Effects of unsteady conditions on propulsion generated by the hand’s motion in swimming: a systematic review

The understanding of swimming propulsion is a key factor in the improvement of performance in this sport. Propulsive forces have been quantified under steady conditions since the 1970s, but actual swimming involves unsteady conditions. Thus, the purpose of the present article was to review the effects of unsteady conditions on swimming propulsion based on studies that have compared steady and unsteady conditions while exploring their methods, their limitations and their results, as well as encouraging new studies based on the findings of this systematic review. A multiple database search was performed, and only those studies that met all eligibility criteria were included. Six studies that compared steady and unsteady conditions using physical experiments or numerical simulations were selected. The selected studies verified the effects of one or more factors that characterise a condition as unsteady on the propulsive forces. Consequently, much research is necessary to understand the effect of each individual variable that characterises a condition as unsteady on swimming propulsion, as well as the effects of these variables as a whole on swimming propulsion.     

The emergence of a new logic? The theorizing of a new practice in the highly institutionalized context of Swedish voluntary sport

The purpose of this article is to contribute to the understanding of the emergence and change in institutional logics by analyzing the theorization (e.g., Greenwood, Suddaby, & Hinings, 2002) of a new and distinctly “different” practice in Swedish voluntary sport: drive-in sport. The article builds on data from 29 interviews with key actors involved in the organizing of drive-in sport in four municipalities. The findings show that two problems were constructed to legitimize drive-in sport: norm-breaking behavior displayed by youth during weekend nights, and organized sport's failure to live up to a sport-for-all ideal. The findings also show that it is perceived that in order for drive-in sport to be the solution to both these problems, the activities need to be arranged in a particular way. The findings are discussed in relation to recent developments in Swedish organized sport as an institutional context. Additionally, the discussion puts forth the value of the theorization concept in terms of furthering our understanding of the social-constructionist interpretive processes that underpin the broader processes of change documented in previous sport-related studies of change in institutional logics.     

‘Re-branding’ women’s football by means of a new Sports product: a case study of women’s football in Denmark

Women’s football (soccer in the US) does not reach the same overall popularity levels as men’s football measured on a variety of factors, i.e. league attendances, participants, media attention, fan engagement or strength of business models as it translates into brand equity and revenue generation. This article investigates how a new sports product, i.e. a new football (soccer ball) labelled ‘Sensational 1’, and its interaction with positive participation numbers concerning women’s football in Denmark can enhance the brand equity of women’s football in Denmark and exploit the associated commercial opportunities. In doing so, the article discusses how this development relates to factors like winning and success, passion and the business of sports, accountability and role models, brand articulation and marketability in the context of women’s football in Denmark.     

Accelerations – a new approach to quantify physical performance decline in male elite soccer?

Abstract

The aim of the current study was (1) to investigate whether the number of accelerations is a more precise estimate of performance decline in soccer compared to distances with high-speed running (HSR) and (2) to compare changes in the number of accelerations and HSR distances across playing positions in order to examine whether the match profiles of the physical measures are consistent or demonstrate high interposition variability. The dataset includes domestic home games (N?=?34) over three full seasons (2012–2014) for a team in the Norwegian Elite League. The change in the number of accelerations throughout the match demonstrates a more clear pattern compared to the distance covered by HSR. In numbers of accelerations, a systematic and linear decrease can be observed throughout the match, with 34% less accelerations from the first to the last 5-minute period of the game (6.7 vs. 4.4 accelerations). This pattern of results captures the change in the number of accelerations across all positions. HSR distance had more variability during the match. All five positions investigated displayed a similar trend in accelerations and HSR profiles after the peak periods in each half. In contrast to the absolute number of accelerations, there were major positional differences in the mean HSR distance during the match. Our data suggest a more visible performance decline in the number of accelerations from the start to the end of the game, than the decline in the distance covered by HSR distance.     

Validity and reliability of a new method for measuring putting stroke kinematics using the TOMI® system

Abstract

The purpose of this study was to determine the validity and reliability of a new method for measuring three-dimensional (3D) putting stroke kinematics using the TOMI® device. A putting robot and a high-speed camera were used to simultaneously collect data for the validity evaluation. The TOMI® device, when used in conjunction with standard 3D coordinate data processing techniques, was found to be a valid and reliable method for measuring face angle, stroke path, putter speed, and impact spot at the moment of ball contact. The validity of the TOMI® measurement system was quantified using the 95% limits of agreement method for each aforementioned variable. The practical significance of each validity score was assessed by incorporating the maximum estimated measurement error into the stroke of the putting robot for 10 consecutive putts. All putts were executed from a distance of 4 m on a straight and flat synthetic putting surface. Since all putts were holed successfully, the measurement error for each variable was deemed to be negligible for the purposes of measuring putting stroke kinematics. The influence of key kinematic errors, at impact, on the outcome of a putt was also determined.     

Dynamic balance performance varies by position but not by age group in elite Rugby Union players – a normative study

This cohort study aimed to provide normative Y Balance Test scores for an elite Rugby Union population, while investigating the effect player age groups (senior/under-20), playing positions (forwards/backs) and anthropometrics (height and body mass) had on performance. Two-hundred and sixty-one elite male under-20 (n = 50) and senior (n = 211) players completed baseline Y Balance Test during the 2015/2016 season. One-way ANCOVA and post-hoc t-tests were used to investigate the effect playing position, player group, height and weight had on performance. The cohort was then stratified into groups (age group and/or playing position), and normative percentiles were presented. There was a statistically significant difference (p < 0.05) in Y Balance Test performance between playing positions, when controlling for age group. This difference did not remain when controlling for player body mass. Post-hoc analysis demonstrated that backs had a longer normalised reach distance, with medium-large and small-medium effect sizes for the under-20 and senior cohorts respectively. The one-way ANCOVA analysis suggests that this difference is likely due to the larger differences in player body mass between forward and back playing positions. The normative values presented in this paper may be used by clinicians and researchers to aid injury prevention and rehabilitation strategies.     

Relative age effects in Swiss talent development – a nationwide analysis of all sports

Relative age effects (RAE) generate consistent participation inequalities and selection biases in sports. The study aimed to investigate RAE across all sports of the national Swiss talent development programme (STDP). In this study, 18 859 youth athletes (female N = 5353; mean age: 14.8 ± 2.5 y and male N = 13 506; mean age: 14.4 ± 2.4 y) in 70 sports who participated in the 2014 competitive season were evaluated. The sample was subdivided by sex and the national level selection (NLS, N = 2464). Odds ratios (ORs) of relative age quarters (Q1-Q4) and 95% confidence intervals (CI) were calculated. In STDP, small RAE were evident for females (OR 1.35 (95%-CI 1.24, 1.47)) and males (OR 1.84 (95%-CI 1.74, 1.95)). RAE were similar in female NLS athletes (OR 1.30 (95%-CI 1.08, 1.57)) and larger in male NLS athletes (OR 2.40 (95%-CI 1.42, 1.97)) compared to athletes in the lower selection level. In STDP, RAE are evident for both sexes in several sports with popular sports showing higher RAE. RAE were larger in males than females. A higher selection level showed higher RAE only for males. In Switzerland, talent identification and development should be considered as a long-term process.     

Influence of a proprioceptive training on functional ankle stability in young speed skaters – a prospective randomised study

The influence of a 12-week-proprioceptive training on functional ankle stability was investigated in young speed skaters. Twenty-eight speed skaters were randomly divided into an intervention (n = 14) and into a control group (n = 14). A 15-min circle training was performed 5 times per week over a 12-week period. Measurements were taken prior to the training, after 6 and 12 weeks of training. Kinaesthesia was evaluated with the Isomed2000 in all movements of the ankle joint. Dynamic balance was tested with the Biodex Stability System at the stable level 8 and at the unstable level 2, measuring the overall stability index, the anterior/posterior and the medial/lateral scores. Static single-leg stance was evaluated using the Kistler force platform. Kinaesthesia of the intervention group improved significantly for plantarflexion of the right foot (P = 0.001) after 12 weeks. Dynamic balance showed significant differences in the intervention group after 12 weeks in comparison with the first measurement for each foot in the overall stability index, the anterior/posterior and the medial/lateral scores (P ≤ 0.017, respectively) at the unstable level 2. Functional ankle stability improved in terms of dynamic balance after 12 weeks of proprioceptive training. Therefore, inclusion of proprioceptive exercises in the daily training programme is recommended for young speed skaters.     

Movement pattern and physiological response in recreational small-sided football – effect of number of players with a fixed pitch size

Recreational soccer is an effective health-promoting activity, but it is unclear how different game formats influence internal and external load. Thus, to be able to advise how to maximise the outcome of recreational football, we examined movement pattern and physiological response in 11 untrained men (32.6 ± 6.7 yrs, 23.3 ± 4.9 fat%, 43.4 ± 5.3 ml·min^?1·kg^?1) during three football sessions comprising 4 × 12 min of 3v3, 5v5 or 7v7 with a constant pitch size of 20 × 40 m. Movement pattern, heart rate (HR), blood lactate and RPE were measured during and after the 12-min periods. Greater (P < 0.05) total distance and high-speed distance was covered during 3v3 than 5v5 (14 and 30%) and 7v7 (15 and 75%). Mean HR was higher in 3v3 (85.7 ± 5.7%HRmax) and 5v5 (84.2 ± 5.1%HRmax) than in 7v7 (80.7 ± 4.6%HRmax, P < 0.05) and percentage time >90%HR was higher in 3v3 (43 ± 18%, P < 0.05) than in 5v5 (28 ± 21%) and 7v7 (18 ± 14%). Blood lactate was higher in 3v3 (7.4 ± 2.7 mmol·l^?1) than in 7v7 (4.5 ± 2.2 mmol·l^?1, P < 0.001) but not in 5v5 (6.1 ± 2.1 mmol·l^?1, P = 0.061). RPE was higher in 3v3 (6.7 ± 2.3, P < 0.01) than in 5v5 (5.2 ± 2.2) and 7v7 (4.3 ± 2.3). In conclusion, higher external and internal load was found with fewer players, when the pitch size is fixed.     

Fluctuation – a common but neglected pattern of physical activity behaviour: An exploratory review of studies in recent 20 years

Background: Regular physical activity (PA) is beneficial for physical and psychological well-being, yet many people do not achieve these health benefits due to irregular PA participation which is also known as fluctuation. Limited attention has been given to the phenomenon of fluctuation in the PA behaviour literature. Objective: The aim of this review was to explore and to map definitions, measurements, behavioural evidence, and factors related to PA fluctuation. Methods: Eligible studies were initially identified by a systematic search of articles conducted in four databases: Scopus, PubMed, PsycINFO, and SPORTDiscus between January 1996 and March 2016. Inclusion and exclusion criteria were set to check the eligibility of all articles. Additional articles were included by manual searching and expert recommendation. Results: Fifteen articles were finally included. Definitions of fluctuation are understood from two perspectives, either as a stage in the process of behaviour change, or as a particular PA phenomenon consisting of lapse and readoption. Common features were extracted: behavioural irregularity, high risk of drop-out, intention and readiness for PA, low automaticity, and limited self-regulation. Furthermore, fluctuation identification was summarised in three approaches such as stage algorithm, self-identified PA lapse and readoption, and prospective within-person variation in meeting the PA guidelines. Regarding the empirical evidence, this review found that people in PA fluctuation were significantly distinct from those in preparation and maintenance of PA behavioural performance, as well as distinct in psychosocial features. Conclusions: Notwithstanding the limitations, this review has provided valuable insight into the phenomenon of PA fluctuation.     

Sport disciplines,types of sports,and waist circumference in young adulthood – a population-based twin study

Purpose: The benefits of physical activity (PA) in preventing abdominal obesity are well recognized, but the role of different sport disciplines remains open. We aimed, therefore, to investigate how participation in different sport disciplines, and the number and types of sports engaged in are associated with waist circumference (WC) in young adulthood. Methods: This population-based cohort study comprised 4027 Finnish twin individuals (1874 men), with a mean age of 34 y (32–37), who answered a survey, including self-measured WC. We extracted the number and identified the types (aerobic, power, and mixed) of the different sport disciplines respondents reported participating in. Results: The number of sport disciplines participated in was inversely associated with WC, the linear decrease averaging 1.38?cm (95% CI 1.10–1.65) per each additional sport discipline. The result persisted after adjustment for the main covariates, such as volume of PA and diet quality. Among dizygotic twin pairs discordant for sports participation (0–2 vs. 5 or more disciplines), the mean within-pair difference in WC was 4.8?cm (95% CI 0.4–9.1) for men and 11.2?cm (95% CI 4.4–18.0) for women; among discordant monozygotic pairs, no differences were observed. In men, all three types of sports were individually associated with smaller WC, while in women, only mixed and power sports showed this association. Conclusions: Participation in several sport disciplines and sport types was associated with smaller WC among young adults in their mid-30s. Shared genetic background may explain some of the associations.     

Back to the Future – in support of a renewed emphasis on generic agility training within sports-specific developmental pathways

Perhaps as a consequence of increased specialism in training and support, the focus on engendering and maintaining agility as a generic quality has diminished within many contemporary sports performance programmes. Reflecting this, we outline a rationale suggesting that such a decreased focus represents an oversight which may be detrimental to maximising the potential of performers. We present an evidence-based argument that both generic and specific elements of agility performance should be consistently emphasised within long-term performance-training programmes. We contend that prematurely early specialisation in athlete development models can diminish focus on generic movement skill development with a subsequent detriment in adult performance. Especially when this is coupled with poor primary physical education and limited movement experiences. More speculatively, we propose that generic agility can play a role in operationalising movement development through facilitating skill transfer: thereby enabling the learning of new skills, reduce incidence of injury and facilitating re-learning of old skills during rehabilitation and Return-to-Play processes.     

Test–retest reliability of a new device for assessing ankle joint threshold to detect passive movement in healthy adults

This study aimed to evaluate the test–retest reliability of a new device for assessing ankle joint kinesthesia. This device could measure the passive motion threshold of four ankle joint movements, namely plantarflexion, dorsiflexion, inversion and eversion. A total of 21 healthy adults, including 13 males and 8 females, participated in the study. Each participant completed two sessions on two separate days with 1-week interval. The sessions were administered by the same experimenter in the same laboratory. At least 12 trials (three successful trials in each of the four directions) were performed in each session. The mean values in each direction were calculated and analysed. The ICC values of test–retest reliability ranged from 0.737 (dorsiflexion) to 0.935 (eversion), whereas the SEM values ranged from 0.21° (plantarflexion) to 0.52° (inversion). The Bland–Altman plots showed that the reliability of plantarflexion–dorsiflexion was better than that of inversion–eversion. The results evaluated the reliability of the new device as fair to excellent. The new device for assessing kinesthesia could be used to examine the ankle joint kinesthesia.     

Lacrosse History,a History of One Sport or Two? A Comparative Analysis of Men's Lacrosse and Women's Lacrosse in the United States

Men's lacrosse and women's lacrosse share a name, but their histories differ. Both sports developed and became organised in close concert with the race, class and gender expectations of the eras. As a result, the sports began with rules that reflected those norms. Over time, the sports developed separately and generated unique forms, even as they sustained moments of interaction. Therefore, men's lacrosse and women's lacrosse are different sports. Using comparisons as the mode through which to view the sports, this article explores the organised beginnings of men's lacrosse and women's lacrosse to establish that the sports began and continued within identity-based norms. Through the discussion of the practical distinctions and critical understandings of the differences between the games, the author poses that these dissimilarities are relevant in considerations of the separate sports as they continue to change in the larger US sporting context. As sports such as basketball demonstrate, these arguments matter because broad-scale comparisons of women's sports to men's frequently render women's sport participants, and the sports they play, inferior. Notably, women's lacrosse participants also employed comparisons to distinguish and claim their history as unique from that of men's lacrosse. A comparative analysis highlights points of disjuncture between the sports and contextualises the importance of gender in the articulations of difference.     

A dolphin only looks like a fish: Players’ behaviour analysis is not enough for game understanding in the light of the systems approach – a response to the reply by McGarry and Franks

Abstract

In this article I defend my previously published system approach to game playing in sports (Lebed, 2006). Founded on the main argument of mine about insufficiency of performance analysis only for games study, it is based on an inter-disciplinary comprehension of sporting game events from four different angles: the logical-philosophical, the behavioural (performance), the anthropological, and complexity angles. The paper consists of four parts, corresponding to the four angles. The first three parts offer deconstructive and reconstructive analysis. The three provide criticism of McGarry and Frank's arguments against my view of complex dynamical systems in sports. The logical analysis negates my opponents’ general view of a match (a process) as a dynamical system. The behaviour analysis refutes their claim about couple oscillator dynamics as a universal dynamically interpreted model of game playing. The anthropological panoramic vision of sporting games leads me to conclude that my opponents’ analysis of two exclusively interacting sides in a squash or soccer contest is too narrow and insufficient to explain the broad diversity of games. According to the, classification suggested in Lebed (2004), I offer seven possible models that can systematically reflect different groups of games. In the fourth part, the complexity angle is analysed from a constructive point of view. Here I take one of the above seven models and try to outline a ‘‘soccer-like’’ game perspective modelling founded on the view of play process as a conflict of two four-level self-regulating complex systems, where each one is additionally involved in its own loop of cybernetic regulation.     

Defensive transition in soccer – are prompt possession regains a measure of success? A quantitative analysis of German Fußball-Bundesliga 2010/2011

Abstract

The aim of the study was to evaluate the time required by German Bundesliga soccer teams to recover ball possession – which was operationalised as defensive reaction time – and identify both the differences between top teams and the rest of the league and the influence of match status on the aforementioned indicator. Therefore, teams were classified into 3 distinct groups according to their final league position: top, in-between and bottom. In total, all 306 games of the season 2010/2011 were analysed post-event. Top teams recovered ball possession quickest after losing it in comparison to the other groups and demonstrated lower defensive reaction times (approximately 1 s in each match status) compared to the remaining teams. Moreover, all groups showed the lowest defensive reaction times when trailing. The results of this study imply that recovering ball possession as quickly as possible after losing possession was an important determinant of successful defensive performance in German Bundesliga season 2010/2011. Further, the current score seemed to be highly influential on the defensive reaction time. The implications of the results for future research, especially considering opponent interactions, are critically discussed.     

The relationship between physical activity,fitness, physical complaints and BMI in German adults – results of a longitudinal study

Objectives: This study’s aims were to describe the development of physical activity, physical fitness (PF), subjective (physical complaints (PC)) and objective (Body mass index (BMI)) health measures and to examine the relationship between the development trajectories. In addition, the study also aimed to assess the influence of sociodemographic determinants (age, sex, socioeconomic status (SES)) in German adults over a period of 18 years. Methods: The longitudinal study population comprises of 721 men and women, aged 33–76 years over the study period. There was self-report of physical activity and PC and testing of physical fitness and BMI in each study year (1992, 1997, 2002 and 2010). Latent growth curve models were used to analyse the development. Results: Physical activity slightly increased while fitness, PC and BMI worsened over the course of 18 years. Sex, age and SES play important roles concerning physical activity, fitness and health. Several integrative associations could be detected between physical activity, fitness, PC and BMI as well as their trajectories. In particular, high initial levels of physical activity and fitness protect from high PC and BMI.The slope of physical activity was not significantly associated with slopes of fitness, PC and BMI. However, increase of fitness resulted in decrease of PC. Conclusions: A general positive development regarding the amount of physical activity could be detected. However, if it is only an unsystematic increase of physical activity, this is not in itself enough to achieve health benefits. The strengthening of fitness should be focused when increasing physical activity, since only then a health benefit is possible.     

The role of community sports coaches in creating optimal social conditions for life skill development and transferability – a salutogenic perspective

Sport is widely recognised as having the potential to enhance the personal development of socially vulnerable youth, yet there is very limited knowledge on how community sports coaches can create optimal social conditions for life skill development and transferability. We adopt a salutogenic approach in order to study whether and how community sports coaches create these optimal social conditions. Based on the salutogenic framework, a thematic analysis was conducted of 15 in-depth interviews with community sports coaches providing sports lessons to socially vulnerable youth. As part of the interviews, the sports coaches were presented with several training scenarios and asked how they would respond in specific training situations. The results showed that the sports coaches aimed to create meaningful sporting experiences for youths. These meaningful sporting experiences were considered a precondition for keeping youths engaged in the sporting activities, as well as a precondition for life skill development. The sports coaches specifically focused on creating little moments of success and on making sure that the youths felt they belonged to a group. In order to ensure that the youths could experience moments of success, specific coaching strategies were implemented to increase the youths’ comprehensibility and manageability in specific sport situations. According to the sports coaches, experiencing little moments of success could contribute to an increase in socially vulnerable youths’ understanding of the everyday challenges that they face, as well as contribute to their ability to deal with these challenges. Creating meaningful sporting experiences may help youths ‘to learn to cope' – a skill that could be beneficial over their lifespan and in different societal domains.