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Panizzolo F.A.,University of Western Australia | Green D.J.,University of Western Australia | Green D.J.,Liverpool John Moores University | Lloyd D.G.,University of Western Australia | And 4 more authors.
Gait and Posture | Year: 2013

Older adults have been shown to naturally select a walking speed approximately 20% slower than younger adults. We explored the possibility that a reduction in preferred speed in older adults represents a strategy to preserve the mechanical function of the leg muscles. We examined this question in the soleus muscle in eight healthy young (25.8 ± 3.5 years) and eight healthy older adults (66.1 ± 2.3 years) who were paired so that their preferred speed differed by ~20%. Soleus muscle fascicle lengths were recorded dynamically using ultrasound, together with simultaneous measurements of soleus EMG activity and ankle joint kinematics while (a) older adults walked on a treadmill at a speed 20% above their preferred speed (speeds matched to the preferred speed of young adults), and (b) young and older adults walked at their preferred treadmill speeds. Analyses of mean muscle fascicle length changes revealed that, at matched speeds, older adults had a statistically different soleus fascicle length pattern compared to young adults, where the muscle's stretch-shorten cycle during stance was diminished. However, older adults walking at their preferred speed exhibited a more pronounced stretch-shorten cycle that was not statistically different from young adults. Conserving muscle length patterns through a reduction in speed in older adults may represent a physiologically relevant modulation of muscle function that permits greater force and power production. Our findings offer a novel mechanical explanation for the slower walking speed in older adults, whereby a reduction in speed may permit muscles to function in a mechanically similar manner to that of younger adults. © 2013 Elsevier B.V. Source


Levinger I.,Victoria University of Melbourne | Shaw C.S.,Deakin University | Stepto N.K.,Victoria University of Melbourne | Cassar S.,Victoria University of Melbourne | And 5 more authors.
Clinical Medicine Insights: Cardiology | Year: 2015

High-intensity interval exercise (HIIE) has gained popularity in recent years for patients with cardiovascular and metabolic diseases. Despite potential benefits, concerns remain about the safety of the acute response (during and/or within 24 hours postexercise) to a single session of HIIE for these cohorts. Therefore, the aim of this study was to perform a systematic review to evaluate the safety of acute HIIE for people with cardiometabolic diseases. Electronic databases were searched for studies published prior to January 2015, which reported the acute responses of patients with cardiometabolic diseases to HIIE (≥80% peak power output or ≥85% peak aerobic power, VO2peak). Eleven studies met the inclusion criteria (n = 156; clinically stable, aged 27-66 years), with 13 adverse responses reported (∼8% of individuals). The rate of adverse responses is somewhat higher compared to the previously reported risk during moderate-intensity exercise. Caution must be taken when prescribing HIIE to patients with cardiometabolic disease. Patients who wish to perform HIIE should be clinically stable, have had recent exposure to at least regular moderate-intensity exercise, and have appropriate supervision and monitoring during and after the exercise session. © the authors, publisher and licensee Libertas Academica Limited. Source


Thijssen D.H.J.,Liverpool John Moores University | Thijssen D.H.J.,Radboud University Nijmegen | Maiorana A.J.,Advanced Heart Failure and Cardiac Transplant Service | Maiorana A.J.,Curtin University Australia | And 6 more authors.
European Journal of Applied Physiology | Year: 2010

The effects of inactivity and exercise training on established and novel cardiovascular risk factors are relatively modest and do not account for the impact of inactivity and exercise on vascular risk. We examine evidence that inactivity and exercise have direct effects on both vasculature function and structure in humans. Physical deconditioning is associated with enhanced vasoconstrictor tone and has profound and rapid effects on arterial remodelling in both large and smaller arteries. Evidence for an effect of deconditioning on vasodilator function is less consistent. Studies of the impact of exercise training suggest that both functional and structural remodelling adaptations occur and that the magnitude and time-course of these changes depends upon training duration and intensity and the vessel beds involved. Inactivity and exercise have direct "vascular deconditioning and conditioning" effects which likely modify cardiovascular risk. © 2009 The Author(s). Source


Green D.J.,University of Western Australia | Green D.J.,Liverpool John Moores University | Panizzolo F.A.,University of Western Australia | Lloyd D.G.,University of Western Australia | And 5 more authors.
Exercise and Sport Sciences Reviews | Year: 2016

We propose the hypothesis that soleus muscle function may provide a surrogate measure of functional capacity in patients with heart failure. We summarize literature pertaining to skeletal muscle as a locus of fatigue and present our recent findings, using in vivo imaging in combination with biomechanical experimentation and modeling, to reveal novel structure-function relationships in chronic heart failure skeletal muscle and gait. © 2015 by the American College of Sports Medicine. Source


Strueber M.,Hannover Medical School | Strueber M.,University of Leipzig | Larbalestier R.,Advanced Heart Failure and Cardiac Transplant Service | Jansz P.,Heart Lung Transplant Unit | And 9 more authors.
Journal of Heart and Lung Transplantation | Year: 2014

Background: The post-market Registry to Evaluate the HeartWare Left Ventricular Assist System (ReVOLVE) is an investigator-initiated registry established to collect post-CE Mark Trial clinical data on patients receiving a HeartWare ventricular assist device (HVAD) in the European Union and Australia. Methods: The ReVOLVE is a multi-center, prospective, single-arm registry performed at seven centers in Europe and two in Australia. Herein we describe a total of 254 commercial HVAD implants according to labeled indications between February 2009 and November 2012. Summary statistics included patients' demographics, adverse events, length of support and outcomes. Results: Compared with the clinical trial supporting the CE Mark of the HeartWare system, patient selection differed in that patients were older, and there were higher proportions of females and patients with idiopathic cardiomyopathies in the ReVOLVE cohort. Duration of support ranged from 1 to 1,057 days, with a mean of 363 ± 280 days (median 299.5 days). Transplantation was done in 56 patients (22%), explant for recovery was performed in 3 patients (1%), 43 died while on support (17%), and 152 (60%) remain on the device. Success in patients with the HeartWare system was 87% at 6 months, 85% at 1 year, 79% at 2 years and 73% at 3 years. Adverse event rates were low, comparable or improved when compared to the CE Mark Trial. Conclusion: Real-world use of the HeartWare system continues to demonstrate excellent clinical outcomes in patients supported with the device. © 2014 International Society for Heart and Lung Transplantation. All rights reserved. Source

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