An analysis of the relationship between the linear hammer speed and the thrower applied forces during the hammer throw for male and female throwers

The purpose of this study was to investigate the relationship between the cable force and linear hammer speed in the hammer throw and to identify how the magnitude and direction of the cable force affects the fluctuations in linear hammer speed. Five male (height: 1.88 +/- 0.06 m; body mass: 106.23 +/- 4.83 kg) and five female (height: 1.69 +/- 0.05 m; body mass: 101.60 +/- 20.92 kg) throwers participated and were required to perform 10 throws each. The hammer's linear velocity and the cable force and its tangential component were calculated via hammer head positional data. As expected, a strong correlation was observed between decreases in the linear hammer speed and decreases in the cable force (normalised for hammer weight). A strong correlation was also found to exist between the angle by which the cable force lags the radius of rotation at its maximum (when tangential force is at its most negative) and the size of the decreases in hammer speed. These findings indicate that the most effective way to minimise the effect of the negative tangential force is to reduce the size of the lag angle.     

Bowling ball dynamics revealed by miniature wireless MEMS inertial measurement unit

This paper presents a novel sensor technology to deduce the dynamics of a bowling ball. The sensor, a miniature wireless inertial measurement unit (IMU), incorporates MEMS accelerometers and angular rate gyros, a microcontroller, a low power RF transceiver, and a rechargeable battery. When embedded in a bowling ball, the IMU transmits the acceleration and angular velocity data that define the dynamics of the ball starting with the bowler’s delivery and its motion in the lane. Example results from professional bowlers illustrate how this technology can be used to assess bowler skill and ball performance. For instance, the IMU accurately measures the spin dynamics of the ball which are crucial to develop the ball “hook.” An analysis of ball dynamics in the lane is distilled to a measurable “hook potential” metric for further assessing bowler skill. Finally, the sensor presented herein is believed to be the world’s smallest, wireless IMU. This highly miniaturized and wireless design will enable parallel training systems for many sports, including basketball, baseball, crew, cricket, golf, fly fishing, soccer, softball, tennis, rowing, among others.     

Changes in locomotive rates during senior elite rugby league matches

Abstract

The aim of this study was to quantify the changes in locomotive rates across the duration of senior elite rugby league matches. A semi-automated image recognition system (ProZone 3, ProZone®, Leeds, England) was used to track the movements of 59 players from six teams during three competitive matches. The players were classified into one of four positional groups: props (n = 9), back row (n = 9), pivots (n = 14) or outside backs (n = 27). Players' movements were classified as low, high or very high intensity running and reported as locomotive rates (distance covered per minute played) for successive quarters of each match. Analysis of variance revealed that only the outside backs showed a significantly lower overall locomotive rate during the final quarter compared to the first (P < 0.05). However, locomotive rates for high and very high intensity running during the final quarter were significantly lower (P < 0.05) than the first quarter among outside backs, pivots and props despite no change in the rate of involvements in contact. On the basis of these findings, it is suggested that high and very high intensity running locomotive rates may be more affective methods of detecting fatigue during competitive matches than overall locomotive rate.     

Influence of sex and limb dominance on lower extremity joint mechanics during unilateral land-and-cut manoeuvres

Limb dominance theory suggests that females tend to be more one-leg dominant and exhibit greater kinematic and kinetic leg asymmetries than their male counterparts, contributing to the increased risk of anterior cruciate ligament injury among female athletes. Thus, the purpose of this study was to examine the influences of sex and limb dominance on lower extremity joint mechanics during unilateral land-and-cut manoeuvres. Twenty-one women and 21 men completed land-and-cut manoeuvres on their dominant limb as well as their nondominant limb. Three-dimensional kinematics and kinetics were calculated bilaterally for the entire stance phase of the manoeuvre. Women performed land-and-cut manoeuvres with altered hip motions and loads as well as greater knee abduction at touchdown compared to men. Dominant limb land-and-cut manoeuvres where characterised by decreased hip flexion at touchdown as well as decreased hip flexion and adduction range of motion compared to nondominant land-and-cuts regardless of sex. The observed sex differences are consistent with previous research regarding mechanisms underlying the sex disparity in anterior cruciate ligament injury rates. However, observed differences regarding limb dominances appear somewhat arbitrary and did not suggest that the dominant or nondominant limb would be at increased risk of anterior cruciate ligament injury.     

The evidence for the impact of policy on physical activity outcomes within the school setting: A systematic review

BackgroundDespite the well-established health benefits of physical activity (PA) for young people (aged 4–19 years), most do not meet PA guidelines. Policies that support PA in schools may be promising, but their impact on PA behavior is poorly understood. The aim of this systematic review was to ascertain the level and type of evidence reported in the international scientific literature for policies within the school setting that contribute directly or indirectly to increasing PA.MethodsThis systematic review is compliant with Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Six databases were searched using key concepts of policy, school, evaluation, and PA. Following title and abstract screening of 2323 studies, 25 progressed to data synthesis. Methodological quality was assessed using standardized tools, and the strength of the evidence of policy impact was described based on pre-determined codes: positive, negative, inconclusive, or untested statistically.ResultsEvidence emerged for 9 policy areas that had a direct or indirect effect on PA within the school setting. These were whole school PA policy, physical education, sport/extracurricular PA, classroom-based PA, active breaks/recess, physical environment, shared use agreements, active school transport, and surveillance. The bulk of the evidence was significantly positive (54%), 27% was inconclusive, 9% was significantly negative, and 11% was untested (due to rounding, some numbers add to 99% or 101%). Frequency of evidence was highest in the primary setting (41%), 34% in the secondary setting, and 24% in primary/secondary combined school settings. By policy area, frequency of evidence was highest for sport/extracurricular PA (35%), 17% for physical education, and 12% for whole school PA policy, with evidence for shared use agreements between schools and local communities rarely reported (2%). Comparing relative strength of evidence, the evidence for shared use agreements, though sparse, was 100% positive, while 60% of the evidence for whole school PA policy, 59% of the evidence for sport/extracurricular PA, 57% of the evidence for physical education, 50% of the evidence for PA in classroom, and 50% of the evidence for active breaks/recess were positive.ConclusionThe current evidence base supports the effectiveness of PA policy actions within the school setting but cautions against a “one-size-fits-all” approach and emphasizes the need to examine policy implementation to maximize translation into practice. Greater clarity regarding terminology, measurement, and methods for evaluation of policy interventions is needed.     

Body composition differences by age and playing standard in male rugby union and rugby league: A systematic review and meta-analysis

ABSTRACT

This systematic review and meta-analysis aimed to determine differences in body compositionn between playing standard and age in male rugby union and rugby league athletes. The MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines for design, implementation, and reporting were followed. Studies were required to be in male rugby union or league and have body composition as the primary or secondary outcome. Data was required to be presented separately for positional groups and body composition presented as whole-body. A systematic search was performed in PubMed, Cochrane Library, MEDLINE, SPORTDiscus, and CINHAHL via EBSCOhost. 57 studies were included for meta-analysis. Results highlighted significantly higher fat-free mass in senior elite than senior sub-elite or junior elite athletes for all RU and RL forwards. Small and non-significant differences were found in fat mass between rugby union playing standards and age categories. Rugby league senior elite forwards had less fat mass than junior elite forwards. Practitioners should prioritise training and nutritional strategies that maximise fat-free mass development, especially in junior elite cohorts.     

The effect of limb dominance on lower limb functional performance – a systematic review

Lower limb dominance (or lateral preference) could potentially effect functional performance. Clinicians are often asked to make judgements as to when a patient has sufficiently “recovered” from an injury, typically using strength and dynamic performance outcome measures. The primary purpose of this study was to systematically review the literature in relation to limb dominance within active adult populations and discuss some limitations to current methods and relate this to current clinical practice. A search of MEDLINE and CINAHL and EMBASE databases and reference lists of those articles identified was performed. Eleven articles were selected for meta-analysis. There was no statistical effect of limb dominance for any of the functional tests: isokinetic quadriceps and hamstring tests, hamstring:quadriceps ratios, single-leg hop for distance, single-leg vertical jump and vertical ground reaction force following a single-leg vertical jump. Pooled symmetry values varied from 94.6% to 99.6% across the tests, above the clinically accepted benchmark of 90% used in clinical practice. Although the results of this study must be used with discretion, asymmetries in the tasks described in this analysis should be viewed as undesirable and remedied accordingly. Further research is needed to quantify asymmetries, particularly in relation to sport-specific contexts.     

‘Race’ talk! Tensions and contradictions in sport and PE

Background: The universal sport discourses of meritocracy and equality are so engrained that few challenge them. The most cursory interest in sport, Physical Education (PE), and society will reveal that the lived reality is quite different. Racial disparities in the leadership and administration of sport are commonplace worldwide; yet, from research into ‘race’ in sport and PE, awareness of these issues is widespread, where many know that racism takes place it is generally claimed to be somewhere else or someone else. For many, this racism is part of the game and something to manipulate to steal an advantage; for others, it is trivial. This paper explores the contradictions and tensions of the author’s experience of how sport and PE students talk about ‘race’ and racism. ‘Race’ talk is considered here in the context of passive everyday ‘race’ talk, dominant discourses in sporting cultures, and colour blindness.

Theoretical framework: Drawing on Guinier and Torres’ [2003. The Miner's Canary: Enlisting Race, Resisting Power, Transforming Democracy. London: Harvard University Press] ideas of resistance through political race consciousness and Bonilla-Silva’s [2010. Racism Without Racists: Colour-Blind Racism and the Persistence of Racial Inequality in the United States. Plymouth: Rowan and Littlefield] notion of colour blindness, the semantics of ‘race’ and racialisation in sport and PE are interrogated through the prism of critical race theory (CRT). CRT is used here to centre ‘race’ and racialised relations where disciplines have consciously or otherwise excluded them. Importantly, the centring of ‘race’ by critical race scholars has advanced a strategic and pragmatic engagement with this slippery concept that recognises its paradoxical but symbolic location in society.

Discussion: Before exploring ‘race’ talk in the classroom, using images from the sport media as a pedagogical tool, the paper considers how ‘race’ is recreated and renewed. The paper then turns to explore how the effortless turn to everyday ‘race’ talk in the classroom can be viewed as an opportunity to disrupt racialised assumptions with the potential to implicate those that passively do so. Further, the diagnostic, aspirational, and activist goals of political race consciousness are established as vehicles for a positive sociological experience in the classroom.

Conclusion: The work concludes with a consideration of the uses and dangers of passive ‘race’ talk and the value of a political race consciousness in sport and PE. Part of the explanation for the perpetuation of ‘race’ talk and the relative lack of concern with its impact on education and wider society is focused on how the sovereignty of sport and PE trumps wider social concerns of ‘race’ and racism because of at least four factors: (1) the liberal left discourses of sporting utopianism, (2) the ‘race’ logic that pervades sport, based upon the perceived equal access and fairness of sport as it coalesces with the (3) ‘incontrovertible facts’ of black and white superiority (and inferiority) in certain sports, ergo the racial justifications for patterns of activity in sport and PE, and (4) the racist logic of the Right perpetuated through a biological reductionism in sport and PE discourses.     

The downside of being irrelevant and aloof: Exploring why individuals do not attend sport

Understanding what influences an individual to transition from awareness that a sport team exists to attraction to that team is of critical importance in the management and development of consumer bases. Determining the factors that prevent individuals at a stage of awareness from becoming attracted is of equal importance. In this paper we use a social identity approach to explore reasons for non-attendance. Qualitative data were gathered from a mixed-method online survey administered to registered participants in a large football (soccer) association in New South Wales. The questionnaire included an open-ended question allowing individuals who had not attended a match during the previous 12 months to elaborate on the reasons that they did not attend. The seventy-five individuals who responded to this open-ended question comprise the sample for this research. Data highlighted that cognitive apathy and disidentification were both salient cognitive responses associated with individuals who did not attend. Furthermore, club values and characteristics were shown to influence team-based perceptions. The findings present implications for sport teams to overcome cognitive apathy and disidentification through organisation-initiated efforts to disseminate information and promote the team, as well as efforts to align team characteristics and values with consumer perceptions.     

Out of Sight, (Not Yet) Out of Mind: The Impact of Tie Strength on Direct Interaction and Social Surveillance Among Geographically Close and Long-Distance Facebook Friends

Social networking sites are considered a valuable resource to maintain existing friendships even over considerable distances. The present study emphasizes tie strength as a crucial determinant for the use of interactive and passive features among 302 active Facebook users and friends of different relational closeness (close friends vs. casual friends vs. acquaintances) as well as a moderator for the impact of physical distance. As expected, tie strength affected direct interaction linearly, whereas social surveillance followed a quadratic trend. Furthermore, moderation analyses revealed less frequent direct interaction between close friends and stronger surveillance of casual friends’ profiles as physical distance increases. These results indicate different functions in relationship maintenance for both behaviors as direct interaction aims at nurturing current relationships, while surveillance serves as a catalyst for promising future communications. As a consequence, physical distance influences direct interaction adversely due to emerging constraints but also contains informational value encouraging information-seeking behaviors.