Journal of Science and Medicine in Sport

Editorial Board

2012-01-01

Same tools, but a shift of context

Gregory S. Kolt — 2012-01-01

In a recent discussion with colleagues and graduate students we explored the growth of the physical activity and health research and practice areas over the past 15 or so years. Interestingly, the graduate students in our discussion were somewhat surprised to learn that many people now working in this area, did in fact not receive their original training in this area, but rather in other disciplines ranging from psychology, medicine, and epidemiology to sport and exercise science, physical education, and public health, just to mention a few. Others include architecture and urban design, town planning, physiotherapy, information technology, nursing, health promotion, physiology, etc. In summarising our discussion I used the phrase “same tools, but a shift of context”.

Measurement of subacromial impingement of the rotator cuff

P.C. Hughes, R.A. Green, N.F. Taylor — 2011-08-22

Abstract: Objective: Recent evidence suggests that shoulder impingement syndrome arises from primary rotator cuff pathology and may be related to the inability of the rotator cuff to prevent superior humeral head migration in shoulder elevation. Impingement involves compression of subacromial structures, including the rotator cuff. Previously, clinical tests have been shown to be inaccurate in diagnosing rotator cuff impingement. A lack of anatomical validity might explain the inaccuracy of these tests. This study aimed to clarify the anatomical basis of subacromial compression of the rotator cuff by analysing the compression forces generated and observing the structures impinged in a variety of shoulder positions. Design: This observational case series involved the dissection of nine embalmed cadaveric shoulders. Method: Pressure transducers were placed deep to the coracoid process, coracoacromial ligament, the anterior acromion and the posterior acromion. Shoulders were moved into internal and external rotation from the positions of flexion, abduction and extension. At each position, pressure readings were recorded and structures being compressed observed visually. Results: Highest pressures were recorded in flexion/internal rotation at the coracoacromial ligament, in abduction/internal rotation at the coracoid process (both involving the rotator interval) and in abduction/internal rotation at the coracoacromial ligament (involving supraspinatus). Supraspinatus was also observed to be compressed in extension/external rotation (against the anterior acromion). Infraspinatus was compressed in extension/external rotation (against the posterior acromion), while subscapularis was compressed in flexion/internal rotation and flexion/external rotation (both against the coracoid process). Conclusion: This study identifies shoulder positions likely to impinge particular rotator cuff tendons.

A comparison of augmented low-Dye taping and ankle bracing on lower limb muscle activity during walking in adults with flat-arched foot posture

Melinda M. Franettovich, George S. Murley, Bianca S. David, Adam R. Bird — 2011-08-31

Abstract: Objective: To compare the effect of taping and bracing on lower limb muscle activity during gait. Design: Cross-sectional laboratory study. Methods: Twenty-seven asymptomatic adults with flat-arched foot posture were recruited to this study. They walked over-ground under three randomly allocated conditions: (i) barefoot; (ii) augmented low-Dye taping; (iii) replaceable ankle brace. Electromyographic (EMG) activity from tibialis posterior, tibialis anterior, peroneus longus and medial gastrocnemius was measured for each condition. Peak EMG amplitude and time of peak EMG amplitude were assessed from stance phase data. A series of one-way repeated measure analysis of variance followed by Bonferroni post hoc tests were undertaken (α=0.05). Results: Tibialis posterior peak EMG amplitude decreased by 22% and 33% with bracing and taping (respectively), compared to barefoot. Peak amplitude was also decreased for peroneus longus by 34% and 30% and for tibialis anterior by 19% and 13% with bracing and taping (respectively), compared to barefoot. Small significant changes in time of peak EMG amplitude were found for tibialis posterior and tibialis anterior with taping and bracing compared to barefoot. The effect of taping and bracing was only different for tibialis posterior peak EMG amplitude, with tape producing a 15% reduction compared to bracing. Conclusion: The augmented low-Dye tape and replaceable ankle brace used in this study could be useful in managing overuse and dysfunction of selected leg muscles, particularly tibialis posterior, by reducing their level of activation during walking.

Video analysis of craniofacial soccer incidents: A prospective study

2011-10-03

Abstract: Objective: The aim of this study was to assess the occurrence of incidents involving the craniofacial region during Brazilian Professional Soccer League matches. The mechanisms of these incidents and the association between their characteristics and severity were also analyzed. Design: Prospective Epidemiology Study. Methods: A total of 113 first division matches of the Brazilian Soccer League were analyzed in 2009. Data collected included incident type, site affected, causing agent, severity, player position, field zone, referee decision and time of the match when the incident took place. Descriptive analysis considered absolute and relative frequencies and 95% confidence intervals. Fisher Exact Tests were used to test associations (p≤0.05). Results: Out of all matches, in 84.1% at least one craniofacial region related incident happened, totaling 227 incidents (mean of 2.0 per match). With reference to incident mechanisms and characteristics, 91.2% were hits and the most affected site was the face (70.0%). The most frequent causing agent was the upper extremity (59.5%) and the most frequently affected player was the striker (31.7%). The incident severity was associated with player position (p<0.01), the causing agent (p<0.01), field zone (p<0.01), site affected (p=0.03) and incident type (p<0.01). Conclusions: Soccer presented a high number of incidents against head and face during professional practice in Brazil, representing a real risk to athletes. Preventive strategies should be focused on game rule observance and “fair play”.

Encouraging junior community netball players to learn correct safe landing technique

2011-10-19

Abstract: Objective: Behavioural factors and beliefs are important determinants of the adoption of sports injury interventions. This study aimed to understand behavioural factors associated with junior community netball players’ intentions to learn correct landing technique during coach-led training sessions, proposed as a means of reducing their risk of lower limb injury. Design: Cross-sectional survey. Methods: 287 female players from 58 junior netball teams in the 2007/2008-summer competition completed a 13-item questionnaire developed from the Theory of Planned Behaviour (TPB). This assessed players’ attitudes (four items), subjective norms (four), perceived behavioural control (four) and intentions (one) around the safety behaviour of learning correct landing technique at netball training. All items were rated on a seven-point bipolar scale. Cluster-adjusted logistic regression was used to assess which TPB constructs were most associated with strong intentions. Results: Players had positive intentions and attitudes towards learning safe landing technique and perceived positive social pressure from significant others. They also perceived themselves to have considerable control over engaging (or not) in this behaviour. Players’ attitudes (p<0.001) and subjective norms (p<0.001), but not perceived behavioural control (p=0.49), were associated with strong intentions to learn correct landing technique at training. Conclusions: Injury prevention implementation strategies aimed at maximising junior players’ participation in correct landing training programs should emphasise the benefits of learning correct landing technique (i.e. change attitudes) and involve significant others and role models whom junior players admire (i.e. capitalise on social norms) in the promotion of such programs.

Exercise prescription for patients with type 2 diabetes and pre-diabetes: A position statement from Exercise and Sport Science Australia

2011-05-30

Abstract: Type 2 diabetes mellitus (T2DM) and pre-diabetic conditions such as impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) are rapidly increasing in prevalence. There is compelling evidence that T2DM is more likely to develop in individuals who are insufficiently active. Exercise training, often in combination with other lifestyle strategies, has beneficial effects on preventing the onset of T2DM and improving glycaemic control in those with pre-diabetes. In addition, exercise training improves cardiovascular risk profile, body composition and cardiorespiratory fitness, all strongly related to better health outcomes. Based on the evidence, it is recommended that patients with T2DM or pre-diabetes accumulate a minimum of 210min per week of moderate-intensity exercise or 125min per week of vigorous intensity exercise with no more than two consecutive days without training. Vigorous intensity exercise is more time efficient and may also result in greater benefits in appropriate individuals with consideration of complications and contraindications. It is further recommended that two or more resistance training sessions per week (2–4 sets of 8–10 repetitions) should be included in the total 210 or 125min of moderate or vigorous exercise, respectively. It is also recommended that, due to the high prevalence and incidence of comorbid conditions in patients with T2DM, exercise training programs should be written and delivered by individuals with appropriate qualifications and experience to recognise and accommodate comorbidities and complications.

Physical activity and screen time behaviour in metropolitan, regional and rural adolescents: A -sectional study of Australians aged 9–16 years

James Dollman, Carol Maher, Tim S. Olds, Kate Ridley — 2011-07-11

Highlights: ► Rural Australian adolescents are more active than their metropolitan counterparts. ► Metropolitan Australian males engage in more screen time than rural counterparts. ► Organised sport participation is similar among metropolitan and rural adolescents.Abstract: Objectives: While there is consistent evidence that rural adults in Australia are less active than their urban counterparts, studies relating geographical remoteness to activity patterns in Australian adolescents have yielded inconsistent results. The aim of this study was to describe objectively and subjectively measured patterns of physical activity and sedentary behaviours across remoteness categories in a representative sample of 9–16 year old Australians. Design: Cross-sectional observational study. Methods: 2071 Australian adolescents provided self-report use of time data on four days and wore a pedometer for at least 6 days within the 2007 Australian National Children's Nutrition and Physical Activity Survey. Comparisons of activity patterns were made across four objectively-determined remoteness categories (Major City, Inner Regional, Outer Regional and Remote), adjusting for household income, parental education and age. Results: Adolescents living in major cities self-reported 11–29min less moderate to vigorous physical activity each day than their counterparts living in geographically more remote areas, and took 150–850 fewer steps each day. While there were no differences in time spent in sport or active transport, differences in free play participation were significant. Males in major cities also reported higher levels of screen time. Differences were somewhat more marked among males than among females. Conclusions: Activity levels among Australian adolescents show contrasting patterns of geographical differences to those found in Australian adults. Higher levels of free play among rural Australian adolescents may be due to more available space and less fear of traffic and stranger risks.

Correlation between BMI and motor coordination in children

2011-08-10

Abstract: Objectives: To analyze the association between motor coordination (MC) and body mass index (BMI) across childhood and early adolescence. Design: This study is cross-sectional. Methods: Data were collected in 7175 children (boys n=3616, girls n=3559), ages 6–14 years. BMI was calculated from measured height and weight [body mass (kg)/height (m2)]. Motor coordination was evaluated using Kiphard-Schilling's body coordination test (KTK). Spearman's rank correlation was used to study the association between BMI and MC. A Kruskal–Wallis test was used to analyze the differences in MC between children of normal weight, overweight and obese children. Results: Correlations between MC and BMI were negative and varied between 0.05 and 0.49. The highest negative correlations for both boys and girls was at 11 years of age. There was a general pattern of increasing negative correlations in both genders from 6 to 11 years of age and then a decrease in correlation strengths through 14 years of age. In both boys (χ2(2)=324.01; p<0.001) and girls (χ2(2)=291.20; p<0.001) there were significant differences in MC between the three groups’ weight status. Normal weight children of both sexes demonstrated significantly higher MC scores than overweight. Obese children in both sexes had the lowest MC scores among all three groups. Conclusion: Motor coordination demonstrated an inverse relationship with BMI across childhood and into early adolescence. The strength of the inverse relation increased during childhood, but decreased through early adolescence. Overweight and obese children of both sexes demonstrated significantly lower MC than normal weight children.

Voices in the playground: A qualitative exploration of the barriers and facilitators of lunchtime play

Rebecca M. Stanley, Kobie Boshoff, James Dollman — 2011-09-23

Abstract: Objectives: To explore children's perceptions of the factors influencing their engagement in physical activity during the “critical” lunchtime period, using a social–ecological framework. Design: This study was an in-depth descriptive qualitative design. Methods: Fifty-four South Australian children aged 10–13 years participated in same-gender focus groups. Transcripts, field notes and activity documents were analysed using content analysis. Using an inductive thematic approach, data were coded and categorised into perceived barriers and facilitators according to a social–ecological model. Results: Children identified a range of environmental, social and intrapersonal barriers and facilitators. Bullying/teasing, the school uniform and school rules were exposed as explicit barriers to lunchtime play. Other important barriers included lack of access to, and poor suitability of, space, lack of access to programs/facilities and equipment, and lack of peer and teacher support. Perceived facilitators of lunchtime physical activity centred on access to equipment, enjoyment, motivation to improve skills, and peer support and acceptance. The freedom to make up or modify rules for games was also perceived to be a facilitator of lunchtime play. Conclusions: Communicating with children has been an effective approach in uncovering perceived barriers and facilitators to lunchtime play that may not have been previously considered in the quantitative correlate literature. Lunchtime interventions targeting children's physical activity should focus on addressing the barriers perceived to be important to lunchtime play.

Effects of synchronous music on treadmill running among elite triathletes

Peter C. Terry, Costas I. Karageorghis, Alessandra Mecozzi Saha, Shaun D’Auria — 2011-08-01

Abstract: Objectives: Music can provide ergogenic, psychological, and psychophysical benefits during physical activity, especially when movements are performed synchronously with music. The present study developed the train of research on synchronous music and extended it to elite athletes. Design: Repeated-measures laboratory experiment. Method: Elite triathletes (n=11) ran in time to self-selected motivational music, a neutral equivalent and a no-music control during submaximal and exhaustive treadmill running. Measured variables were time-to-exhaustion, mood responses, feeling states, RPE, blood lactate concentration, oxygen consumption and running economy. Results: Time-to-exhaustion was 18.1% and 19.7% longer, respectively, when running in time to motivational and neutral music, compared to no music. Mood responses and feeling states were more positive with motivational music compared to either neutral music or no music. RPE was lowest for neutral music and highest for the no-music control. Blood lactate concentrations were lowest for motivational music. Oxygen consumption was lower with music by 1.0%–.7%. Both music conditions were associated with better running economy than the no-music control. Conclusions: Although neutral music did not produce the same level of psychological benefits as motivational music, it proved equally beneficial in terms of time-to-exhaustion and oxygen consumption. In functional terms, the motivational qualities of music may be less important than the prominence of its beat and the degree to which participants are able to synchronise their movements to its tempo. Music provided ergogenic, psychological and physiological benefits in a laboratory study and its judicious use during triathlon training should be considered.

Oxygen uptake kinetics and middle distance swimming performance

2011-07-29

Abstract: Objective: The aim of this study was to determine whether kinetics and specifically, the time constant of transitions from rest to heavy (τpH) and severe (τpS) exercise intensities, are related to middle distance swimming performance.Design: Fourteen highly trained male swimmers (mean±SD: 20.5±3.0yr; 75.4±12.4kg; 1.80±0.07m) performed an discontinuous incremental test, as well as square wave transitions for heavy and severe swimming intensities, to determine kinetics parameters using two exponential functions.Methods: All the tests involved front-crawl swimming with breath-by-breath analysis using the Aquatrainer swimming snorkel. Endurance performance was recorded as the time taken to complete a 400m freestyle swim within an official competition (T400), one month from the date of the other tests.Results: T400 (Mean±SD) (251.4±12.4 s) was significantly correlated with τpH (15.8±4.8s; r=0.62; p=0.02) and τpS (15.8±4.7s; r=0.61; p=0.02). The best single predictor of 400m freestyle time, out of the variables that were assessed, was the velocity at , which accounted for 80% of the variation in performance between swimmers. However, τpH and were also found to influence the prediction of T400 when they were included in a regression model that involved respiratory parameters only.Conclusions: Faster kinetics during the primary phase of the response is associated with better performance during middle-distance swimming. However, appears to be a better predictor of T400.

Taekwondo training speeds up the development of balance and sensory functions in young adolescents

Shirley S.M. Fong, Siu-ngor Fu, Gabriel Y.F. Ng — 2011-07-29

Abstract: Objectives: This study aimed (1) to identify the developmental status of balance and sensory functions in young adolescents as compared to adults and, (2) to explore the effect of Taekwondo (TKD) training on the development of balance and sensory systems in young adolescents. Design: Cross-sectional controlled trial. Methods: Sixty-six participants including 42 adolescents (21 TKD practitioners, 21 non-TKD practitioners) and 24 adults were tested. The sway velocity of centre of gravity was recorded during standing on the non-dominant leg on a Smart Equitest ® system. The somatosensory, vestibular and visual ratios were also measured with the machine. Results: Adult participants swayed slower than both TKD and non-TKD adolescent groups during single leg stance with eyes open (p=0.007 and p<0.001, respectively). The TKD adolescent group, in turn, swayed slower than the non-TKD adolescent group (p<0.001). Adult participants had better visual ratio than both TKD and non-TKD adolescents (p=0.001 and p<0.001, respectively) while there was no difference between the TKD and non-TKD adolescents (p=0.164). For the vestibular ratio, there was no significant difference between adult participants and TKD adolescents (p=0.432). Adolescents who did not practice TKD showed significantly lower vestibular ratio than TKD adolescents and adults (p=0.003 and p<0.001, respectively). In addition, there was no significant difference in the somatosensory ratio among the 3 participant groups (p=0.711). Conclusions: Participation in TKD appears to speed up the development of postural control and vestibular function in adolescents. Clinicians might advocate TKD exercise as a therapeutic intervention for young people with balance or vestibular dysfunctions.

Reliability of the 8-repetition maximum test in men and women

J. David Taylor, James P. Fletcher — 2011-08-08

Abstract: Objective: The 8-repetition maximum test has been recommended as a method of prescribing an intensity for resistance training in healthy adults, athletes, and patients with health conditions. Yet, limited research related to the reliability of 8-repetition maximum testing has been conducted. The purpose of this study was to determine the reliability of the 8-repetition maximum test in men and women. Design: Test–retest reliability study. Methods: Twenty-eight people (14 males, 14 females, mean age=23.0 years [standard deviation=1.3]) with no exercise contraindications participated in this study. After familiarization, each participant underwent 8-repetition maximum testing using 4 different exercises. For all participants, the 8-repetition maximum test was performed during 2 sessions with 2–3 days between sessions. The intraclass correlation coefficient (ICC[1,2]), typical error as the coefficient of variation (TECV), and the Bland–Altman plot were used to assess reliability. Unpaired t-test was used to determine the influence of gender on differences between initial test and retest values. Results: Excellent reliability of the 8-repetition maximum test was found for all exercises (ICC[1,2]>0.9). The range of TECV values was 3.4–10.4%. The Bland–Altman plot illustrated that 27 out of 28 data points for total 8-repetition maximum scores were within the 95% limits of agreement. Unpaired t-test indicated no significant difference between men and women in variations between initial test and retest 8-repetition maximum scores. Conclusion: The findings of this study suggest that an 8-repetition maximum test protocol that includes familiarization is reliable in men and women.

Distinguishing psychological characteristics of expert cricket batsmen

Juanita R. Weissensteiner, Bruce Abernethy, Damian Farrow, John Gross — 2011-08-08

Abstract: Objectives: This paper sought to determine the psychological characteristics and skills that are fundamental to batting success in the sport of cricket. Design and method: Following on from the findings of an earlier qualitative investigation which suggested that a favourable mix of psychological attributes and skills are critical to high performance in batting (Weissensteiner et al.), adult-aged batsmen of two different skill levels (highly skilled n=11; lesser skilled n=10) completed a battery of psychological tests that included measures of mental toughness (Mental Toughness Inventory), perfectionism (Multidimensional Perfectionism Scale), coping ability (Athletic Coping Skills Inventory-28), and optimism (Attributional Styles Questionnaire). Results: Contrary to the research hypothesis, it was found that the highly skilled batsmen were only distinguishable from batsmen of lesser skill by their higher degree of global mental toughness. The skilled batsmen scored significantly higher on mental toughness dimensions relating to motivation (Personal Bests, Task Value and Commitment), coping skill (Perseverance) and self-belief (Potential). Conclusions: If mental toughness can be reliably predicted at an earlier age, it may be an attribute worthy of inclusion in future talent identification and development programs.

Physical demands of professional rugby league training and competition using microtechnology

Tim J. Gabbett, David G. Jenkins, Bruce Abernethy — 2011-08-08

Abstract: Objectives: To investigate the physical demands of professional rugby league match-play using microtechnology, and to compare these demands with typical training activities used to prepare players for competition.Design: Prospective cohort study.Methods: Thirty elite rugby league players participated in this study. Seven hundred and eighty-six. training data sets and 104 data sets from National Rugby League matches were collected over one playing season. Movement was recorded using a commercially available microtechnology unit (minimaxX, Catapult Innovations), which provided information on speeds, distances, accelerations, physical collisions and repeated high-intensity efforts.Results: Mean distances covered during match-play by the hit-up forwards, wide-running forwards, adjustables, and outside backs were 3,569m, 5,561m, 6,411m, and 6,819m, respectively. Hit-up forwards and wide-running forwards were engaged in a greater number of moderate and heavy collisions than the adjustables and outside backs, and more repeated high-intensity effort bouts per minute of play (1 bout every 4.8–6.3min). The physical demands of traditional conditioning, repeated high-intensity effort exercise, and skill training activities were all lower than the physical demands of competition.Conclusions: These results demonstrate that absolute distances covered during professional rugby league matches are greater for outside backs, while the collision and repeated high-intensity effort demands are higher for hit-up forwards and wide-running forwards. The specific physical demands of competitive play, especially those demands associated with collisions and repeated high-intensity efforts, were not well matched by those observed in traditional conditioning, repeated high-intensity effort exercise, and skills training activities. Further research is required to investigate whether modifications need to be made to these training activities to better prepare players for the demands of National Rugby League competition.

Lower extremity kinematic asymmetry in male and female athletes performing jump-landing tasks

Evangelos Pappas, Felipe P. Carpes — 2011-09-19

Abstract: Objectives: Higher side-to-side asymmetry among female athletes compared to their male counterparts during bilateral athletic tasks such as landing from a jump has been proposed as a potential source of non contact knee injuries. However, the kinematic symmetry and potential sex differences during the initial (and most dangerous) phase of bilateral landings have not been examined. The objective of this project is to evaluate lower extremity kinematic asymmetry among recreational athletes during forward jump landing and drop landing tasks.Design: Repeated measures laboratory experiment.Methods: Thirteen male and 15 female athletes performed landing tasks on a force plate while kinematic data were collected. Kinematic asymmetry between legs was calculated for the initial phase of landing for lower extremity kinematics. ANOVA tests and effect size calculations were used to measure the effect of sex, landing task and their interaction on kinematic asymmetry.Results: Athletes exhibited higher asymmetry for knee valgus (d=0.5, p=0.006) and hip adduction (d=0.5, p=0.057) when performing forward compared to drop landings. Females landed with greater knee valgus asymmetry than males during forward landings (d=0.7, p=0.078) and with greater ankle abduction asymmetry during drop landings (d=0.5, 0.091).Conclusions: Female athletes exhibited greater frontal plane knee and ankle kinematic asymmetry than males during forward landings which may be related to the higher rate of ACL injury. Forward landings elicited greater hip adduction and knee valgus asymmetries than drop landings and, therefore it may be more appropriate for field testing when screening for asymmetries.

Acknowledgement of Reviewers

2012-01-01