962 resultados para Interval exercise


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Effectiveness of brief/minimal contact self-activation interventions that encourage participation in physical activity (PA) for chronic low back pain (CLBP >12 weeks) is unproven. The primary objective of this assessor-blinded randomized controlled trial was to investigate the difference between an individualized walking programme (WP), group exercise class (EC), and usual physiotherapy (UP, control) in mean change in functional disability at 6 months. A sample of 246 participants with CLBP aged 18 to 65 years (79 men and 167 women; mean age ± SD: 45.4 ± 11.4 years) were recruited from 5 outpatient physiotherapy departments in Dublin, Ireland. Consenting participants completed self-report measures of functional disability, pain, quality of life, psychosocial beliefs, and PA were randomly allocated to the WP (n = 82), EC (n = 83), or UP (n = 81) and followed up at 3 (81%; n = 200), 6 (80.1%; n = 197), and 12 months (76.4%; n = 188). Cost diaries were completed at all follow-ups. An intention-to-treat analysis using a mixed between-within repeated-measures analysis of covariance found significant improvements over time on the Oswestry Disability Index (Primary Outcome), the Numerical Rating Scale, Fear Avoidance-PA scale, and the EuroQol EQ-5D-3L Weighted Health Index (P < 0.05), but no significant between-group differences and small between-group effect sizes (WP: mean difference at 6 months, 6.89 Oswestry Disability Index points, 95% confidence interval [CI] -3.64 to -10.15; EC: -5.91, CI: -2.68 to -9.15; UP: -5.09, CI: -1.93 to -8.24). The WP had the lowest mean costs and the highest level of adherence. Supervised walking provides an effective alternative to current forms of CLBP management.

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Kuznetsov independence of variables X and Y means that, for any pair of bounded functions f(X) and g(Y), E[f(X)g(Y)]=E[f(X)] *times* E[g(Y)], where E[.] denotes interval-valued expectation and *times* denotes interval multiplication. We present properties of Kuznetsov independence for several variables, and connect it with other concepts of independence in the literature; in particular we show that strong extensions are always included in sets of probability distributions whose lower and upper expectations satisfy Kuznetsov independence. We introduce an algorithm that computes lower expectations subject to judgments of Kuznetsov independence by mixing column generation techniques with nonlinear programming. Finally, we define a concept of conditional Kuznetsov independence, and study its graphoid properties.

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Background Exercise training is considered an effective strategy to improve metabolic disease. Despite this, less is known regarding exercise training in the prevention and susceptibility of LDL subfraction oxidation, particularly in an aged population. 
Methods Eleven aged (55 ± 4 yrs) and twelve young (21 ± 2 yrs) participants were randomly separated into an experimental or control group as follows: young exercise (n = 6); young control (n = 6); aged exercise (n = 6) and aged control (n = 5). The participants assigned to the exercise groups performed 12 weeks of moderate intensity (55–65% VO2max) exercise training. Venous blood was extracted at baseline, and 48 h following 12 weeks of exercise and assayed for a range of metabolites associated with lipid composition and lipoprotein susceptibility to oxidation. 
Results Although there was no difference in the oxidation potential (time ½ max) of LDL I, II or III between groups at baseline (p > 0.05), there was an increase in time ½ max for LDL I following exercise within the aged exercise group (p < 0.05). Moreover, α-tocopherol concentration was selectively lower in the aged exercise group, compared to the young exercise at baseline. The lipid composition of LDL I, LDL II, LDL III, VLDL, HDL2, HDL3 and serum lipid hydroperoxides remained unchanged as a function of exercise training and ageing (p > 0.05). 
Conclusion The primary finding of this study demonstrates that adaptations in LDL resistance to oxidation occur following 12 weeks of exercise training in the aged, and this may be of clinical significance, as oxidation of LDL has been implicated in atherosclerosis.

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New Findings

What is the central question of this study?Exercise performance is limited during hypoxia by a critical reduction in cerebral and skeletal tissue oxygenation. To what extent an elevation in systemic free radical accumulation contributes to microvascular deoxygenation and the corresponding reduction in maximal aerobic capacity remains unknown.What is the main finding and its importance?We show that altered free radical metabolism is not a limiting factor for exercise performance in hypoxia, providing important insight into the fundamental mechanisms involved in the control of vascular oxygen transport.

Exercise performance in hypoxia may be limited by a critical reduction in cerebral and skeletal tissue oxygenation, although the underlying mechanisms remain unclear. We examined whether increased systemic free radical accumulation during hypoxia would be associated with elevated microvascular deoxygenation and reduced maximal aerobic capacity (). Eleven healthy men were randomly assigned single-blind to an incremental semi-recumbent cycling test to determine  in both normoxia (21% O2) and hypoxia (12% O2) separated by a week. Continuous-wave near-infrared spectroscopy was employed to monitor concentration changes in oxy- and deoxyhaemoglobin in the left vastus lateralis muscle and frontal cerebral cortex. Antecubital venous blood samples were obtained at rest and at  to determine oxidative (ascorbate radical by electron paramagnetic resonance spectroscopy), nitrosative (nitric oxide metabolites by ozone-based chemiluminescence and 3-nitrotyrosine by enzyme-linked immunosorbent assay) and inflammatory stress biomarkers (soluble intercellular/vascular cell adhesion 1 molecules by enzyme-linked immunosorbent assay). Hypoxia was associated with increased cerebral and muscle tissue deoxygenation and lower  (P < 0.05 versus normoxia). Despite an exercise-induced increase in oxidative–nitrosative–inflammatory stress, hypoxia per se did not have an additive effect (P > 0.05 versus normoxia). Consequently, we failed to observe correlations between any metabolic, haemodynamic and cardiorespiratory parameters (P > 0.05). Collectively, these findings suggest that altered free radical metabolism cannot explain the elevated microvascular deoxygenation and corresponding lower  in hypoxia. Further research is required to determine whether free radicals when present in excess do indeed contribute to the premature termination of exercise in hypoxia.

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PURPOSE: This preliminary investigation was designed to test the hypothesis that high intensity single-leg exercise can cause extensive cell DNA damage, which subsequently may affect the expression of the HO-1 gene. METHODS: Six (n=6) apparently healthy male participants (age 27 + 7 yrs, stature 174 + 12 cm, body mass 79 + 4 kg and BMI 24 + 4 kg/m2) completed 100 isolated and continuous maximal concentric contractions (minimum force = 200 N, speed of contraction = 60°/sec) of the rectus femoris muscle. Using a spring-loaded and reusable Magnum biopsy gun with a 16-gauge core disposable biopsy needle, skeletal muscle micro biopsy tissue samples were extracted at rest and following exercise. mRNA gene expression was determined via two-step quantitative real-time PCR using GAPDH as a reference gene. RESULTS: The average muscle force production was 379 + 179 N. High intensity exercise increased mitochondrial 8-OHdG concentration (P < 0.05 vs. rest) with a concomitant decrease in total antioxidant capacity (P < 0.05 vs. rest). Exercise also increased protein oxidation as quantified by protein carbonyl concentration (P < 0.05 vs. rest). HO-1 expression increased (> 2-fold change vs. rest) following exercise, and it is postulated that this change was not significant due to low subject numbers (P > 0.05). CONCLUSION: These preliminary findings tentatively suggest that maximal concentric muscle contractions can cause intracellular DNA damage with no apparent disruption to the expression of the antioxidant stress protein HO-1. Moreover, it is likely that cell oxidant stress is required to activate the signal transduction cascade related to the expression of HO-1. A large-scale study incorporating a greater subject number is warranted to fully elucidate this relationship.

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Lycopene can exert antioxidant effects against peripheral and cellular oxidative stress and may be associated with reduced diabetic risk. Conversely, exercise-induced free radicals are thought to underpin many of the desirable whole-body adaptations following training and the use of antioxidants within the exercise model remains debatable. PURPOSE: To investigate the effect of lycopene supplementation on oxidative stress and glucose homeostasis following acute aerobic exercise. METHOD: Twenty-eight (n=28) apparently healthy male volunteers were recruited (age 24 ± 4 years; weight 78 ± 10 kg; height 178 ± 8 cm; 2max 40 ± 7 ml·kg-1 ·min-1 ) in a randomised, single blind, placebo-controlled study. Participants were required to attend the Laboratory on two occasions: prior to and following 6 weeks of supplementation of either 10mg lycopene (LG; n=15) or placebo (PG; n=13) followed by a bout of acute exercise for one hour at 65% 2max. Exogenous glucose oxidation was then measured on an isotope ratio mass spectrometer in a sub-group of participants (n=14) following exercise, by administration of a standard oral glucose tolerance test (OGTT; 75g glucose). Venous blood samples were drawn for measurement of oxidative stress parameters, plasma glucose and insulin. RESULTS: Plasma lycopene increased in LG only (0.01 ± 0.004 vs.0.02 ± 0.007 µmol/L; P <0.05) following supplementation and remained elevated post exercise compared to PG (0.01 ± 0.004 vs. 0.02 ± 0.009 µmol/L; P <0.05). There were no changes in other markers of oxidative stress (SOD, LOOHs, F2 ISP and Alkoxyl radical) either between or within the trials, (P >0.05, respectively). A main effect for an increase in insulin was observed two hours post OGTT in the sub-groups (Pooled data, P <0.05) but trends in the HOMA scores were evident with a 57% increase for LG (2.20 ± 1.84 vs. 5.14 ± 2.5; P >0.05) and an 11% decrease for PG (2.17 ± 1.06 vs. 1.94 ± 1.53; P >0.05). No change in plasma glucose was detected at any point, or after the OGTT (P >0.05). CONCLUSION: In healthy males, lycopene supplementation had no effect on post exercise levels of ROS or markers of lipid peroxidation, despite an increase in plasma lycopene. However, lycopene supplementation may affect post exercise insulin sensitivity in response to glucose consumption, but further parallel research is required.

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Musculoskeletal (MSK) complaints are common within primary care (1) (2) (3) but some General Practitioners (GPs)/family physicians do not feel comfortable managing these symptoms (3), preferring to refer onto hospital specialists or Integrated Clinical Assessment and Treatment Services (ICATs). Long waiting times for hospital outpatient reviews are a major cause of patient inconvenience and complaints (4). We therefore aimed to establish a GP-ran MSK and sport and exercise medicine (SEM) clinic based within a Belfast GP surgery that would contribute to a sustainable improvement in managing these common conditions within primary care as well as reducing waiting times for patients with these conditions to see a specialist. This shift from hospital-based to community-based management is in-keeping with recent policy changes within the UK health-system, including Transforming Your Care within Northern Ireland (NI) (5). The GP-ran MSK and SEM clinic was held monthly within a Belfast GP practice, staffed by one GP with a specialist interest in MSK and SEM conditions and its performance was reviewed over a three month period. Parameters audited included cases seen, orthopaedic and x-ray referral rates and secondary care referrals comparing the GP practice’s performance to the same time period in the previous year as well as patient satisfaction questionnaires.

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A new niche of densely populated, unprotected networks is becoming more prevalent in public areas such as Shopping Malls, defined here as independent open-access networks, which have attributes that make attack detection more challenging than in typical enterprise networks. To address these challenges, new detection systems which do not rely on knowledge of internal device state are investigated here. This paper shows that this lack of state information requires an additional metric (The exchange timeout window) for detection of WLAN Denial of Service Probe Flood attacks. Variability in this metric has a significant influence on the ability of a detection system to reliably detect the presence of attacks. A parameter selection method is proposed which is shown to provide reliability and repeatability in attack detection in WLANs. Results obtained from ongoing live trials are presented that demonstrate the importance of accurately estimating probe request and probe response timeouts in future Independent Intrusion Detection Systems.

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The problem-Musculoskeletal (MSK) symptoms are common within primary care but some GPs are not comfortable managing these; waiting times for hospital appointments are a major cause of patients’ complaints. Current UK healthcare policies emphasise a need for more community-based management. We aimed to pilot an innovative general practice-based clinic to improve the management of MSK and Sport and Exercise Medicine (SEM) symptoms within general practice.

The approach-This project was conducted in an inner-city practice of approximately 9,000 patients and 5 GP partners. The practice commissioned a novel monthly 4-hour clinic staffed by one GP with a specialist interest in MSK and SEM conditions. Each patient was allocated a 20-minute appointment. All primary care staff within the practice could refer any patient for whom they considered hospital referral appropriate, with no specific exclusion criteria. Management plans included injection therapy, exercise prescription and onward referral. After three months (August-October 2014) numbers of consultations, sources of referral, reasons for referral and management outcomes were described; patient satisfaction was assessed by questionnaire, offered to 10 randomly selected patients by reception staff and self-completed by patients. Costs of the clinic were compared to current options.

Findings- All patients (14 males; 21 females; aged 35-77 years), were seen within four weeks of referral (one third of orthopaedic referrals in 2013 waited over 9 weeks for appointment). Most were referred from other GPs; some came from physiotherapy and podiatry. Shoulder problems were the most frequent reason for referral. The commonest management option was steroid injection, with most patients being given advice regarding exercise and analgesia; there were 3 onward referrals (2 physiotherapy; 1 rheumatology).

Comparing August-October data in 2014 and 2013, total, orthopaedic and rheumatology referrals were reduced by 147, 2 and 3, respectively; within the practice MSK presentations and physiotherapy and x-ray referrals were 60, 47 and 90 fewer, respectively.

The cost per attendance at the clinic was £61; initial orthopaedic-ICAT assessments cost £82 and a consultant appointment £213.

Satisfaction questionnaires were returned by all 10 selected participants and provided positive feedback, expressing preference for community-based, rather than hospital, management.

Consequence- Our pilot study indicates that this novel service model has potential for efficient and effective management of MSK and SEM complaints in primary care, reducing the need for hospital referral and the clinical burden on general practices. The innovation deserves further evaluation in a full-scale trial to determine its generalisability to other practice settings and populations.

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Stroke survivors often have upper limb (UL) hemiparesis, limiting their ability to perform activities of daily life (ADLs). Intensive, task-oriented exercise therapy (ET) can improve UL function, but motivation to perform sufficient ET is difficult to maintain. Here we report on a trial in which a workstation was deployed in the homes of chronic stroke survivors to enable tele-coaching of ET in the guise of computer games. Participants performed 6 weeks of 1 hour/day, 5 days/week ET. Hand opening and grasp were assisted with functional electrical stimulation (FES). The primary outcome measure was the Action Research Arm Test (ARAT). Secondary outcome measures included a quantitative test of UL function performed on the workstation, grasp force measurements and transcranial magnetic stimulation (TMS). Improvements were seen in the functional tests, but surprisingly, not in the TMS responses. An important finding was that participants commencing with intermediate functional scores improved the most.

CONCLUSIONS: 1) Daily, tele-supervised FES-ET in chronic stroke survivors is feasible with commercially-available technology. 2) The intervention can significantly improve UL function, particularly in people who start with an intermediate level of function. 3) Significant improvements in UL function can occur in the absence of changes in TMS responses.