Kidney tubule health scores and their associations with incident CKD in women living with HIV.

OBJECTIVES: Individual kidney tubule biomarkers are associated with chronic kidney disease (CKD) risk in people living with HIV (PLWH). Whether a combination of kidney biomarkers can be integrated into informative summary scores for PLWH is unknown. METHODS: We measured eight urine biomarkers of kidney tubule health at two visits over a 3-year period in 647 women living with HIV in the Women's Interagency Health Study. We integrated biomarkers into factor scores using exploratory factor analysis. We evaluated associations between CKD risk factors and factor scores, and used generalized estimating equations to determine associations between factor scores and risk of incident CKD. RESULTS: Factor analysis identified two unique factor scores: a tubule reabsorption score comprising alpha-1-microglobulin, beta-2-microglobulin and trefoil factor-3; and a tubule injury score comprising interleukin-18 and kidney injury molecule-1. We modelled the two factor scores in combination with urine epidermal growth factor (EGF) and urine albumin. Predominantly HIV-related CKD risk factors were independently associated with worsening tubule reabsorption scores and tubule injury scores. During a median follow-up of 7 years, 9.7% (63/647) developed CKD. In multivariable time-updated models that adjusted for other factor scores and biomarkers simultaneously, higher tubule reabsorption scores [risk ratio (RR) = 1.27, 95% confidence interval (CI): 1.01-1.59 per 1 SD higher time-updated score], higher tubule injury scores (RR = 1.36, 95% CI: 1.05-1.76), lower urine EGF (RR = 0.75, 95% CI: 0.64-0.87), and higher urine albumin (RR = 1.20, 95% CI: 1.02-1.40) were jointly associated with risk of incident CKD. CONCLUSIONS: We identified two novel and distinct dimensions of kidney tubule health that appear to quantify informative metrics of CKD risk in PLWH.

External mechanical work in the galloping racehorse.

Horse locomotion is remarkably economical. Here, we measure external mechanical work of the galloping horse and relate it to published measurements of metabolic cost. Seven Thoroughbred horses were galloped (ridden) over force plates, under a racing surface. Twenty-six full strides of force data were recorded and used to calculate the external mechanical work of galloping. The mean sum of decrements of mechanical energy was -876 J (±280 J) per stride and increments were 2163 J (±538 J) per stride as horses were accelerating. Combination with published values for internal work and metabolic costs for galloping yields an apparent muscular efficiency of 37-46% for galloping, which would be reduced by energy storage in leg tendons. Knowledge about external work of galloping provides further insight into the mechanics of galloping from both an evolutionary and performance standpoint.

Short-interval intracortical inhibition to the biceps brachii is present during arm cycling but is not different than a position- and intensity-matched tonic contraction.

We have previously shown that supraspinal excitability is higher during arm cycling than a position- and intensity-matched tonic contraction. The present study sought to determine if short-interval intracortical inhibition (SICI) was present during arm cycling and if so, if the amount of SICI was different from an intensity-matched tonic contraction. SICI was assessed using conditioning stimuli (CS) of 70 and 90% of active motor threshold (AMT) and a test stimulus (TS) of 120% AMT at an interstimulus interval (ISI) of 2.5 ms. SICI was elicited in all participants; on average (i.e., cycling and tonic contraction grouped) test MEP amplitudes were reduced by 64.2% (p < 0.001) and 62.8% (p = 0.001) following conditioning stimuli of 70% and 90% AMT, respectively. There was no significant difference in extent of SICI between tasks (p = 0.360). These data represent the novel finding that SICI is present during arm cycling, a motor output partially mediated by spinal interneuronal networks. The amount of SICI, however, was not different from that during a position- and intensity-matched tonic contraction, suggesting that SICI is not likely a cortical mechanism contributing to higher supraspinal excitability during arm cycling compared to tonic contraction.

Intensity matters: effects of cadence and power output on corticospinal excitability during arm cycling are phase and muscle dependent.

The present study investigated the effects of cadence and power output on corticospinal excitability to the biceps (BB) and triceps brachii (TB) during arm cycling. Supraspinal and spinal excitability were assessed using transcranial magnetic stimulation (TMS) of the motor cortex and transmastoid electrical stimulation (TMES) of the corticospinal tract, respectively. Motor-evoked potentials (MEPs) elicited by TMS and cervicomedullary motor-evoked potentials (CMEPs) elicited by TMES were recorded at two positions during arm cycling corresponding to mid-elbow flexion and mid-elbow extension (i.e., 6 and 12 o'clock made relative to a clock face, respectively). Arm cycling was performed at combinations of two cadences (60 and 90 rpm) at three relative power outputs (20, 40, and 60% peak power output). At the 6 o'clock position, BB MEPs increased ~11.5% as cadence increased and up to ~57.2% as power output increased ( P < 0.05). In the TB, MEPs increased ~15.2% with cadence ( P = 0.013) but were not affected by power output, while CMEPs increased with cadence (~16.3%) and power output (up to ~19.1%, P < 0.05). At the 12 o'clock position, BB MEPs increased ~26.8% as cadence increased and up to ~96.1% as power output increased ( P < 0.05), while CMEPs decreased ~29.7% with cadence ( P = 0.013) and did not change with power output ( P = 0.851). In contrast, TB MEPs were not different with cadence or power output, while CMEPs increased ~12.8% with cadence and up to ~23.1% with power output ( P < 0.05). These data suggest that the "type" of intensity differentially modulates supraspinal and spinal excitability in a manner that is phase- and muscle dependent. NEW & NOTEWORTHY There is currently little information available on how changes in locomotor intensity influence excitability within the corticospinal pathway. This study investigated the effects of arm cycling intensity (i.e., alterations in cadence and power output) on corticospinal excitability projecting to the biceps and triceps brachii during arm cycling. We demonstrate that corticospinal excitability is modulated differentially by cadence and power output and that these modulations are dependent on the phase and the muscle examined.

Maternal and neonatal outcomes of pregnancies in women with Addison's disease: a population-based cohort study on 7.7 million births.

OBJECTIVE: To assess if pregnancies among women with Addison's disease (AD) are at higher risk of adverse maternal and neonatal outcomes. DESIGN: Population-based retrospective cohort study. SETTING/POPULATION: All births in the United States' Healthcare Cost and Utilization Project-Nationwide Inpatient Sample from 2003 to 2011. METHODS: Baseline characteristics were compared between women with AD and those without, and prevalence over time was measured. Logistic regression was used to estimate the effect of AD on maternal and neonatal outcomes by calculating the crude and adjusted odds ratios (OR) and corresponding 95% confidence intervals (95% CI). RESULTS: We calculated a prevalence of AD in pregnancy of 5.5/100 000, increasing from 5.6 to 9.6/100 000 (P = 0.0001) over the 9-year study period. Compared with women without AD, women with AD were more likely to deliver preterm (OR 1.50, 95% CI 1.16-1.95), deliver by caesarean section (OR 1.32, 95% CI 1.08-1.61), have impaired wound healing (OR 4.28, 95% CI 2.55-7.18), develop infections (OR 2.44, 95% CI 1.66-3.58) and develop thromboembolism (OR 5.21, 95% CI 2.15-12.63), require transfusions (OR 6.69, 95% CI 4.69-9.54), and have prolonged postpartum hospital admissions (OR 5.71, 95% CI 4.37-7.47). Maternal mortality was significantly higher than in the comparison group (OR 22.30, 95% CI 6.82-72.96). Congenital anomalies (OR 3.62, 95% CI 2.05-6.39) and small-for-gestational age infants (OR 1.78, 95% CI 1.15-2.75) were more likely in these pregnancies. CONCLUSIONS: Addison's disease significantly increases the risk of severe adverse maternal and neonatal outcomes, so pregnant women with AD are best managed in tertiary-care centres. TWEETABLE ABSTRACT: Pregnancies complicated by Addison's disease have an increased risk of adverse maternal and neonatal outcomes.

Validity of short food questionnaire items to measure intake in children and adolescents: a systematic review.

BACKGROUND: Short food questions are appealing to measure dietary intakes. METHODS: A review of studies published between 2004 and 2016 was undertaken and these were included in the present study if they reported on a question or short item questionnaire (≤50 items, data presented as ≤30 food groups) measuring food intake or food-related habits, in children (aged 6 months to 18 years), and reported question validity or reliability. Thirty studies met the inclusion criteria. RESULTS: Most questions assessed foods or food groups (n = 29), with the most commonly assessed being fruit (n = 22) or vegetable intake (n = 23), dairy foods and discretionary foods (n = 20 studies each). Four studies assessed food habits, with the most common being breakfast and meal frequency (n = 4 studies). Twenty studies assessed reliability, and 25 studies determined accuracy and were most commonly compared against food records. Evaluation of question performance relied on statistical tests such as correlation. CONCLUSIONS: The present study has identified valid and reliable questions for the range of key food groups of interest to public health nutrition. Questions were more likely to be reliable than accurate, and relatively few questions were both reliable and accurate. Gaps in repeatable and valid short food questions have been identified that will provide direction for future tool development.

Pain pressure threshold of a muscle tender spot increases following local and non-local rolling massage.

BACKGROUND: The aim of the present study was to determine the acute effect of rolling massage on pressure pain threshold (PPT) in individuals with tender spots in their plantar flexor muscles. METHODS: In a randomized control trial and single blinded study, tender spots were identified in 150 participants' plantar flexor muscles (gastrocnemius or soleus). Then participants were randomly assigned to one of five intervention groups (n = 30): 1) heavy rolling massage on the calf that exhibited the higher tenderness (Ipsi-R), 2) heavy rolling massage on the contralateral calf (Contra-R), 3) light stroking of the skin with roller massager on the calf that exhibited the higher tenderness (Sham), 4) manual massage on the calf that exhibited the higher tenderness (Ipsi-M) and 5) no intervention (Control). PPT was measured at 30 s and up to 15 min post-intervention via a pressure algometer. RESULTS: At 30 s post-intervention, the Ipsi-R (24 %) and Contra-R (21 %) demonstrated higher (p < 0.03) PPT values compared with Control and Sham. During 15 min post-intervention, PPT was higher (p < 0.05) following Ipsi-R (19.2 %), Contra-R (15.9 %) and Ipsi-M (10.9 %) compared with Control. There was no difference between the effects of three deep tissue massages (Ipsi-R, Ipsi-M and Contra-R) on PPT. DISCUSSION: Whereas the increased PPT following ipsilateral massage (Ipsi-R and Ipsi-M) might be attributed to the release of fibrous adhesions; the non-localized effect of rolling massage on the contralateral limb suggests that other mechanisms such as a central pain-modulatory system play a role in mediation of perceived pain following brief tissue massage. CONCLUSION: Overall, rolling massage over a tender spot reduces pain perception. TRIAL REGISTRATION: ClinicalTrials.gov ( NCT02528812 ), August 19(th), 2015.

Screening histories and contact with physicians as determinants of cervical cancer risk in Montreal, Quebec.

BACKGROUND: Cervical cancer (cca) is largely a preventable disease if women receive regular screening, which allows for the detection and treatment of preinvasive lesions before they become invasive. Having been inadequately screened is a common finding among women who develop cca. Our primary objective was to determine the Pap screening histories of women diagnosed with cca in Montreal, Quebec. Secondary objectives were to determine the characteristics of women at greatest risk of cca and to characterize the level of physician contact those women had before developing cca. METHODS: The Invasive Cervical Cancer Study, a population-based case-control study, consisted of Greater Montreal residents diagnosed with histologically confirmed cca between 1998 and 2004. Respondents to the 2003 Canadian Community Health Survey and a sample of women without cca obtained from Quebec medical billing records served as controls. RESULTS: During the period of interest, 568 women were diagnosed with cca. Immigrants and women speaking neither French nor English were at greatest risk of cca. Most of the women in the case group had been screened at least once during their lifetime (84.8%-90.4%), but they were less likely to have been screened within 3 years of diagnosis. Having received care from a family physician or a medical specialist other than a gynecologist within the 5 years before diagnosis was associated with a greater risk of cca development. CONCLUSIONS: Our findings provide evidence of the need for an organized population-based screening program. They also underscore the need for provider education to prevent missed opportunities for cca screening when at-risk women seek medical attention.

FT-IR spectroscopy analysis of HF-treated mineral soils, a direct approach for deciphering organo-mineral interactions.

Soil organic matter (SOM) constitutes roughly 60% organic carbon (OC) and therefore plays a crucial role in regulating global climate. However, our understanding of the long-term dynamics of the soil carbon pool remains constrained by limitations in analytical approaches capable of providing high resolution molecular-level information from arguably the most complex biomaterial on the planet. In this contribution, we combine hydrofluoric acid (HF) treatment with a spectroscopic approach as a strategy to provide refined molecular-level information on the interactions between soil minerals and SOM. Critically, we have not seen the use of this combined approach anywhere in the literature and strongly believe that it could allow us to improve our overall understanding to the mechanisms and pathways that regulate SOM transformation. Results clearly illustrates which organic structures are preferentially adsorbed to soil minerals and are likely to be protected from degradation, as well as spatial co-variations of SOM with specific mineral components such as Al3+, Si4+ and dibasic cations such as Mg2+as a function of their importance in the interaction process.•Soil samples were collected from different land-use types in rural farming communities of the Upper Rio Grande Valley.•Samples were oven dried, disaggregated, sieved, treated with 10% HF, rinsed and oven dried.•Oven dried samples were subjected to Mid-infrared (4000-400 cm-1), XRD and ED-XRF analyses.

High speed field kinematics of foot contact in elite galloping horses in training.

REASONS FOR PERFORMING STUDY: Mechanical characterisation of the high speed gallop has significant importance for animal welfare and basic biology. Kinematic parameters such as the velocity of each foot at contact can inform theories of why animals gallop, and supplant epidemiological investigation into the mechanisms of musculoskeletal injury. OBJECTIVE: To determine the velocity at which the fore and hind hooves of elite galloping horses impact the surface. METHODS: High speed videography was used to measure the horizontal and vertical velocity of the hoof immediately prior to impact, and the subsequent sink (vertical) and slip (horizontal) distances travelled by the hoof into the surface. Horse speed ranged from 11-19 m/s. In total 170 forelimb and 168 hindlimb foot falls from 89 horses were analysed. RESULTS: Horizontal and vertical hoof velocity increased with speed (P<0.001). Horizontal hoof velocity was significantly greater in the hindlimbs compared to the forelimbs (P<0.001) and was greater in the nonlead limbs compared to the lead limbs (P<0.001). Vertical hoof velocity was significantly greater in the lead limb than the nonlead limb (P<0.001). Overall, forelimbs contacted the ground with a more acute velocity vector angle than hindlimbs (P<0.001). Lead limbs contacted the ground at more acute angles than nonlead limbs (P<0.001). Vertical and horizontal velocities were highly correlated to sink and slip distance. CONCLUSION: Hindlimbs impact the surface at higher velocity than forelimbs, which is likely to result in higher peak impact forces in the hindlimbs. This runs counter to the finding of lower incidence of injury in hindlimbs. POTENTIAL RELEVANCE: Explanations consistent with these findings include the hindlimbs more effectively dampening peak impact forces, or that other injury mechanisms, such as limb vibration and limb load at mid stance, play an important role in injury.

The impact of isolated tibial disease on outcomes in the critical limb ischemic population.

BACKGROUND: Most patients with critical limb ischemia (CLI) have multilevel infrainguinal peripheral arterial disease (M-PAD). One-third of CLI patients will have isolated tibial disease (ITD). The treatments for multilevel disease or ITD differ depending on whether open or endovascular procedures are used, but we questioned whether outcomes from these procedures differ. We evaluated outcomes of CLI patients after open and/or endovascular revascularization for CLI and assessed the impact of disease distribution. METHODS: Four hundred forty-six CLI patients (Rutherford 4-6) who underwent revascularization from 2001 to 2005 were evaluated arteriographically and followed after revascularization with noninvasive testing. Based on arteriographic data, all patients with ITD (occlusions in one or more tibial arteries) were compared with patients with occlusive femoropopliteal disease with or without concomitant tibial occlusions (M-PAD). Patients with disease solely above the inguinal ligament were excluded. Clinical data (survival, amputation-free survival, primary patency, secondary patency, limb salvage, maintenance of ambulation, and maintenance of living status) were acquired from a prospective vascular database, allowing the comparison of revascularization outcomes according to disease distribution. RESULTS: In this study, 36% of patients had ITD and 64% presented with M-PAD. The severity of ischemia at presentation was rest pain (28.5%), ulceration (42.3%), and gangrene (29.1%). In this study, 92% presented exclusively with infrainguinal disease, and 8% presented with both suprainguinal and infrainguinal disease. Risk factors included diabetes mellitus (61.2%), smoking (61.0%), coronary artery disease (57.9%), hypertension (84.3%), hyperlipidemia (40.4%), obesity (15.5%), and chronic obstructive pulmonary disease (19.3%). In comparing the ITD and M-PAD groups, there was no difference in primary patency at 2 years. All other outcomes were statistically different out to 3 years including survival (50.4% vs. 62.6%; p=0.0026, hazard ratio [HR] 0.669); amputation-free survival (35.1% vs. 50.2%; p=0.0062; HR 0.595); limb salvage (65.2% vs. 74.4%; p=0.0062; HR 0.595); maintenance of ambulation (68.9% vs. 76.9%; p=0.0352; HR 0.644); maintenance of living status (79.0% vs. 84.8%; p=0.0403; HR 0.599); and secondary patency (66.8% vs. 74.8%; p=0.0309; HR 0.665). Multivariate analyses reveal that ITD is not an independent predictor of outcome after controlling for confounding factors, of which tissue loss and end-stage renal disease correlate most consistently with poor clinical outcomes. CONCLUSION: After revascularization for CLI, ITD carries a worse prognosis (amputation-free survival, limb salvage, survival, maintenance of ambulation, and independent living status) compared with patients with M-PAD, despite the "greater" disease burden in M-PAD patients. ITD patients are more likely to have confounding factors such as diabetes mellitus, renal disease, and worse ischemia at presentation than those with M-PAD. The recognition of ITD may be helpful in identifying high-risk patients but is not an independent risk factor for poor outcomes.

Professionals delivering palliative care to people with COPD: qualitative study.

This article describes health and social care professionals' perceptions of palliative care and facilitators and barriers to the delivery of such care for patients with advanced chronic obstructive pulmonary disease. Health professionals participated in semi structured interviews and focus groups which were analysed using content analysis. According to participants, care of patients with chronic obstructive pulmonary disease is focused upon the management of symptoms, with emphasis focused predominately on an acute model of care. Key barriers towards the delivery of palliative care included the reluctance to negotiatie end-of-life decisions and a perceived lack of understanding among patients and carers regarding the illness trajectory. Consequently the delivery of palliative care was viewed as a specialist role rather than an integral component of care. There is a need for education and training for health and social care professions to plan and provide high quality end-of-life care.

The influence of temperature and pressure factors in supercritical fluid extraction for optimizing nonpolar lipid extraction from buttermilk powder.

The milk fat globule membrane, readily available in buttermilk, contains complex lipids claimed to be beneficial to humans. Phospholipids, including sphingolipids, exhibit antioxidative, anticarcinogenic, and antiatherogenic properties and have essential roles in numerous cell functions. Microfiltration coupled with supercritical fluid extraction (SFE) may provide a method for removing triacylglycerols while concentrating these nutritionally valuable lipids into a novel ingredient. Therefore, SFE as a method for phospholipid concentration needs to be optimized for triacylglycerol removal in buttermilk. The SFE conditions were assessed using a general full factorial design; the experimental factors were pressure (15, 25, and 35 MPa) and temperature (40, 50, and 60 degrees C). Particularly interesting is that only triacylglycerols were removed from buttermilk powder. Little to no protein loss or aggregation was observed compared with the untreated buttermilk powder. Calculated theoretical values showed a linear increase for lipid solubility as pressure, temperature, or both were increased; however, experimental values showed nonlinearity, as an effect of temperature. In addition, the particular SFE parameters of 35 MPa and 50 degrees C displayed enhanced extraction efficiency (70% total lipid reduction).

Phospholipid enrichment in sweet and whey cream buttermilk powders using supercritical fluid extraction.

Milk fat globule membrane contains many complex lipids implicated in an assortment of biological processes. Microfiltration coupled with supercritical fluid extraction (SFE) has been shown to provide a method of concentrating these nutritionally valuable lipids into a novel ingredient. In the dairy industry there are several by-products that are rich in phospholipids (PL) such as buttermilk, whey, and whey cream. However, PL are present at low concentrations. To enrich PL in buttermilk powders, regular buttermilk and whey buttermilk (by-product of whey cream after making butter) were microfiltered and then treated with SFE after drying. The total fat, namely nonpolar lipids, in the powders was reduced by 38 to 55%, and phospholipids were concentrated by a factor of 5-fold. Characterization of the PL demonstrated specific molecular fatty amide combinations on the sphingosine (18:1) backbone of sphingomyelin with the greatest proportion being saturated; the most common were 16:0, 20:0, 21:0, 22:0, 23:0, and 24:0. Two unsaturated fatty amide chains, 23:1 and 24:1, were shown to be elevated in a whey cream buttermilk sample compared with the others. However, most unsaturated species were not as abundant.

Short communication: Evaluation of supercritical fluid extraction aids for optimum extraction of nonpolar lipids from buttermilk powder.

The milk fat globule membrane, present in buttermilk, contains complex lipids such as phospholipids. Microfiltration coupled with supercritical fluid extraction (SFE) may provide a method of enriching these nutritionally valuable lipids into a novel ingredient. Therefore, SFE as a method for phospholipid enrichment needs to be optimized for lipid removal effectiveness. The role of matrix additions to the buttermilk powder for extraction efficiency was evaluated. Diatomaceous earth (biosilicates), Teflon beads, and physical vibration were tested and shown to reduce total lipid by 86, 78, and 70%, respectively. Four consecutive treatments were shown to exhaust the system; however, similar extraction efficiencies were noted for 1 treatment with biosilicate addition, 2 treatments with physical vibration, or 3 treatments with added Teflon beads. The extracted lipid material consisted of the nonpolar fraction, and protein concentration was observed to increase slightly compared with the control. Although higher lipid extraction was achieved from the powder with addition of diatomaceous earth, a removable aid is ideal for an edible product.

In vitro technique in estimation of passive mechanical properties of bovine heart part II. Constitutive relation and finite element analysis.

A pseudo-elastic constitutive equation describing the mechanical properties of bovine myocardium was developed. The myocardium was modeled as a hyperelastic transversely isotropic material with a minimum viscoelastic loses. The material parameters for the proposed constitutive equations were determined using GA regression technique. In this work, the development of a constitutive equation based on principal stretch ratios is explained. The predictive capability of proposed model was compared against the experimental data obtained from part one. Finally, the constitutive equations were implemented into a commercial finite element program and the results of the mathematical model and FEM were compared with the experimental data.

In vitro technique in estimation of passive mechanical properties of bovine heart part I. Experimental techniques and data.

Myocardium generally demonstrates viscoelastic behavior. Since the stress-stain relationships of tissues are pseudo-elastic, their mechanical behavior can be defined as hyperelastic. In this work, mechanical properties of bovine heart were studied. In this study, the experimental technique for testing myocardium is explained and the experimental data are presented. First, the heart was perfused and the specimens were cut from different regions of the heart. Second, the materials preferred direction was identified. Then, a series of uniaxial, biaxial and equibiaxial test were performed on specimens taken from: left ventricle free wall (LVFW), right ventricle free wall (RVFW), left ventricle mid-wall (LVMW) and apex. Test specimens were preconditioned by applying cyclic load to reduce the viscoelastic effect. After preconditioning, the samples were tested at various stretch rates and loading conditions. Finally, a conclusion is made on the experimental data.

Acceptability of blood and blood substitutes.

Alternatives to donor blood have been developed in part to meet increasing demand. However, new biotechnologies are often associated with increased perceptions of risk and low acceptance. This paper reviews developments of alternatives and presents data, from a field-based experiment in the UK and Holland, on the risks and acceptance of donor blood and alternatives (chemical, genetically modified and bovine). UK groups perceived all substitutes as riskier than the Dutch. There is a negative association between perceived risk and acceptability. Solutions to increasing acceptance are discussed in terms of implicit attitudes, product naming and emotional responses.

Accuracy of the TurfTrax Racing Data System for determination of equine speed and position.

REASONS FOR PERFORMING STUDY: The speed and position data collected by TurfTrax Racing Data Limited during UK Thoroughbred racing have potential to benefit equine science and welfare. The size (the 2006 data set alone consists of 30,932 individual horse starts across 2667 races) and nature (speed and 2D position for each horse at 4 updates per second) of the data make it a unique resource for questions in equine safety, welfare, performance, and animal locomotion. OBJECTIVE: To determine the accuracy of the TurfTrax tracking system in estimating the speed and position of horses during racing. METHODS: Measurements from the TurfTrax wireless tracking system were compared with those of a survey-grade global positioning system (GPS) receiver. RESULTS: The TurfTrax system was found to give position measurements to within +/- 11 and +/- 64 cm in the fore-aft and lateral directions, respectively, averaging +/- 38 cm (interquartile range) and speed to within 0.15 m/s. POTENTIAL RELEVANCE: The data collected by the TurfTrax system are of sufficient accuracy to inform new diagnoses, training regimens and basic locomotor scientific studies. The position data can provide the precise distance, going, inclination, rate of turn and pack positioning through which each horse has raced. The speed profile can be used to examine the level of exertion, effect of training regimens and influence of racecourse features on performance. A first clinical application would be to analyse retrospectively these factors on occurrence of injury to compare with past training regimens, levels of exertion, and/or racecourse conditions.