The effect of mechanical loading on the size and shape of bone in pre-, peri-, and postpubertal girls: a study in tennis players

Exercise during growth results in biologically important increases in bone mineral content (BMC). The aim of this study was to determine whether the effects of loading were site specific and depended on the maturational stage of the region. BMC and humeral dimensions were determined using DXA and magnetic resonance imaging (MRI) of the loaded and nonloaded arms in 47 competitive female tennis players aged 8-17 years. Periosteal (external) cross-sectional area (CSA), cortical area, medullary area, and the polar second moments of area (I_p, mm⁴) were calculated at the mid and distal sites in the loaded and nonloaded arms. BMC and I _p of the humerus were 11-14% greater in the loaded arm than in the nonloaded arm in prepubertal players and did not increase further in peri- or postpubertal players despite longer duration of loading (both, _p < 0.01). The higher BMC was the result of a 7-11% greater cortical area in the prepubertal players due to greater periosteal than medullary expansion at the midhumerus and a greater periosteal expansion alone at the distal humerus. Loading late in puberty resulted in medullary contraction. Growth and the effects of loading are region and surface specific, with periosteal apposition before puberty accounting for the increase in the bone's resistance to torsion and endocortical contraction contributing late in puberty conferring little increase in resistance to torsion. Increasing the bone's rt.osistance to torsion is achieved hy modifying bone shape and mass, not necessarily bone density.

Safety attitudes and beliefs of junior Australian football players

Objectives: To describe the safety attitudes and beliefs of junior (aged 16–18 years) Australian football players.

Setting: Six Victorian Football League Under 18 (VFL U18) clubs in Victoria, Australia.

Methods: Cross sectional survey. Altogether 103 players completed a self report questionnaire about their safety beliefs and perceptions of support when injured, across three contexts in which they played: VFL U18 club, local club, and school.

Results: Although only 6% believed it was safe to play with injuries, 58% were willing to risk doing so. This increased to almost 80% when players perceived that their chances of being selected to play for a senior elite team would be adversely affected if they did not play. There were significant differences in the perceived level of support for injured players and in the ranking of safety as a high priority across the three settings. In general, the VFL U18 clubs were perceived as providing good support for injured players and giving a high priority to safety issues, but local clubs and particularly schools were perceived to address these issues less well.

Conclusions: Junior Australian football players have certain beliefs and perceptions in relation to injury risk that have the potential to increase injuries. These negative beliefs need to be addressed in any comprehensive injury prevention strategy aimed at these players.

Players, clubs, events and the Trade Practices Act : a primer for sporting clubs

The Trade Practices Act (TPA) has had an enormous impact on how corporations in Australia may conduct their business. In relation to sporting clubs, it limits the freedom of clubs to deal with players, each other and the public. While previously many clubs may have escaped the ambit of the TPA because they were not “corporations”, state equivalent Fair Trading legislation and the introduction of the national competition policy in 1995 have effectively expanded the scope of consumer and competition regulation to include individuals and associations. Consequently, an understanding of the nature and scope of trade practices regulation is now important for any sporting organisation—regardless of size or structure. This paper identifies the legislative provisions most likely to impact upon sporting clubs and examines some possible circumstances in which clubs might find themselves exposed to liability.

The transition from schoolboy to elite sportsman: education and training and early career players in the AFL

IIn this paper we discuss some of the findings of a research project funded by the Australian Football League (AFL) titled: Getting the Balance Right: Professionalism, Performance, Prudentialism and Playstations in the Life of AFL Footballers. The research explored the following issues: the emergence and evolution of a 'professional identity' for AFL footballers an identity that has many facets including the emerging ideas that a professional leads a balanced life, and has a prudent orientation to the future, to life after football. This 'professional identity' isn't natural, and must be developed through a range of 'professional development' activities (a common link to all other 'professions'). In the AFL at this time professional development has a focus on engaging players in a variety of education and training activities TAFE & University courses, and workshops and seminars that the industry has put in place to educate players about issues that the industry sees as important.

The paper focuses on our research with players we classified as Early Career. For many of these 17 to 21 year old young men the later years of secondary schooling were compromised in their pursuit of an AFL career. Their subsequent drafting is followed by intense efforts to physically prepare for football. In this context our research indicates that many Early Career players put football first, second and third. Education and training, and professional development come further down their list of priorities.

Are unilateral and bilateral patellar tendinopathy distinguished by differences in anthropometry, body composition, or muscle strength in elite female basketball players?

Background: Overuse injury to the patellar tendon (patellar tendinopathy) is a major reason for interrupted training and competition for elite athletes. In both sexes, the prevalence of unilateral and bilateral tendinopathy has been shown to differ. It has been proposed that bilateral pathology may have a different aetiology from unilateral pathology. Investigation of risk factors that may be unique to unilateral and bilateral patellar tendinopathy in female athletes may reveal insights into the aetiology of this condition.
Objectives: To examine whether anthropometry, body composition, or muscle strength distinguished elite female basketball players with unilateral or bilateral patellar tendinopathy.
Methods: Body composition, anthropometry, and muscle strength were compared in elite female basketball players with unilateral (n = 8), bilateral (n = 7), or no (n = 24) patellar tendinopathy. Body composition was analysed using a dual energy x ray absorptiometer. Anthropometric measures were assessed using standard techniques. Knee extensor strength was measured at 180°/s using an isokinetic dynamometer. z scores were calculated for the unilateral and bilateral groups (using the no tendinopathy group as controls). z scores were tested against zero.
Results: The tibia length to stature ratio was approximately 1.3 (1.3) SDs above zero in both the affected and non-affected legs in the unilateral group (p<0.05). The waist to hip ratio was 0.66 (0.78) SD above zero in the unilateral group (p<0.05). In the unilateral group, leg lean to total lean ratio was 0.42 (0.55) SD above zero (p<0.07), the trunk lean to total lean ratio was 0.63 (0.68) SD below zero (p<0.05), and leg fat relative to total fat was 0.47 (0.65) SD below zero (p<0.09). In the unilateral group, the leg with pathology was 0.78 (1.03) SD weaker during eccentric contractions (p<0.07).
Conclusions: Unilateral patellar tendinopathy has identifiable risk factors whereas bilateral patellar tendinopathy may not. This suggests that the aetiology of these conditions may be different. However, interpretation must respect the limitation of small subject numbers.

Anthropometry, physical performance, and ultrasound patellar tendon abnormality in elite junior basketball players: a cross-sectional study

Objective: Patellar tendinopathy has been reported to be associated with many intrinsic risk factors. Few have been fully investigated. This cross-sectional study examined the anthropometric and physical performance results of elite junior basketball players with normal or abnormal patellar tendons to see if any measures were associated with changes in tendon morphology.

Methods: Agility, leg strength, endurance, and flexibility were measured in 71 male and 64 female players. A blinded radiologist ultrasonographically examined their patellar tendons and athletes were grouped as having normal or abnormal tendons. One-way ANOVA was used to test for differences in anthropometric and physical performance data for athletes whose tendons were normal or abnormal (unilateral or bilateral tendinopathy) on ultrasound.

Results: Results show that females with abnormalities in their tendons had a significantly better vertical jump (50.9±6.8 cm) than those with normal tendons (46.1±5.4 cm) (p = 0.02). This was not found in males. In males, the mean sit and reach in those with normal tendons (13.2±6.7 cm) was greater (p<0.03) than in unilateral tendinopathy (10.3±6.2 cm) or in bilateral tendinopathy (7.8±8.3 cm). In females, those with normal tendons (13.3±4.8 cm) and bilateral tendinopathy (15.8±6.2 cm) were distinctly different from those with unilateral tendinopathy (7.9±6.6 cm).

Conclusion: Flexibility and vertical jump ability are associated with patellar tendinopathy and the findings warrant consideration when managing young, jumping athletes.

Reproducibility and clinical utility of tendon palpation to detect patellar tendinopathy in young basketball players

Background—Palpation is an important clinical test for jumper's knee.

Objectives—To (a) test the reproducibility of palpation tenderness, (b) evaluate the sensitivity and specificity of palpation in subjects with clinical symptoms of jumper's knee, and (c) determine whether tenderness to palpation may serve as a useful screening test for patellar tendinopathy. The yardstick for diagnosis of patellar tendinopathy was ultrasonographic abnormality.

Methods—In 326 junior symptomatic and asymptomatic athletes' tendons, palpation was performed by a single examiner before ultrasonographic examination by a certified ultrasound radiologist. In 58 tendons, palpation was performed twice to test reliability. Tenderness to palpation was scored on a scale from 0 to 3 where 0 represented no pain, and 1, 2, and 3 represented mild, moderate, and severe tenderness respectively.

Results—Patellar tendon palpation was a reliable examination for a single examiner (Pearson r = 0.82). In symptomatic tendons, the positive predictive value of palpation was 68%. As a screening examination in asymptomatic subjects, the positive predictive value of tendon palpation was 36–38%. Moderate and severe palpation tenderness were better predictors of ultrasonographic tendon pathology than absent or mild tenderness (p<0.001). Tender and symptomatic tendons were more likely to have ultrasound abnormality than tenderness alone (p<0.01).

Conclusions—In this age group, palpation is a reliable test but it is not cost effective in detecting patellar tendinopathy in a preparticipation examination. In symptomatic tendons, palpation is a moderately sensitive but not specific test. Mild tenderness in the patellar tendons in asymptomatic jumping athletes should be considered normal.

Classification of self-consumable highlights for soccer video summaries

An effective scheme for soccer summarization is significant to improve the usage of this massively growing video data. The paper presents an extension to our recent work which proposed a framework to integrate highlights into play-breaks to construct more complete soccer summaries. The current focus is to demonstrate the benefits of detecting some specific audio-visual features during play-break sequences in order to classify highlights contained within them. The main purpose is to generate summaries which are self-consumable individually. To support this framework, the algorithms for shot classification and detection of near-goal and slow-motion replay scenes is described. The results of our experiment using 5 soccer videos (20 minutes each) show the performance and reliability of our framework.

Professional education and training for early career players in the Australian Football League: footy first, second and third

In this presentation we discuss some of the findings of a research project funded by the Australian Football League (AFL) titled: Getting the Balance Right: Professionalism, Performance, Prudentialism and Playstations in the Life of AFL Footballers. The research explored the following issues: the emergence and evolution of a ‘professional identity’ for AFL footballers – an identity that has many facets including the emerging ideas that a professional leads a balanced life, and has a prudent orientation to the future, to life after football. This ‘professional identity’ isn’t natural, and must be developed through a range of ‘professional development’ activities (a common link to all other ‘professions’). In the AFL at this time professional development has a focus on engaging players in a variety of education and training activities – TAFE & University courses, and workshops and seminars that the industry has put in place to educate players about issues that the industry sees as important.

The presentation will focus on our research with players we classified as Early Career players. For many of these 17 to 21 year old young men the later years of secondary schooling were compromised in their pursuit of an AFL career, and their subsequent drafting is followed by intense efforts to physically prepare them for football. In this context our research indicates that many Early Career players put football first, second and third – education and training, and industry expectations that they participate in this sort of professional development come further down their list of priorities.

All part of the hetero-normative? Women football fans` voices on players` sexual (mis)conduct

From interviews conducted in Victoria with women fans of Australian Rules Football, this paper examines their perceptions and rationalisations of alleged sexual misconduct by players. The paper is situated in the seeming contradiction of women avidly supporting male dominated sports despite players being implicated in misconduct against their gender. Women fans' voices about the reported misconduct are explored. These fall into two main categories that are referred to as the 'predatory female' and the 'rogue male' narratives. The former suggests that the sexual assertiveness of some women - the 'groupies' - unlocks men's primal sexuality. The latter points to footballers being immersed in a hyper-masculine sub-culture that predisposes them to treat women in an arbitrary, demeaning manner. The fans' voices, while condemning players' misconduct, suggest that predatory females, by actively seeking out footballers, become victims
because they trigger testosterone driven male responses. Rogue male behaviour is deprecated, but understood as stemming from masculine ways, accentuated by team bonding, that leads some individuals into misconduct, possibly as a means of emphasising their masculinity within their group. Explaining player misconduct in these ways enables fans to distance themselves from it and continue their passionate support of
football.

Eccentric decline squat protocol offers superior results at 12 months compared with traditional eccentric protocol for patellar tendinopathy in volleyball players

Background: Conservative treatment of patellar tendinopathy has been minimally investigated. Effective validated treatment protocols are required.

Objectives: To investigate the immediate (12 weeks) and long term (12 months) efficacy of two eccentric exercise programmes for the treatment of patellar tendinopathy.

Methods: This was a prospective randomised controlled trial of 17 elite volleyball players with clinically diagnosed and imaging confirmed patellar tendinopathy. Participants were randomly assigned to one of two treatment groups: a decline group and a step group. The decline group were required to perform single leg squats on a 25° decline board, exercising into tendon pain and progressing their exercises with load. The step group performed single leg squats on a 10 cm step, exercising without tendon pain and progressing their exercises with speed then load. All participants completed a 12 week intervention programme during their preseason. Outcome measures used were the Victorian Institute of Sport Assessment (VISA) score for knee function and 100 mm visual analogue scale (VAS) for tendon pain with activity. Measures were taken throughout the intervention period and at 12 months.

Results: Both groups had improved significantly from baseline at 12 weeks and 12 months. Analysis of the likelihood of a 20 point improvement in VISA score at 12 months revealed a greater likelihood of clinical improvements in the decline group than the step group. VAS scores at 12 months did not differ between the groups.

Conclusions: Both exercise protocols improved pain and sporting function in volleyball players over 12 months. This study indicates that the decline squat protocol offers greater clinical gains during a rehabilitation programme for patellar tendinopathy in athletes who continue to train and play with pain.

Sun exposure and sun protection behaviours among young adult sport competitors

Objective: To explore the relationship between sun protection and physical activity in young adults (18-30 years) involved in four organised sports.

Methods: Participants (n=237) in field hockey, soccer, tennis and surf sports completed a self-administered survey on demographic and sun-protective behaviours while playing sport. Differences in sun-protective behaviour were explored by sport and by gender.

Results: Sunburn during the previous sporting season was high (69%). There were differences between sports for sunburn, sunscreen use and reapplication of sunscreen. Lifesaving had the highest rates compared with the other three sports. Hats and sunglasses worn by participants varied significantly by sports. A greater proportion of soccer and hockey players indicated they were not allowed to wear a hat or sunglasses during competition. For all sports, competition was played mainly in the open with no shade provision for competitors while they were playing. There were some gender differences within each of the sports. Female soccer and tennis players were more likely to wear sunscreen compared with males. Female hockey players were more likely to wear a hat compared with males.

Conclusions: Our findings highlight that there is still room for improvement in sun-protective behaviours among young adult sport competitors. There is a need for a systematic approach to sun protection in the sporting environments of young adults.

Implications: Health promotion efforts to increase physical activity need to be paired with sun protection messages.

Promoting comprehensive sun protection policies and practices in outdoor sports: a qualitative study of perceived priorities and practicalities

Sun protection policies, environments, practices, and attitudes in sporting club contexts might be significant determinants of sun exposure among adult sporting participants. Face-to-face interviews, using standardised, open-ended questions were conducted with 20 club officials from four sports: soccer, hockey, tennis and surf lifesaving. Thematic content analysis identified a number of salient themes. Formal sun protection policies were well-implemented in surf lifesaving, but less so in soccer, hockey and tennis clubs, which often had informal sun protection practices in place. Officials perceived sun protection to be important, which was related to perceived exposure levels, the type of sport, length of time played and the season. Consistent logistical and practical considerations emerged, including limited resources, availability of shade, and lack of control over sporting facilities, uniform regulations and games scheduling. Sun protection efforts often focused on children more than adult players. Reciprocal responsibility was an important theme, where it was perceived that responsibility for sun protection should be equally shared between the club and the member. In this study it was found that reciprocal responsibility, duty of care and sport-specific practical requirements might significantly influence the success of policy, environmental and education initiatives for sun protection in sporting settings.

MMP2 and MMP9 plasma levels as markers of bone remodeling : a study on young male tennis players

Introduction
Our goal is to study the effects of tennis practice in pre-pubescent boys on bone remodeling, by means of enzyme activity involved in balance of matrix remodeling (MMP2 and MMP9).
Results
Mineral bone density has been found higher in the dominant arm (P < 0.0001) as well as MMP2 and MMP9 levels in plasma (P < 0.05).
Conclusion
Tennis practice in children increases bone remodeling, which can be assessed by MMP dosage, in addition of densitometry technique.