This paper describes the use of a web-site for the dissemination of the community-based '10,000 steps' program which was originally developed and evaluated in Rockhampton, Queensland in 2001-2003. The website provides information and interactive activities for individuals, and promotes resources and programs for health promotion professionals. The dissemination activity was assessed in terms of program adoption and implementation. In a 2-year period (May 2004-March 2006) more than 18,000 people registered as users of the web-site (logging more than 8.5 billion steps) and almost 100 workplaces and 13 communities implemented aspects of the 10,000 steps program. These data support the use of the internet as an effective means of disseminating ideas and resources beyond the geographical borders of the original project. Following this preliminary dissemination, there remains a need for the systematic study of different dissemination strategies, so that evidence-based physical activity programs can be translated into more widespread public health practice.
Performance-predictive parameters have been established for rowers representing different quality levels, sexes, weight categories and classifications, but none have been designed for very young rowers (age <14). The objective of this study was to predict 1000-m rowing ergometer performance based on 12 anthropometric and six physiological variables in 48 male rowers (age range 12.0-13.9 year; mean+/-S.D. 12.94+/-0.61) and to determine the key parameters that would perhaps provide a scientific basis for talent identification and the selection process in rowing. The subjects completed an incremental maximal treadmill test. Their body height (r=-0.79), body mass (r=-0.60), lean body mass (r=-0.82), leg length (r=-0.72), arm length (r=-0.71), bicristal diameter (r=-0.63), biacromial diameter (r=-0.73), upper arm girth (r=-0.34), forearm girth (r=-0.63), thigh girth (r=-0.29), calf girth (r=-0.54), maximal oxygen uptake (in L/min, r=-0.89; and in mL/kg/min, r=-0.36), maximal ventilation (r=-0.77), and oxygen uptake at ventilatory anaerobic threshold (r=-0.87) correlated with 1000-m time (p<0.05), while percent body fat, percent of maximal oxygen uptake at ventilatory anaerobic threshold and maximal lactate did not. Performance correlated significantly with age (r=-0.46; p<0.01), so it was important to consider this effect in the resulting regression models. Multiple regression procedures indicated that the model comprising anthropometric and physiological variables combined best predicts performance (R(2)=0.85), followed by models that comprised physiological (R(2)=0.80) and anthropometric (R(2)=0.76) variables alone. In conclusion, in rowers aged 12-13 year a higher aerobic capacity (as measured by maximal oxygen uptake in L/min), and a larger body size are beneficial for performance over 1000-m rowing ergometer distance.
Team-sport athletes who normally reside at sea level occasionally play games at altitudes sufficient to impair endurance performance. To investigate the effect of intermittent normobaric hypoxic exposure on performance in generic and game-specific tests at altitude, 22 senior club level rugby players performed baseline tests before single-blind random assignment to one of three groups: hypoxia-altitude (n=9), normoxia-altitude (n=6), and normoxia-sea level (n=7). The hypoxia-altitude group underwent 9-13 sessions of intermittent hypoxic exposure (concentration of inspired oxygen=13-10%) over 15 days, then repeated the performance tests within 12h of travelling to 1550m. The normoxia-altitude group underwent placebo exposures by breathing room air before repeating the tests at altitude, whereas the normoxia-sea level group underwent placebo exposures before repeating the tests at sea level. Hypoxic exposure consisted of alternately breathing 6min hypoxic gas and 4min ambient air for 1h at rest. Performance measures gathered at each testing session were maximum speed, sub-maximum heart-rate speed and sub-maximum lactate speed during a 20-m incremental running test, mean time in six 70-m sprints, repetitive explosive power and other measures from seven 5.5-min circuits of a rugby simulation. Repetitive explosive power ( approximately -16%) and 20-m shuttle performance ( approximately -3%) decreased substantially at altitude compared to sea level. Acclimatisation to hypoxia had a beneficial effect on sub-maximum heart rate and lactate speed but little effect on other performance measures. In conclusion, 1550-m altitude substantially impaired some measures of performance and the effects of prior adaptation via 9-13 sessions of intermittent hypoxia were mostly unclear.
This study was conducted to determine if anthropometric and fitness testing scores can be used to discriminate between players that were selected or not selected in an elite Under 18 Australian Rules Football side. A training squad of 40 Australian Rules Football players was assessed on a battery of standard anthropometric and fitness tests just prior to the selection of the 30 man player roster for the upcoming season. Results showed that the selected players were significantly (P<0.05) taller and had greater upper body strength than non-selected players. A discriminant analysis was performed which predicted with an accuracy of 80% whether each player was successful or unsuccessful in gaining selection. This suggested that physical conditioning and anthropometric measurements do play an important part in determining selection in elite junior Australian Rules Football teams. However the discriminant function predicted non-selected players (90.9%) better than it predicted selected players (75.9%). Selected Under 18 players were found to be similar to the values reported for elite to sub-elite senior players on height, sit and reach, CMJ and perhaps aerobic fitness, but considerably less than the senior players on 3RM bench press and body mass.
The underlying mechanisms of altitude training are still a matter of controversial discussion but erythropoietic adaptations with an increase of total haemoglobin mass (tHb) have been shown in several studies, partly depending on an adequate hypoxic dose. The aim of this retrospective study was to investigate if a 3 weeks sojourn at moderate altitude (1816 m) with conventional training sessions (live and train at moderate altitude), especially under real and uncontrolled conditions, results in an increased tHb. tHb was measured in seven male cyclists competing at elite level (German national cycling team, U23 category) prior to the ascent to altitude and immediately after descent to sea-level. The athletes completed a 21 days altitude training camp living at 1816 m and training at 1800-2400 m during the competitive season. No significant difference was found in tHb after the altitude sojourn (prior 927+/-109g vs. 951+/-113g post, 95% CI -13-61g). Additionally, the analysis of red cell volume, plasma volume and blood volume or haemoglobin concentration [Hb] as well as haematocrit (Hct) did not reveal any significant changes. The data supports the theory that an adequate hypoxic dose is required for adaptations of the erythropoietic system with an increase of tHb and a threshold of approximately 2100-2500 m has to be exceeded.
A majority of sports science research is undertaken in universities and dedicated research centres, such as institutes of sport. Reviews of literature analysing and categorising research have been carried out, but categories identified have been limited to research design and data gathering techniques. Hence there is a need to include categories such as discipline, subjects and targeted sport. A study was conducted using document analysis method to gather data that described and categorised performance-based sports science research projects in Australian universities and institutes of sport. An instrument was designed that could be used by researchers to analyse and profile research in the area of sports science. The instrument contained six categories: targeted sport, primary study area, participant type, research setting, methodology and data gathering techniques. Research documents analysed consisted of 725 original unpublished research reports/theses. Results showed that over two-thirds of research projects were targeted to specific sports and, of this group, nearly half involved four sports: cycling, rowing, athletics and swimming. Overall, physiology was the most researched scientific discipline. The most frequently used research method was experimental design, and the most frequently used data gathering technique was physiological (performance) measures. Two-thirds of research was conducted in laboratory settings, and nearly half of the research was conducted with elite or sub-elite athletes as participants/subjects. The findings of this study provide an overall synopsis of performance-based sports science research conducted in Australia over the last 20 years, and should be of considerable importance in the ongoing development of sports science research policy in Australia.
The present study investigated the interactions between parents' and children's physical activity levels by examining whether or not parents who exercise have children who participate in sport. Of primary interest was an investigation of trends in these interactions over time. Information was collected from 10-13 y old children in 1985 (n = 2463) and then again in 1997-99 (n = 1469), about their sports participation and their perceptions of parents' exercise habits. Boys' participation in at least one sport declined from 87% in 1985 to 76% in 1997/1999 while, among girls, participation fell from 80% to 71%. According to their children's perceptions, mothers exercising regularly fell from 36% to 31% between surveys, while fathers exercising regularly fell from 39% to 32%. Interactions between parents' and children's exercise and sports behaviours were examined employing chi-square analysis techniques. Results showed gender-specific relationships for the 1985 sample, such that active fathers were associated with increased participation in sports by boys, and inactive mothers were associated with less participation in sports by girls. These interactions seemed to diminish over time. It is possible that changes in social structures during this time may be affecting familial behaviour relationships, such as the role modelling of active behaviours.
Rising youth obesity is a serious public health concern. There is a widespread view that declining physical activity is contributing to this trend. A total of 929 young South Australians (age=9-15 years) were surveyed in 1985 and 2004 on usual physical activity in several contexts, including attitudes to physical activity. Eight of 10 South Australian schools participating in the 1985 Schools Health and Fitness Survey were revisited in 2004. Comparisons were made on: organised sport, active transport, physical education (PE), playground activity, vigorous physical activity (VPA), total leisure-time physical activity (LTPA), and attitudes to PE and school sport. The questionnaire and method of administration were identical in both surveys. There were no differences between surveys in club and school sport participation, walking to school, and reported enjoyment of PE and school sport. In 2004 fewer children rode to school, but PE classes were more frequent. The percentage of children who 'sit and talk' during school breaks had increased, with a decreased percentage of older girls who 'run around' during school breaks. There was a significantly higher LTPA in MET.min in 2004 for boys, which was particularly evident at higher percentiles. There were no changes in mean or distribution of LTPA for the whole sample or girls. The percentage of respondents reporting >/=3 bouts of VPA in the previous week rose from 51% (1985) to 76% (2004). There is no consistent evidence of declining physical activity among South Australian youth. It is apparent that physical activity in some contexts has declined, while in other contexts levels are the same or higher than in 1985. This underscores the complex nature of physical activity and the influences on this behaviour.
Skeletal muscle glucose uptake and metabolism are major determinants of whole body glucose metabolism in response to exercise and insulin stimulation. An understanding of the mechanisms responsible for increased muscle glucose uptake under these conditions is crucial for identifying strategies that enhance insulin action and exercise performance. Regular exercise, by favourably influencing the intramuscular determinants of glucose uptake, enhances insulin action. For this reason, it is recommended in the prevention and management of disease states that are characterised by insulin resistance ("metabolic syndrome"). Increased skeletal muscle glucose uptake, as a consequence of carbohydrate ingestion, maintains carbohydrate supply to contracting muscle, at a time when glycogen levels are reduced, and is associated with enhanced performance. Thus, both health and exercise performance are influenced by the metabolism of glucose within skeletal muscle.
Physical fitness, participation in physical activity, fundamental motor skills and body composition are important contributors to the health and the development of a healthy lifestyle among children and youth. The New South Wales Schools Fitness and Physical Activity Survey, 1997, was conducted to fill some of the gaps in our knowledge of these aspects of the lives of young people in New South Wales. The survey was conducted in February and March, 1997 and collected data on a randomly-selected sample of students (n = 5518) in Years 2, 4, 6, 8 and 10. Measures were taken on body composition (height and weight, waist and hip girths, skinfolds), health-related fitness (aerobic capacity, muscular strength, muscular endurance, flexibility), fundamental motor skills (run, vertical jump, catch, overhand throw, forehand strike and kick), self-reported physical activity, time spent in sedentary recreation, and physical education (PE) classes. The methods are described to assist in the development of surveys of other populations and to provoke debate relevant to the development and dissemination of standard approaches to monitoring the fitness, physical activity habits and body composition of Australian children and youth. Finally, we offer comments on some of the strengths and limitations of the methods employed.
The one-repetition maximum (1RM) test is considered the gold standard for assessing muscle strength in non-laboratory situations. Since most previous 1RM reliability studies have been conducted with experienced young participants, it is unclear if acceptable test-retest reliability exists for untrained middle-aged individuals. This study examined the reliability of the 1RM strength test of untrained middle-aged individuals. Fifty-three untrained males (n=25) and females (n=28) aged 51.2+/-0.9 years participated in the study. Participants undertook the first 1RM test (T1) 4-8 days after a familiarisation session with the same exercises. 1RM was assessed for seven different exercises. Four to eight days after T1, participants underwent another identical 1RM test (T2). Ten weeks later, 27 participants underwent a third test (T3). Intraclass correlation coefficients (ICC), typical error as a coefficient of variation (TEcv), retest correlation, repeated measures ANOVA, Bland-Altman plots, and estimation of 95% confidence limits were used to assess reliability. A high ICC (ICC>0.99) and high correlation (r>0.9) were found for all exercises. TEcv ranged from 2.2 to 10.1%. No significant change was found for six of the seven exercises between T1 and T2. Leg press was slightly higher at T2 compared to T1 (1.6+/-0.6%, p=0.02). No significant change was found between T2 and T3 for any exercise. 1RM is a reliable method of evaluating the maximal strength in untrained middle-aged individuals. It appears that 1RM-testing protocols that include one familiarisation session and one testing session are sufficient for assessing maximal strength in this population.
While sprint track running events, lasting 10-25 secs, are characterised by an anaerobic metabolic dominance, no actual track running data exist which have quantified the relative energy system contributions. Using previous methods employed by our laboratory, including 'in race' measures of VO2, accumulated oxygen deficit (AOD), blood lactate concentration and estimated phosphocreatine degradation (La/PCr), the aerobic-anaerobic energy system contributions to 100-m and 200-m events were calculated. For the 100-m event, results indicated a relative aerobic-anaerobic energy system contribution (based on AOD measures) of 21%-79% and 25-75% for males and females respectively (9%-91% and 11%-89% based on La/PCr measures; p<0.05 for both genders for 100-m from AOD estimates). For the 200-m, a 28%-72% and 33%-67% contribution for male and female athletes was estimated (21%-79% and 22%-78% based on La/PCr measures; NS from AOD estimates). A range of energy system contribution estimates for events of these durations have previously been proposed using a variety of techniques. The data from the current study also show different results depending on the measurement technique utilised. While AOD measures are often used to estimate anaerobic energy contribution, at such high exercise intensities (and brief exercise durations) as used in the present study, AOD measures showed larger aerobic energy estimates than expected.
Developing policy and strategic initiatives to increase population levels of physical activity (PA) requires constant referral to the epidemiological evidence base. This paper updates the evidence that PA confers a positive benefit on health, using research studies in the peer-reviewed scientific literature published between 2000-2003. Areas covered include updates in all-cause mortality and in cardiovascular disease prevention, diabetes, stroke, mental health, falls and injuries, and in obesity prevention. Recent evidence on PA and all-cause mortality replicates previous findings, and is consistent with current Australian moderate PA recommendations. Recent papers have reinforced our understanding of the cardiovascular protective effects of moderate PA, with new evidence that walking reduces the risk of CVD and, in two studies, at least as much as vigorous activity. The evidence base for protective effects of activity for women, older adults and for special populations has strengthened. Cancer prevention studies have proliferated during this period but the best evidence remains for colon cancer, with better evidence accumulating for breast cancer prevention, and uncertain or mixed evidence for the primary prevention of other cancers. Important new controlled-trial evidence has accumulated in the area of type 2 diabetes: moderate PA combined with weight loss, and a balanced diet can confer a 50-60% reduction in risk of developing diabetes among those already at high risk. Limited new evidence has accumulated for the role of PA in promoting mental health and preventing falls.
An estimated 2.7 million non-fatal unintentional sports and recreational injuries are treated in U.S. hospital emergency departments (EDs) annually. However, little is known about the number of sports and recreational injuries resulting from violent behavior.
Data for 2001-2003 on sports and recreational injuries were obtained from the National Electronic Injury Surveillance System-All Injury Program (NEISS-AIP)-a national sample of 66 U.S. EDs. National estimates and rates of persons treated for violence-related sports and recreational injuries in EDs are compared to those treated for unintentional sports and recreational injuries. Types of injuries and injury circumstances are described.
During the study period, an estimated 6,705 (8.3 per 100,000; 95% confidence intervals (CI), 6.3-10.3) children and teenagers with violence-related sports and recreational injuries were treated in U.S. EDs annually, compared to 2,698,634 children and teenagers with unintentional sports and recreational injuries. Thus, violent behavior accounted for 0.25% of sports and recreational injuries. The highest incidence rate (13.6 per 100,000) for violence-related sports and recreational injuries was for children aged 10-14 years. Most patients with violence-related sports and recreational injuries were treated and released from the ED. A majority of those with violence-related sports and recreational injuries were injured to the head/neck region (52.2%), of which 24.1% were treated for traumatic brain injuries. Most violent injuries resulted from being pushed or hit (65.6%); the most common sports and recreational activity varied by age: playground (65.2%) for children < or =9 years; bicycling (26.7%) for 10-14-year-olds; basketball (45.3%) for 15-19-year-olds.
National ED surveillance systems can provide useful information pertaining to prevention programs designed to reduce sports and recreational injuries resulting from violent behavior and unintentional causes.
The management of an athlete with recurrent concussions, whether persistently symptomatic or not, remains anecdotal. There are no evidence-based guidelines upon which a team physician can advise the athlete. All doctors involved in athlete care need to be aware of the potential for medicolegal problems if athletes are inappropriately returned to sport prematurely or in the case of professional athletes held out of sport or retired on the basis of non-scientific recommendations.
The purpose of this study was to evaluate the concurrent validity of a modified version of the widely used previous day physical activity recall (PDPAR-24) self-report instrument in a diverse sample of Australian adolescents comprising Aboriginal and Torres Strait Islanders (A&TSI) and non-indigenous high school students. A sample of 63 A&TSI and 59 non-indigenous high school students (N=122) from five public secondary schools participated in the study. Participants completed the PDPAR-24 after wearing a sealed electronic pedometer on the previous day. Significant positive correlations were observed between the self-reported physical activity variables (mean MET level, blocks of vigorous activity, and blocks of moderate-to-vigorous physical activity) and 24-h step counts. Validity coefficients (rho) ranged from 0.29 to 0.34 (p<0.05). A significant inverse correlation was observed for self-reported screen time and 24-h step count (rho=-0.19, p<0.05). Correlations for A&TSI students were equal to or greater than those observed for non-indigenous students. The PDPAR-24 instrument is a quick, unobtrusive, and cost-effective assessment tool that would be useful for evaluating physical activity and sedentary behaviour in population-based studies.
A popular method to attempt to enhance performance is for athletes to sleep at natural or simulated moderate altitude (SMA) when training daily near sea level. Based on our previous observation of periodic breathing in athletes sleeping at SMA, we hypothesised that athletes' sleep quality would also suffer with hypoxia. Using two typical protocols of nocturnal SMA (2650 m), we examined the effect on the sleep physiology of 14 male endurance-trained athletes. The selected protocols were Consecutive (15 successive exposure nights) and Intermittent (3x 5 successive exposure nights, interspersed with 2 normoxic nights) and athletes were randomly assigned to follow either one. We monitored sleep for two successive nights under baseline conditions (B; normoxia, 600 m) and then at weekly intervals (nights 1, 8 and 15 (N1, N8 and N15, respectively)) of the protocols. Since there was no significant difference in response between the protocols being followed (based on n=7, for each group) we are unable to support a preference for either one, although the likelihood of a Type II error must be acknowledged. For all athletes (n=14), respiratory disturbance and arousal responses between B and N1, although large in magnitude, were highly individual and not statistically significant. However, SpO2 decreased at N1 versus B (p<0.001) and remained lower on N8 (p<0.001) and N15 (p<0.001), not returning to baseline level. Compared to B, arousals were more frequent on N8 (p=0.02) and N15 (p=0.01). The percent of rapid eye movement sleep (REM) increased from N1 to N8 (p=0.03) and N15 (p=0.01). Overall, sleeping at 2650 m causes sleep disturbance in susceptible athletes, yet there was some improvement in REM sleep over the study duration.
Haemoglobin mass (Hb mass), maximum oxygen consumption (VO2max), simulated 4000 m individual pursuit cycling performance (IP4000), and haematological markers of red blood cell (RBC) turnover were measured in 8 male cyclists before and after (A) 31 d of altitude training at 2690 m. The dependent variables were measured serially after altitude on d A3-4, A8-9 and A20-21. There was no significant change in Hb mass over the course of the study and VO2max at d A9 was significantly lower than the baseline value (79.3 +/- 0.7 versus 81.4 +/- 0.6 ml x kg(-1) x min(-1), respectively). No increase in Hb mass or VO2max was probably due to initial values being close to the natural physiological limit with little scope for further change. When the IP4000 was analysed as a function of the best score on any of the three test days after altitude training there was a 4% improvement that was not reflected in a corresponding change in VO2max or Hb mass. RBC creatine concentration was significantly reduced after altitude training, suggesting a decrease in the average age of the RBC population. However, measurement of reticulocyte number and serum concentrations of erythropoietin, haptoglobin and bilirubin before and after altitude provided no evidence of increased RBC turnover. The data suggest that for these elite cyclists any benefit of altitude training was not from changes in VO2max or Hb mass, although this does not exclude the possibility of improved anaerobic capacity.
Existing literature suggests that tests for maximal oxygen uptake (VO2max) should last 8-12 minutes and that prolonged tests do not produce valid measurements. The research underlying this suggestion has been performed with non-athletic populations and trained athletes may be more tolerant of longer protocols. Eleven rowers (8 males, 3 females) each underwent four different incremental tests on a standard rowing ergometer in randomised counterbalanced order. One of the tests was continuous with workload increments each minute (IT1MIN). This test lasted an average of 12 min+/-4 s (SEM). The other three tests were discontinuous and consisted of 7 stages separated by 1-minute recovery intervals. Stage durations of 3, 4 and 5 min were used in the different tests (IT3MIN, IT4MIN and IT5MIN). Mean values for VO2max were almost identical for IT1MIN (4.56+/-0.22 L x min(-1)), IT3MIN (4.60+/-0.23 L x min(-1)) and IT4MIN (4.60+/-0.21 L x min(-1)), while IT5MIN produced a significantly lower value (4.47+/-0.21 L x min(-1), p<0.05). There was no significant difference between protocols in peak post-exercise blood lactate concentration (approx 13 mmol x L(-1) in each case), but IT1MIN produced lower peak heart rates and higher respiratory exchange ratios. We conclude that with well trained rowing athletes discontinuous test protocols involving 7 stages of 3-4 minutes duration can provide valid measurements of VO2max.
This study examined whether the predictive outcomes of the Chester step test (CST) would be influenced by arm dynamics. Participants completed the CST on two separate occasions, once using active arms and once using passive arms. Results revealed that when compared to the passive arm protocol, the use of active arms led to a mean increase in heart rate of approximately 7 beats per minute across all of the incremental stages. However, this increase had little impact upon predicted VO(2max). Consequently, these results indicate that when performing the CST, participants are able to adopt an arm action that is compatible with personal preference.
The aim of this study was to compare the effects of two high-intensity interval training (HIT) programmes on maximal oxygen uptake (.VO(2max)), the lactate threshold (LT) and 3000 m running performance in moderately trained male runners. .VO(2max), the running speed associated with .VO(2max) (V.VO(2max)), the time for which V.VO(2max) can be maintained (T(max)), the running speed at LT (v(LT)) and 3000 m running time (3000 mTT) were determined before and following three different training programmes performed for 10 weeks. Following the pre-test, 17 moderately trained male runners (V O(2max)=51.6+/-2.7ml kg(-1)min(-1)) were divided into training groups based on their 3000 mTT (Group 1, G(1), N=6, 8 x 60% of T(max) at V.VO(2max), 1:1 work:recovery ratio; Group 2, G(2), N=6, 12 x 30s at 130% V.VO(2max), 4.5 min recovery; control group, G(CON), N=5, 60 min at 75% V.VO(2max)). G(1) and G(2) performed two HIT sessions and two 60 min recovery run sessions (75% V.VO(2max)) each week. Control subjects performed four 60 min recovery run sessions (75% V.VO(2max)) each week. In G(1), significant improvements (p<0.05) following HIT were found in .VO(2max) (+9.1%), V.VO(2max) (+6.4%), T(max) (5%), v(LT) (+11.7%) and 3000 mTT (-7.3%). In G(2), significant improvements (p<0.05) following HIT were found in .VO(2max) (+6.2%), V.VO(2max)(+7.8%), T(max) (+32%) and 3000 mTT (-3.4%), but not in v(LT) (+4.7%; p=0.07). No significant changes in these variables were found in G(CON). The present study has shown that 3000 m running performance, .VO(2max), V.VO(2max), T(max) and v(LT) can be significantly enhanced using different HIT programmes in moderately trained runners, but that changes in performance and physiological variables may be more profound using prolonged HIT at intensities of V.VO(2max) with interval durations of 60% T(max).
The purpose of this study was to compare the forward two and one half somersault dive in a pike position (105B) performed by females (n=25) and the forward three and one half somersault dive in a pike position (107B) performed by males (n=25) to determine changes required by females to successfully perform 107B. Video data of the dives performed at the 1999 FINA World Diving Cup were captured and digitised to obtain times and postures of the divers at specific events including hurdle landing, takeoff, and entry. Estimates of hurdle flight height and mass-normalised work done on the springboard were obtained from hurdle and flight times. Females performing 105B had significantly less hip and knee flexion at landing from the hurdle than males performing 107B. It is known from simulations that the ability to land in a very flexed position without absorbing energy depends on the ability to generate large extension torques at landing. Therefore, it is likely that females need to increase strength to successfully complete 107B.
This study compared the energy cost (EC) (J x kg(-1) x m(-1)) of running on grass and soft dry beach sand. Seven male and 5 female recreational runners performed steady state running trials on grass in shoes at 8, 11 and 14 km x h(-1). Steady state sand runs, both barefoot and in shoes, were also attempted at 8 km x h(-1) and approximately 11 km x h(-1). One additional female attempted the grass and sand runs at 8 km x h(-1) only. Net total EC was determined from net aerobic EC (steady state VO2, VCO2 and RER) and net anaerobic EC (net lactate accumulation). When comparing the surface effects (grass, sand bare foot and sand in shoes) of running at 8 km x h(-1) (133.3 m x min(-1)) in 9 subjects who most accurately maintained that speed (133.3 +/- 2.2 m x min(-1)), no differences (P>0.05) existed between the net aerobic, anaerobic and total EC of sand running barefoot or in shoes, but these measures were all significantly greater (P<0.05) than the corresponding values when running on grass. Similarly, when all running speed trials (n = 87) performed by all subjects (n = 13) for each surface condition were combined for analysis, the sand bare foot and sand in shoes values for net aerobic EC, net anaerobic EC and net total EC were significantly greater (P<0.001) than the grass running measures, but not significantly different (P>0.05) from each other. Expressed as ratios of sand to grass running EC coefficients, the sand running barefoot and sand in shoes running trials at 8 km x h(-1) revealed values of 1.6 and 1.5 for net aerobic EC, 3.7 and 2.7 for net anaerobic EC and 1.6 and 1.5 for net total EC respectively. For all running speeds combined, these coefficients were 1.5 and 1.4 for net aerobic EC, 2.5 and 2.3 for net anaerobic EC and 1.5 and 1.5 for net total EC for sand running barefoot and in shoes respectively. Sand running may provide a low impact, but high EC training stimulus.
This study investigated the relationship between age, lumbar spine bone mineral density (LS BMD) and muscular strength of peri and postmenopausal women between 45 and 65 years either taking or not taking hormone replacement therapy (HRT). Ninety six women were tested for LS BMD (L2-L4), one repetition maximum (1RM) bench press and squat, maximal voluntary isometric contraction (MVC) of the knee extensors and peak torque of back extensor muscles at a speed of 30 degrees s(-1). Bone and strength data were analysed to evaluate the relationships in incrementing five year age groups and based on groups either taking or not taking HRT. ANOVA revealed significant differences in LS BMD between the 45-49 and 55-59 (F[3,92]=2.6411, p<0.05; -8%) age groups amounting to an annual bone loss of 0.8% for this Australian based population. Non significant LS BMD results were evident after controlling for the influence of age and menopausal status on the groups either taking or not taking HRT. Significant differences between the 45-49 and 60-64 (F[3,92]=2.7463, p<0.05) age groups for 1RM bench press and the 45-49 and 60-64, 50-54 and 60-64, and, 55-59 and 60-64 (F[3,92]=4.2816, p<0.05) age groups for 1RM squat amounting to an 18.8% and 37.5% loss of dynamic upper and lower body strength, respectively. Group correlation coefficients ranged between (r=-0.20 and -0.34, p<0.05) for LS BMD, strength and age. The conclusions demonstrate a concomitant decline in maximal muscle strength and bone density between women 45 and 65 years irrespective of HRT. These results also demonstrate a 50% greater decline in lower body strength compared to upper body strength between women 45 and 65 years.
This study investigated whether or not immediate post-game recovery procedures could enhance the rate of recovery in Australian football players in the first 48 hr after a game. Control, stretch, pool walking and hot/cold recoveries were trialled. Typical next day recovery training (25 min of pool exercise) was also performed after each game. Muscle soreness ratings and measures of flexibility (sit and reach) and power (6-s cycling sprint and vertical jump) were obtained 45 hr pre-game (Thursdays) (baseline), 15 hr post-game (Sundays, prior to "next day" recovery) and 48 hr post-game (Mondays). Performance ratios (Sunday and Monday scores divided respectively by the Thursday score) were used as the primary index of recovery. Muscle soreness was significantly greater (p<0.01) than baseline on both Sunday and Monday in all conditions, but no differences between the three recoveries and control were evident. On Sunday, vertical jump and 6-s work and power scores were only significantly lower than baseline values in control and performance ratios recorded two significant differences (vertical jump: pool walking > control, p<0.01; 6-s power: stretch > control, p<0.01) and moderate to large effect sizes (>0.3). No differences were found between the three experimental recoveries. On Monday no significant differences were recorded in performance between the recoveries and the effect sizes were of lower magnitude. In conclusion, recovery of muscle soreness, flexibility and power at 48 hr post-game was not significantly enhanced by performing an immediate post-game recovery beyond that achieved by performing only next day recovery training.
The aim of this study was to examine the reliability and validity of field tests for assessing physical function in mid-aged and young-old people (55-70 y). Tests were selected that required minimal space and equipment and could be implemented in multiple field settings such as a general practitioner's office. Nineteen participants completed 2 field and 1 laboratory testing sessions. Intra-class correlations showed good reliability for the tests of upper body strength (lift and reach, R= .66), lower body strength (sit to stand, R = .80) and functional capacity (Canadian Step Test, R= .92), but not for leg power (single timed chair rise. R = .28). There was also good reliability for the balance test during 3 stances: parallel (94.7% agreement), semi-tandem (73.7%), and tandem (52.6%). Comparison of field test results with objective laboratory measures found good validity for the sit to stand (cf 1RM leg press, Pearson r= .68, p < .05), and for the step test (cf PWC140, r = -.60, p < .001), but not for the lift and reach (cf 1RM bench press, r = .43, p > .05), balance (r = -.13, -.18, .23) and rate of force development tests (r = -.28). It was concluded that the lower body strength and cardiovascular function tests were appropriate for use in field settings with mid-aged and young-old adults.
The aim of this prospective, cohort study was to determine the clinical and performance related utility of haematological and iron-related screening in elite athletes. Three hundred and three male and 273 female elite athletes underwent routine medical screening over a three-year period. In association with a standard medical consultation, a full blood count and iron-related variables were measured. Ten male athletes had a serum ferritin less than 30ng/mL and satisfied AIS criteria for iron supplementation. In only one case was a disorder identified which was not expected following the clinical history and examination. Fifty-two female athletes had a serum ferritin less than 30ng/mL and satisfied AIS criteria for iron supplementation. In the females, there were no instances in which a medical condition was identified which was not expected following the clinical history and examination. In both groups, clinically non-significant abnormalities were generally minor or isolated reductions in haemoglobin and/or haematocrit, and alterations in red cell parameters or single measures of iron status.
Screening for haematological and iron-related abnormalities in athletes has a low yield. Due to the critical nature of the effects of anaemia and low serum ferritin on some aspects of performance it is reasonable to perform a haemoglobin and a serum ferritin on male and female athletes entering an elite training program. Isolated abnormalities which are close to the limits of their normal ranges and not accompanied by symptoms or signs of illness can almost certainly be ignored.
New evidence suggests that regular moderate intensity physical activity confers substantial health benefits. This information needs to be conveyed to exercise and sports professionals, as they have a potential lead role in broader public education to encourage physical activity. This study reports data from a survey of attenders at a sports medicine/sports science conference in Sydney in November 1999. Of the 292 who responded, only one third had ever heard of the United States Surgeon General's report on physical activity and health, and 43% had heard of the Active Australia initiative. Those who were members of Sports Medicine Australia (SMA), female or younger responders were more likely to recall Active Australia. An understanding of the moderate physical activity message was highest among sports physicians, and those who already perceived physical activity advice to be part of their role, and lowest among exercise and posrts scientists. The study suggests the need for professional education strategies to be developed in this area for exercise and sports scientists.
The aim of this study was to evaluate changes in the three dimensional lower limb kinematics during a simulated cycling time trial.
Ten experienced male road cyclists performed a 60 min cycling test at a workload based on previous onset of blood lactate accumulation (OBLA) testing. The time trial (TT) was divided into six 10 min periods consisting of 8 min cycling at steady state (88% of OBLA) followed by a 90 s effort phase (140% of OBLA) and a 30 s recovery phase (60% of OBLA). Three-dimensional kinematic data (200 Hz) were recorded in the last minute of each steady state phase with specific attention directed at changes in range of motion (ROM) and consistency of orientation at the hip, knee and ankle joints during drive phase.
from repeated measures ANOVA indicated a mean effect for test duration on the drive phase ROM in both hip extension (p=0.027) and ankle dorsi flexion (p<0.001). The SD of the mean tibial rotation during the drive phase was the only measure of movement consistency that showed an effect for test duration (p=0.031).
These findings indicated that participants tended to increase the ROM in hip extension and ankle flexion during drive phase at the end of a TT. Changes in the consistency of tibial rotation during the drive phase may be an important indicator of fatigue and should be monitored by coaches during training due to its possible relationship with injury and fatigue.
The purpose of this study was to examine the heart rate reserve (HRR) at first and second ventilatory thresholds (VT's) in postmenopausal women and compare it with optimal intensity range recommended by the ACSM (40-84%HRR). An additional aim was to evaluate whether a higher aerobic power level corresponded to a higher HRR at VT's.
Fifty-eight postmenopausal women participated in this study (aged 48-69). A graded 25 Wmin(-2) cycle ergometer (Monark E839) exercise protocol was performed in order to assess aerobic power. The heart rate and gas-exchange variables were measured continuously using a portable gas analyzer system (Cosmed K4b). The first (VT1) and the second (VT2) VT's were determined by the time course curves of ventilation and O2 and CO2 ventilatory equivalents. A K-means clustering analysis was used in order to identify VO2max groups (cut-off of 30.5 mlkg(-1)min(-1)) and differences were evaluated by an independent sample t-test. Bland-Altman plots were performed to illustrate the agreement between methods.
The women's HRR values at VT1 were similar to 40% HRR in both VO2max groups. At VT2 both VO2max groups exhibited negative differences (P<0.01) for the predicted 84%HRR intensity (-14.46% in the lower VO2max group and -16.32% in the higher VO2max group).
An upper limit of 84% overestimates the %HRR value for the second ventilatory threshold, suggesting that the cardiorespiratory target zone for this population should be lower and narrower (40-70%HRR).
The literature regarding the blood pressure response to AAS use is equivocal. In addition, there is currently little data available on the Rate Pressure Product (RPP) response to anabolic androgenic steroids (AAS) use. The experimental aim of this study was to investigate the effects of AAS administration in combination with resistance training on blood pressure and rate pressure product in male amateur bodybuilders and compare the results with a morphologically matched, resistance trained control group. Subjects were divided into two groups (n=16 AAS users; n=16 controls). Systolic and Diastolic Blood Pressure, RPP. Resting Heart Rate and Body Composition measurements were obtained before (Pre), during (During) and 6-8 weeks following (Post) the AAS cycle in the AAS users with similar time intervals for the control group. No significant cardiovascular or morphological changes in the control group were found throughout the study. Significant increases in both diastolic (P<0.01) and mean arterial blood pressures (P<0.05) were found from Pre to Post cycle in the AAS group. RPP also increased significantly (P<0.01) from pre to post AAS cycle. All cardiovascular parameters returned to normal baseline measurements between 6 and 8 weeks post cycle. No blood pressure measurements throughout the study were consistent with clinically defined hypertension. The findings indicate that the AAS group exhibited significant increases in standard cardiovascular measurements compared with the control bodybuilders, and provides a contraindication to AAS use especially in borderline hypertensives.
Skeletal muscle cramp has been proposed as the aetiology of exercise-related transient abdominal pain (ETAP). The aim of this study was to determine whether or not localised electromyographic (EMG) activity indicative of skeletal muscle cramp is elevated during ETAP. Surface EMG activity was quantified at the site of ETAP in 14 symptomatic individuals (ETAP group) while the pain was present and after the pain subsided. Additionally, measurements were taken in another 14 subjects (Comparison group) who performed the same experimental procedure but did not experience ETAP. In the ETAP group, localised EMG activity did not increase when the pain was present or decrease when the pain subsided. The level of EMG activity detected while the pain was present was indistinguishable from noise (0.20+/-0.18microV). No difference was observed between the ETAP and Comparison groups in the level of localised EMG activity (p=0.89) at any time. After the pain subsided in the ETAP group, EMG activity was recorded at the site of the pain while the subjects performed a diaphragm-dependent sniff manoeuvre (8.3+/-0.7microV) and a maximum voluntary contraction of the abdominal muscles (17.5+/-0.7microV). It was concluded that ETAP is not associated with elevated EMG activity, suggesting that the pain is not the result of muscle cramping.
A questionnaire was administered to 848 participants (76% runners, 24% walkers) at the conclusion of the 14 km City to Surf community run in order to investigate their experience of exercise-related transient abdominal pain (ETAP). Twenty-seven percent of respondents reported experiencing ETAP during the event, with the condition reported more frequently (p< 0.01) by runners (30%) than walkers (16%). ETAP was mostly described as well-localised (88%) and of an aching (25%), sharp (22%) or cramping (22%) sensation. The most commonly-reported sites of the pain were the right (46%) and left lumbar (23%) regions of the abdomen. Forty-two percent of the respondents who experienced ETAP reported that the pain was detrimental to their performance. Reports of ETAP decreased with age (r= -0.23, p< 0.01) but were unrelated to gender, body mass index or the time taken to complete the event. Among respondents who ran, those who consumed a large mass of food relative to body weight in the time interval 1-2 hr before the event were more likely to develop symptoms of ETAP (p < 0.05). The nutritional content of the pre-event meal did not influence the experience of ETAP. Sufferers of ETAP were more likely to experience nausea (r = 0.12, p< 0.01) and report shoulder tip pain (r= 0.14, p< 0.01). The results indicate that ETAP is a commonly experienced problem and provide insights into the cause of the complaint.
Although trauma to pregnant women is a potential risk during sport, as there is no published information about the magnitude of this risk, it is presumed to be low. Whilst there is an emerging literature about the risk of adverse outcomes following severe and catastrophic trauma to pregnant women, this literature almost exclusively focuses on road trauma victims or the result of assault. This paper describes the risk of abdominal injuries to women participants across a range of sports in Australia. An extensive search of the available literature could not identify any studies that had discussed this issue specifically in pregnant women. Studies, which have reported injuries in athletes, have generally found abdominal/chest injuries to account for fewer than 2% of all injuries, even in contact sports. Most of these published studies do not differentiate between the chest and abdomen and provide no specfic details on the exact nature or mechanisms of the injuries. Given the limitations of the published studies, an examination of data from two Australian general injury databases (one describing hospital admissions, the other hospital emergency department presentations), three Australian sports-injury treatment databases (sports medicine clinic attendances and medical coverage services) and one cohort study was undertaken to describe sports-related abdominal injuries. These analyses confirm that the risk of abdominal injury during sport is very low. In conclusion, currently there is not an adequate evidence-base for quantifying the risk of abdominal injuries during sport in women, let alone pregnant women or for justifying a ban of sport on this basis. Recommendations for future epidemiological sports injury studies and the potential for linkages with perinatal morbidity and mortality databases are given.
Twelve male golfers who experienced low back pain (LBP) whilst playing or practicing golf and 18 asymptomatic golfers were recruited and divided into handicap-specific groups; low-handicap golfers, with a handicap between 0 and 12 strokes; and high-handicap golfers, with a handicap of between 13 and 29 strokes. The myoelectric activity of the lumbar erector spinae (ES) and the external obliques (EO) was recorded via surface electromyography (EMG), whilst the golfers performed 20 drives. The root mean square (RMS) was calculated for each subject and the data for the ES and EO were normalised to the EMGs recorded whilst holding a mass equal to 5% of the subjects' body mass at arms length and whilst performing a double-leg raise, respectively. The results showed that the low-handicap LBP golfers tended to demonstrate reduced ES activity at the top of the backswing and at impact and greater EO activity throughout the swing. The high-handicap LBP golfers demonstrated considerably more ES activity compared with their asymptomatic counterparts, whilst EO activity tended to be similar between the high-handicap groups. The reduced ES activity demonstrated by the low-handicap LBP group may be associated with a reduced capacity to protect the spine and its surrounding structures at the top of the backswing and at impact, where the torsional loads are high. When considering this with the increased EO activity demonstrated by these golfers, it is reasonable to suggest that these golfers may be demonstrating characteristics/mechanisms that are responsible for or are a cause of LBP.
This study evaluated and compared the effectiveness of two different off-season, short-term basketball training programs on physical and technical abilities of young basketball players. Twenty-seven adolescent basketball players (14.7+/-0.5 years; Tanner stage: 3.5+/-0.5) were randomly divided into a specialized basketball training group (SP, n=10), a mixed basketball plus conditioning training group (MX, n=10) and a control group (n=7). Training included five sessions per week (100-120 min each) and was performed for 4 weeks. Maximal oxygen uptake was similarly improved after SP (4.9+/-1.8%) and MX (4.9+/-1.4%), but there was no effect on ventilatory threshold. Peak and mean power output measured during the Wingate test were also improved by a similar magnitude after SP (21+/-5%) and MX (15+/-6%). Trunk muscle endurance was equally increased (SP: 23+/-4%, MX: 25+/-5%), but arms endurance was improved significantly more after MX (50+/-11%) compared to SP (11+/-14%, p<0.05). Performance in four basketball technical skills was similarly increased (by 17-27%) in both groups, with a tendency for greater improvement of the SP groups in the technical skills of shooting and passing. These results indicate that a SP basketball training program, performed exclusively on-court was as effective as a MX training program in terms of aerobic and anaerobic fitness improvement. Furthermore, the decrease of the total on-court training time in the MX group resulted in a tendency for a smaller improvement of basketball technical skills. In conclusion, both SP and MX training are equally effective in order to limit and/or reverse the detraining effects that occur during the off-season in basketball.
This study aimed to examine whether athletes are able to self-select their optimal warm up and to propose a methodological approach in investigating the effects of warm up on performance. Nine male subjects underwent a free field warm up (FWU) at a self-selected intensity and duration during which heart rate (HR) and rectal temperature (Tre) were monitored. The intensity of this warm up was subsequently estimated from the HR obtained during an incremental test to determine maximal power (Pmax). Performance (cycle time to exhaustion at Pmax), HR and Tre, were then examined following either: NWU (no warm up); RWU (reference warm up based on FWU); RWU-10 (warm up intensity diminished by 10% compared to RWU); and RWU+10 (warm up intensity increased by 10% compared to RWU). Results showed no significant difference in HR (P = 0.37) and Tre increase (P= 0.77) between FWU and RWU. Performance improvement after warm up conditions gave RWU (56%; ie, 5/9 subjects) >RWU-10 (33%; ie, 3/9) >RWU+10 (11%; ie, 1/9) >NWU with significant differences between RWU and NWU (P < 0.01); RWU and RWU+10 (P < 0.01); RWU-10 and NWU (P < 0.01). A warm up intensity ranging from 54-72% Pmax, and inducing an increase in heart rate to 80 +/- 6% HRmax, was found to be optimal. While most athletes were able to self-determine the intensity of their optimal warm up, for others there is still a need for control.
The aim of this audit was to assess the yield of a selection of laboratory tests as part of the clinical assessment of the fatigued athlete. Clinical charts and blood test results of fifty consecutive athletes who presented with the primary complaint of fatigue were retrospectively reviewed. Blood tests results reviewed were: haematology (haemoglobin, red cell count, mean cell volume, mean cell haemoglobin content, platelets, white cell count, differential white cell count); erythrocyte sedimentation rate; serum biochemistry (urea, creatinine, electrolytes, urate, glucose, liver function tests, albumin, globulin); blood iron status (serum iron, total iron binding capacity, percent transferring saturation, and ferritin concentration); thyroid stimulating hormone; and immune measures (Epstein-Barr virus serology, cytomegalovirus serology). We identified only 3 abnormal results that contributed to the diagnosis of medical disease as a cause for fatigue. Laboratory testing identified 2 fatigued female athletes with serum ferritin concentration between 15 microg L(-1) and 20 microg L(-1) plus two of the other criteria of iron concentration (serum iron <10 micromol L(-1), iron binding capacity > 68 micromol L(-1), or transferrin saturation <15%). We concluded that the yield from a selection of blood tests investigating fatigued athletes was low. Future study is needed to further define the role of laboratory testing and to study whether low iron stores in the absence of anaemia is related to symptoms in fatigued athletes.
The epidemiological rationale for a focus on physical activity (PA) among Aboriginal and Torres Strait Islander (ATSI) people is compelling. PA programs have significant potential to benefit ATSI people and their communities through their contribution to reducing chronic disease, improving physical and mental health and well-being, and improving social factors such as community connectedness. Despite the powerful rationale for a focus on PA in ATSI communities, few published intervention studies have demonstrated the effectiveness of community strategies to promote increased PA among ATSI people. There are however, some examples of ongoing community programs in the 'grey' literature, which illustrate ongoing work in this domain. In view of the paucity of work in this area, there is an urgent need for (1) more research into the effectiveness of innovative strategies for increasing PA among ATSI people: (2) translation of effective strategies into dissemination trials; and (3) fast tracking of research in this area into the scientific literature.
To compare three methods for assessing wear time from accelerometer data: automated, log-books and a combination of the two.
Forty-five office workers wore an Actigraph GT3X accelerometer and kept a detailed activity log-book for 7 days. The automated method used six algorithms to determine non-wear time (20, 60, or 90 min of consecutive zero counts with and without 2-min interruptions); the log-book method used participant recorded on/off times; the combined method used the 60-min automated filter (with ≤2 min interruptions) plus detailed log-book data. Outcomes were number of participants with valid data, number of valid days, estimates of wear time and time spent in sedentary, light, moderate and vigorous activity. Percentage misclassification, sensitivity, specificity, and area under the receiver-operating curve were compared for each method, with the combined method as the reference.
Using the combined method, 34 participants met criteria for valid wear time (≥10 h/day, ≥4 days). Mean wear times ranged from 891 to 925 min/day and mean sedentary time s from 438 to 490 min/day. Percentage misclassification was higher and area under the receiver-operating curve was lower for the log-book method than for the automated methods. Percentage misclassification was lowest and area under the receiver-operating curve highest for the 20-min filter without interruptions, but this method had fewer valid days and participants than the 60 and 90-min filters without interruptions.
Automated filters are as accurate as a combination of automated filters and log-books for filtering wear time from accelerometer data. Automated filters based on 90-min of consecutive zero counts without interruptions are recommended for future studies.
This paper reviews the evidence behind the methodological decisions accelerometer users make when assessing habitual physical activity in children aged 0-5 years. The purpose of the review is to outline an evidence-guided protocol for using accelerometry in young children and to identify gaps in the evidence base where further investigation is required. Studies evaluating accelerometry methodologies in young children were reviewed in two age groups (0-2 years and 3-5 years) to examine: (i) which accelerometer should be used, (ii) where the accelerometer should be placed, (iii) which epoch should be used, (iv) how many days of monitoring are required, (v) how many minutes of monitoring per day are required, (vi) how data should be reduced, (vii) which cut-point definitions for identifying activity intensity should be used, and (viii) which physical activity outcomes should be reported and how. Critique of the available evidence provided a basis for the development of a recommended users protocol in 3-5-year olds, although several issues require further research. Because of the absence of methodological studies in children under 3 years, a protocol for the use of accelerometers in this age range could not be specified. Formative studies examining the utility, feasibility and validity of accelerometer-based physical activity assessments are required in children under 3 years of age. Recommendations for further research are outlined, based on the above findings, which, if undertaken, will enhance the accuracy of accelerometer-based assessments of habitual physical activity in young children.
Exposure to altitude results in a reduction in partial pressure of oxygen in the arterial blood and a reduction in oxygen content. In an attempt to maintain aerobic metabolism during increased effort, a series of acclimatization responses occur. Among the most conspicuous of these responses is an increase in hemoglobin (Hb) concentration. The increase in Hb has been construed as the fundamental adaptation enabling increases in aerobic power and performance to occur on return to sea-level. However, the use of altitude to boost training adaptations and improve elite sea-level performance, although tantalizing, is largely unproven. The reasons appear to be many, ranging from the poor experimental designs employed, to the numerous strategies designed to manipulate the altitude experience and the large inter-individual differences in response patterns. However, other factors may also be important. Acclimatization has also been shown to induce alteration in selected properties of the muscle cell, some of which may be counterproductive. The processes involved in cation cycling, as an example, appear to be down-regulated. Changes in these processes could impair certain types of performance.