satisfaction of psychological needs for autonomy, competence, and relatedness. The satisfaction of these three psychological needs predicted autonomous motivation. Satisfying the need for competence positively predicted perceived sport performance, but autonomous motivation was not significantly related to perceived performance.

Quantification of swimmers' ability to apply force in the water: the potential role of two new variables during tethered swimming

This study aimed 1) to examine variables that may quantify the ability to apply force in the water and 2) to test their relationship with free swimming performance. Sixteen regional-level swimmers participated in this study. Average (Favg) and maximum (Fmax) forces were measured for 30 s arm stroke tethered swimming in a flume at zero and 1.389 m/s water flow speeds. The maximum and average force's relative changes (ΔFmax and ΔFavg, respectively) were calculated between tethered swimming at zero and 1.389 m/s water flow speeds. Free swimming speeds were obtained from 25, 50, and 100 m front crawl trials, and were correlated with ΔFmax and ΔFavg. A negative correlation was found between ΔFmax and 25, 50 and 100 m speeds (r =  -0.84, r = -0.74, r = -0.55; p < 0.05, respectively) and ΔFavg correlated negatively with 25 and 50 m speeds (r = -0.63, r = -0.54; p < 0.05, respectively), but it did not correlate with 100 m swimming speed. The relative change in force could be used to quantify the ability to apply force in the water. This could aid coaches to understand if changes in swimmers' ability to apply force in the water contribute to improvements in performance.

The Effect of a Coordinative Training in Young Swimmers' Performance

This study investigated the effects of a coordinative in-water training. Total 26 young swimmers (16 boys) were divided in a training group (that performed two sets of 6 × 25-m front crawl, with manipulated speed and stroke frequency, two/week for eight weeks) and a control group. At the beginning and end of the training period, swimmers performed 50-m front crawl sprints recorded by seven land and six underwater Qualisys cameras. A linear mixed model regression was applied to investigate the training effects adjusted for sex. Differences between sex were registered in terms of speed, stroke length, and stroke index, highlighting that an adjustment for sex should be made in the subsequent analysis. Between moments, differences were noticed in coordinative variables (higher time spent in anti-phase and push, and lower out-of-phase and recovery for training group) and differences between sex were noticed in performance (stroke length and stroke index). Interactions (group * time) were found for the continuous relative phase, speed, stroke length, and stroke index. The sessions exerted a greater (indirect) influence on performance than on coordinative variables, thus, more sessions may be needed for a better understanding of coordinative changes since our swimmers, although not experts, are no longer in the early learning stages.

An ecological-dynamical approach to golf science: implications for swing biomechanics, club design and customisation, and coaching practice

It has previously been argued that science has only made a limited contribution to the sport of golf, particularly the human element. This lack of impact could, in part, be attributed to the absence of an appropriate theoretical framework in most empirical investigations of the golf swing. This position paper outlines an ecological-dynamical approach to golf science that is better able to capture the interactions among the many structural parts of a golfer, and the relations between a golfer, his or her equipment, and his or her surrounding environment than other theoretical approaches have hitherto. It is proposed that the conjoining of principles and concepts of ecological psychology and dynamical systems theory could make a significant contribution to the enhancement of knowledge and understanding of swing biomechanics, club design and customisation, and coaching practice. This approach could also provide a platform on which to integrate the various subdisciplines of sport and human movement science to gain a more holistic understanding of golf performance.

Personality and Sport Experience of 20-29-Year-Old Polish Male Professional Athletes

More and more research reports assert that sport experience has an influence on shaping the personality of athletes. This paper aims at validating the connection between personality and sport experience. The research subject of were young Polish male athletes (N = 1,260) aged 20-29, out of 42 sports disciplines, with sport experience ranging from 3 to 12 years. In order to test the personality of the research subjects, a five-factor model of personality called the Big Five was applied. Statistical calculations and analyses were carried out with ver. 25 of the IBM SPSS Statistics software. The research has shown that all personality traits correlate in a statistically significant way with sport experience (p < 0.001): there is a negative correlation of sports experience with neuroticism and a positive correlation with traits such as extraversion, openness to experience, agreeableness, and conscientiousness. Thus, we have identified a relationship between sport experience and personality traits of the researched Polish male athletes-the longer the sport experience, the lower level of neuroticism and higher levels of extraversion, openness to experience, agreeableness, and conscientiousness. Duration of sport experience has a considerable influence on forming the personality of Polish male athletes. However, the interpretation of just the results regarding high level of extraversion and conscientiousness distinguishes Polish male athletes (20-29 years old) from the Polish male population of non-training people.

Integrative Proposals of Sports Monitoring: Subjective Outperforms Objective Monitoring

Current trends in sports monitoring are characterized by the massive collection of tech-based biomechanical, physiological and performance data, integrated through mathematical algorithms. However, the application of algorithms, predicated on mechanistic assumptions of how athletes operate, cannot capture, assess and adequately promote athletes' health and performance. The objective of this paper is to reorient the current integrative proposals of sports monitoring by re-conceptualizing athletes as complex adaptive systems (CAS). CAS contain higher-order perceptual units that provide continuous and multilevel integrated information about performer-environment interactions. Such integrative properties offer exceptional possibilities of subjective monitoring for outperforming any objective monitoring system. Future research should investigate how to enhance this human potential to contribute further to athletes' health and performance. This line of argument is not intended to advocate for the elimination of objective assessments, but to highlight the integrative possibilities of subjective monitoring.

A method to inform team sport training activity duration with change point analysis

Duration is a key component in the design of training activities in sport which aim to enhance athlete skills and physical qualities. Training duration is often a balance between reaching skill development and physiological targets set by practitioners. This study aimed to exemplify change point time-series analyses to inform training activity duration in Australian Football. Five features of player behaviour were included in the analyses: disposal frequency, efficiency, pressure, possession time and player movement velocity. Results of the analyses identified moments of change which may be used to inform minimum or maximum activity durations, depending on a practitioner’s objectives. In the first approach, a univariate analysis determined change points specific to each feature, allowing practitioners to evaluate activities according to a single metric. In contrast, a multivariate analysis considered interactions between features and identified a single change point, reflecting the moment of overall change during activities. Six iterations of a training activity were also evaluated resulting in common change point locations, between 196 and 252 seconds, which indicated alterations to player behaviour between this time period in the training activities conduction. Comparisons of feature segments before and after change points revealed the extent to which player behaviour changed and can guide such duration decisions. These methods can be used to evaluate athlete behaviour and inform training activity durations.

Biomechanical Process of Skeletal Muscle under Training Condition Based on 3D Visualization Technology

With the development and popularization of 3D technology, human behavior recognition has gradually developed from plane feature recognition to elevation feature recognition. In the process of collecting motion characteristics, the research on skeletal muscle will lead to a series of data in time series, which is the basis of sports biomechanics research and sports training. Some important semantic information such as centerline and joint center can be obtained by further data processing. The results of the study showed that the three-dimensional coordinate positions of the femur and pelvic attachment points of the muscles surrounding the hip joint from the pelvis were measured and positioned. A 3D model is built to simulate the human skeletal model subjected to speeds of 3 and 7 m/s, and different motion velocities can exhibit different motions. The research in this study shows that using 3D technology and comprehensively utilizing the expertise of biomechanical analysis and graphical modeling to study the mechanical properties of bone joints and soft tissues provide new ways and methods.

Talent detection—importance of the will and the ability when starting a sport activity

The early identification of sports talents includes finding the right sport and is of great importance for both scientists and practitioners. In this article, special attention will be paid to the entry into sports in general as a basis of a talent development process. Sport-specific evidence from a variety of talent development models will be listed and research gaps will be identified. For this purpose, this article refers to a model that can be classified as both process and structure oriented and tries to find domain-specific application. A framework is presented as a research approach in which the different scientific disciplines can bring together their subject areas. This enables so-called ability–personality profiles consisting individual constellations of motivation variables, interests, skills, and experience to be studied together and incorporated into the talent development process. The arrangement of movement offers should be oriented to the individual profiles. At the same time, movement experiences can offer the basis for the formation of interests, motivation, and sport-motor skills, i.e., of the will and the ability. Taking the will into account as well as the ability could lead people to detect their own talent (based on contents of the presented framework) and the sport that is suitable for them, and thus be ready for the entry to the path of talent development.

Clarifying the Biomechanical Concept of Coordination Through Comparison With Coordination in Motor Control

Coordination is a multidisciplinary concept in human movement science, particularly in the field of biomechanics and motor control. However, the term is not used synonymously by researchers and has substantially different meanings depending on the studies. Therefore, it is necessary to clarify the meaning of coordination to avoid confusion. The meaning of coordination in motor control from computational and ecological perspectives has been clarified, and the meanings differed between them. However, in biomechanics, each study has defined the meaning of the term and the meanings are diverse, and no study has attempted to bring together the diversity of the meanings of the term. Therefore, the purpose of this study is to provide a summary of the different meanings of coordination across the theoretical landscape and clarify the meaning of coordination in biomechanics. We showed that in biomechanics, coordination generally means the relation between elements that act toward the achievement of a motor task, which we call biomechanical coordination. We also showed that the term coordination used in computational and ecological perspectives has two different meanings, respectively. Each one had some similarities with biomechanical coordination. The findings of this study lead to an accurate understanding of the concept of coordination, which would help researchers formulate their empirical arguments for coordination in a more transparent manner. It would allow for accurate interpretation of data and theory development. By comprehensively providing multiple perspectives on coordination, this study intends to promote coordination studies in biomechanics.

Association between offensive and defensive playing style variables and ranking position in a national football league

The aim of this study was to determine the association of playing style and efficacy variables with football success in a professional football league. Match statistics were obtained from 23 football teams competing in the 2017-2018 and 2018-2019 seasons of the Spanish national league(LaLiga). Offensive and defensive playing style and efficacy variables were calculated. Pearson's correlation coefficient tests and principal component analysis (PCA) were applied to establish the influence of these variables on the number of points obtained at the end of the season and on the ranking position. In isolation, the efficacy of completion showed the highest association with ranking points and position. A two-dimension PCA explained 77.8% of the variance in the ranking position. In dimension-1 (58.5%), game initiative and attack building, and in dimension-2 (19.3%), efficacy of defensive containment and a lower rate of long passes were within the variables that explained more variance in the ranking position. Success in football, measured by ranking position at the end of the Spanish national league, was associated with several playing style and efficacy variables. Overall, a dominant game style with high efficacy to finish attacking plays, and an offensive game initiative, are most associated with successful football.

Beyond animated skeletons: How can biomechanical feedback be used to enhance sports performance?

Biomechanical feedback technologies are becoming increasingly prevalent in elite athletic training environments but how the kinematic and kinetic data they produce can be best used to improve sports techniques and enhance sports performance is unclear. This paper draws on theoretical and empirical developments in the motor control, skill acquisition, and sports biomechanics literatures to offer practical guidance and strategic direction on this issue. It is argued that the information produced by biomechanical feedback technologies can only describe, with varying degrees of accuracy, what patterns of coordination and control are being adopted by the athlete but, crucially, it cannot prescribe how these patterns of coordination and control should be modified to enhance sports performance. As conventional statistical and theoretical modelling paradigms in applied sports biomechanics provide limited information about patterns of coordination and control, and do not permit the identification of athlete-specific optimum sports techniques, objective criteria on which to base technical modifications that will consistently lead to enhanced performance outcomes cannot reliably be established for individual athletes. Given these limitations, an alternative approach, which is harmonious with the tenets of dynamical systems theory and aligned with the pioneering insights of Bernstein (1967) on skill acquisition, is advocated. This approach involves using kinematic and kinetic data to channel the athlete's search towards their own unique 'optimum' pattern of coordination and control as they actively explore their perceptual-motor workspace during practice. This approach appears to be the most efficacious use of kinematic and kinetic data given current biomechanical knowledge about sports techniques and the apparent inability of existing biomechanical modelling approaches to accurately predict how technique changes will impact on performance outcomes for individual athletes.

The influence of environmental and task constraint interaction on skilled behaviour in Australian Football

The design of sports practice environments can be informed through data collected and analysed according to principles of the constraints-led approach. In this study, three manipulated environmental (area per player, number of players and team outnumber) and two task (activity objective and disposal limitations) constraints were measured during professional Australian Football training activities (n = 112) to determine their relationship with skilled behaviour. Linear regression modelling of the five manipulated constraints explained 68% of the variance in disposal frequency but only 22% in skill efficiency. Activities with scoring objectives, limited to kicking or which permitted all disposals, reduced the disposal frequency per player. Activities which permitted all disposals were also weakly, negatively associated with skill efficiency. A Classification Based on Association analysis measured the interaction between manipulated constraints and their relationships with possession time and pressure. When compared to the null model, the analysis improved pressure classification accuracy by 5.9% and did not improve possession time classification accuracy. This indicates skills were often performed under varying spatial and temporal constraints during many of the training activities. This study presents multivariate analytical methods which consider constraint interaction, enhancing how practitioners can evaluate and inform training design in sport.

Weaving Lines of Inquiry: Promoting Transdisciplinarity as a Distinctive Way of Undertaking Sport Science Research

The promotion of inter- and multidisciplinarity - broadly drawing on other disciplines to help collaboratively answer important questions to the field - has been an important goal for many professional development organisations, universities, and research institutes in sport science. While welcoming collaboration, this opinion piece discusses the value of transdisciplinary research for sports science. The reason for this is that inter- and multidisciplinary research are still bound by disciplinary convention - often leading sport science researchers to study about a phenomenon based on pre-determined disciplinary ways of conceptualising, measuring, and doing. In contrast, transdisciplinary research promotes contextualised study with a phenomenon, like sport, unbound by disciplinary confines. It includes a more narrative and abductive way of performing research, with this abduction likely opening new lines of inquiry for attentive researchers to follow. It is in the weaving of these lines where researchers can encounter new information, growing knowledge in-between, through, and beyond the disciplines to progressively entangle novel and innovative insights related to a phenomenon or topic of interest. To guide innovation and the development of such research programmes in sport science, we lean on the four cornerstones of transdisciplinarity proposed by Alfonso Montuori, exemplifying what they could mean for such research programmes in sport science.

Application of a continuous pressure metric for Australian football

Pressure is an important constraint on sports performance and is typically measured through manual notational analysis. A continuous representation of pressure, along with semi-automated measurement, would serve to improve the efficiency of practice design and analysis, as well as provide additional context to player competition performance. Using spatiotemporal data collected from wearable tracking devices, the present study applied Kernel Density Estimation to estimate the density of players, relative to the ball carrier, at point of skill execution during elite Australian Football training. Two environmental constraints were measured (area per player and number of players) to determine the relationship between these training design manipulations and density. Density was also compared with existing notational analysis measurements of pressure. Results indicated that a higher density on skills was associated with successful skill executions. The opposite relationship was found between notational analysis pressure measurement and skill effectiveness. A strong inverse relationship was found between environmental constraint manipulation and density, whereby increasing field size and playing number decreased the density on skill involvements. The findings offer insight into the continuous measurement of pressure and encourage practitioners to utilize training design manipulations to influence density as a constraint on skills.

The Knowledge Map of Sport and Exercise Psychology: An Integrative Perspective

The present work contains a personal perspective on what sport and exercise psychology (SEP) is today. It is a global synthesis of research about psychological aspects related to the context and practice of sport and exercise. The intended impact was to positively influence teaching SEP to students, to promote interdisciplinary research and practice, and to assist the development of SEP as an applied science by helping experts develop a more holistic view of the field. Over 650 theoretical and review articles about psychological concepts in connection to sport and exercise were read in the process of creating a conceptual model that reflects the essence of SEP and leads to a conceptualization of SEP based on research topics. The result was a knowledge map of SEP made up of four main research clusters: biopsychological descriptors, external variables, psychological skills, and applied SEP practice. In terms of interdisciplinarity, the present perspective on SEP suggests that sport and exercise can be used as a research paradigm or natural laboratory to study psychological aspects relevant to various scientific fields, and that sport and exercise can be used as a therapeutic framework in response to challenges that researchers and practitioners in these fields are typically addressing.

Identifying coordination between joint movements during a throwing task with multiple degrees of freedom

It is known that coordination between joint movements is crucial for the achievement of motor tasks and has been studied extensively. Especially, in sports biomechanics, researchers are interested in determining which joint movements are coordinated to achieve a motor task. However, this issue cannot be easily addressed with the methods employed in previous studies. Therefore, we aimed to propose a method for identifying joint coordination. Subsequently, we examined which joint movements were coordinated using accurate overhead throwing, which required reduction in vertical hand velocity variability. Fourteen baseball players participated by attempting throwing using a motion capture system. The index of coordination for each joint movement and the effect of deviation of one joint movement on vertical hand velocity were quantified. Our results showed that the shoulder internal/external rotation angle (θ_1-IE) and the other joint movements or the shoulder horizontal flexion/extension angular velocity (ω_1-FE) and the other joint movements were coordinated. These results could be explained by the fact that the effects of the deviation of the shoulder internal rotation angle (θ_1-I) and shoulder horizontal flexion angular velocity (ω_1-F) on vertical hand velocity were larger than those of the other joint movements. This meant that it was necessary to cancel the deviations of θ_1-IE and ω_1-FE by the other joint movements. These findings indicate that the method proposed in this study enables the identification of which joint movements are coordinated in multiple degrees of freedom.

Methodological Considerations for Furthering the Understanding of Constraints in Applied Sports

Commonly classified as individual, task or environmental, constraints are boundaries which shape the emergence of functional movement solutions. In applied sport, an ongoing challenge is to improve the measurement, analysis and understanding of constraints to key stakeholders. Methodological considerations for furthering these pursuits should be centred around an interdisciplinary approach. This integration of methodology and knowledge from different disciplines also encourages the sharing of encompassing principles, concepts, methods and data to generate new solutions to existing problems. This narrative review discusses how a number of rapidly developing fields are positioned to help guide, support and progress an understanding of sport through constraints. It specifically focuses on examples from the fields of technology, analytics and perceptual science. It discusses how technology is generating large quantities of data which can improve our understanding of how constraints shape the movement solutions of performers in training and competition environments. Analytics can facilitate new insights from numerous and complex data through enhanced non-linear and multivariate analysis techniques. The role of the perceptual sciences is discussed with respect to generating outputs from analytics that are more interpretable for the end-user. Together, these three fields of technology, analytics and perceptual science may enable a more comprehensive understanding of constraints in sports performance.

Lower-Body Aquatic Training Prescription for Athletes

ABSTRACT

Holmberg, PM, Gorman, AD, Jenkins, DG, and Kelly, VG. Lower-body aquatic training prescription for athletes. J Strength Cond Res 35(3): 859-869, 2021-Traditionally prescribed to manage various medical ailments and promote healing, aquatic immersion may provide a favorable environment to undertake preparatory training tasks given its profound biological effects that extend across most homeostatic systems. In addition to understanding these effects, which are related to the fundamental principles of hydrodynamics, there is a need to consider the acute physiomechanical responses to alterations of key constraints associated with particular preparatory tasks. Evidence suggests that the manipulation of different constraints during aquatic training can enable a unique setting to complement, supplement, or supplant land-based programming to maintain or improve physical capacities in athletes without exacerbating physiological stress. Thus, this article focuses on the interplay of constraints and their associated outcomes to provide information that can be used to program lower-body aquatic training for athletes. In addition, the aim of the article is to summarize the literature on aquatic training to highlight the outcomes that occur when certain constraints are manipulated.

Decision-Making Skills in Youth Basketball Players: Diagnostic and External Validation of a Video-Based Assessment

Decision-making is a central skill of basketball players intending to excel individually and contribute to their teams’ success. The assessment of such skills is particularly challenging in complex team sports. To address this challenge, this study aimed to conceptualize a reliable and valid video-based decision-making assessment in youth basketball. The study sample comprised youth basketball players of the German U16 national team (n = 17; M_Age = 16.01 ± 0.25 years) and students of a sports class (n = 17; M_Age = 15.73 ± 0.35 years). Diagnostic validity was tested by determination of the performance levels according to response accuracy as well as response time in the assessment. External validity was examined by investigation of the correlation between the diagnostic results of the elite athletes and their real game performance data associated with passing skills. Logistic regression analysis revealed that the diagnostic results discriminate between performance levels (χ²(2) = 20.39, p < 0.001, Nagelkerke’s R² = 0.60). Multiple regression analysis demonstrated a positive relationship between the diagnostic results and assists (F(2,10) = 4.82, p < 0.05; R² = 0.49) as well as turnovers per game (F(2,10) = 5.23, p < 0.05; R² = 0.51). However, no relationship was detected regarding the assist-turnover ratio. Further, response time discriminated within the elite athletes’ performance data but not between performance levels while for response accuracy the opposite is the case. The results confirm the diagnostic and external validity of the assessment and indicate its applicability to investigate decision-making skills in youth basketball.

A Review of Forward-Dynamics Simulation Models for Predicting Optimal Technique in Maximal Effort Sporting Movements

The identification of optimum technique for maximal effort sporting tasks is one of the greatest challenges within sports biomechanics. A theoretical approach using forward-dynamics simulation allows individual parameters to be systematically perturbed independently of potentially confounding variables. Each study typically follows a four-stage process of model construction, parameter determination, model evaluation, and model optimization. This review critically evaluates forward-dynamics simulation models of maximal effort sporting movements using a dynamical systems theory framework. Organismic, environmental, and task constraints applied within such models are critically evaluated, and recommendations are made regarding future directions and best practices. The incorporation of self-organizational processes representing movement variability and “intrinsic dynamics” remains limited. In the future, forward-dynamics simulation models predicting individual-specific optimal techniques of sporting movements may be used as indicative rather than prescriptive tools within a coaching framework to aid applied practice and understanding, although researchers and practitioners should continue to consider concerns resulting from dynamical systems theory regarding the complexity of models and particularly regarding self-organization processes.

Understanding individual differences in lifting mechanics: Do some people adopt motor control strategies that minimize biomechanical exposure

The movement strategy an individual uses to complete a lift can influence the resultant biomechanical exposure on their low back. We hypothesize that some lifters may choose a motor control strategy to minimize exposure to the low back, where others may not. Lower magnitudes of exposure to the low back coupled with less variability in lift-to-lift exposure and in features of movement strategy related to biomechanical exposure would support that such lifters consider minimizing exposure in their motor control strategy. We tested this hypothesis by investigating if differences in variability of low back exposure measures, as well as features of movement strategy related to resultant low back exposures differed across lifters. Twenty-eight healthy adults participated in the study where ten repetitions of a lifting task with the load scaled to 75% of participant's one-repetition maximum were completed. In all trials, whole-body kinematics and ground reaction forces were collected. Lifters were grouped as low, moderate or high relative exposure based on low back flexion angles and normalized L4/L5 extensor moments when lifting. Principal component analysis was used to identify independent movement strategy features, and statistical testing determined which features differed between high and low exposure lifts. Variability in low back exposures and movement features associated with relative biomechanical exposure were compared across lifter classifications. Significantly less variability was observed in low back exposures among the low exposure lifter group. Additionally, a trend towards lower variability in movement features associated with relative biomechanical exposure was also observed in low exposure lifters. These findings provide initial support for the hypothesis that some lifters likely define a motor control strategy that considers minimizing biomechanical exposure in addition to completing the lift demands. Future work should explore how state and trait-based factors influence an individual to consider biomechanical exposure within their motor control strategy in lifting.

'Knowing as we go': a Hunter-Gatherer Behavioural Model to Guide Innovation in Sport Science

Where do novel and innovative ideas in sport science come from? How do researchers and practitioners collectively explore the dynamic landscape of inquiry, problem, solution and application? How do they learn to skilfully navigate from current place and practice toward the next idea located beyond their current vantage point? These questions are not just of philosophical value but are important for understanding how to provide high-quality support for athletes and sport participants at all levels of expertise and performance. Grounded in concepts from social anthropology, and theoretically positioned within an ecological dynamics framework, this opinion piece introduces a hunter-gatherer model of human behaviour based on wayfinding, situating it as a conceptual guide for implementing innovations in sport science. Here, we contend that the embedded knowledge of a landscape that guides a successful hunting and gathering party is germane to the pragmatic abduction needed to promote innovation in sport performance, leading to the inquisition of new questions and ways of resolving performance-preparation challenges. More specifically, exemplified through its transdisciplinarity, we propose that to hunt 'new ideas' and gather translatable knowledge, sport science researchers and practitioners need to wayfind through uncharted regions located in new performance landscapes. It is through this process of navigation where individuals will deepen, enrich and grow current knowledge, 'taking home' new ideas as they find their way.

Analysing patterns of coordination and patterns of control using novel data visualisation techniques in vector coding

OBJECTIVE

Vector coding is a non-linear data analysis technique that quantifies inter-segmental coordination and coordination variability. The traditional approach of reporting time-series data from vector coding can be problematic when overlaying multiple trials on the same illustration. The objective of this study was to describe and present novel data visualisations for displaying the coordination pattern, segmental dominancy, range of motion on an angle-angle diagram, and coordination variability. This allows for a comparison of data across multiple participants with a focus on single subject analysis.

METHODS

Novel data visualisation techniques that involve the use of colour and data bars to map and profile coordination pattern and coordination variability data. The introduction and profiling of inter-data point range of motion quantifies range of motion of the dominant segment on an angle-angle plot and illustrates patterns of movement control. As an example, the dataset used the Istituto Ortopedico Rizzoli foot model to describe rearfoot-forefoot and shank-foot coordination during stance.

RESULTS

The use of colour mapping provides the option to inspect an entire dataset and to compare data across multiple participants, groups, and segment couplings. Combining coupling angle mapping with segmental dominancy profiling offers an intuitive and instant summary on coupling angle distribution. The novel inclusion of inter-data point range of motion profiling provides meaning to the interpretation of segmental dominancy data and demonstrates distinct patterns of movement control.

CONCLUSIONS

The use of colour mapping and profiling techniques highlighted differences in coordination pattern and coordination variability data across several participants that questions the interpretation and relevance of reporting group data. Colour mapping and profiling techniques are ideal reporting methods to compliment prospective multiple single-subject design studies and to classify commonalities and differences in patterns of coordination and patterns of control between individuals or trials. The data visualisation approaches in the current study may provide further insight on overuse injuries, exercise prescription and rehabilitation interventions.

Validity, reliability and usefulness of smartphone and kinovea motion analysis software for direct measurement of vertical jump height

Jumping is a simple exercise determined by several biomechanical and physiological factors. Measures of vertical jump height are common and easy to administer tests of lower limb muscle power that are carried out with several types of equipment. This study aimed to validate and address the usefulness of the combination of smartphone and computer-based applications (Smartphone-Kinovea) against a laboratory-based Motion Capture System. One hundred and twelve healthy adults performed three maximal-effort countermovement jumps each. Both instruments measured the heights of the 336 trials concurrently while tracking the excursion of the body center of gravity. The vertical velocity at take-off v_to and the impulse J were computed with jump height h measures. Intraclass correlation coefficient (ICC) results indicated very high agreement for h and v_to (0.985) and almost perfect agreement for J (0.997), and Cronbach's α=0.99. Low mean differences were observed between instruments for h: -0.22 ± 1.15 cm, v_to: -0.01 ± 0.04 m/s, and J: -0.56 ± 2.92 Ns, all p<0.01. The smallest worthwhile change (SWC) and the typical error of measurement (SEM) were 1.34 cm, 0.81 cm for h; 1.15 m/s, 0.03 m/s for v_to, and 2.93 Ns, 2.25 Ns for J, so the usefulness of the method is established (SWC/SEM>1). Bland-Altman plots showed very low mean systematic bias ± random errors (-0.22 ± 2.25 cm; -0.01 ± 0.08 m/s; -0.56 ± 5.73 Ns), without association between their magnitudes (r²=0.005, r²=0.005, r²=0.001). Finally, very high to practically perfect correlation between isntruments were observed (r = 0.985; r = 0.986; r = 0.997). Our results suggest that the Smartphone-Kinovea method is a valid and reliable, low-cost instrument to monitor changes in jump performance in a healthy, active population diverse in gender and physical condition.

Game Related Statistics Discriminate National and Foreign Players According to Playing Position and Team Ability in the Women's Basketball EuroLeague

The aim of the present study was to examine the differences in game-related statistics between national and foreign female basketball players in the Women’s EuroLeague, according to playing positions and team ability. The official box-scores of 112 games from the 2016–2017 season of the Women’s EuroLeague (FIBA) were examined. Players were categorised based upon country of nationality versus competition (i.e., foreign or national), playing positions (i.e., Guards, Forwards, Centers), and team ability (i.e., four groups using a cluster of k-means analysis according to the winning percentage of each team during the competition). A structural coefficient (SC) above |0.30| was used to identify the variables that best differentiated the national and foreign players. Results showed that foreign players had a better performance according to team ability and playing position for most of the performance indicators, with higher values for minutes played, percentage of successful 2-point field-goals, percentage of successful free-throws, and percentage of assists. Moreover, foreign players performed better in variables associated with offensive situations, while national players were prevailing with indicators associated with defensive actions. These results have highlighted the unique contributions of foreign and national players, based upon playing position and team ability, to team success in the Euroleague. This information will assist the recruitment process of national and foreign athletes for coaches to develop successful elite female basketball teams.

Training or Synergizing? Complex Systems Principles Change the Understanding of Sport Processes

There is a need to update scientific assumptions in sport to promote the critical thinking of scientists, coaches, and practitioners and improve their methodological decisions. On the basis of complex systems science and theories of biological evolution, a systematization and update of theoretical and methodological principles to transform the understanding of sports training is provided. The classical focus on learning/acquiring skills and fitness is replaced by the aim of increasing the diversity/unpredictability potential of teams/athletes through the development of synergies. This development is underpinned by the properties of hierarchical organization and circular causality of constraints, that is, the nestedness of constraints acting at different levels and timescales. These properties, that integrate bottom-up and top-down all dimensions and levels of performance (from social to genetic), apply to all types of sport, ages, or levels of expertise and can be transferred to other fields (e.g., education, health, management). The team as the main training unit of intervention, the dynamic concept of task representativeness, and the co-adaptive and synergic role of the agents are some few practical consequences of moving from training to synergizing.

Criteria-Based Return to Sport Decision-Making Following Lateral Ankle Sprain Injury: a Systematic Review and Narrative Synthesis

OBJECTIVE

The aim of this systematic review was to identify prospective studies that used a criteria-based return to sport (RTS) decision-making process for patients with lateral ankle sprain (LAS) injury.

DESIGN

Systematic review and narrative synthesis.

DATA SOURCES

The PubMed (MEDLINE), Web of Science, PEDro, Cochrane Library, SPORTDiscus (EBSCO), ScienceDirect, and Scopus databases were searched to 23 November 2018.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies were included if they prospectively applied a criteria-based RTS decision-making process for patients with LAS injury, but were excluded if they merely gathered outcome measures at the RTS time point. Studies were also excluded if patients were recovering from ankle fracture, high ankle sprain, medial ankle sprain, chronic ankle instability or complex ankle injury.

RESULTS

No studies were identified that used a criteria-based RTS decision-making process for patients with LAS injury. We were unable to conduct a quantitative synthesis or meta-analysis, therefore we provide a narrative synthesis of relevant questionnaires, as well as clinical and functional assessments commonly used in studies retrieved in the search.

CONCLUSION

There are currently no published evidence-based criteria to inform RTS decisions for patients with an LAS injury. Based on our narrative synthesis, we propose a number of variables that could be used to develop a criteria-based RTS decision paradigm. Future research should aim to reach consensus on these variables and apply them to actual RTS decisions within prospective study designs. Furthermore, we suggest that complex systems theory and the RTS continuum could be used to inform the development of an RTS decision-making paradigm for athletes with LAS injury.

Interdisciplinary Sport Research Can Better Predict Competition Performance, Identify Individual Differences, and Quantify Task Representation

Sport performance consists of interacting individual, task and environmental constraints, but research has used a monodisciplinary, rather than an interdisciplinary approach to understand performance. This study used Australian football (AF) as the exemplar sport to investigate the value of an interdisciplinary approach to understand sport performance. Through this, it was also possible to quantify individual differences and representative task design. Fifty-nine semi-professional Australian footballers participated. Based upon accessibility, combinations of these players completed physiological (3 × 1 km trial) and perceptual-cognitive-motor (small-sided game, SSG) tests, with coach rating of psychological skill (mental toughness coach, MTC). Univariate monodisciplinary models indicated that all tests predicted disposal efficiency; 3 × 1 km trial (p = 0.047), SSG (p = 0.001), and MTC (p = 0.035), but only the SSG predicted coaches' vote (p = 0.003). A multivariate interdisciplinary model indicated that SSG and MTC tests predicted disposal efficiency with a better model fit than the corresponding univariate model. The interdisciplinary model formulated an equation that could identify individual differences in disposal efficiency. In addition, the interdisciplinary model showed that the higher representative SSG test contributed a greater magnitude to the prediction of competition performance, than the lower representative MTC rating. Overall, this study demonstrates that a more comprehensive understanding of sport performance, individual differences, and representative tasks, can be obtained through an interdisciplinary approach.

Over 50 Years of Researching Force Profiles in Rowing: What Do We Know?

There has been substantial interest in the mechanisms underpinning the skilled movements of on-water rowing for more than 150 years. Contemporary attention from biomechanical research has focused on the important relationship between kinetics (such as force application at the oar) and performance. A range of instrumentation systems have been developed and used in both academic and applied training contexts to better understand this relationship. Both qualitative and quantitative analytical approaches have been used in conjunction with these instrumentation systems for observing differences in propulsive force patterns between rowers. Despite the use of these analytical approaches, there is still limited consensus surrounding which characteristics of force profiles are associated with better rowing performance. Newell's model of constraints is provided as a framework for understanding why this lack of clarity exists surrounding force profile characteristics and performance. Further to this, direction for further research is provided by a framework that outlines two main streams: (1) exploration of constraints and how they are related to force profile characteristics; and (2) after controlling for constraints, exploration of performance and how it is related to force profile characteristics. These two steps are sequential, with an understanding of constraints influencing how we understand the interaction of force profiles and performance.