Physiological, perceptual and technical responses to on-court tennis training on hard and clay courts

The aim of this study was to investigate the effect of court surface (clay v hard-court) on technical, physiological and perceptual responses to on-court training. Four high-performance junior male players performed two identical training sessions on hard and clay courts, respectively. Sessions included both physical conditioning and technical elements as led by the coach. Each session was filmed for later notational analysis of stroke count and error rates. Further, players wore a global positioning satellite device to measure distance covered during each session; whilst heart rate, countermovement jump distance and capillary blood measures of metabolites were measured before, during and following each session. Additionally a respective coach and athlete rating of perceived exertion (RPE) were measured following each session. Total duration and distance covered during of each session were comparable (P>0.05; d<0.20). While forehand and backhands stroke volume did not differ between sessions (P>0.05; d<0.30); large effects for increased unforced and forced errors were present on the hard court (P>0.05; d>0.90). Furthermore, large effects for increased heart rate, blood lactate and RPE values were evident on clay compared to hard courts (P>0.05; d>0.90). Additionally, while player and coach RPE on hard courts were similar, there were large effects for coaches to underrate the RPE of players on clay courts (P>0.05; d>0.90). In conclusion, training on clay courts results in trends for increased heart rate, lactate and RPE values, suggesting sessions on clay tend towards higher physiological and perceptual loads than hard courts. Further, coaches appear effective at rating player RPE on hard courts, but may underrate the perceived exertion of sessions on clay courts.

Flipper strokes can predict energy expenditure and locomotion costs in free-ranging northern and Antarctic fur seals

Flipper strokes have been proposed as proxies to estimate the energy expended by marine vertebrates while foraging at sea, but this has never been validated on free-ranging otariids (fur seals and sea lions). Our goal was to investigate how well flipper strokes correlate with energy expenditure in 33 foraging northern and Antarctic fur seals equipped with accelerometers, GPS, and time-depth recorders. We concomitantly measured field metabolic rates with the doubly-labelled water method and derived activity-specific energy expenditures using fine-scale time-activity budgets for each seal. Flipper strokes were detected while diving or surface transiting using dynamic acceleration. Despite some inter-species differences in flipper stroke dynamics or frequencies, both species of fur seals spent 3.79 ± 0.39 J/kg per stroke and had a cost of transport of ~1.6-1.9 J/kg/m while diving. Also, flipper stroke counts were good predictors of energy spent while diving (R(2) = 0.76) and to a lesser extent while transiting (R(2) = 0.63). However, flipper stroke count was a poor predictor overall of total energy spent during a full foraging trip (R(2) = 0.50). Amplitude of flipper strokes (i.e., acceleration amplitude × number of strokes) predicted total energy expenditure (R(2) = 0.63) better than flipper stroke counts, but was not as accurate as other acceleration-based proxies, i.e. Overall Dynamic Body Acceleration.

Impact of admission glucose and diabetes on recanalization and outcome after intra-arterial thrombolysis for ischaemic stroke

BACKGROUND: Stroke patients with diabetes and admission hyperglycaemia have worse outcomes than non-diabetics, with or without intravenous thrombolysis. Poor vessel recanalization was reported in diabetics treated with intravenous thrombolysis. AIMS: This study aimed to determine the impact of admission glucose and diabetes on recanalization and outcome after intra-arterial thrombolysis. METHODS: We analysed 389 patients (213 men, 176 women) treated with intra-arterial thrombolysis. The association of diabetes and admission glucose value with recanalization, outcome, mortality, and symptomatic intracranial haemorrhage was determined. Recanalization was classified according to thrombolysis in myocardial infarction grades. Outcome was measured using the modified Rankin Scale at three-months and categorized as favourable (modified Rankin Scale 0-2) or poor (modified Rankin Scale 3-6). RESULTS: The rate of partial or complete recanalization (thrombolysis in myocardial infarction 2-3) did not differ between patients with and without diabetes (67% vs. 66%; P = 1·000). Mean admission glucose values were similar in patients with poor recanalization (thrombolysis in myocardial infarction 0-1) and patients with partial or complete recanalization (thrombolysis in myocardial infarction 2-3; 7·3 vs. 7·3 mmol/l; P = 0·746). Follow-up at three-months was obtained in 388 of 389 patients. Clinical outcome was favourable (modified Rankin Scale 0-2) in 189 patients (49%) and poor (modified Rankin Scale 3-6) in 199 patients (51%). Mortality at three-months was 20%. Diabetics were more likely to have poor outcome (72% vs. 48%; P = 0·001) and to be dead (30% vs. 19%; P = 0·044) at three-months. After multivariable analysis, there remained an independent relationship between diabetes and outcome (P = 0·003; odds ratio 3·033, 95% confidence interval 1·452-6·336), but not with mortality (P = 0·310; odds ratio 1·436; 95% confidence interval 0·714-2·888). Moreover, higher age (P = 0·001; odds ratio 1·039; 95% confidence interval 1·017-1·061), higher baseline National Institutes of Health Stroke Scale score (P < 0·0001; odds ratio 1·130; 95% confidence interval 1·079-1·182), location of vessel occlusion as categorical variable (P < 0·0001), poor collaterals (P = 0·02; odds ratio 1·587; 95% confidence interval 1·076-2·341), poor vessel recanalization (P < 0·0001; odds ratio 4·713; 95% confidence interval 2·627-8·454), and higher leucocyte count (P = 0·032; odds ratio 1·094; 95% confidence interval 1·008-1·188) were independent baseline predictors of poor outcome. Higher admission glucose was associated with poor outcome (P = 0·006) and mortality (P < 0·0001). After multivariate analyses, glucose remained independently associated with poor outcome (P = 0·019; odds ratio 1·150; 95% confidence interval 1·023-1-292) and mortality (P = 0·005; odds ratio 1·183; 95% confidence interval 1052-1·331). The rate of symptomatic intracranial haemorrhage was similar in diabetics and non-diabetics (6·7% vs. 4·6%; P = 0·512). Mean admission glucose was higher in patients with symptomatic intracranial haemorrhage than without (8·58 vs. 7·26 mmol/l; P = 0·010). Multivariable analysis confirmed an independent association between admission glucose and symptomatic intracranial haemorrhage (P = 0·027; odds ratio 1·187; 95% confidence interval 1·020-1·381). CONCLUSIONS: Diabetes and glucose value on admission did not influence recanalization after intra-arterial thrombolysis; nevertheless, they were independent predictors of poor outcome after intra-arterial thrombolysis and a higher admission glucose value was an independent predictor of symptomatic intracranial haemorrhage. This indicates that factors on the capillary, cellular, or metabolic level may account for the worse outcome in patients with elevated glucose value and diabetes.

White blood cell count predicts reduction in coronary heart disease mortality with pravastatin

Background-Elevated serum inflammatory marker levels are associated with a greater long-term risk of cardiovascular events. Because 3-hydroxy-3-methylglutaryl coenzyme-A reductase inhibitors (statins) may have an antiinflammatory action, it has been suggested that patients with elevated inflammatory marker levels may have a greater reduction in cardiovascular risk with statin treatment. Methods and Results-We evaluated the association between the white blood cell count (WBC) and coronary heart disease mortality during a mean follow-up of 6.0 years in the Long-Term Intervention With Pravastatin in Ischemic Disease (LIPID) Study, a clinical trial comparing pravastatin (40 mg/d) with a placebo in 9014 stable patients with previous myocardial infarction or unstable angina. An increase in baseline WBC was associated with greater coronary heart disease mortality in patients randomized to placebo (hazard ratio for 1 X 10(9)/L increase in WBC, 1.18; 95% CI, 1.12 to 1.25; P<0.001) but not pravastatin (hazard ratio, 1.02; 95% CI, 0.96 to 1.09; P=0.56; P for interaction=0.004). The numbers of coronary heart disease deaths prevented per 1000 patients treated with pravastatin were 0, 9, 30, and 38 for baseline WBC quartiles of <5.9, 6.0 to 6.9, 7.0 to 8.1, and >8.2X10(9)/L, respectively. WBC was a stronger predictor of this treatment benefit than the ratio of total to high-density lipoprotein cholesterol and a global measure of cardiac risk. There was also a greater reduction (P=0.052) in the combined incidence of cardiovascular mortality, nonfatal myocardial infarction, and stroke with pravastatin as baseline WBC increased ( by quartile: 3, 41, 61, and 60 events prevented per 1000 patients treated, respectively). Conclusions-These data support the hypothesis that individuals with evidence of inflammation may obtain a greater benefit from statin therapy.

Granulocyte-colony-stimulating factor mobilizes bone marrow stem cells in patients with subacute ischemic stroke: the Stem Cell Trial of Recovery EnhanceMent After Stroke (STEMS) Pilot Randomized, Controlled Trial (ISRCTN 16784092)

Background and Purpose - Loss of motor function is common after stroke and leads to significant chronic disability. Stem cells are capable of self-renewal and of differentiating into multiple cell types, including neurones, glia, and vascular cells. We assessed the safety of granulocyte-colony-stimulating factor (G-CSF) after stroke and its effect on circulating CD34 stem cells. Methods - We performed a 2-center, dose-escalation, double-blind, randomized, placebo-controlled pilot trial (ISRCTN 16784092) of G-CSF (6 blocks of 1 to 10 g/kg SC, 1 or 5 daily doses) in 36 patients with recent ischemic stroke. Circulating CD34 stem cells were measured by flow cytometry; blood counts and measures of safety and functional outcome were also monitored. All measures were made blinded to treatment. Results - Thirty-six patients, whose mean SD age was 768 years and of whom 50% were male, were recruited. G-CSF (5 days of 10 g/kg) increased CD34 count in a dose-dependent manner, from 2.5 to 37.7 at day 5 (area under curve, P0.005). A dose-dependent rise in white cell count (P0.001) was also seen. There was no difference between treatment groups in the number of patients with serious adverse events: G-CSF, 7/24 (29%) versus placebo 3/12 (25%), or in their dependence (modified Rankin Scale, median 4, interquartile range, 3 to 5) at 90 days. Conclusions - ”G-CSF is effective at mobilizing bone marrow CD34 stem cells in patients with recent ischemic stroke. Administration is feasible and appears to be safe and well tolerated. The fate of mobilized cells and their effect on functional outcome remain to be determined. (Stroke. 2006;37:2979-2983.)

An exploration of treatment burden and patient capacity in people with stroke

Background and aims: Advances in modern medicine have led to improved outcomes after stroke, yet an increased treatment burden has been placed on patients. Treatment burden is the workload of health care for people with chronic illness and the impact that this has on functioning and well-being. Those with comorbidities are likely to be particularly burdened. Excessive treatment burden can negatively affect outcomes. Individuals are likely to differ in their ability to manage health problems and follow treatments, defined as patient capacity. The aim of this thesis was to explore the experience of treatment burden for people who have had a stroke and the factors that influence patient capacity. Methods: There were four phases of research. 1) A systematic review of the qualitative literature that explored the experience of treatment burden for those with stroke. Data were analysed using framework synthesis, underpinned by Normalisation Process Theory (NPT). 2) A cross-sectional study of 1,424,378 participants >18 years, demographically representative of the Scottish population. Binary logistic regression was used to analyse the relationship between stroke and the presence of comorbidities and prescribed medications. 3) Interviews with twenty-nine individuals with stroke, fifteen analysed by framework analysis underpinned by NPT and fourteen by thematic analysis. The experience of treatment burden was explored in depth along with factors that influence patient capacity. 4) Integration of findings in order to create a conceptual model of treatment burden and patient capacity in stroke. Results: Phase 1) A taxonomy of treatment burden in stroke was created. The following broad areas of treatment burden were identified: making sense of stroke management and planning care; interacting with others including health professionals, family and other stroke patients; enacting management strategies; and reflecting on management. Phase 2) 35,690 people (2.5%) had a diagnosis of stroke and of the 39 co-morbidities examined, 35 were significantly more common in those with stroke. The proportion of those with stroke that had >1 additional morbidities present (94.2%) was almost twice that of controls (48%) (odds ratio (OR) adjusted for age, gender and socioeconomic deprivation; 95% confidence interval: 5.18; 4.95-5.43) and 34.5% had 4-6 comorbidities compared to 7.2% of controls (8.59; 8.17-9.04). In the stroke group, 12.6% of people had a record of >11 repeat prescriptions compared to only 1.5% of the control group (OR adjusted for age, gender, deprivation and morbidity count: 15.84; 14.86-16.88). Phase 3) The taxonomy of treatment burden from Phase 1 was verified and expanded. Additionally, treatment burdens were identified as arising from either: the workload of healthcare; or the endurance of care deficiencies. A taxonomy of patient capacity was created. Six factors were identified that influence patient capacity: personal attributes and skills; physical and cognitive abilities; support network; financial status; life workload, and environment. A conceptual model of treatment burden was created. Healthcare workload and the presence of care deficiencies can influence and be influenced by patient capacity. The quality and configuration of health and social care services influences healthcare workload, care deficiencies and patient capacity. Conclusions: This thesis provides important insights into the considerable treatment burden experienced by people who have had a stroke and the factors that affect their capacity to manage health. Multimorbidity and polypharmacy are common in those with stroke and levels of these are high. Findings have important implications for the design of clinical guidelines and healthcare delivery, for example co-ordination of care should be improved, shared decision-making enhanced, and patients better supported following discharge from hospital.

Cholesterol-lowering management of stroke : inconsistencies of evidence and practice

Cholesterol-lowering treatment by statins is an important and costly issue; however, its role in stroke has not been well documented. The aim of the present study was to review literature and current practice regarding cholesterol-lowering treatment for stroke patients. A literature review was conducted on lipids in stroke and their management with both statins and diet, including the cost-effectiveness of medical nutrition therapy. Qualifying criteria and prescription procedures of the Pharmaceutical Benefits Scheme (PBS) were also reviewed. Data on lipid levels and statin prescriptions were analysed for 468 patients admitted to a stroke unit. The literature shows that management with both medication and diet can be effective, especially when combined; however, 60% of patients with an ischaemic event had fasting total cholesterol measures ≥4 mmol/L (n = 231), with only 52% prescribed statins on discharge (n = 120). Hypercholesterolaemia is an underdiagnosed and undertreated risk factor within the stroke population. It appears that the PBS has not kept pace with advances in the evidence in terms of statin use in the stroke population, and review is needed. The present review should address the qualifying criteria for the stroke population and recommendations on referral to dietitians for dietary advice. Cholesterol-lowering treatment for both stroke patients and the wider population is an area that needs awareness raising and review by the PBS, medical practitioners and dietitians. The role of dietary and pharmacological treatments needs to be clearly defined, including adjunct therapy, and the cost-effectiveness of medical nutrition therapy realised.