Journal of Science and Medicine in Sport - Articles in Press

Hypoleptinaemia in extreme body mass models: The case of international rugby players - Corrected Proof

S. Bréban, C. Chappard, C. Jaffré, C.L. Benhamou — 2010-01-25

Abstract: Leptinaemia has been poorly studied in athlete populations with the consequences of athletic hypoleptinaemia yet to be examined. Our aim was to determine if systemic leptinaemia is influenced in high body mass athletes. We recruited 24 rugby players (21.5±4.7 years; 11.8±2.9h/week) and 26 controls (22.3±3.1 years; 1.9±1.4h/week). BMD (whole body (WB), limbs, lumbar spine and non-dominant femur) and body composition (WB Lean Mass (LM) and FM) were measured by Dual X-ray Absorptiometry. Circulating levels of serum leptin (ng/ml), adiponectin (μg/ml), insulin (ng/ml), osteocalcin (ng/ml) and CTx (ng/ml) were assessed by ELISA assays. BMD were significantly higher in rugby players vs controls, at all bone sites, yet after adjustments for body mass index. They had significantly higher LM and FM but no differences in %FM. They had significantly higher osteocalcin but lower CTx, insulin and leptin concentrations. Leptin levels were strongly correlated to %FM (r=0.85, p<0.0001), as well as to absolute FM (r=0.77, p=0.0002), in the rugbymen group. Rugby practice was associated to a bone remodelling process in favour of bone formation. There was a significant hypoleptinaemia in our rugby players, while their percent FM was equivalent and absolute FM significantly higher than the control levels. These data suggest that leptin is under control of physical activity and not just fat mass.

Adjusting step count recommendations for anthropometric variations in leg length - Corrected Proof

2010-01-22

Abstract: Recent public health recommendations for step frequency over a given timeframe (stepsmin−1) associated with moderate-intensity physical activity (MPA) have been developed. The recommendation suggests 100 stepsmin−1. This estimate overlooks the impact of anthropometric differences between individuals, notably leg length, which is related to step frequency. Therefore this study examined the impact of leg length on stepsmin−1 associated with MPA. Twenty adults age 20–40 years (age 26.4±4.6 years, 9 males) walked over-ground at five walking speeds (0.5ms−1, 0.75ms−1, 1.0ms−1, 1.25ms−1, and 1.5ms−1), lasting 6min each, while wearing a portable gas analyser. Participants’ step frequency (stepsmin−1) for each walking speed was determined using a hand-tally counter. Random effects models were used to predict stepsmin−1 from METs and participant anthropometric measures (body mass index and leg length [cm]). Model estimates were used to predict stepsmin−1 corresponding to heights ranging from 5ft. to 6ft. 6in. (6 in increments). Overall, 100 stepsmin−1 corresponded to expending 3 METs (SEE 3.49 stepsmin−1, R2=0.68). As leg length increased estimated stepsmin−1 decreased by −1.15stepsmin−1 (95CI −2.19 to −0.10 stepsmin−1). Based on leg length for individuals 5ft to 6ft 6in., stepsmin−1 ranged from 111 to 85, respectively. Established stepsmin−1 cutpoints associated with MPA are general public health guidelines and anthropometric differences in leg length should be accounted for when developing step frequency recommendations for physical activity or weight loss studies that include individuals of varying height.

Maximal oxygen uptake, ventilatory thresholds and mechanical power during cycling in Tropical climate in Guadeloupean elite cyclists - Corrected Proof

O. Hue, S. Antoine-Jonville, O. Galy, S. Blonc — 2010-01-22

Abstract: The Tropical climate imposes a high level of physiological stress, which could modify the target heart rate in training load prescription, as the recommendations are often determined by maximal oxygen uptake testing in temperature-neutral laboratories. To test this hypothesis, 7 high-level cyclists performed two randomised maximal tests in neutral (19.2±0.9°C; 51.7±1.3% RH) and Tropical environment (25.8±1.1°C; 63.7±2.3% RH). Neither maximal oxygen uptake nor ventilatory threshold was influenced by the environmental conditions. However, ventilation (p<0.005) and the respiratory equivalent in O2 (p<0.05) were significantly higher in the Tropical environment, whereas maximal power output and the time to attain maximal oxygen uptake were significantly lower (p<0.05 for both). Moreover, the ventilatory cost of cycling (expressed in LW−1) was significantly greater in the Tropical condition (0.40±0.03LW−1 vs. 0.32±0.05LW−1, in Tropical vs. Neutral; condition effect: p<0.005; condition×time: p<0.001). Rectal temperature was influenced by neither the environmental conditions nor exercise (36.7±0.1 and 37.0±0.1°C vs. 36.8±0.1 and 37.1±0.2°C, in Tropical vs. Neutral, before and after exercise) but was influenced by condition×time (p<0.05). The heart rate (HR) values usually used for training prescription were not significantly different (154±5bpm vs. 156±4bpm and 172±4bpm vs. 167±4bpm in Tropical vs. Neutral climate, for the first and second thresholds, respectively). We concluded that the usual parameters measured during maximal exercise to establish training programs are not impaired in moderate Tropical environment. Nevertheless, the thermal stress attested by the increased ventilatory cost of cycling could have prevented the cyclists from performing a true maximal test in Tropical conditions.

Fielders and batters are injured too: A prospective cohort study of injuries in junior club cricket - Corrected Proof

Caroline F. Finch, Peta White, Rebecca Dennis, Dara Twomey, Andrew Hayen — 2009-12-25

Abstract: Internationally, there is a lack of good quality, prospectively collected injury data reported for junior club cricketers. This study describes injury rates according to age level of play and playing positions in junior community-level club cricketers to identify priorities for prevention. A prospective cohort study was used to monitor injuries in 88 under 12 years (U12), 203 U14 and 120 U16 players from the Ballarat Junior Cricket Association, Australia over the 2007/2008 playing season. Injury rates were calculated per 1000 participations when batting, bowling or fielding in matches and training sessions. Injury rate ratios were used to compare rates across age levels of play and position of play. Overall, 47 injuries were reported. Injury rates increased with age level of play with only one U12 player injured. Match injury rates were 3.57 per 1000 U14 participations versus 4.80 per 1000 U16 participations. Training injury rates were 4.20 per 1000 U14 participations versus 5.11 per 1000 U16 participations. On a proportionate basis, injuries occurred equally to fielders, batters and bowlers. There was a trend towards more injuries occurring while batting and fielding in matches, and more injuries occurring while bowling and batting during training sessions. In conclusion, injury rates in junior cricket players are low, but increase with age level of play. Unlike adult forms of the game, injuries occur to fielders and batters at least as frequently as to bowlers, indicating that preventive strategies need to be developed for all junior players and not just bowlers, as has been the focus previously.

Influence of posture and body type on the experience of exercise-related transient abdominal pain - Corrected Proof

Darren P. Morton, Robin Callister — 2009-12-18

Abstract: The aim of this study was to evaluate the influence of posture and body type on the experience of exercise-related transient abdominal pain (ETAP). Postural and somatotype assessments were performed on 104 active males and 55 active females aged 18.6±0.4 years (mean±SD) and were correlated against their self-reported experience of ETAP. Individuals demonstrating kyphosis were more likely to be susceptible to ETAP (p<0.01). Among the individuals susceptible to ETAP, the extent of kyphosis and lordosis influenced the pain severity (p<0.05). There was no relationship between any measure of body type and ETAP. The findings indicate that postural abnormality, particularly in the thoracic region, influences the experience of ETAP.

Influence of sex on the “Athlete's Heart” in trained cyclists - Corrected Proof

Thomas Rowland, Melissa Roti — 2009-12-18

Abstract: Compared to females, male endurance athletes have generally been considered to demonstrate greater values of cardiac mass and volume (the “athlete's heart”). However, studies addressing this issue have frequently failed to match training volumes between groups or provided inadequate adjustment of variables for body size and composition. This study compared echocardiographic anatomic features in 8 female and 8 male competitive cyclists with a similar training history. Conforming to most previous reports, left ventricular mass and end diastolic dimension, adjusted for fat free body mass and body surface area, respectively, were greater in the males (3.56±0.83gkg−1 versus 2.50±0.38gkg−1; 41.7±2.2mm and 37.4±2.5mm per BSA0.5). This study indicated that when training volume as well as body size and composition are considered, male endurance athletes exhibit greater cardiac dimensions and mass compared to their female counterparts.

Position statement on physical activity and exercise intensity terminology - Corrected Proof

Kevin Norton, Lynda Norton, Daryl Sadgrove — 2009-12-11

Abstract: The terminology used for monitoring and promoting physical activity and exercise among health and fitness professionals varies considerably. There is a large array of descriptor terms reported in the literature and used in day-to-day practice and this inconsistency can be confusing for clients and practitioners alike. The variation in terminology also makes it difficult to track changes in activity patterns over time and across studies. There are also a range of objective and relative intensity cut-offs used to describe the same intensity descriptors. This position statement addresses the question of standardisation of physical activity and exercise intensity terminology and makes recommendations that should assist those undertaking research and prescribing physical activity/exercise as well as those clients who are receiving professional guidance.

The short-term effects of high volume image guided injections in resistant non-insertional Achilles tendinopathy - Corrected Proof

2009-11-30

Abstract: We investigated neovascularisation, tendon thickness and clinical function in chronic resistant Achilles tendinopathy following high volume image guided injections (HVIGI). The subjects involved 11 athletes (mean age 43.5 years±11.6, range 22–59) with resistant tendinopathy of the main body of the Achilles tendon for a mean of 51.4 months (±55.56, range 4–144) who failed to improve with an eccentric loading program (mean 11.8 months±2.6, range 8–16). The morphological features, neovascularisation and maximal tendon thickness were assessed with power Doppler ultrasound. Clinical function was measured with the Victorian Institute of Sports Assessment-Achilles tendon (VISA-A) questionnaire. All the tendinopathic Achilles tendons were injected with 10mL of 0.5% bupivacaine hydrochloride, 25mg of hydrocortisone acetate, and 40mL of 0.9% NaCl saline solution under real time ultrasound guidance. All outcome measures were recorded at baseline and after a short-term follow-up (mean 2.9 weeks, range 2–4). The results showed a statistically significant difference between baseline and 3-week follow-up in all the outcome measures after HVIGI. The grade of neovascularisation reduced (3–1.1, p=0.003), the maximal tendon diameter decreased (8.7–7.6mm, p<0.001), and the VISA-A scores improved (46.3–84.1, p<0.001). In conclusion, HVIGI for resistant tendinopathy of the main body of the Achilles tendon is effective to improve symptoms, reduce neovascularisation, and decrease maximal tendon thickness at short-term follow-up.

Stop injecting corticosteroid into patients with tennis elbow, they are much more likely to get better by themselves! - Corrected Proof

Hamish Osborne — 2009-11-30

Tennis elbow is a common presentation to family practitioners and various medical specialists. Injectable corticosteroids have been used and continue to be used as one of the mainstays of treatment for tennis elbow. This is in spite of the fact that shortcomings have existed regarding its use since one of the earliest published clinical trials. Seven of thirteen patients injected had recurrence of symptoms during follow-up studies of at least 6 months with only 38% obtaining permanent relief.

Quantifying movement demands of AFL football using GPS tracking - Corrected Proof

Ben Wisbey, Paul G. Montgomery, David B. Pyne, Ben Rattray — 2009-11-09

Abstract: Global positioning system (GPS) monitoring of movement patterns is widespread in elite football including the Australian Football League (AFL). However documented analysis of this activity is lacking. We quantified the movement patterns of AFL football and differences between nomadic (midfield), forward and defender playing positions, and determined whether the physical demands have increased over a four season period. Selected premiership games were monitored during the 2005 (n=80 game files), 2006 (n=244), 2007 (n=632) and 2008 (n=793) AFL seasons. Players were fitted with a shoulder harness containing a GPS unit. GPS data were downloaded after games and the following measures extracted: total distance (km), time in various speed zones, maximum speed, number of surges, accelerations, longest continuous efforts and a derived exertion index representing playing intensity. In 2008 nomadic players covered per game 3.4% more total distance (km), had 4.8% less playing time (min), a 17% higher exertion index (per min), and 23% more time running >18kmh−1 than forwards and defenders (all p<0.05). Physical demands were substantially higher in the 2008 season compared with 2005: an 8.4% increase in mean speed, a 14% increase in intensity (exertion index) and a 9.0% decrease in playing time (all p<0.05). Nomadic players in AFL work substantially harder than forwards and defenders in covering more ground and at higher running intensities. Increases in the physical demands of AFL football were evident between 2005 and 2008. The increasing speed of the game has implications for game authorities, players and coaching staff.

The relationship between joint range of motion, muscular strength, and race time for sub-elite flat water kayakers - Corrected Proof

Mark R. McKean, Brendan Burkett — 2009-11-09

Abstract: Upper body strength and flexibility are common training activities in elite flat water kayaking yet the relationship between joint range of motion, muscular strength, and race time is unclear. The aim of this research was to firstly quantify the flexibility and strength of sub-elite kayakers and then determine the relationship of this data to performance race times. Twenty-nine national standard kayak paddlers were assessed for shoulder and pelvic flexibility, upper body strength, and performance time. The shoulder internal and external rotation range of movement for kayak paddlers was reduced in comparison to other populations. For the female paddlers significant (p<0.01) and strong correlations (r>0.70) were found between shoulder flexion range of movement, shoulder strength, and strength endurance. Strength scores for kayak paddlers are reported for the first time showing the Pull:Push strength ratio for male kayak paddlers was 129%, and for females 147%. The strength ratio was significantly different (p<0.01) across gender and also different to published ratios from other sports. Several other measures were also significantly different across gender. All paddlers showed significant and strong correlations between the three 8RM shoulder strength exercises, highlighting the importance of maintaining balance of strength for the muscles acting on the shoulder. There was only one measure, the strength endurance Bench-Pull-Max-Power for females that significantly and strongly correlated to the on-water performances; identifying the poor relationship between current dry land training activities and race performance. No single strength or ROM measure correlated strongly with on-water performances for either sex, as a sport kayaking appears to reduce the ROM about the shoulder joint.

Does plyometric training improve strength performance? A meta-analysis - Corrected Proof

Eduardo Sáez-Sáez de Villarreal, Bernardo Requena, Robert U. Newton — 2009-11-09

Abstract: Majority of the research suggests plyometric training (PT) improves maximal strength performance as measured by 1RM, isometric MVC or slow velocity isokinetic testing. However, the effectiveness of PT depends upon various factors. A meta-analysis of 15 studies with a total of 31 effect sizes (ES) was carried out to analyse the role of various factors on the effects of PT on strength performance. The inclusion criteria for the analysis were: (a) studies using PT programs for lower limb muscles; (b) studies employing true experimental design and valid and reliable measurements; (c) studies including sufficient data to calculate ES. When subjects can adequately follow plyometric exercises, the training gains are independent of fitness level. Subjects in either good or poor physical condition, benefit equally from plyometric work, also men obtain similar strength results to women following PT. In relation to the variables of program design, training volume of less than 10 weeks and with more than 15 sessions, as well as the implementation of high-intensity programs, with more than 40 jumps per session, were the strategies that seem to maximize the probability to obtain significantly greater improvements in performance (p<0.05). In order to optimise strength enhancement, the combination of different types of plyometrics with weight-training would be recommended, rather than utilizing only one form (p<0.05). The responses identified in this analysis are essential and should be considered by the strength and conditioning professional with regard to the most appropriate dose–response trends for PT to optimise strength gains.

The −174 G/C polymorphism of the IL6 gene is associated with elite power performance - Corrected Proof

2009-10-26

Abstract: The −174 G/C polymorphism [rs1800795] of the IL6 gene is a candidate to explain individual variations in health and exercise related phenotypes. We compared −174 G/C genotypic and allelic frequencies in three groups of men of the same Caucasian (Spanish) descent: elite endurance athletes (cyclists, runners; n=100); elite power athletes (jumpers, throwers, sprinters; n=53) and non-athletic controls (n=100). The frequency of the GG genotype (P=0.030) and G allele (P=0.026) was higher in the power athletes group compared with the control group. The frequency of the GG genotype (P=0.033) and G allele (P=0.013) was also higher in the power athletes group compared with the endurance athletes group. The odds ratio of being a power athlete if the subject had the GG genotype (dominant model) was 2.471 (95% confidence interval: 1.242–4.915) compared to the control group or the endurance athlete group. We did not find differences between the control and endurance athlete groups. In summary, our findings suggest that the G allele of the IL6 −174 G/C polymorphism might favour sprint/power sports performance.

Fundamental movement skills among Australian preschool children - Corrected Proof

Louise L. Hardy, Lesley King, Louise Farrell, Rona Macniven, Sarah Howlett — 2009-10-23

Abstract: Early childhood is a critical period for the development of fundamental movement skills (FMS). Children who do not master FMS are more likely to experience failure in the motor domain and less likely to participate in sport and games during childhood and adolescence. Studies among primary school aged children report low levels of FMS mastery indicating the need to implement FMS programs during the preschool years. Cross-sectional study of 425 children attending preschools in the Sydney, Australia in 2008. FMS were assessed using the Test of Gross Motor Development-2 including locomotor (run, gallop, hop, horizontal jump) and object control (strike, catch, kick overhand throw) skills. Data were analysed using linear regression and chi-squared analyses. Total locomotor score was higher among girls compared with boys (p<0.00); however only the hop was significantly different (p=0.01). Boys had higher total (p<0.00) and individual object control scores compared with girls, except the catch (p=0.6). The prevalence of mastery differed across each FMS. Girls generally had higher mastery of locomotor skills and boys had higher mastery of object control skills. These findings highlight the need to provide structured opportunities which facilitate children's acquisition of FMS, which may include providing gender separated games, equipment and spaces. That mastery of FMS is low in primary school children indicates the importance of early intervention programs in preschools. Preschools and child care centers hold promise as a key setting for implementing FMS programs.

Identifying symmetry in running gait, using a single inertial sensor - Corrected Proof

James B. Lee, Kattie J. Sutter, Christopher D. Askew, Brendan J. Burkett — 2009-10-23

Abstract: Running gait has been shown to alter due to changes in intensity. It was hypothesised that a sacral mounted single inertial sensor could identify the centre of mass (COM) vertical accelerations. This study aimed to validate this new technique against a criterion measure and to determine the influence of changes in running intensity on COM vertical acceleration and the symmetry of COM vertical acceleration between left and right steps. Ten athletes ran for 5min at their self-selected pace, plus 1km/h above and below this velocity. Validity of the single inertial sensor was determined by comparing COM vertical acceleration against that measured with a six-camera infrared system. Large correlation (r=0.96), a small typical error of estimate (1.84), and mean bias (0.02) were found between the two systems. The greatest magnitude in COM vertical acceleration occurred at the slowest running pace and decreased as pace increased. Sixty percent of the athletes exhibited asymmetry during at least one running pace; 30% were asymmetrical across all three velocities. While significant changes in COM vertical acceleration occurred between the different running velocities, this did not always result in a change in symmetry. This study found that a single inertial sensor can be used as a valid means of measuring COM vertical acceleration. This technique can detect changes in the COM vertical acceleration that may change with running velocity. Gait symmetry (using COM vertical acceleration) during running was also quantified using the inertial sensor.

The acute effects of different whole-body vibration amplitudes and frequencies on flexibility and vertical jumping performance - Corrected Proof

2009-10-23

Abstract: Frequency and amplitude determine the training load of whole-body vibration (WBV) exercise and thereby possible neuromuscular adaptations. We investigated the effects of amplitude and frequency of a single bout of WBV on flexibility and squat jump performance (SJ) and the time-course of these effects. In the amplitude study, twenty-five females performed three vibration protocols (VPs) for 6min at frequency of 25Hz and amplitudes of 4mm, 6mm, and 8mm and one control protocol (CP). In the frequency study, eighteen females performed three VPs at 6mm amplitude and frequencies of 15Hz, 20Hz, and 30Hz and one CP. Flexibility and SJ were measured before, immediately-post and 15min recovery. All protocols were performed on a side-to-side alternating vibration plate. In the amplitude study, flexibility was improved (p<0.01) immediately-post in VP4, VP6, VP8 (31.8±8.2, 31.9±7.6, 31.5±7.9, respectively) and at 15min recovery (31.6±8.1, 31.5±7.9, 31.0±8.2, respectively) vs. pre-vibration (30.2±8.6, 30.3±8.1, 30.2±8.3, respectively), but remained unchanged in CP (30.6±8.3 immediately-post, 30.7±8.2 at 15min vs. 30.4±8.2 pre-vibration). In the frequency study, flexibility was improved (p<0.01) immediately-post in VP15, VP20, VP30 (31.5±5.2, 31.3±5, 31.7±5.3, respectively) and at 15min recovery (31.3±5.4, 31.3±5.0, 31.3±5.3, respectively) vs. pre-vibration (30.6±5.4, 30.2±5.7, 30.3±5.9, respectively), but not in CP (30.7±5.1 immediately-post, 30.6±5 at 15min vs. pre-vibration 30.5±5.7). There were no significant effects of amplitude or frequency on SJ. In conclusion, a single WBV bout using a side-to-side alternating vibration plate may increase flexibility which persists for at least 15min, without altering jumping performance. These effects were observed irrespective of frequency and amplitude.

Accuracy and reliability of GPS devices for measurement of movement patterns in confined spaces for court-based sports - Corrected Proof

Rob Duffield, Machar Reid, John Baker, Wayne Spratford — 2009-10-23

Abstract: The aim of this study was to assess the accuracy and reliability of global positioning system (GPS) measures of distance and speed, compared to a high-resolution motion analysis system, for confined movement patterns used in many court-based sports. A single male participant performed 10 repetitions of four respective drills replicating court-based movement patterns and six repetitions of a random movement drill that replicated tennis match-play movement patterns. Two 1Hz and two 5Hz GPS devices concurrently measured distance covered and speed of all court-based drills. A 22 camera VICON motion analysis system, operating at 100Hz, tracked the position of an 18mm reflective marker affixed to one of the GPS devices to provide the criterion movement data. Results indicated that both 1 and 5Hz GPS devices under reported distance covered as well as both mean and peak speed compared to the VICON system (P<0.05). The coefficient of variation for both GPS devices for distance and speed measures ranged between 4 and 25%. Further, the faster the speed and more repetitive the movement pattern (over a similar location), the greater the measurement error. The inter-unit reliability for distance and speed measures of both 1 and 5Hz systems for movements in confined spaces was generally low to moderate (r=0.10–0.70). In conclusion, for court-based sports or movements in confined spaces, GPS technology under reports distance covered and both mean and peak speed of movement.

MCT1 genetic polymorphism influence in high intensity circuit training: A pilot study - Corrected Proof

2009-10-23

Abstract: Monocarboxylate Transporter 1 (MCT1) mediates the transport of the main fraction of lactate across the sarcolemma. A common polymorphic MCT1 variant has been identified, but its role in high intensity exercise performance has not been defined. We investigated the influence of MCT1 A1470T polymorphism (rs1049434) on lactate accumulation after high intensity circuit training. Ten men aged 20–26 performed three controlled circuit training (CWT) sessions at 60%, 70%, and 80% of the 15 repetition maximum (15RM), in non-consecutive days. CWT included three sets of a circuit of eight exercises, obtaining lactate measurements immediately after each set had been completed. Two independent variables were analysed: MTC1 genotypes according to the presence or absence of the A1470T polymorphism, and the intensity of circuit training. Genotype distributions were in Hardy–Weinberg equilibrium, being 30% wild-type, 50% heterozygotes, and 20% mutated homozygotes. Mean lactate concentration at 80% of 15RM were significantly higher than the mean lactate values at the other intensities (p<0.01). Significant differences between genetic groups were found in the lactate accumulation slope at 80% of 15RM (p=0.02) and in the maximal lactate concentration reached by all subjects in the study (Lmax) (p=0.03). The carriers of the A1470T polymorphism in the MTC1 gene seem to exhibit a worse lactate transport capability into the less active muscle cells for oxidation.

Match running performance in elite Australian Rules Football - Corrected Proof

Aaron J. Coutts, John Quinn, Joel Hocking, Carlo Castagna, Ermanno Rampinini — 2009-10-23

Abstract: There is little information describing the match running demands of elite-level Australian Rules Football (AF). The aims of this study were to examine: (1) match running demands; and (2) the influence of periods of increased physical activity on subsequent running performance in the Australian Football League. Time-motion analyses were performed 1–9 times per player from 16 professional AF players from the same club during games in 2005–2007, using portable global positioning systems during 65 matches. Game movements (standing, walking, jogging, running, higher-speed running, and sprinting) and distances (total distance covered [TD]; low-intensity activity [LIA, distance <14.4kmh−1]; and, high-intensity running distance [HIR, distance>14.4kmh−1]) were collected. The influence of the first half physical activities on second half activities, and each quarter on the subsequent quarter were analysed. The mean (±SD) TD and HIR distance covered during the games were 12,939±1145m and 3880±663m respectively. There were reductions in TD in the second (−7.3%), third (−5.5%) and fourth (−10.7%) quarters compared to the first quarter (p<0.01). The HIR was reduced after the first quarter (p<0.001). Players that covered larger TD or HIR during the first half or quarter decreased distance in the next half and quarter, respectively (p<0.001). These results show that a reduction in exercise intensity is inevitable during an AF match and that higher intensity activities reduce towards the end of games. High average speed during each half or quarter also affects subsequent running performance in elite-level AF.

Comparison of segmental linear and angular momentum transfers in two-handed backhand stroke stances for different skill level tennis players - Corrected Proof

Lin-Hwa Wang, Hwai-Ting Lin, Kuo-Cheng Lo, Yung-Chun Hsieh, Fong-Chin Su — 2009-10-19

Abstract: The purpose of this study was to investigate the differences of momentum transfer from the trunk and upper extremities to the racket between open and square stances for different skill levels players in the two-handed backhand stroke. The motion capture system with twenty-one reflective markers attached on anatomic landmarks of the subject was used for two-handed backhand stroke motion data collection. Twelve subjects were divided into an advanced group and an intermediate group based on skill level. The three-dimensional linear and angular momentums of the trunk, upper arm, forearm, hand and racket were used for kinetic chain analysis. Results showed that all players with the square stance had significantly larger backward linear momentum contribution in trunk and upper arm than with the open stance (p<.05) irrespective of playing level. However, the external rotation angular momentum of the shoulder joint was significantly larger with an open stance than with a square stance (p=.047). Comparison of playing levels showed that the intermediate group performed higher linear momentum in three components of the trunk, upper arm backward linear momentum, and trunk right bending angular momentum than the advanced group significantly (p<.05). The advanced group reduces trunk linear movement to keep stability and applies trunk and linkage segment rotation to generate backhand stroke power. The advanced group also has a quick backswing for increasing acceleration and maintains longer in the follow-through phase for shock energy absorption. This information could improve training protocol design for teaching the two-handed backhand stroke and teaching players, especially beginners, how to make an effective stroke.

Relationship between rowing ergometer performance and physiological responses to upper and lower body exercises in rowers - Corrected Proof

2009-10-19

Abstract: The aim of this investigation was to compare the physiological responses of 2000m rowing ergometer test with 7-min bench pull and leg press tests. We hypothesised that leg press exercise contributes to 2000m rowing ergometer test results, rather than bench pull performed by arms. College level rowers (n=12) performed 2000m rowing test and after one day 7-min bench pull and leg press (50% from the 1 RM). Stroke rate, heart rate (HR), blood lactate (LA) and ratings of perceived exertion (RPE) were measured during all tests. The number of repetitions was highest during 2000m rowing test (194.2±19.5) and lowest during bench pull (122.6±17.7) (during leg press 173.5±11.8). Differences between 2000m rowing test, leg press and bench pull tests were significant in mean and maximal HR. In LA concentration, the highest values were at 3rd min of recovery after rowing test (14.8±1.7mmoll−1). Between bench pull (8.8±1.9 and 8.5±2.7mmoll−1) and leg press (11.8±2.5 and 11.2±2.3mmoll−1) tests, the difference in LA concentration was not significant (p>0.05). Ratings of perceived exertion were highest in 2000m rowing test (19.3±0.9), difference with leg press and bench pull tests was not significant. There were significant relationships in mean and maximal HR (r=0.713–0.767) and Borg scale (r=0.764) during rowing test and leg press. The number of repetitions during leg press exercise correlated significantly with rowing test time (r=−0.677). In conclusion, this study suggests that in rowers there are major differences in the physiological adaptation to upper body and leg exercise, performed at similar intensities. Leg press exercise could be used to measure sport-specific strength endurance in rowers.

Factors affecting walking activity of older people from culturally diverse groups: An Australian experience - Corrected Proof

2009-10-15

Abstract: This study sought to investigate the walking habits of older people from diverse cultural backgrounds, and to identify the factors associated with their walking. Three hundred and thirty three people over the age of 60 years were recruited from seven culturally diverse groups from the Western suburbs of Melbourne, Australia. A survey questionnaire recording physical activity, and various factors related to activity, was interviewer-administered in the participants’ preferred language. Data were analysed using Kruskal–Wallis, χ2 and Mann–Whitney tests. Forty-seven percent of the participants walked at least 150min per week, with no significant difference in prevalence between genders or cultural groups. Some cultural differences were found in relation to reasons and locations for walking, and women were more likely than men to report walking in the shopping mall, whilst men were more likely than women to report walking in the park and along walking trails. Those who attained >150min of walking were more likely to report health and fitness as reasons for walking, to perceive their walking environment as more pleasurable, to use walking trails, and to consider their environment safe and to facilitate social interaction. This study indicates that the continued advocating of walking as a health promoting activity should be central to future campaigns to increase physical activity in this age group. The provision of locations that are accessible, safe, aesthetically pleasing, and encourage social engagement are likely to facilitate older people's participation in walking. For maximum effectiveness, however, strategies may benefit from being tailored to meet specific gender and cultural preferences.

Using EMGs and kinematics data to study the take-off technique of experts and novices for a pole vaulting short run-up educational exercise - Corrected Proof

2009-10-08

Abstract: This study attempts to characterise the electromyographic activity and kinematics exhibited during the performance of take-off for a pole vaulting short run-up educational exercise, for different expertise levels. Two groups (experts and novices) participated in this study. Both groups were asked to execute their take-off technique for that specific exercise. Among the kinematics variables studied, the knee, hip and ankle angles and the hip and knee angular velocities were significantly different. There were also significant differences in the EMG variables, especially in terms of (i) biceps femoris and gastrocnemius lateralis activity at touchdown and (ii) vastus lateralis and gastrocnemius lateralis activity during take-off. During touchdown, the experts tended to increase the stiffness of the take-off leg to decrease braking. Novices exhibited less stiffness in the take-off leg due to their tendency to maintain a tighter knee angle. Novices also transferred less energy forward during take-off due to lack of contraction in the vastus lateralis, which is known to contribute to forward energy transfers. This study highlights the differences in both groups in terms of muscular and angular control according to the studied variables. Such studies of pole vaulting could be useful to help novices to learn expert's technique.

Serum collagen-derived peptides are unaffected by physical training in older sedentary subjects - Corrected Proof

Véronique A. Cornelissen, Robert H. Fagard, Paul J. Lijnen — 2009-10-08

Abstract: Cardiac fibrosis occurs with normal aging and may have important pathological consequences. Accumulating evidence shows that biochemical assessment of fibrosis using collagen markers such as serum levels of the aminoterminal propeptide of types I and III collagen (PINP, PIIINP) and the carboxyterminal telopeptide of type I collagen (ICTP) represents a practical, validated and non-invasive method to assess myocardial collagen turnover. It is generally accepted that a sedentary lifestyle may be at least partly responsible for the age-related changes in the cardiovascular system. We aimed to investigate whether dynamic aerobic endurance training at lower or higher intensity (33% and 66% of heart rate reserve) may influence markers of collagen synthesis (PINP, PIIINP) and degradation (ICTP) in at least 55-year-old healthy sedentary men and women. A randomised crossover study comprising three 10-week periods was performed. In the first and third period, participants exercised at, respectively, lower or higher intensity in random order, with a sedentary period in between. Training programs were identical except for intensity and were performed three times 50min/week. 39 (18 men) out of 48 randomised participants completed the study; age averaged 59 years. Serum concentrations of PINP, PIIINP and ICTP were determined at baseline and at the end of each 10-week period. Our results showed that 10 weeks of endurance training at lower or higher intensity did not significantly alter serum markers of collagen synthesis and degradation in healthy older men and women.

Strength increases in upper and lower body are larger with longer inter-set rest intervals in trained men - Corrected Proof

2009-10-08

Abstract: The purpose of the current study was to compare different rest interval durations on upper and lower body strength. Thirty-six recreationally trained men were randomly assigned to 1min (G1; n=12), 3min (G3; n=12) or 5min (G5; n=12) rest interval groups. Each group performed the same resistance training program. Maximal strength was assessed at baseline, mid-point (8 weeks) and post-training (16 weeks) for the bench press and leg press exercises. For the bench press, significant increases were demonstrated within G3 and G5 at 8 weeks and at 16 weeks versus baseline (p<0.05). Additionally, for the bench press, G5 (98.2±3.7kg) was significantly stronger than G1 (92.5±3.8kg) at 16 weeks (p<0.05). For the leg press, significant increases were demonstrated within all groups at 8 weeks and at 16 weeks versus baseline (p<0.05). Additionally, for the leg press, G5 (290.8±23.5kg) was significantly stronger than G1 (251.0±15.8kg) at 8 weeks (p<0.01) and G3 (305.0±23.9kg) and G5 (321.7±21.7kg) were significantly stronger than G1 (276.7±10.7kg) at 16 weeks (p<0.05). The findings of the current study indicate that utilising 3 or 5min rest intervals between sets may result in significantly greater increases in upper and lower body strength beyond the initial weeks of training versus utilising 1-min rest intervals between sets.

Factors associated with increased propensity for hamstring injury in English Premier League soccer players - Corrected Proof

Gary Henderson, Christopher A. Barnes, Matthew D. Portas — 2009-10-05

Abstract: The aim of this study was to concurrently model the influence of a number of physical and performance parameters on subsequent incidence of hamstring injury in a squad of English Premier League soccer players. Thirty six healthy, male, elite, professional soccer players (age 22.6±5.2 years, height 1.81±0.08m, mass 75.8±9.4kg, lean mass 69.0±8.0kg) were assessed during the first week of pre-season training for anthropometry, flexibility, lower limb strength and power, speed and agility. Over the subsequent 45 week competitive season all hamstring injuries were diagnosed and recorded. Multiple logistic regression analysis was performed to link individual physical and performance capabilities with propensity to sustain a hamstring injury. A model containing age, lean mass, non-counter movement jump (NCM) performance and active hip flexion range of movement (ROM) was significantly (p<0.05) associated with increased propensity for hamstring injury. Odds for sustaining an injury increased ×1.78 for each 1 year increase in age, ×1.47 for each 1cm increase in NCM and ×1.29 for each 1° decrease in active range of hip flexion. Older, more powerful and less flexible soccer players are at greater risk of sustaining a hamstring injury. Support staff should identify such individuals and make appropriate interventions to minimise risk without compromising performance capabilities.

Does the demand for asymmetric functional lower body postures in lateral sports relate to structural asymmetry of the pelvis? - Corrected Proof

Melanie D. Bussey — 2009-09-30

Abstract: Pelvic asymmetry has been thought to alter body mechanics and result in increased strain on bony and soft tissues possibly producing asymmetrical skeletal adaptations. The purpose of the present study was to determine if there is a greater prevalence of pelvic skeletal asymmetry in athletes who participate in a sport that requires a lateral dominance combined with increased spinal flexion and rotation. This is a descriptive laboratory study using a cross-sectional design. Sixty healthy female university age elite athletes and non-athletes participated in the study. The height and width of the anterior superior iliac spine (ASIS) and posterior superior iliac spine (PSIS) were measured using an electromagnetic tracking device with stylus. Using these measures a pelvic asymmetry ratio (PAR) was calculated for each athlete based on the difference in slope between the two ASIS and between the two PSIS. PAR was first assessed as a continuous variable to determine any differences in range of asymmetry between groups. All athletes were then assessed for prevalence of asymmetry as defined by a PAR score greater than 0.05. The results showed that there was a significant group effect in the magnitude and prevalence of asymmetry, with the lateral dominant group having significantly more of both. This study demonstrates that potentially there is an association between the asymmetrical nature of lateral dominant sports and pelvic skeletal asymmetry. However, there are possibly two confounding variables in age of initial participation and presence of low back pain that require further exploration.

The Yo-Yo Intermittent Recovery Test (Level 1) to discriminate elite junior Australian football players - Corrected Proof

James P. Veale, Alan J. Pearce, John S. Carlson — 2009-09-30

Abstract: The Yo-Yo Intermittent Recovery (IR) Test is currently used to assess endurance performance in team sport athletes. However, to date, no data has been presented on its application to an elite junior Australian football (AF) playing group. Therefore, the aim of this study was to evaluate the Yo-Yo Intermittent Recovery Test Level 1 (IR1) ability to discriminate between junior AF players at two different playing standards and a group of non-athletic healthy males. Sixty age matched participants (16.6±0.5 years) spread over three groups (20 per group): elite junior footballers; sub-elite junior footballers; and non-athletic healthy males participated in this study. Participants undertook a single Yo-Yo test performance on an indoor basketball court for each group. A one-way ANOVA with Scheffe's post hoc analysis revealed the elite junior footballers covered a significantly greater total distance (p<0.001) and completed a significantly greater number of high-intensity efforts (p<0.001) in comparison to their sub-elite counterparts, whilst both AF groups performed significantly better (p<0.001) than the non-athletic healthy males. This study demonstrates the ability of the Yo-Yo IR1 to discriminate endurance performance between elite and sub-elite AF players, whilst further distinguishing AF players from a non-athletic healthy control group.

Vertical jump in female and male basketball players—A review of observational and experimental studies - Corrected Proof

Gal Ziv, Ronnie Lidor — 2009-09-30

Abstract: The main purpose of this article was to review a series of studies (n=26; 15 observational and 11 experimental) examining vertical jump (VJ) performances in female and male basketball players. Information on the tests used in these studies and their specific protocols, and the training programs conducted to improve VJ ability in elite basketball players, was assessed. It was found that vertical jump values varied greatly, from 22 to 48cm in female players and from 40 to 75cm in male players. These large variations can be explained mostly by the differences in testing protocols (each VJ protocol examined different physiological pathways) and skill level of players. The variations in VJ values among studies were greatly reduced when they used the same protocol. In addition, short plyometric training sessions as part of the strength and conditioning program were found to enhance VJ performances in basketball players. Based on the reviewed studies, five limitations associated with the testing protocols and the strength and conditioning programs used in the studies were outlined, among them the use of multiple testing protocols and lack of experimental studies. Three recommendations for basketball and strength and conditioning coaches were suggested, for one of which was including plyometric training in the annual training program.

Physiological attributes of triathletes - Corrected Proof

R. Suriano, D. Bishop — 2009-09-30

Abstract: Triathlons of all distances can be considered endurance events and consist of the individual disciplines of swimming, cycling and running which are generally completed in this sequential order. While it is expected that elite triathletes would possess high values for submaximal and maximal measures of aerobic fitness, little is known about how these values compare with those of single-sport endurance athletes. Earlier reviews, conducted in the 1980s, concluded that triathletes possessed lower values than other endurance athletes. An update of comparisons is of interest to determine if the physiological capacities of elite triathletes now reflect those of single-sport athletes or whether these physiological capacities are compromised by the requirement to cross-train for three different disciplines. It was found that although differences in the physiological attributes during swimming, cycling and running are evident among triathletes, those who compete at an international level possess values that are indicative of success in endurance-based individual sports. Furthermore, various physiological parameters at submaximal workloads have been used to describe the capacities of these athletes. Only a few studies have reported the lactate threshold among triathletes with the majority of studies reporting the ventilatory threshold. Although observed differences among triathletes for both these submaximal measures are complicated by the various methods used to determine them, the reported values for triathletes are similar to those for trained cyclists and runners. Thus, from the limited data available, it appears that triathletes are able to obtain similar physiological values as single-sport athletes despite dividing their training time among three disciplines.

Real-time versus post-game GPS data in team sports - Corrected Proof

Robert J. Aughey, Cameron Falloon — 2009-09-30

Abstract: Real-time (RT) GPS is used to monitor performance during Australian Football matches. Typically athlete targets monitored in RT are set from post-game (PG) data. The validity of RT compared to PG data is not yet known. This study compared RT data for key parameters to those obtained PG, using MinimaxX GPS. RT was different to PG for jog 4.2–5.0, run 5.0–6.9, sprint 6.9–10.0ms−1, and total distance (CV=6.4–19.6%). The signal to noise ratio was low for jog and run distance. For sprint noise exceeded the signal, with the opposite true for total distance. Caution must be applied if using RT data to monitor performance, especially if targets are set for players using PG data.

Effects of active vs. passive recovery on repeated rugby-specific exercises - Corrected Proof

A. Jougla, J.P. Micallef, D. Mottet — 2009-09-30

Abstract: The aim of this study was to determine the effects of active vs. passive recovery on performance of a rugby-specific intermittent test in rugby union players. Seven male rugby players (20.6±0.5 yrs; 181.9±10.0cm; 94.5±12.8kg) performed in random order, over two separate sessions, a specific repeated-sprint rugby test, the Narbonne test (6×4 consecutive actions: 1, scrummaging; 2, agility sprinting; 3, tackling; 4, straight sprinting) with 30s of passive or active recovery (running at 50% of maximal aerobic speed). The Narbonne tests were completed before (pre-test) and after (post-test) a 30-min rugby match. During the Narbonne test, scrum forces, agility and sprint times, heart rate and rate of perceived exertion were measured. Scrum forces were lower in active (74.9±13.4kg) than in passive recovery (90.4±20.9kg), only during the post-test (p<0.05). Fatigue index (%) (p<0.05) and total sprint time (s) (p<0.01) were significantly greater in active than in passive recovery, both during the pre-test (11.5±5.7% vs. 6.7±4.5% and 18.1±1.3s vs. 16.9±0.9s) and the post-test (7.3±3.3% vs. 4.3±1.5% and 18.3±1.6s vs. 16.9±1.1s). Consequently, the results indicated that passive recovery enabled better performance during the Narbonne test. However, it is obviously impractical to suggest that players should stand still during and following repeated-sprint bouts: the players have to move to ensure they have taken an optimal position.

Counting organised sport injury cases: Evidence of incomplete capture from routine hospital collections - Corrected Proof

Rebecca Mitchell, Caroline Finch, Soufiane Boufous — 2009-09-30

Abstract: Organised sports are a popular form of physical activity, but unfortunately, participation can result in injury. Despite this, there have been surprisingly few studies that have reported the population rate of sports injury. Data from the 2005 New South Wales (NSW, Australia) Population Health Survey were analysed to describe self-reported injury experiences during participation in organised sports activities and the source of treatment for such injuries during a 12-month period in a population representative sample of adults aged 16+ years. At interview, 2414 respondents stated that they had participated in organised sport in the previous 12 months and just under one-third (30.9%) reported that they had been injured during this participation. Half of all injuries required formal treatment from a health or medical practitioner. Physiotherapists most commonly provided treatment for sports injury (26.6% of cases) followed by general practitioners (15.6%). Only 2.8% of all injured sports participants were admitted to hospital for their injury and a further 6.1% received treatment in an emergency department. This corresponds to at most only 8.9% of all treated sports injuries receiving treatment in a hospital setting. Population-based estimates of the rate and burden of sports injuries that rely solely on routine hospital data collections are likely to grossly underestimate the size of the problem, as very few cases are treated in a hospital setting.

Association with physical fitness, serum hormones and sleep during a 15-day military field training - Corrected Proof

Jarno Tyyskä, Juha Kokko, Mika Salonen, Mikko Koivu, Heikki Kyröläinen — 2009-09-30

Abstract: The present study aimed to investigate the association between physical fitness, sleep duration and hormonal responses during a 15-day military field training (MFT). The purpose of MFT was to practice offensive manoeuvres in a countryside area. Nine army officers volunteered to participate, and their daily working routine mainly consisted of tasks in the headquarters that required on-call-duty at all times. Physical fitness and body composition were measured just before MFT. Serum testosterone (TES) and cortisol (COR) concentrations and sex-hormone-binding globulin (SHBG) were measured before MFT, as well as 8 and 15 days after the beginning of MFT. Heart rate (HR) was recorded for approximately 24h on days 8, 11 and 15 of MFT. Based on HR responses, there was no evidence of cardiorespiratory strain, hormonal responses or energy deficit during MFT. Although the changes in hormonal concentrations were insignificant, they were well correlated with physical fitness (r=0.67, p=0.05). Furthermore, the TES/SHGB ratio decreased by 28% in subjects whose VO2max was under 44mlkg−1min−1. On average, subjects slept for 6.20h per day, but the sleeping rhythm was disturbed due to military tasks. This diurnal sleeping time was strongly associated with TES/COR ratio (r=0.78, p=0.01). These results indicate that MFT causes very individual stress reactions, despite the low levels of physical strain and energy deficit. We therefore concluded that the observed hormonal responses were mainly due to sleep deprivation and low physical fitness.

Motor fitness in Dutch youth: Differences over a 26-year period (1980–2006) - Corrected Proof

2009-09-30

Abstract: This study aimed to compare neuromotor fitness test scores of 9–12-year-old Dutch youth in 2006 with scores of same aged children in 1980. Body height, body weight and performance on neuromotor fitness test items were measured in 2050 Dutch children from 9 to 12 years in 2006 and were compared with data of 2603 same aged Dutch children measured in 1980 with the same neuromotor fitness test battery. Dutch 9–12 year olds in 2006 were significantly taller and heavier than their peers in 1980. Age- and sex-specific performance on almost all neuromotor fitness test items was significantly worse in 2006. Thus, our data suggest that neuromotor fitness of Dutch youth has significantly decreased over the past 26 years.

Normative values of hip strength in adult male association football players assessed by handheld dynamometry - Corrected Proof

Chris M. Hanna, Mark L. Fulcher, C. Raina Elley, Simon A. Moyes — 2009-09-30

Abstract: Chronic groin pain is a common problem in association football players. Normative values for the strength of hip muscles, measured in an accurate and accessible manner, are needed to gauge strength and inform return to play decisions in this group. The purpose of this study was to define normative values of hip muscle strength using handheld dynamometry. A series of reliable clinical tests that are commonly used when making return to sport decisions in athletes with chronic adductor related groin pain have been selected. One hundred and twenty adult male association football players, free from injury, were recruited. Isometric strength of the hip flexors and adductor muscles was measured using a handheld dynamometer. Mean age was 24.9 years (SD 5.9). Eighty participants (67%) had experienced groin pain in the past. Mean strength for dominant leg hip flexion was 47.3kg (95% confidence interval 45.6–49.0), non-dominant leg hip flexion was 42.5kg (41.1–43.9), adduction at 0° hip flexion was 35.6kg (34.1–37.1), adduction at 45° was 32.0kg (30.9–33.1), and adduction at 90° was 25.5kg (24.4–26.5). This study establishes reference ranges and predictive equations for maximal isometric contraction strength of the hip muscles in non-injured adult male association football players. This information will assist assessment and management of an athlete's return to play following injury.

The impact of socioeconomic position on sport participation among South Australian youth - Corrected Proof

James Dollman, Nicole R. Lewis — 2009-09-30

Abstract: Organised sport among youth makes a substantial contribution to daily energy expenditure. This study investigated socioeconomic gradients in sport participation and predictors of participation. A representative sample of young South Australians (10–15y; n=1737) was surveyed on organised sport participation in the previous 12 months, and predictors derived from the Children's Physical Activity Correlates scale and a parent survey. Four constructs were derived: ‘is it worth it?’ (perceived outcomes); ‘am I able?’ (perceived competency); ‘reinforcing’ (parental support); and ‘enabling’ (perceived barriers, from the parent survey). Socioeconomic position (SEP) was operationalised by an area-level indicator, the Socioeconomic Indicator for Advantage (SEIFA), split into tertiles. Sport participation was higher among high (highest SEIFA tertile) compared with low (lowest SEIFA tertile) SEP children. All predictors except ‘am I able?’ were positively associated with sport participation among boys and girls. Of these predictors, the ‘enabling’ construct varied by SEP among both boys and girls, with high SEP children reporting fewer barriers to participation. High SEP girls reported higher scores on ‘reinforcing’ and ‘is it worth it?’ than their low SEP counterparts. Low SEP girls reported lower levels of both instrumental and affective support from parents to play sport. There are distinct SEP gradients in sport participation, as well as its psychosocial and environmental predictors among South Australian youth. Low SEP girls are the most disadvantaged in terms of parental support to participate in sport. Interventions targeting this vulnerable group are urgently required.

Effect of heat exposure on thermoregulation and hockey-specific response time in field hockey goalkeepers - Corrected Proof

Marcelle Malan, Brian Dawson, Carmel Goodman, Peter Peeling — 2009-09-30

Abstract: This study examined the thermoregulatory responses in field hockey goalkeepers during games (Part A), and assessed the effect of heat stress on hockey-specific response time (Part B). In Part A, core temperature (Tc), skin temperature (Tsk), body mass, fluid consumption and heart rate (HR) responses of six goalkeepers during two premier level club games in the Western Australian (winter) hockey season were recorded. Part B assessed the same measures, plus a response time test on four goalkeepers playing a simulated game inside a climate chamber in cool (COOL: 20°C, 40% RH) and hot (HOT: 35°C, 40% RH) conditions. In Part A, the mean (±SD) Tc and Tsk measured in games was 38.49±0.20°C and 34.99±0.99°C, with increases from baseline of 1.34±0.19°C and 1.08±0.30°C, respectively. Most of the increase in Tc resulted from the pre-game warm-up. In Part B, Tc and Tsk only increased significantly (p<0.05) from baseline in the HOT condition (0.62±0.18°C and 1.61±0.82°C, respectively). Response time was significantly slower (0.87±0.14s, p<0.01) after heat exposure, compared to COOL (0.75±0.15s), but the number of correct responses was not affected. For optimal performance, careful attention should be given to strategies to limit Tc increases in field hockey goalkeepers during matches.

A systematic review on the effectiveness of external ankle supports in the prevention of inversion ankle sprains among elite and recreational players - Corrected Proof

Janine Margarita R. Dizon, Josephine Joy B. Reyes — 2009-09-30

Abstract: Epidemiological studies have shown that 10–28% of all sports injuries are ankle sprains, leading to the longest absence from athletic activity compared to other types of injuries. This study was conducted to evaluate the effectiveness of external ankle supports in the prevention of inversion ankle sprains and identify which type of ankle support was superior to the other. A search strategy was developed, using the keywords, ankle supports, ankle brace, ankle tapes, ankle sprains and athletes, to identify available literature in the databases (MEDLINE, PubMed, CINAHL, EMBASE, etc.), libraries and unpublished papers. Trials which consider adolescents and adults, elite and recreational players as participants were the study of choice. External ankle supports comprise ankle tape, brace or orthosis applied to the ankle to prevent ankle sprains. The main outcome measures were frequency of ankle sprains. Two reviewers assessed the quality of the studies included using the Joanna Briggs Institute (JBI Appraisal tool). Whenever possible, results were statistically pooled and interpreted. A total of seven trials were finally included in this study. The studies included were of moderate quality, with blinding as the hardest criteria to fulfill. The main significant finding was the reduction of ankle sprain by 69% (OR 0.31, 95% CI 0.18–0.51) with the use of ankle brace and reduction of ankle sprain by 71% (OR 0.29, 95% CI 0.14–0.57) with the use of ankle tape among previously injured athletes. No type of ankle support was found to be superior than the other.

Hydrodynamic glide efficiency in swimming - Corrected Proof

Roozbeh Naemi, William J Easson, Ross H Sanders — 2009-09-30

Abstract: The glide is a major part of starts, turns and the stroke cycle in breaststroke. Glide performance, indicated by the average velocity, can be improved by increasing the glide efficiency, that is, the ability of the body to minimise deceleration. This paper reviews the factors that affect glide efficiency. In the first part of the review the sources of resistive force are reviewed including surface friction (skin drag), pressure (form) drag and resistance due to making waves (wave drag). The effect of body surface characteristics on the skin drag, the effect of the depth of the swimmer on wave drag, and the effects of posture and alignment, body size and shape on the form drag are reviewed. The effects of these variables on the added mass, that is, the mass of water entrained with the body are explained. The ‘glide factor’ as a measure of glide efficiency that takes into account the combined effect of the resistive force and the added mass is described. In the second part methods of quantifying the resistive force are reviewed. Finally, the ‘hydro-kinematic method’ of measuring glide efficiency is evaluated.

Mortality and longevity of elite athletes - Corrected Proof

Masaru Teramoto, Timothy J. Bungum — 2009-09-30

Abstract: The health benefits of leisure-time physical activity are well known, however the effects of engaging in competitive sports on health are uncertain. This literature review examines mortality and longevity of elite athletes and attempts to understand the association between long-term vigorous exercise training and survival rates. Fourteen articles of epidemiological studies were identified and classified by type of sport. Life expectancy, standardised mortality ratio, standardised proportionate mortality ratio, mortality rate, and mortality odds ratio for all causes of death were used to analyse mortality and longevity of elite athletes. It appears that elite endurance (aerobic) athletes and mixed-sports (aerobic and anaerobic) athletes survive longer than the general population, as indicated by lower mortality and higher longevity. Lower cardiovascular disease mortality is likely the primary reason for their better survival rates. On the other hand, there are inconsistent results among studies of power (anaerobic) athletes. When elite athletes engaging in various sports are analysed together, their mortality is lower than that of the general population. In conclusion, long-term vigorous exercise training is associated with increased survival rates of specific groups of athletes.

Bone properties in child and adolescent male hockey and soccer players - Corrected Proof

2009-09-30

Abstract: Children and adolescents who train extensively in high-impact, weight-bearing activities have enhanced bone mineral density. The purpose of this study was to evaluate bone strength, as reflected by quantitative ultrasound (QUS, Sunlight Omniscence), of child (10–12 yrs old) and adolescent (14–16 yrs old) male soccer and hockey players in comparison with age-matched controls. The groups included 30 child (CH) and 31 adolescent (AH) hockey players, 26 child (CS) and 30 adolescent (AS) soccer players, as well as 34 child (CC) and 31 adolescent (AC) healthy, non-athletic, age-matched controls. All athletes trained at an elite level year-round, with no difference in training volume between groups. Ultrasound speed of sound (SOS) was measured at the distal-radius and mid-tibia. In both age groups, hockey players were the heaviest and had the highest fat-free mass. No differences were found among groups in total energy intake, calcium or vitamin D intake. Radial and tibial SOS increased with age. Hockey players had higher radial SOS in both age groups (children: CH:3763±74, CS:3736±77, CC:3721±88m/s; adolescents: AH:3809±105, AS:3767±85, AC:3760±94m/s). Tibial SOS was higher in soccer players compared with controls. In spite of the higher body mass and fat-free mass in hockey players, their tibial SOS was similar to the non-athletes in both age groups. These findings support previous suggestions of sport-specific effects on bone strength. However, they need to be corroborated with longitudinal or prospective intervention studies.

Characterising the slope of the distance–time relationship in swimming - Corrected Proof

J. Dekerle, G. Brickley, M. Alberty, P. Pelayo — 2009-09-30

Abstract: The aim of the present study was to assess whether the critical speed calculated by the slope of the distance–time relationship (Sd–t) represents the boundary between the heavy and severe intensity domains in swimming and would be sustainable during intermittent exercise. Nine competitive male swimmers (mean±SD: aged 21.2±2.6 yrs; peak of 3866±529mLmin−1) performed, (a) four fixed-distance (100–200–400–800m) all-out efforts to determine Sd–t and peak ; (b) three constant-speed efforts to exhaustion (TTE) at and 5% above and below Sd–t ( and , respectively); (c) a set of 10×400m at Sd–t with 40-s recovery in between. Capillary blood lactate concentration ([La]B), oxygen uptake (), and RPE remained stable at (TTE=48.9±14.1min) with end values of 3.8±1.9mmolL−1, 87±14% peak , and 4.7±1.3. TTE decreased at (8.6±3.1min), with end [La]B of 10.2±1.9mmolL−1. Peak was reached at exhaustion. Similarly, Sd–t could only be maintained for 24.3±7.7min with an increase in RPE and [La]B, reaching its peak (95±5% peak ). RPE increased but [La]B remained stable throughout the ten 400m blocks performed at Sd–t (overall time of 53.9±2.7min). The physiological responses when swimming 5% below and 5% above Sd–t are those characterising the heavy and severe intensity domain, respectively. While Sd–t lies within the severe intensity domain, intermittent swims at this intensity induce [La]B steady state alongside high rates of perceived exertion.

Analysis of a reactive agility field test - Corrected Proof

Warren B. Young, Ben Willey — 2009-09-30

Abstract: The purpose of this research was to evaluate a reactive agility test by determining the relationships between the total time recorded for the test and various components. A tester used side-step movements to provide a stimulus for the athlete to change direction. By using electronic timing and high speed video analysis of the test, three times were recorded. These were the time taken for the tester to display the stimulus to change direction (tester time), the time taken by the participant to respond to the stimulus (decision time), and the time taken by the participant to change direction and sprint to the left or right (response movement time). Thirty-one semi-professional Australian Rules football players were assessed by analysing the mean of eight trials of the reactive agility test. The greatest correlation with total time was r=0.77 for decision time (p=0.00), with movement time and tester time producing coefficients of 0.59 (p=0.00) and 0.37 (p=0.04), respectively. The coefficient of variation for the mean tester time was 5.1%. It was concluded that perceptual skill as measured by decision time is an important component of the reactive agility test and the tester time should be controlled by using high speed video recordings to isolate its influence.

Parent influences on preschoolers’ objectively assessed physical activity - Corrected Proof

Melody Oliver, Grant M. Schofield, Philip J. Schluter — 2009-09-30

Abstract: The purposes of this study were to examine the relationship between accelerometer-derived physical activity (PA) in preschoolers and their parents, and to investigate other potential child and parental associates of child PA. Families of children aged 2–5 yrs were recruited in Auckland, New Zealand, from October 2006 to July 2007. Consenting children and parents had their height, weight, and waist circumference measured and were asked to wear accelerometers over 7 consecutive days, measuring PA in 15s epochs. Accelerometer data were gathered from 78 children, 62 mothers and 20 fathers over a median of 6.5–7 days, and converted to estimated daily PA rates for each individual using negative binomial generalised estimating equation (GEE) modelling. Potential associates of children's daily PA rates were then assessed using normal GEE models with exchangeable correlation structures. After taking account of all factors in the final multivariable model, parental PA rates (coefficient 0.09, 95% CI 0.03, 0.16, P=0.01) and child age (coefficient 0.11, 95% CI 0.01, 0.21, P=0.03) were the only factors significantly associated with child PA rates. Younger children may stand to benefit from PA intervention, and encouraging parental involvement in preschool PA interventions may be useful for increasing PA levels in young children. More work in this field is needed to corroborate these findings, improve generalisability, and determine causality.

Reduced humeral torsion predicts throwing-related injury in adolescent baseballers - Corrected Proof

Rod J. Whiteley, Roger D. Adams, Leslie L. Nicholson, Karen A. Ginn — 2009-09-30

Abstract: The amount of torsion in the humerus is determined by both genetic and activity-related factors, and affects the external rotation range of motion available at the shoulder. Previous research has shown athletes participating in throwing sports to have a greater amount of humeral retrotorsion in their dominant arm. The purpose of this study was to investigate the predictive ability of both the genetic and activity-related aspects of humeral torsion regarding throwing-related injury. The amount of humeral torsion in both arms of 35 high level adolescent male baseballers (mean age 16.6 years±0.6 years) was measured at study commencement. Significantly increased humeral retrotorsion in the dominant arm compared to the non-dominant arm was found (p=0.04). These athletes were followed for a period of 30 months, and any injury to their throwing arm which resulted in missing either a game or practice was recorded. ROC curve analysis was used to determine the predictive ability of humeral torsion with respect to the occurrence of injury to the throwing arm. Of the 35 athletes, 19 suffered a throwing arm injury. AUC values derived from ROC analysis showed humeral torsion in the non-dominant arm (AUC: 0.679, 95% CI: 0.502–0.857), as well as the average of the humeral torsion in both arms (0.692, 0.512–0.873), to be predictive of injury. Torsion in the dominant arm was not a significant throwing arm injury predictor. Thus non-dominant arm humeral torsion (the genetic contribution) was found to be the predictor of throwing arm injury.