Visual access to an outdoor range early in life, but not environmental complexity, increases meat chicken ranging behavior

Not all chickens access an outdoor range when the opportunity is provided. This may be related to the abrupt change in environments from the stable rearing conditions to the complexity of the outdoor range. We aimed to prepare chickens to range by increasing the complexity of the indoor environment early in life with the intention to encourage range use. Mixed sex Cobb500 chickens were allocated to 1 of 3 treatment groups: visual access (VA) treatment provided VA to the outdoor range from day old via transparent pop-hole covers; environmental complexity (EC) treatment provided an artificial haybale, fan with streamers and a solid vertical barrier; Control treatment was a representative conventional environment. Chickens were given access to the outdoor range at 21 d of age. Behavior in the home pen was assessed in wk 1, 2 and 5 and individual ranging behavior was monitored through radio frequency identification (RFID) technology. The VA chickens were more active compared to EC (P = 0.006) and Control (P = 0.007) chickens and spent more time foraging than control chickens (P = 0.036) during the first week of life. More VA chickens accessed the range area compared to EC chickens (P = 0.015). VA chickens accessed the range sooner after they were first provided access and spent more time on the range than EC and control chickens (P < 0.001). Mortality was lower in the VA treatment compared to EC (P = 0.024) and control group (P = 0.002). There was evidence that VA chickens weighed less than Control and EC chickens, however results were inconsistent between age and sex. Hence, providing meat chickens with VA to an outdoor range early in life increased activity in early life, decreased latency to first access the range and increased time on the range and lowered mortality. Future work should aim to understand the mechanism behind these changes in behavior to develop recommendations for producers to implement in commercial conditions.

Leukocyte-dependent effects of platelet-rich plasma on cartilage loss and thermal hyperalgesia in a mouse model of post-traumatic osteoarthritis

OBJECTIVE

Platelet-rich plasma (PRP) is an emerging therapeutic strategy for treatment of osteoarthritis (OA); however, there is a lack of preclinical and clinical evidence for its efficacy and its mechanism of action is unclear. In the current study, we utilized leukocyte poor-PRP (LP-PRP) and leukocyte rich-PRP (LR-PRP) to mimic clinical point of care formulations and assessed their potential to alter disease progression in a mouse model of post-traumatic OA.

METHOD

Three-month-old wild-type male FVB/N mice received destabilization of the medial meniscus (DMM) surgery to induce OA. To assess the efficacy of LP-PRP and LR-PRP, mice were given intraarticular injections at 2-, 7- and 28-days post-surgery. Mice were then assessed at 5-, 9-, and 13-weeks post-surgery for changes in chronic pain using the hot plate nociceptive assay. At 14-weeks, OA pathogenesis was evaluated using histology and phase-contrast μCT.

RESULTS

Treatment with LP-PRP and to a lesser extent LR-PRP preserved cartilage volume and surface area compared to phosphate-buffered saline (PBS) as measured by phase-contrast μCT. However, both treatments had higher Osteoarthritis Research Society International (OARSI) and synovitis scores compared to sham, and neither substantially improved scores compared to PBS controls. With respect to thermal hyperalgesia, PBS-treated mice displayed reduced latency to response compared to sham, and LR-PRP but not LP-PRP improved latency to response at 5-, 9- and 13-weeks post-surgery compared to PBS.

CONCLUSION

The results of this study suggest that effects of PRP therapy on OA progression and disease-induced hyperalgesia may be leukocyte-dependent. And while LP-PRP and to a lesser extent LR-PRP protect from volume and surface loss, significant pathology is still seen within OA joints. Future work is needed to understand how the different components of PRP effect OA pathogenesis and pain, and how these could be modified to achieve greater therapeutic efficacy.

The use of cognitive screens within major trauma centres in England: A survey of current practice

Introduction

Major trauma centres are effective in reducing morbidity and mortality rates following serious injury. Many patients attending major trauma centres present with traumatic brain injuries, requiring specialist assessment in screening for potential cognitive deficits. Numerous cognitive screens exist but it is currently unclear which are used most frequently within major trauma centres. This study aimed to identify which screening tools are used most frequently in major trauma centres in England to enable discussion around their suitability for this clinical population.

Method

Electronic surveys were distributed via a mailing list to Clinical Psychologists and Clinical Neuropsychologists in major trauma centres across England to gather data on the use of cognitive screens.

Results

Fourteen Clinical Psychologists in Neuropsychology participated. Results suggest major trauma centres in England are currently using the ACE-III (50%) or MoCA (42%) as the most frequently used screens for cognitive difficulties following traumatic brain injury. Cognitive screening pathways are multi-disciplinary involving OTs (86%), psychologists (qualified 79%; assistant 57%) psychiatrists (36%), mental health nurses (7%) and therapy assistants (7%).

Conclusions

Major trauma centres are using evidence-based cognitive screens at present, but further work is needed to develop more effective, better validated cognitive screens for traumatic brain injury populations. Increased inter-professional discussion on the practice of cognitive screening would be beneficial for patients seen within major trauma centres.

VIII. On the movements of the flame in the explosion of gases

(1.) On the Rate of Movement of the Flam, and the produced in theExplosion of Gases. Humphry Davy was the first to observe the rate at which an explosion of gases was propagated in a tube, and he also made the first rough experiment on the tem­perature reached in an explosion. When gas from the distillation of coal (which he found more inflammable than fire-damp) was mixed with eight times its volume ofair, and was fired in a glass tube 1 foot long and 1/4 inch in diameter, the flame took more than a second to traverse the tube. When cyanogen mixed with twice its volume of oxygen was fired in a bent tube over water, the quantity of water displaced showed that the gases had expanded fifteen times their original bulk. Bunsen, in 1867, made the first careful measurement of the rate at which an explosion is propagated in gases, and he also made the first systematic researches on the pressure and temperature produced by the explosion of gases in closed vessels. His results led him to the remarkable conclusion that there was a discontinuous combustion in explosions. When electrolytic gas, or when carbonic oxide with haltits volume of oxygen, is fired, only one-third of the mixture is burnt, according to Bunsen, raising the temperature of the whole to about 3000° C. No further chemical action then occurs until the gaseous mixture falls, by cooling, below 2500° C. Then a further combustion begins, and so on<italic>per Saltum</italic>. These deductions were criticised by Berthelot, who pointed out that they assumed the constancy of the specific heats of steam and of carbonic acid at high temperatures.

Flock use of the range is associated with the use of different components of a multi-tier aviary system in commercial free-range laying hens

1. The objective of this study was to investigate the association of using a multi-tier aviary system and access to range on flock uniformity in free-range laying hens, and to determine whether the extent of range use or flock uniformity can be predicted from the use of different levels of the aviary system.2. A total of 13,716 Lohmann Brown hens from five commercial free-range flocks housed in identical houses on the same farm were individually weighed at 16 weeks of age and allocated to five replicate areas within each house. Hen movement in the multi-tier aviary system and on the range was individually monitored using radio frequency identification (RFID). All hens had access to the range from 18 to 22 weeks of age and were exposed to the same management conditions.3. Whilst only one flock significantly changed its flock uniformity with time, they differed from each other in uniformity and body weight (P = 0.001).4. Hens spent most of their available time on the lower aviary tier (7.29 ± 0.029 h/hen/day) and on the upper aviary tier (4.29 ± 0.024 h/hen/day) while the least amount of time was spent on the range and in the nest boxes (0.93 ± 0.005 h/hen/day and 1.48 ± 0.007 h, respectively, P = 0.001).5. Range use was negatively correlated (r = -0.30) to the time spent on the upper aviary tier and positively correlated (r = 0.46) to the time spent on the lower aviary tier (P = 0.001). Bivariate analysis revealed that range and upper aviary resp. lower aviary tier usage had a significant curvilinear association.6. In conclusion, the study showed that range use was associated to the time hens spent on the different tiers of the aviary system. Flock uniformity varied between flocks but was not associated with either range and aviary system usage.

The need for an alternative method to determine intravascular volumes

It is well described that numerous environmental factors, including exercise, modulate plasma volume (PV). These modulations prove problematic when a number of haematological markers are measured as a concentration in blood plasma. A primary example is haemoglobin concentration ([Hb]), a marker of erythropoiesis commonly used within medicine and also used to detect blood doping. Natural changes in PV can confound [Hb] values when a volume change is detected rather than a true change in haemoglobin mass (Hb_mass) (e.g. volume expansion resulting in a [Hb] decrease and pseudo-anemia vs. Hb_mass decline resulting in anaemia). Currently, there is no simple solution to correct for PV shifts, and this has proven problematic when monitoring volumetric health markers in clinical and anti-doping settings. This narrative review explores the influence that PV shifts have on volumetric biomarkers, such as [Hb]. The progressive expansion in PV observed during multi-day endurance events will be summarised, and the observed impact PV variance has on concentration-based markers will be quantified. From this, the need for alternative methods to correct [Hb] for volume fluctuations is highlighted. Available methods for calculating intravascular volumes are then discussed, with a focus on a recently developed approach using a panel of 'volume descriptive' biomarkers from a standard blood test. Finally, the practical applications of this novel PV blood test within both anti-doping and clinical settings will be examined.

Formal evaluation of PYNK: Breast Cancer Program for Young Women-the patient perspective

PURPOSE

The aim of the present study was to assess patient satisfaction with pynk: Breast Cancer Program for Young Women so as to determine how the program might be improved and to provide feedback to donors.

METHODS

All pynk patients who had consented to have their information entered in our database and who supplied us with their e-mail address were invited to complete a 58-item online questionnaire consisting of multiple choice and open-ended questions. Domains included demographics, provision of written and spoken information, support, infertility risk, research awareness, attitudes toward discharge, and general feedback.

RESULTS

Of 120 pynk patients approached, 61 (51%) participated. More than 90% were satisfied or very satisfied with the timing, usefulness, and clarity of spoken and written information given, and 69% found the service and support provided by the nurse navigator to be the most helpful component of the program. Of those who had received systemic therapy, 93% recalled a health care provider initiating a discussion of the risk of treatment-related infertility, and 67% were referred to a fertility clinic. On the negative side, 11%-27% were unaware of various services provided by pynk, and 11% were unaware of pynk's ongoing research. One third of patients were unhappy or ambivalent about the prospect of discharge from the program.

CONCLUSIONS

Patient satisfaction with this novel program for young women with breast cancer is high. This study highlights the critical role that the nurse navigator plays in patient support and dissemination of information. In contrast to other reported surveys of young cancer patients, pynk patients are routinely given the opportunity to undergo fertility preservation.

Argininosuccinate lyase in enterocytes protects from development of necrotizing enterocolitis

Necrotizing enterocolitis (NEC), the most common neonatal gastrointestinal emergency, results in significant mortality and morbidity, yet its pathogenesis remains unclear. Argininosuccinate lyase (ASL) is the only enzyme in mammals that is capable of synthesizing arginine. Arginine has several homeostatic roles in the gut and its deficiency has been associated with NEC. Because enterocytes are the primary sites of arginine synthesis in neonatal mammals, we evaluated the consequences of disruption of arginine synthesis in the enterocytes on the pathogenesis of NEC. We devised a novel approach to study the role of enterocyte-derived ASL in NEC by generating and characterizing a mouse model with enterocyte-specific deletion of Asl (Asl(flox/flox); VillinCre(tg/+), or CKO). We hypothesized that the presence of ASL in a cell-specific manner in the enterocytes is protective in the pathogenesis of NEC. Loss of ASL in enterocytes resulted in an increased incidence of NEC that was associated with a proinflammatory state and increased enterocyte apoptosis. Knockdown of ASL in intestinal epithelial cell lines resulted in decreased migration in response to lipopolysaccharide. Our results show that enterocyte-derived ASL has a protective role in NEC.

Integrated copy number and gene expression analysis detects a CREB1 association with Alzheimer's disease

Genetic variation, both single-nucleotide variations and copy number variations (CNV), contribute to changes in gene expression. In some cases these variations are meaningfully correlated with disease states. We hypothesized that in a genetically heterogeneous disorder such as sporadic Alzheimer's disease (AD), utilizing gene expression as a quantitative trait and CNVs as a genetic marker map within the same individuals in the context of case-control status may increase the power to detect relevant loci. Using this approach an 8-kb deletion was identified that contains a PAX6-binding site on chr2q33.3 upstream of CREB1 encoding the cAMP responsive element-binding protein1 transcription factor. The association of the CNV to AD was confirmed by a case-control association study consisting of the Texas Alzheimer Research and Care Consortium and NIA-LOAD Family Study data sets.

Olfactory copy number association with age at onset of Alzheimer disease

OBJECTIVES

Copy number variants (CNVs) have been recognized as a source of genetic variation that contributes to disease phenotypes. Alzheimer disease (AD) has high heritability for occurrence and age at onset (AAO). We performed a cases-only genome-wide CNV association study for age at onset of AD.

METHODS

The discovery case series (n = 40 subjects with AD) was evaluated using array comparative genome hybridization (aCGH). A replication case series (n = 507 subjects with AD) was evaluated using Affymetrix array (n = 243) and multiplex ligation-dependent probe amplification (n = 264). Hazard models related onset age to CNV.

RESULTS

The discovery sample identified a chromosomal segment on 14q11.2 (19.3-19.5 Mb, NCBI build 36, UCSC hg18 March 2006) as a region of interest (genome-wide adjusted p = 0.032) for association with AAO of AD. This region encompasses a cluster of olfactory receptors. The replication sample confirmed the association (p = 0.035). The association was found for each APOE4 gene dosage (0, 1, and 2).

CONCLUSION

High copy number in the olfactory receptor region on 14q11.2 is associated with younger age at onset of AD.

Training patterns and negative health outcomes in triathlon: longitudinal observations across a full competitive season

AIM

Despite heavy training requirements, triathlon is a sport that is rapidly increasing in popularity. Yet, there is limited research detailing the relationship between training, the incidence of injuries and illness, psychological stress, overtraining and athlete burnout amongst triathletes. Six hypotheses relating inter-individual differences to training factors were generated to evaluate change in self-reported measures of these negative health outcomes over a training year.

METHODS

Thirty, well-trained, triathletes (males n=20: age=27.1±9.1 years and females n=10: age=27.4±6.6 years) from a local triathlon club participated in this study. The study commenced during pre-season training, and involved weekly monitoring of each athlete until the end of the competitive season 45 weeks later. Linear Mixed Modelling was used for the analysis.

RESULTS

Signs and symptoms of injury and illness (SAS) were significantly associated with increases in training factors (P≤0.05); however, greatest impact on SAS was produced by psychological stressors (P≤0.001). Common symptoms of overtraining were significantly affected by increases in exposure to both training and psychological stressors (P≤0.05). Mood disturbance was not significantly affected by training factors (P>0.05) but rather increases in psychological stressors (P≤0.001). Finally, each of the three athlete burnout subscales were significantly affected by both psychological (P≤0.001) stressors as well as varying combinations of training factors (P≤0.05).

CONCLUSIONS

Exposure to stressors (either training or psychological) had significant effects on all negative health outcomes assessed.

Effectiveness and safety of a structured swimming program in previously sedentary women during pregnancy

OBJECTIVE

To determine whether undertaking a swimming program in sedentary women during pregnancy would improve maternal fitness without adverse fetal consequences.

METHODS

Prospective observational investigation of healthy sedentary pregnant women participating in a monitored swimming program.

RESULTS

Twenty-three women attended swimming sessions from 16 to 28 weeks of gestation resulting in increasing distances swum and improved aerobic fitness as measured by physical work capacity (PWC170) (p = 0.003). Resting maternal heart rate decreased (p = 0.041) and resting systolic (p = 0.092) and diastolic (p = 0.971) blood pressures remained unchanged over gestation. The mean fetal heart rates decreased with advancing gestational age (p = 0.001), consistent with normal physiology. Non-stress tests and umbilical artery systolic/diastolic ratios were similar before and after swimming sessions, providing evidence that fetal well-being was unchanged.

CONCLUSIONS

A structured swimming program in sedentary pregnant women increases maternal fitness without any alteration in maternal and fetal well-being.

Effect of caffeine supplementation on repeated sprint running performance

AIM

This study examined the effects of 6 mgxkg(-1) caffeine ingestion in team-sport players (N.=10) on repeated-sprint running performance (5 sets of 6 x 20 m) and reaction times, 60 min after caffeine or placebo ingestion.

METHODS

Best single sprint and total set sprint times, blood lactate and simple and choice reaction times (RT) were measured.

RESULTS

Total sprint times across sets 1, 3 and 5 (departure every 25 s) were significantly faster after caffeine (85.49+/-5.55 s) than placebo (86.98+/-5.78 s) (P<0.05). Similarly, total sprint times across sets 2 and 4 (departure every 60 s), were significantly faster after caffeine (55.99+/-3.64 s) than placebo (56.77+/-3.74 s) (P<0.05). Significantly higher blood lactates were recorded in caffeine compared to placebo after set 3 (13.1+/-1.2 vs 10.3+/-1.4 mmolxL(-1)) (P<0.05) and set 5 (13.1+/-1.3 vs 10.3+/-1.6 mmolxL(-1)) (P<0.01). There were no significant effects on simple or choice RT, although effect sizes suggested improved post-exercise times after caffeine.

CONCLUSION

Caffeine ingestion 60 min prior to exercise can enhance repeated sprint running performance and is not detrimental to reaction times.

Two unrelated children with distal long arm deletion of chromosome 7: clinical features, cytogenetic and gene marker studies

Two phenotypically abnormal, unrelated children with deletion of the distal segment of 7q (7q32 leads to pter) are described. In one instance the mother was the carrier of a balanced translocation between chromosomes 6 and 7, and in the second case the deletion was a de novo event. Their phenotype were compared to previously reported cases and found to have many non-specific clinical features in common. Gene marker studies for some of the genes tentatively localized to chromosome 7 showed no anomalous segregation. The Hageman coagulation factor (Factor XII) activity in both probands was normal, and heterozygosity for alleles of the Kidd blood group in the first proband excludes assignment of the Kidd locus to the distal portion of chromosome 7q.

Effect of hydrotherapy on recovery from fatigue

The present study investigated the effects of three hydrotherapy interventions on next day performance recovery following strenuous training. Twelve cyclists completed four experimental trials differing only in 14-min recovery intervention: cold water immersion (CWI), hot water immersion (HWI), contrast water therapy (CWT), or passive recovery (PAS). Each trial comprised five consecutive exercise days of 105-min duration, including 66 maximal effort sprints. Additionally, subjects performed a total of 9-min sustained effort (time trial - TT). After completing each exercise session, athletes performed one of four recovery interventions (randomly assigned to each trial). Performance (average power), core temperature, heart rate (HR), and rating of perceived exertion (RPE) were recorded throughout each session. Sprint (0.1 - 2.2 %) and TT (0.0 - 1.7 %) performance were enhanced across the five-day trial following CWI and CWT, when compared to HWI and PAS. Additionally, differences in rectal temperature were observed between interventions immediately and 15-min post-recovery; however, no significant differences were observed in HR or RPE regardless of day of trial/intervention. Overall, CWI and CWT appear to improve recovery from high-intensity cycling when compared to HWI and PAS, with athletes better able to maintain performance across a five-day period.

Oral contraceptive phase has no effect on endurance test

Thirteen female cyclists/triathletes (mean peak VO(2) = 53.0 + 5.6 ml . kg (-1) . min (-1)) using a monophasic oral contraceptive (OC) performed an endurance test (1-h cycle) at three time points of an OC cycle. Testing times were during the OC consumption phase (CONS), early in the OC withdrawal phase (WITH1) and late in the OC withdrawal phase (WITH2). Resting endogenous serum oestradiol and progesterone concentrations were measured. Power output, heart rate (HR), ventilation (V(E)), oxygen consumption (VO(2)), respiratory exchange ratio (RER), rating of perceived exertion (RPE), blood lactate and blood glucose were measured throughout the 1-h test. Serum oestradiol levels were greater during WITH2 compared to the CONS (p < 0.05). No significant differences were present between the testing times for mean power output (172 - 173 watts), HR (163 - 166 bpm), VO(2) (41.3 - 41.7 mL . kg (-1) . min (-1)), RER (0.93 - 0.94), RPE (14.5 - 14.8) and blood glucose concentration (5.3 - 5.5 mmol . L (-1)) (p > 0.05). Greater mean V. (E) (by 3.4 and 5.7 L . min (-1)) and VE/VO(2) (by 1.0 and 2.0) values were measured during CONS compared to WITH1 and WITH2 respectively and blood lactate values (by 1.2 mmol . L (-1)) compared to WITH1 only (p < 0.05). Despite variation in some physiological variables, there was no difference in endurance performance throughout an OC cycle in endurance trained female athletes.

Quantification of the physiological and performance characteristics of on-court tennis drills

OBJECTIVE

To determine the physiological responses and stroke characteristics of common on-court tennis training drills.

METHODS

Six high-performance players performed 1 x6 repetitions of four common on-court training drills on two separate occasions; once with 30:30 seconds work:rest, and once with 60:30 seconds work:rest. Heart rate (HR), blood lactate [La(-)], distance covered by the player (GPS) and rate of perceived exertion (RPE) were measured before the start of each drill and after the first and last repetition. Measures of shot count and accuracy and post-impact ball velocity per drill were also recorded.

RESULTS

Significant differences were observed between drills in measures of [La(-)] and RPE both during ([La(-)] 2.1-4.4 mmol/l; RPE 2.6-5.1) and after ([La(-)] 4.4-10.6 mmol/l; RPE 4.3-7.6) drills, yet individual HR responses (160-182 beats/minute) were similar. Increased work times (60 v 30 seconds) also produced consistently raised [La(-)] and RPE responses, yet players' average movement velocities and forehand ball speed and accuracy remained consistent. Significant decreases in forehand ball speed and accuracy were observed during higher-intensity training drills, whereas significantly lower mean movement velocities underpinned performance of less intensive drills.

CONCLUSIONS

The four drills produced physiological responses that reflect previously reported normal or maximal matchplay demands. These results point to the adaptations possible with adjustment of training drill type and load specific to matchplay demands or training phase.

Effects of rest interval during high-repetition resistance training on strength, aerobic fitness, and repeated-sprint ability

The effect of altering the rest period on adaptations to high-repetition resistance training is not well known. Eighteen active females were matched according to leg strength and repeated-sprint ability and randomly allocated to one of two groups. One group performed resistance training with 20-s rest intervals between sets, while the other group employed 80-s rest intervals between sets. Both groups performed the same total training volume and load. Each group trained 3 days a week for 5 weeks [15- to 20-repetition maximum (RM), 2 - 5 sets]. Repeated-sprint ability (5x6-s maximal cycle sprints), 3-RM leg press strength, and anthropometry were determined before and after each training programme. There was a greater improvement in repeated-sprint ability after training with 20-s rest intervals (12.5%) than after training with 80-s rest intervals (5.4%) (P = 0.030). In contrast, there were greater improvements in strength after training with 80-s rest intervals (45.9%) than after training with 20-s rest intervals (19.6%) (P = 0.010). There were no changes in anthropometry for either group following training. These results suggest that when training volume and load are matched, despite a smaller increase in strength, 5 weeks of training with short rest periods results in greater improvements in repeated-sprint ability than the same training with long rest periods.

Monitoring 6 Weeks of Progressive Endurance Training with Plasma Glutamine

The distinction between positive and negative training adaptation is an important prerequisite in the identification of any marker for monitoring training in athletes. To investigate the glutamine responses to progressive endurance training, twenty healthy males were randomly assigned to a training group or a non-exercising control group. The training group performed a progressive (3 to 6 x 90 minute sessions per week at 70 % V.O (2max)) six-week endurance training programme on a cycle ergometer, while the control group did not participate in any exercise during this period. Performance assessments (V.O (2max) and time to exhaustion) and resting blood samples (for haemoglobin concentration, haematocrit, cortisol, ferritin, creatine kinase, glutamine, uric acid and urea analysis) were obtained prior to the commencement of training (Pre) and at the end of week 2, week 4 and week 6. The training group showed significant improvements in time to exhaustion (p < 0.01), and V.O (2max) (p < 0.05) at all time points (except week 2 for V.O (2max)), while the control group performance measures did not change. In the training group, haemoglobin concentration and haematocrit were significantly lower (p < 0.01) than pretraining values at week 2 and 4, as percentage changes in plasma volume indicated a significant (p < 0.01) haemodilution (+ 6 - 9 %) was present at week 2, 4 and 6. No changes were seen in the control group. In the training group, plasma glutamine (week 2, 4 and 6), creatine kinase (week 2 and 4), uric acid (week 2 and 4) and urea (week 2 and 4) all increased significantly from pretraining levels. No changes in cortisol or ferritin were found in the training group and no changes in any blood variables were present in the control group. Plasma glutamine was the only blood variable to remain significantly above pretraining (966 +/- 32 micromol . 1 (-1)) levels at week 6 (1176 +/- 24 micromol . 1 (-1); p < 0.05) The elevation seen here in glutamine levels, after 6 weeks of progressive endurance training, is in contrast to previous reports of decreased glutamine concentrations in overtrained athletes. In conclusion, 6 weeks of progressive endurance training steadily increased plasma glutamine levels, which may prove useful in the monitoring of training responses.

Comparison of the VO2 response to 800-m, 1500-m and 3000-m track running events

AIM

The present study examined the VO2 response to middle-distance track running events of 800 m, 1500 m and 3000 m and investigated the relationship between the speed of the VO2 response ((1) and subsequent race performance.

METHODS

Trained 3000-m (n = 8), 1500-m (n = 10) and 800-m (n = 8) male track athletes performed a laboratory GXT plus a run at 14 km x h(-1) and multiple race time trials. For each subject, a bi-exponential model fit from 20 s was used to categorise the O2 response for the best performed track run and also the treadmill run at 14 km x h(-1).

RESULTS

Faster (1 values were noted the shorter the track event, with values of 14, 18.5 and 20.8 s for 800-, 1500- and 3000-m events, respectively. ANOVA results revealed that differences in (1 were significant (P < 0.05) for the 800- and 3000-m, but not for the 800- and 1500-m (P = 0.06) or 1500- and 3000-m events (P = 0.15). Only 1500-m race performance was significantly correlated to race (1 (r = 0.71). Values for (1 at an absolute velocity treadmill run (14 km x h(-1)) did not differ significantly between different events and were not correlated to race performance for any event. From pooled data for all three events, significant correlations (P < 0.01) were noted between tau1 and the speed over the first 800-m (r = -0.54 to -0.68).

CONCLUSIONS

There was a trend for faster (1values the shorter the track event. The significant correlation between tau1 and initial starting velocity suggests this may be attributed to the faster starting velocity of the shorter track events, rather than any differences between athletes per se.

Time-motion analysis of elite field hockey during several games in succession: a tournament scenario

International field hockey tournaments may require teams to play three games within a period of four days. Therefore, there is potential for residual fatigue to affect the movement patterns of players during subsequent games. The purpose of this study was to document changes in time-motion analysis of 14 elite male field hockey players during three games within a period of four days during an international tournament. In addition, the nature of and any changes in repeated-sprint activity were investigated using a criteria of a minimum of three sprints with a mean recovery duration between sprints of < 21 s. The percent of total game time spent standing significantly increased across all three games (7.4+/-.2, 11.2+/-2.7 and 15.6+/-5.6%, respectively, P<0.05). Conversely, the percent time spent jogging significantly decreased from game 1 to game 2 and from game 1 to game 3 (40.5+/-7.3, 34.8+/-7.4 and 29.4+/-5.7%, respectively, P<0.05). Furthermore, the percent time in striding significantly increased from game 1 to game 3 and from game 2 to game 3 (4.1+/-1.3, 5.1+/-0.9 and 5.8+/-1.4%, respectively. P<0.05). Changes in mean motion frequency and duration were recorded across games for the motions of standing, striding and sprinting. The frequency of exercise bouts that met the criteria for 'repeated-sprint' decreased across the three games (17, 11 and 8, respectively). In summary, the results suggest that when elite field hockey players play three games within four days there are significant changes in time-motion analysis.

Reliability of a repeated-sprint test for field-hockey

The purpose of this study was to assess the reliability of a repeated-sprint test, specifically designed for field-hockey, as it was based directly on the time-motion analysis of elite level competition. The test consisted of 6 x 30-m over-ground sprints departing on 25s, with an active recovery (approximately 3.1-3.3 ms(-1)) between sprints. Ten highly trained, male, field-hockey players (mean+/-S.D.: age, 23+/-3 years; body mass, 78.1+/-7.1 kg) participated in this study. Following familiarisation, the subjects performed the repeated-sprint test on two occasions, 7 days apart. The reliability of the test variables was assessed by the typical error of measurement (TE). The total sprint time was very reliable (T(1): 26.79+/-0.76 s versus T2: 26.83+/-0.74 s), as the TE was 0.7% (95% CL, 0.5-1.2%). However, the percent sprint decrement was less reliable (T1: 5.6+/-0.9% versus T2: 5.8+/-1.0%), with the TE being 14.9% (95% CL, 10.8-31.3%). In summary, it is suggested that this field-hockey-specific, repeated-sprint test is very reliable when the results are presented as the total sprint time.

Coupled Bending-Bending Vibrations of Pre-Twisted Cantilever Blading Treated by the Rayleigh-Ritz Energy Method

The Rayleigh-Ritz method is used to determine the natural frequencies and mode shapes of vibration of pre-twisted rectangular cross-section beams. The method is dependent upon a good choice of approximating functions for the dynamic deflection curves. In the present analysis, series of the characteristic functions representing the normal modes of vibration are taken as the approximating functions for the bending displacements in the directions of the co-ordinate axes. The choice of this particular series leads to a considerable reduction in the number of elements in the final matrix equation and also considerably reduces the computing time.

The natural frequencies of vibration are obtained for various width-to-thickness ratio beams with pre-twist angle in the range 0-90°, and the mode shapes of vibration are presented for one particular width to thickness ratio beam. The results are compared to results obtained by other methods and to experimental results, and good agreement is shown to exist.

Physiological and anthropometric characteristics of starters and non-starters and playing positions in elite Australian Rules Football: a case study

A purpose of this study was to determine if pre-season anthropometric and physiological measures were significantly different for the players from one Australian Football League (AFL) club selected to play in the first game of the season compared to the players not selected. Another purpose was to compare fitness test results for defenders, forwards and mid-fielders in the same AFL club. Thirty-four players were tested for isolated quadriceps and hamstrings strength, leg extensor muscle strength and power, upper body strength, sprinting speed, vertical jump (VJ), endurance, skinfolds and hamstring flexibility. The starters who were selected to play the first game were a significantly older and more experienced playing group, and were significantly better (p < 0.05) in measures of leg power, sprinting speed and the distance covered in the Yo Yo intermittent recovery test compared to the non-starters. Although there were trends for the superiority of the starters, the differences in lower and upper body strength, VJ and predicted VO2max were non-significant. The forwards generally produced the worst fitness scores of the playing positions with the midfielders having significantly lower skinfolds and the defenders possessing better hamstring strength and VJ compared to the forwards. It was concluded that some fitness qualities can differentiate between starters and non-starters, at least in one AFL club. Comparisons of playing positions and the development of fitness norms for AFL players require further research.

Effects of immediate post-game recovery procedures on muscle soreness, power and flexiblity levels over the next 48 hours

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.

Energy system contribution to 100-m and 200-m track running events

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.

Comparison of training activities and game demands in the Australian Football League

his paper serves as a companion to our recent study of the movement patterns and game activities of players (from five different positions) during matches in the 2000 Australian Football League season. Using lapsed-time video analysis, the same individual players (n= 11) as filmed in matches were also monitored during 21 in-season, main training sessions conducted by their clubs in order to assess the degree to which training activities matched game demands. In general, the training sessions did not involve physical pressure; therefore there were very few contested marks and ground balls or tackles, shepherds and spoils, thereby not matching these game demands. Players typically had more possessions (kicks and handballs) at training than in games. They also spent a greater percentage of total time standing and less time walking at training than in games. Fast-running and sprinting efforts at training were almost all for durations of <6 secs, which matched game demands, as did changes of direction when sprinting, which were almost all in a 0-90 degrees arc. However, across all players filmed, high intensity (fast-running and sprinting) movements were not performed as frequently at training (one every 76 secs) as in games (one every 51 secs). Therefore, while some game demands were adequately replicated at training, others were not closely simulated, suggesting that, after careful interpretation of these results, some improvements in training practices could be made.

Player movement patterns and game activities in the Australian Football League

In the Australian Football League (AFL), specific game movements and activities have not been studied since the 1970s and 1980s and the game is now much faster than it was 20-30 years ago. Using lapsed-time video analysis, AFL players from five different positions (full forward/full back, centre half forward/centre half back, small forward/small back, mid fielders and ruckmen) had their movement patterns (stand, walk, jog, fast-run, sprint, change of direction) and game activities (possessions, ruck duels, ground ball contests, shepherds, spoils, bumps and tackles) recorded in two games each in the 2000 season. A descriptive analysis of the results was undertaken. The main findings were: full forward/full back were most different from the other positions, as they were seen to stand more and jog and fast-run less: ruckmen and midfielders were involved in more game activities than the other positions; for all positions, there were more than 150 high intensity movements (fast-run plus sprint) in the game, but these accounted for only 4-6% of total movement time: virtually all of the high intensity movements lasted for <6 secs; more than half of all sprints involved at least one change of direction, mostly within the 0-90 degrees arc (left or right) and all ground ball contests took <6 secs, with midfielders having 2-3 times as many as the other positions. Improvements in specific pre-season and in-season training practices for different positions should be possible after careful interpretation of these findings.

The effect of interstate travel on sleep patterns of elite Australian Rules footballers

The purpose of the current study was to examine the effect of interstate air travel on the quality and quantity of sleep in elite Australian Rules football players. Ten elite male athletes, who were members of a Western Australian-based Australian Football League (AFL) team, participated in the study. Sleep pattern was assessed by measuring sleep duration (SLD), sleep efficiency (SE), number of wakings (NW) and total wake time after sleep onset (WT) using a wrist-worn actigraph. Subjective sleep quality (SQ) was assessed using a scale of sleep rating. Throughout the 2002 AFL season, measurements were obtained on the night before (N1), the night of (N2) and the night after (N3) home and away games. Baseline measurements were obtained from five consecutive non-game nights. Compared to baseline, SLD on N1 was increased when home and away (by 51 and 105 mins respectively, p<0.05), while all other measures of sleep pattern were unchanged. On N2, SLD was decreased to a similar degree whether home or away (by 68 and 64 mins respectively, p<0.05), while all other measures of sleep pattern were unchanged. By N3 all measures of sleep pattern had returned to baseline values. Relative to baseline, perception of SQ was worst on N2 of a home game. This study has shown that interstate travel by elite AFL players has no adverse effects on sleep pattern on the night before a game.

Accuracy and reliability of a Cosmed K4b2 portable gas analysis system

The purpose of this study was to assess the validity and reliability of a Cosmed K4b2 portable telemetric gas analysis system. Twelve physically fit males performed a treadmill running session consisting of an easy 10 min run, a hard 3 min run and a 1 min sprint (with rest periods of 10 min separating each run), on four separate occasions. Sessions were identical with the exception of the apparatus used to measure VO2. During two (test-retest) sessions a Cosmed K4b2 portable gas analysis system was used; in another, a laboratory metabolic cart and, in one session, both systems were used to measure VO2 simultaneously. Comparison of Cosmed K4b2 and metabolic cart measurements in isolation revealed significantly (p < 0.05) increased values of VO2, VCO2, FE CO2 (except FE CO2 at 10 min) and lower values of FE O2 for each run duration by the Cosmed system. Linear regression equations to predict metabolic cart results from Cosmed values were, respectively; cart VO2 = 0.926 (Cosmed VO2-0.227 (r2 = 0.84) and cart VCO2 = 1.057 (Cosmed VCO2-0.606 (r2 = 0.92). Bland-Altman plots and comparison of the test-retest cosmed measurements revealed that the K4b2 system showed good repeatability of measurement for measures of VE, VO2 and VCO2, particularly for 10 min and 3 min tests (ICC = 0.7-0.9, p < 0.05). In conclusion, the Cosmed K4b2 portable gas analysis system recorded consistently higher VO2 and VCO2 measurements in comparison to a metabolic cart. However, satisfactory test-retest reliability of the system was demonstrated.

Test-retest reliability of the aerobic power index component of the tri-level fitness profile in a sedentary population

Use of maximal aerobic power (VO2(max)) testing, which requires subjects to exercise to physiological limits, may deter eligible candidates from volunteering for trials and may also be contraindicated in patients suffering from various medical illnesses. An alternative to maximal testing is submaximal testing. The Aerobic Power Index, which represents the aerobic component of the Tri-level Fitness Profile, is a submaximal test that has been shown to be reliable in trained athletes. The purpose of this study was to establish reliability of the Aerobic Power Index, as well as associated variables of VO2 (ml x kg(-1) x min(-1) and rate of perceived exertion (RPE), in a group of sedentary subjects. Results for the 20 subjects who participated in a test-retest trial indicated high reliability (ICC r = 0.98, %TEM 3.87 W x kg(-1); SEM 0.04 W x kg(-1) for the main measurement outcome of Watts per kilogram (W x kg(-1)). Oxygen uptake (ml x kg(-1)min(-1)) also demonstrated high reliability (ICC r = 0.92; %TEM 4.63 ml x kg(-1) x min(-1); SEM 0.58 ml x kg(-1) min (-1), as did RPE (ICC r = 0.97,%TEM 7.78; SEM 0.63). Limits of agreement were -0.02+/-0.16 W x kg(-1). -0.41+/-2.31 ml x kg(-1) x min(-1) for VO2 and -0.05 < or = 2.10 for RPE. These results indicate that the Aerobic Power Index is a reliable submaximal exercise test for use in sedentary subjects.

Effect of wearing an ice cooling jacket on repeat sprint performance in warm/humid conditions

OBJECTIVE

To examine the effect of cooling the skin with an ice jacket before and between exercise bouts (to simulate quarter and half time breaks) on prolonged repeat sprint exercise performance in warm/humid conditions.

METHODS

After an initial familiarisation session, seven trained male hockey players performed two testing sessions (seven days apart), comprising an 80 minute intermittent, repeat sprint cycling exercise protocol inside a climate chamber set at 30 degrees C and 60% relative humidity. On one occasion a skin cooling procedure was implemented (in random counterbalanced order), with subjects wearing an ice cooling jacket both before (for five minutes) and in the recovery periods (2 x 5 min and 1 x 10 min) during the test. Measures of performance (work done and power output on each sprint), heart rates, blood lactate concentrations, core (rectal) and skin temperatures, sweat loss, perceived exertion, and ratings of thirst, thermal discomfort, and fatigue were obtained in both trials.

RESULTS

In the cooling condition, chest (torso) skin temperature, thermal discomfort, and rating of thirst were all significantly lower (p<0.05), but no significant difference (p>0.05) was observed between conditions for measures of work done, power output, heart rate, blood lactate concentration, core or mean skin temperature, perceived exertion, sweat loss, or ratings of fatigue. However, high effect sizes indicated trends to lowered lactate concentrations, sweat loss, and mean skin temperatures in the cooling condition.

CONCLUSIONS

The intermittent use of an ice cooling jacket, both before and during a repeat sprint cycling protocol in warm/humid conditions, did not improve physical performance, although the perception of thermal load was reduced. Longer periods of cooling both before and during exercise (to lower mean skin temperature by a greater degree than observed here) may be necessary to produce such a change.