A survey of mastitis pathogens including antimicrobial susceptibility in southeastern Australian dairy herds.

The objectives for this study were to (1) describe the pathogen profile in quarters from cows with clinical mastitis and in cows with subclinical mastitis in southeastern Australia; and (2) describe antimicrobial susceptibility among isolated pathogens. As a secondary objective, we aimed to compare antimicrobial resistance prevalence in pathogens isolated from clinical and subclinical mastitis samples. A convenience sample of dairy herds (n = 65) from 4 regions in southeastern Australia (Gippsland, Northern Victoria, Tasmania, Western Victoria) were invited to submit milk samples from cows with clinical and subclinical mastitis over a 14-mo period (January 2011 to March 2012). Farmers were instructed to collect aseptic quarter milk samples from the first 10 cases of clinical mastitis for each month of the study. In addition, farmers submitted composite milk samples from cows with subclinical mastitis at 1 or 2 sampling occasions during the study period. Aerobic culture and biochemical tests were used to identify isolates. Isolates were classified as susceptible, intermediate, or resistant to a panel of antimicrobial agents based on the zone of growth inhibition around antimicrobial-impregnated disks, with antimicrobial resistance (AMR) classified as nonsusceptibility by combining intermediate and resistant groups into a single category. Generalized linear mixed models were used to compare the prevalence of AMR between clinical and subclinical mastitis isolates. For clinical mastitis samples (n = 3,044), 472 samples (15.5%) were excluded for contamination. Of the remaining samples (n = 2,572), the most common results were Streptococcus uberis (39.2%), no growth (27.5%), Staphylococcus aureus (10.6%), Escherichia coli (8.4%), and Streptococcus dysgalactiae (6.4%). For subclinical mastitis samples (n = 1,072), 425 (39.6%) were excluded due to contamination. Of the remaining samples (n = 647), the most common results were no growth (29.1%), Staph. aureus (29.1%), and Strep. uberis (21.6%). The prevalence of AMR among common isolates was low for the majority of antimicrobial agents. Exploratory analysis found that the probability of Staph. aureus demonstrating resistance to penicillin was 5.16 times higher (95% confidence interval: 1.68, 15.88) in subclinical isolates relative to clinical Staph. aureus isolates. A similar association was observed for amoxicillin with subclinical Staph. aureus isolates being 4.70 times (95% confidence interval: 1.49, 14.75) more likely to be resistant than clinical Staph. aureus isolates. We concluded that the most common bacteria causing clinical mastitis in dairy herds in Australia is likely to be Strep. uberis, whereas Staph. aureus is likely to be the most common cause of subclinical mastitis. Despite decades of antimicrobial use to control these organisms, AMR appears to be uncommon.

Oriented suspension mechanics with application to improving flow linear dichroism spectroscopy.

Flow linear dichroism is a biophysical spectroscopic technique that exploits the shear-induced alignment of elongated particles in suspension. Motivated by the broad aim of optimizing the sensitivity of this technique, and more specifically by a hand-held synthetic biotechnology prototype for waterborne-pathogen detection, a model of steady and oscillating pressure-driven channel flow and orientation dynamics of a suspension of slender microscopic fibres is developed. The model couples the Fokker-Planck equation for Brownian suspensions with the narrow channel flow equations, the latter modified to incorporate mechanical anisotropy induced by the particles. The linear dichroism signal is estimated through integrating the perpendicular components of the distribution function via an appropriate formula which takes the biaxial nature of the orientation into account. For the specific application of pathogen detection via binding of M13 bacteriophage, it is found that increases in the channel depth are more significant in improving the linear dichroism signal than increases in the channel width. Increasing the channel depth to 2 mm and pressure gradient to 5 × 104 Pa m-1 essentially maximizes the alignment. Oscillating flow can produce nearly equal alignment to steady flow at appropriate frequencies, which has significant potential practical value in the analysis of small sample volumes.

Influences of transversely isotropic rheology and translational diffusion on the stability of active suspensions.

Suspensions of self-motile, elongated particles are a topic of significant current interest, exemplifying a form of 'active matter'. Examples include self-propelling bacteria, algae and sperm, and artificial swimmers. Ericksen's model of a transversely isotropic fluid (Ericksen 1960 Colloid Polym. Sci.173, 117-122 (doi:10.1007/bf01502416)) treats suspensions of non-motile particles as a continuum with an evolving preferred direction; this model describes fibrous materials as diverse as extracellular matrix, textile tufts and plant cell walls. Director-dependent effects are incorporated through a modified stress tensor with four viscosity-like parameters. By making fundamental connections with recent models for active suspensions, we propose a modification to Ericksen's model, mainly the inclusion of self-motility; this can be considered the simplest description of an oriented suspension including transversely isotropic effects. Motivated by the fact that transversely isotropic fluids exhibit modified flow stability, we conduct a linear stability analysis of two distinct cases, aligned and isotropic suspensions of elongated active particles. Novel aspects include the anisotropic rheology and translational diffusion. In general, anisotropic effects increase the instability of small perturbations, while translational diffusion stabilizes a range of wave-directions and, in some cases, a finite range of wavenumbers, thus emphasizing that both anisotropy and translational diffusion can have important effects in these systems.

An investigation of the influence of extracellular matrix anisotropy and cell-matrix interactions on tissue architecture.

Mechanical interactions between cells and the fibrous extracellular matrix (ECM) in which they reside play a key role in tissue development. Mechanical cues from the environment (such as stress, strain and fibre orientation) regulate a range of cell behaviours, including proliferation, differentiation and motility. In turn, the ECM structure is affected by cells exerting forces on the matrix which result in deformation and fibre realignment. In this paper we develop a mathematical model to investigate this mechanical feedback between cells and the ECM. We consider a three-phase mixture of collagen, culture medium and cells, and formulate a system of partial differential equations which represents conservation of mass and momentum for each phase. This modelling framework takes into account the anisotropic mechanical properties of the collagen gel arising from its fibrous microstructure. We also propose a cell-collagen interaction force which depends upon fibre orientation and collagen density. We use a combination of numerical and analytical techniques to study the influence of cell-ECM interactions on pattern formation in tissues. Our results illustrate the wide range of structures which may be formed, and how those that emerge depend upon the importance of cell-ECM interactions.

Premature guinea pigs: a new paradigm to investigate the late-effects of preterm birth.

Preterm birth is common and the associated short-term morbidity well described. The adult-onset consequences of preterm birth are less clear, but cardiovascular and metabolic health may be adversely affected. Although large animal models of preterm birth addressing important short-term issues exist, long-term studies are hampered by significant logistical constraints. Current small animal models of prematurity require terminal caesarean section of the mother; both caesarean birth and early maternal care modify offspring adult cardio-metabolic function. We describe a novel method for inducing preterm labour in guinea pigs. With support comparable to that received by moderately preterm human infants, preterm pups are viable. Growth trajectories between preterm and term-born pups differ significantly; between term equivalent age and weaning ex-preterm animals demonstrate increased weight and ponderal index. We believe this novel paradigm will significantly improve our ability to investigate the cardio-metabolic sequelae of preterm birth throughout the life course and into the second generation.

A biomechanical model of anther opening reveals the roles of dehydration and secondary thickening.

Understanding the processes that underlie pollen release is a prime target for controlling fertility to enable selective breeding and the efficient production of hybrid crops. Pollen release requires anther opening, which involves changes in the biomechanical properties of the anther wall. In this research, we develop and use a mathematical model to understand how these biomechanical processes lead to anther opening. Our mathematical model describing the biomechanics of anther opening incorporates the bilayer structure of the mature anther wall, which comprises the outer epidermal cell layer, whose turgor pressure is related to its hydration, and the endothecial layer, whose walls contain helical secondary thickening, which resists stretching and bending. The model describes how epidermal dehydration, in association with the thickened endothecial layer, creates forces within the anther wall causing it to bend outwards, resulting in anther opening and pollen release. The model demonstrates that epidermal dehydration can drive anther opening, and suggests why endothecial secondary thickening is essential for this process (explaining the phenotypes presented in the myb26 and nst1nst2 mutants). The research hypothesizes and demonstrates a biomechanical mechanism for anther opening, which appears to be conserved in many other biological situations where tissue movement occurs.

A model of crosslink kinetics in the expanding plant cell wall: yield stress and enzyme action.

The plant primary cell wall is a composite material containing stiff cellulose microfibrils that are embedded within a pectin matrix and crosslinked through a network of hemicellulose polymers. This microstructure endows the wall with nonlinear anisotropic mechanical properties and allows enzymatic regulation of expansive cell growth. We present a mathematical model of hemicellulose crosslink dynamics in an expanding cell wall incorporating strain-enhanced breakage and enzyme-mediated crosslink kinetics. The model predicts the characteristic yielding behaviour in the relationship between stress and strain-rate seen experimentally, and suggests how the effective yield and extensibility of the wall depend on microstructural parameters and on the action of enzymes of the XTH and expansin families. The model suggests that the yielding behaviour encapsulated in the classical Lockhart equation can be explained by the strongly nonlinear dependence of crosslink breakage rate on crosslink elongation. The model also demonstrates how enzymes that target crosslink binding can be effective in softening the wall in its pre-yield state, whereas its post-yield extensibility is determined primarily by the pectin matrix.

Developing new veterinary services in milk quality: a review of a recent mastitis risk management co-development in Australia.

A new veterinary service to promote ongoing, incremental improvements in the risk management of mastitis and milk quality was developed between 2005 and 2008. This was designed to enhance the relationship between the farmer and advisor, as an extension of the Countdown Downunder programme, Australia's national mastitis and milk quality programme. This service was co-developed between the Countdown Downunder programme team and a core development group of veterinarians involved with trialling the service, and farmers and social researchers. The service, known as Countdown MAX, involved advisory input at the planning stage, a written risk management plan, multiple engagements between the farm team and advisor for tracking and re-planning, and a service fee. Risk management resources (modules) were developed to be employed at the drying-off and calving periods, and during lactation. During the development and implementation phase eight veterinary practices conducted Countdown MAX consultations on 55 farms. Eighty-eight Countdown MAX modules were delivered in total, with 55% of farms completing more than one module but only 38% of modules reviewed successfully. A social research project examined the implementation of the Countdown MAX service in participating veterinary practices during the development phase. Findings of the project were that the successful uptake of a new mastitis service into a veterinary practice was enhanced through uptake by practice owners of the concept, the formation of a written practice plan, adequate communication and explanation of the new service to all staff, logistical support for the service within the practice, and transfer of mastitis expertise within the practice.

Design criteria for a printed tissue engineering construct: a mathematical homogenization approach.

Cartilage tissue repair procedures currently under development aim to create a construct in which patient-derived cells are seeded and expanded ex vivo before implantation back into the body. The key challenge is producing physiologically realistic constructs that mimic real tissue structure and function. One option with vast potential is to print strands of material in a 3D structure called a scaffold that imitates the real tissue structure; the strands are composed of gel seeded with cells and so provide a template for cartilaginous tissue growth. The scaffold is placed in the construct and pumped with nutrient-rich culture medium to supply nutrients to the cells and remove waste products, thus promoting tissue growth. In this paper we use asymptotic homogenization to determine the effective flow and transport properties of such a printed scaffold system. These properties are used to predict the distribution of nutrient/waste products through the construct, and to specify design criteria for the scaffold that will optimize the growth of functional tissue.

Effect of aging on the stride pattern of veteran marathon runners.

OBJECTIVE: To investigate the stride pattern of different age groups of veteran runners in a marathon road race. METHODS: This kinematic study investigated the stride pattern (stride length, stride period, velocity, stance time, and non-stance time) for 151 runners (78 men aged up to 75-80, 73 women aged up to 60-64) at the 7 mile point. RESULTS: Significant declines for men with aging were found for mean stride length (from 2.4 m at age 40-49 to 2.0 m at age 60+), velocity, and non-stance time (p<0.05), whereas stride period changed little. The findings indicate that the lower velocities of older runners are associated with shorter strides whereas cadence changes little. However, when a statistical adjustment was made for the variation in runners' velocity, it was found that older runners did not have a significantly shorter stride length at any given velocity. CONCLUSION: Although a shorter stride is the mechanical route by which older runners lose velocity, the shorter stride may not be the fundamental cause of the velocity reduction with age. This has implications for researchers and coaches when investigating and training veteran distance runners.

Incidence of sports injuries in elite competitive and recreational windsurfers.

OBJECTIVE: To investigate the incidence of injury in windsurfing and to consider methods of prevention. METHODS: A total of 107 raceboard (RB) and wave/slalom (WS) national/international competitors and recreational (REC) windsurfers completed a questionnaire on injury incidence over two years. Recurrent injury, ability level, and any preventive measures taken were noted. RESULTS: Overall the injury incidence was 1.5/person/year. The WS group suffered more injuries (2.0/person/year) than the RB (1.0) or REC (1.2) group. The most common injury was muscle strain at 35% of new injuries, much higher than in earlier studies. Overall 45% of new injuries were muscle/tendon strains (RB 55%, WS 42%, and REC 43%) and 8% were ligament sprains. In the WS group cuts and abrasions were common. The WS and REC groups reported five and one case of concussion respectively. Nearly a quarter (22%) of new lower body injuries were lower back muscular strain, with 34% of recurrent injuries. Approximately 60% of the remaining lower body soft tissue injuries involved the knee or lower leg, with the ankle/foot most often involved. The shoulder, upper arm, and elbow were the sites of 41% of new upper body soft tissue injuries. The WS group reported 250% more recurrent muscular strains than the RB group. Recurrent ligament injuries (particularly knee) were most common in the WS group. The RB group reported recurrent serious bruising to the lower leg. CONCLUSION: The injury incidence was 1.5/person/year with a high incidence of new and recurrent muscular strain. Lower back muscular strain was prevalent, indicating the need for preventive measures. Wave/slalom was associated with more new and recurrent injuries and the need for head protection.

Contributions of the inside and outside leg to maintenance of curvilinear motion on a natural turf surface.

Little is understood of the mechanisms of locomotion if human subjects are not moving in a straight path. The identification of contributory variables to curved motion would also underpin other non-linear actions such as cutting and turning. The performance of such tasks has relevance to both success in sports and exercise, and accident avoidance in an occupational setting. Comparison of ground reaction force values in successive footstrikes would allow an understanding of the contribution of each limb's movement to motion in a curved path. For ecological validity to field games, two natural-turf covered force platforms were located outdoors in a field. Six males (age 25+/-4.73 years; mass 79.7+/-7.17 kg) wearing standard six-stud soccer boots performed straight and curved trials (radius 5m) at velocities of 4.5 and 5.5 ms(-1). Ground reaction force measures were collected on successive footstrikes at 500 Hz, whilst kinematics of the lower extremity were measured at 50 Hz. Results for two successive footfalls showed greater average total force in straight motion (3.53BW versus 3.08BW), with the outside leg contributing most to the movement pattern in curvilinear motion. Ballistic airtime was reduced from straight to curvilinear motion, creating a greater proportional foot contact time during curved running. This, with lowered total force values, suggested a lower centre of gravity during curved motion to minimise drift towards the tangent of the curve. In curved motion, all vertical force measures were greater for the outside leg, with anterior-posterior forces showing the outside leg provided greater propulsion forces and impulse. Improvement in performance in curvilinear motion should therefore be focused at the outside limb.

Effect of creatine supplementation and sleep deprivation, with mild exercise, on cognitive and psychomotor performance, mood state, and plasma concentrations of catecholamines and cortisol.

RATIONALE: Sleep deprivation has a negative effect on cognitive and psychomotor performance and mood state, partially due to decreases in creatine levels in the brain. Therefore, creatine supplementation should lessen the negative effects of sleep deprivation. OBJECTIVES: The objective of this study was to examine the effect of creatine supplementation and sleep deprivation, with mild exercise, on cognitive and psychomotor performance, mood state, and plasma concentrations of catecholamines and cortisol. METHOD: Subjects were divided into a creatine group (n=10) and a placebo group (n=9). They took 5 g of creatine monohydrate or a placebo, dependent on their group, four times a time a day for 7 days, immediately prior to the experiment. The study was double blind. Subjects undertook tests of random movement generation (RMG), verbal and spatial recall, choice reaction time, static balance and mood state pre-test (0 h), after 6, 12 and 24 h of sleep deprivation, with intermittent exercise. They were tested for plasma concentrations of catecholamines and cortisol at 0 and 24 h. RESULTS: At 24 h, the creatine group demonstrated significantly less change in performance from 0 h (delta) in RMG, choice reaction time, balance and mood state. There were no significant differences between groups in plasma concentrations of catecholamines and cortisol. Norepinephrine and dopamine concentrations were significantly higher at 24 h than 0 h, but cortisol were lower. CONCLUSIONS: Following 24-h sleep deprivation, creatine supplementation had a positive effect on mood state and tasks that place a heavy stress on the prefrontal cortex.

Acute post-parturient haemoglobinuria in dairy cows and phosphorus status.

During the conduct of an experiment designed to examine the nutritional management of dairy cows in late pregnancy, four cows out of 72 suffered from acute haemoglobinuria two to four weeks after calving. Thirty-six thin and 36 fat cows were individually fed one of three diets based on a total mixed ration with different energy or protein concentrations during the last 3 to 4 weeks before expected calving date. After calving, cows grazed pasture and were offered 6 kg dry matter of pelleted concentrates daily. The P concentrations of the feeds offered suggested that the cows' diets were marginally deficient in P relative to requirements. Plasma P concentrations were significantly (P < 0.05) lower in fat cows than in thin cows during the first 6 weeks of lactation (0.87 versus 1.12 mmol/L), but precalving diet had no effect (P > 0.05). Concentrations of plasma inorganic P of the four fat cows that developed acute haemoglobinuria were less than 0.3 mmol/L. However, plasma P concentrations in another 12 cows, none of which displayed overt symptoms, declined to similar levels. It appeared that inadequate dietary P may have predisposed cows to acute haemoglobinuria, but the precipitating cause was not readily obvious.

The effects of restricted energy and fluid intake on simulated amateur boxing performance.

This study examined the effects of serial reductions in energy and fluid intake on two simulated boxing performances separated by 2 days recovery. Eight amateur boxers (age: 23.6 +/- 3.2 years; height 175 +/- 5 cm; body mass [BM] 73.3 +/- 8.3 kg [Mean +/- SD]) performed two simulated boxing bouts (BB) under normal (N-trial) and restricted (R-trial) diets in a counterbalanced design over 5 days. The trials were separated by a 9-day period of normal dietary behavior (X-trial). BM was recorded on days 1, 3, and 5 of each trial. Simulated bouts of three, 3-min rounds with 1-min recovery were completed on days 3 (BB1) and 5 (BB2) of each 5-day trial. Punching force (N) was recorded from 8 sets of 7 punches by a purpose-built boxing ergometer. Heart rate (fC) was monitored continuously (PE3000 Polar Sports Tester, Kempele, Finland), and blood lactate (BLa) and glucose (BG) were determined 4-min post-performance (2300 StaPlus, YSI, Ohio). Energy and fluid intakes were significantly lower in the R-trial (p < .05). Body mass was maintained during the N-trial but fell 3% (p < .05) during the R-trial. There were no significant differences in end-of-bout fC or post-bout BG, but BLa was higher in the N- than the R-trial (p < .05). R-trial punching forces were 3.2% and 4.6% lower, respectively, compared to the corresponding N-trial bouts, but the differences did not reach statistical significance. These results suggest that energy and fluid restrictions in weight-governed sports do not always lead to a significant decrease in performance, but because of the small sample size and big variations in individual performances, these findings should be interpreted with care.

Molecular epidemiology of Streptococcus uberis isolates from dairy cows with mastitis.

Pulsed-field gel electrophoresis and antimicrobial sensitivity testing were used as tools to investigate the epidemiology of Streptococcus uberis mastitis in dairy cows. A total of 62 different strains were found among 138 isolates from the four herds investigated, and between 10 and 26 different strains were found in each herd. There was no strain common to all four herds. Identical strains of S. uberis were detected from different quarters of individual cows and from cows within the same herd, suggesting that transmission from quarter to quarter and cow to cow had occurred. Despite the great variation in S. uberis strains, persistent infection with the same strain within a lactation was observed in most cows. Predominant strains were present in two herds. Preliminary investigations could not clarify why these particular strains might predominate, but in one herd there was a significant difference between the prevalence of clinical mastitis in quarters infected with the predominant strain and that in quarters infected with other strains, suggesting the greater virulence of the predominant strain. The wide variety of S. uberis strains found is consistent with an environmental source of S. uberis. However, evidence of direct transmission, the persistence of infection, and the predominance of particular strains in some herds indicate that S. uberis infections are epidemiologically complex and that the relative importance of these factors in the occurrence of mastitis may differ between herds.

The effects in humans of rapid loss of body mass on a boxing-related task.

The physiological effects of strategies for a rapid loss of body mass immediately before weighing-in for competition in weight-governed sports are unclear. This study examined the effects of a 3%-4% loss in body mass on a boxing-related task. Seven novice amateur boxers completed three 3 min rounds of simulated boxing on a prototype boxing ergometer in an euhydrated state (E-trial) and after exercise-induced thermal dehydration (D-trial). All subjects lost body mass following dehydration-mean body mass fell 3.8 (SD +/- 0.3)% [77.3 (SD +/- 11.3) to 74.4 (SD +/- 10.7) kg, P<0.001] - but changes in plasma volume (PV) were inconsistent. Four subjects suffered reductions in PV between 15% and 30%, one subject maintained his E-trial value and two recorded an increase. The D-trial mean PV value was 8.0 (SD +/- 17.2)% lower but this fall was not statistically significant (P>0.05). Analysis of D-trial boxing performance showed one subject maintained his performance over the two trials and a second improved 17.8%. A two-way ANOVA (condition x time) with repeated measures on both factors showed no significant main effect differences for condition (F1,6 = 3.93 P>0.05), time (F1.83,48 = 1.12, P>0.05) or interaction between them (F1.93,48, P>0.05). Furthermore, neither heart rate nor blood lactate responses in the boxing task differed between trials. These data were affected by the small sample. Power and effect size analysis using eta(2) procedure and removing the outlier data produced a mean fall in boxing performance of 26.8%. However, some subjects appeared able to resist the deleterious effects of a rapid loss of body mass prior to competition and further research is needed to explain the mechanisms under-pinning this ability.

Development of a boxing dynamometer and its punch force discrimination efficacy.

The development of sport-specific dynamometers is an important step towards ecological validity in analysing athlete performance. Design limitations in previous punch-measuring devices have resulted in values which may not or cannot fully reflect the force and multidirectional components in a punch. In developing this boxing dynamometer, a triaxial force measurement system and a boxing manikin interface were combined. The repeatability and accuracy of the dynamomoter were assessed using simulated straight punches. Discrimination efficacy was assessed by comparison of the maximal punching force of seven elite, eight intermediate and eight novice boxers during simulated boxing, throwing straight punches. For the elite, intermediate and novice groups, respectively, the maximal straight punching forces (mean +/- s(mean)) were 4800 +/- 227 N, 3722 +/- 133 N and 2381 +/- 116 N for the rear hand, and 2847 +/- 225 N, 2283 +/- 126 N and 1604 +/- 97 N for the lead hand. For all groups, maximal forces were larger for the rear than the lead hand (P < 0.001). Maximal punching force was greater in the elite than the intermediate group, and greater in the intermediate than the novice group (P < 0.05). The boxing dynamometer discriminated effectively between punching performance at three standards of performance and between the punching force of the rear and lead hands.

Effects of massage on physiological restoration, perceived recovery, and repeated sports performance.

BACKGROUND: Despite massage being widely used by athletes, little scientific evidence exists to confirm the efficacy of massage for promoting both physiological and psychological recovery after exercise and massage effects on performance. AIM: To investigate the effect of massage on perceived recovery and blood lactate removal, and also to examine massage effects on repeated boxing performance. METHODS: Eight amateur boxers completed two performances on a boxing ergometer on two occasions in a counterbalanced design. Boxers initially completed performance 1, after which they received a massage or passive rest intervention. Each boxer then gave perceived recovery ratings before completing a second performance, which was a repeated simulation of the first. Heart rates and blood lactate and glucose levels were also assessed before, during, and after all performances. RESULTS: A repeated measures analysis of variance showed no significant group differences for either performance, although a main effect was found showing a decrement in punching force from performance 1 to performance 2 (p<0.05). A Wilcoxon matched pairs test showed that the massage intervention significantly increased perceptions of recovery (p<0.01) compared with the passive rest intervention. A doubly multivariate multiple analysis of variance showed no differences in blood lactate or glucose following massage or passive rest interventions, although the blood lactate concentration after the second performance was significantly higher following massage (p<0.05). CONCLUSIONS: These findings provide some support for the psychological benefits of massage, but raise questions about the benefit of massage for physiological restoration and repeated sports performance.

Simultaneous measurement of back and front foot ground reaction forces during the same delivery stride of the fast-medium bowler.

Six male cricket bowlers (mean +/- s(mean): age 23.5 +/- 1.3 years; height 1.83 +/- 0.04 m; body weight 826 +/- 20 N) performed their typical bowling action at a set of stumps positioned at standard pitch length (20.1 m). A specially designed force platform rig allowed the correct positioning of two force platforms to be achieved beneath an outdoor polyflex runway (0.017 m depth) for each player's delivery stride pattern. For the back foot, the peak vertical ground reaction force was 1.95 +/- 0.08 kN (2.37 +/- 0.14 BW) and the braking force was 0.77 +/- 0.12 kN (0.94 +/- 0.16 BW). For the front foot, the peak vertical force was 4.80 +/- 0.92 kN (5.75 +/- 0.98 BW) and the braking force was 2.93 +/- 0.56 kN (3.54 +/- 0.67 BW). The mean peak vertical loading rate for front foot contact was 205 +/- 52.8 kN x s(-1) (249 +/- 64 BW x s(-1)) with mean values ranging from 81 to 446 kN x s(-1) (98 to 540 BW x s(-1)). The range for back foot contact was much smaller, 25-70 kN x s(-1) (30-85 BW x s(-1)), with a mean of 41.7 +/- 7.10 kN x s(-1) (50.6 +/- 8.6 BW x s(-1)). Mean peak impact occurred 24 ms after touchdown for the back foot and 16 ms after touchdown for the front foot. At impact, mean peak loading rates were greater for the front foot at 246 kN x s(-1) (298 BW x s(-1)), with a range of 80-483 kN x s(-1) (98-534 BW x s(-1)), than for the back foot at 65 kN x s(-1) (79 BW x s(-1)), with a range of 40-84 kN x s(-1) (49-110 BW x s(-1)).