Differential effects of resveratrol on the dilator responses of femoral arteries, ex vivo.

Resveratrol is a plant-derived phytoalexin with antioxidant, anti-inflammatory and cardio-protective properties and may be a promising therapeutic intervention strategy in cardiovascular disease. Here, we investigated the acute direct effects of trans-resveratrol (RV), on acetylcholine (ACh)-induced and flow-mediated dilation (FMD) of isolated pressurized femoral arteries of young (4-month-old) and old (26-month-old) mice. Vessel exposure to RV enhanced ACh (0.01-1.0 mM)-induced dilation (p < 0.05), but not FMD (@ 5-10 µL⋅min-1) (p < 0.05) in both young and old mice. After RV incubation, acute nitric oxide (NO) production by cultured endothelial cells was increased in response to 0.01 mM ACh, but reduced by flow (5-10 µL⋅min-1; p < 0.05). In isolated femoral arteries from endothelial nitric oxide synthase knockout (eNOS-/-) mice, RV had no overall effect on FMD, but potentiated ACh induced dilation, that was completely abolished by potassium channel blockers, Apamin and Tram 34 (p < 0.01). We demonstrate that the non-metabolised form of RV stimulates ACh-induced dilation via the NO and EDHF pathways, but not FMD by interaction with the cyclo-oxygenase pathway. Our findings have important implications in the use of RV (for both young and aged) under 'normal' non-diseased physiological states.

Physical activity and obesity: is there a difference in association between the Asian- and African- Surinamese adult population?

OBJECTIVE: The role of different physical activity (PA) characteristics, i.e. domain, duration and intensity in obesity prevention still requires investigation. Furthermore, ethnicity can modify the effect of PA on body composition. Therefore, we aim to describe the association between obesity and PA characteristics across the Asian- and African-Surinamese population, living in the capital of Suriname. DESIGN: Between February 2013 and July 2015, we included 1157 healthy subjects, 18-70 years, from the Healthy Life in Suriname (HELISUR) study. We measured height, weight, hip and waist circumference and defined general and central obesity according to World Health Organization (WHO) recommendations. The International Physical Activity Questionnaire was used to assess PA and to calculate the duration (minutes/week) and the total volume (METs-minutes/week) of activity. Ethnicity was self-reported. RESULTS: Out of 1157 participants we included 1079 (42.6% Asian-Surinamese, 40.1% African-Surinamese and 17.3% of other ethnicity), mean age 42.6 ± 13.6 years for analysis. Obesity prevalence ratio (PR) was significantly lower in participants meeting WHO PA recommendations [PR= 0.81 (0.68-0.97)], especially within the commuting [PR= 0.66 (0.47-0.91)] and leisure time domains [PR= 0.67 (0.47-0.94)], compared to participants that did not meet the recommendations. Active minutes/week and total volume of activity were inversely associated with obesity and waist circumference, in the overall (p < 0.05) and in the African-Surinamese population (p < 0.05), but not in the Asian-Surinamese population. CONCLUSION: Meeting PA recommendations, particularly within the commuting and leisure time domains, is associated with lower obesity prevalence in the total population. Among the African-Surinamese population, PA within the leisure time domain, more active minutes/week and higher levels of total volume are associated with a lower obesity prevalence. This is not found in the Asian-Surinamese population.

Home-Based Rehabilitation With Telemonitoring Guidance for Patients With Coronary Artery Disease (Short-Term Results of the TRiCH Study): Randomized Controlled Trial.

BACKGROUND: Cardiac rehabilitation (CR) is an essential part of contemporary coronary heart disease management. However, patients exiting a center-based CR program have difficulty retaining its benefits. OBJECTIVE: We aimed to evaluate the added benefit of a home-based CR program with telemonitoring guidance on physical fitness in patients with coronary artery disease (CAD) completing a phase II ambulatory CR program and to compare the effectiveness of this program in a prolonged center-based CR intervention by means of a randomized controlled trial. METHODS: Between February 2014 and August 2016, 90 CAD patients (unblinded, mean age 61.2 years, SD 7.6; 80/90, 89.0% males; mean height 1.73 m, SD 0.7; mean weight 82.9 kg, SD 13; mean body mass index 27.5 kg/m2, SD 3.4) who successfully completed a 3-month ambulatory CR program were randomly allocated to one of three groups: home-based (30), center-based (30), or control group (30) on a 1:1:1 basis. Home-based patients received a home-based exercise intervention with telemonitoring guidance consisting of weekly emails or phone calls; center-based patients continued the standard in-hospital CR, and control group patients received the usual care including the advice to remain physically active. All the patients underwent cardiopulmonary exercise testing for assessment of their peak oxygen uptake (VO2 P) at baseline and after a 12-week intervention period. Secondary outcomes included physical activity behavior, anthropometric characteristics, traditional cardiovascular risk factors, and quality of life. RESULTS: Following 12 weeks of intervention, the increase in VO2 P was larger in the center-based (P=.03) and home-based (P=.04) groups than in the control group. In addition, oxygen uptake at the first (P-interaction=.03) and second (P-interaction=.03) ventilatory thresholds increased significantly more in the home-based group than in the center-based group. No significant changes were observed in the secondary outcomes. CONCLUSIONS: Adding a home-based exercise program with telemonitoring guidance following completion of a phase II ambulatory CR program results in further improvement of physical fitness and is equally as effective as prolonging a center-based CR in patients with CAD. TRIAL REGISTRATION: ClinicalTrials.gov NCT02047942; https://clinicaltrials.gov/ct2/show/NCT02047942 (Archived by WebCite at http://www.webcitation.org/70CBkSURj).

The effect of aerobic interval training and continuous training on exercise capacity and its determinants.

Objective We aimed to investigate (1) the effects of aerobic interval training (AIT) and aerobic continuous training (ACT) on (sub)maximal exercise measures and its determinants including endothelial function, muscle strength and cardiac autonomic function, and (2) the relationship between exercise capacity and these determinants. Methods Two-hundred coronary artery disease (CAD) patients (58.4 ± 9.1 years) were randomized to AIT or ACT for 12 weeks. All patients performed a cardiopulmonary exercise test and endothelial function measurements before and after the intervention; a subpopulation underwent muscle strength and heart rate variability (HRV) assessments. Results The VO2, heart rate and workload at peak and at first and second ventilatory threshold increased (P-time <0.001); the oxygen uptake efficiency slope (P-time <0.001) and half time of peak VO2 (P-time <0.001) improved. Endothelial function and heart rate recovery (HRR) at 1 and 2 min improved (P-time <0.001), while measures of muscle strength and HRV did not change. Both interventions were equally effective. Significant correlations were found between baseline peak VO2 and (1) quadriceps strength (r = 0.44; P < 0.001); (2) HRR at 2 min (r = 0.46; P < 0.001). Changes in peak VO2 correlated significantly with changes in (1) FMD (ρ = 0.17; P < 0.05); (2) quadriceps strength (r = 0.23; P < 0.05); (3) HRR at 2 min (ρ = 0.18; P < 0.05) and Total power of HRV (ρ = 0.41; P < 0.05). Conclusions This multicentre trial shows equal improvements in maximal and submaximal exercise capacity, endothelial function and HRR after AIT and ACT, while these training methods seem to be insufficient to improve muscle strength and HRV. Changes in peak VO2 were linked to changes in all underlying parameters.

Exercise-induced right ventricular dysfunction is associated with ventricular arrhythmias in endurance athletes.

AIMS: Intense exercise places disproportionate strain on the right ventricle (RV) which may promote pro-arrhythmic remodelling in some athletes. RV exercise imaging may enable early identification of athletes at risk of arrhythmias. METHODS AND RESULTS: Exercise imaging was performed in 17 athletes with RV ventricular arrhythmias (EA-VAs), of which eight (47%) had an implantable cardiac defibrillator (ICD), 10 healthy endurance athletes (EAs), and seven non-athletes (NAs). Echocardiographic measures included the RV end-systolic pressure-area ratio (ESPAR), RV fractional area change (RVFAC), and systolic tricuspid annular velocity (RV S'). Cardiac magnetic resonance (CMR) measures combined with invasive measurements of pulmonary and systemic artery pressures provided left-ventricular (LV) and RV end-systolic pressure-volume ratios (SP/ESV), biventricular volumes, and ejection fraction (EF) at rest and during intense exercise. Resting measures of cardiac function were similar in all groups, as was LV function during exercise. In contrast, exercise-induced increases in RVFAC, RV S', and RVESPAR were attenuated in EA-VAs during exercise when compared with EAs and NAs (P < 0.0001 for interaction group × workload). During exercise-CMR, decreases in RVESV and augmentation of both RVEF and RV SP/ESV were significantly less in EA-VAs relative to EAs and NAs (P < 0.01 for the respective interactions). Receiver-operator characteristic curves demonstrated that RV exercise measures could accurately differentiate EA-VAs from subjects without arrhythmias [AUC for ΔRVESPAR = 0.96 (0.89-1.00), P < 0.0001]. CONCLUSION: Among athletes with normal cardiac function at rest, exercise testing reveals RV contractile dysfunction among athletes with RV arrhythmias. RV stress testing shows promise as a non-invasive means of risk-stratifying athletes.

Effects of aerobic interval training and continuous training on cellular markers of endothelial integrity in coronary artery disease: a SAINTEX-CAD substudy.

In this large multicenter trial, we aimed to assess the effect of aerobic exercise training in stable coronary artery disease (CAD) patients on cellular markers of endothelial integrity and to examine their relation with improvement of endothelial function. Two-hundred CAD patients (left ventricular ejection fraction > 40%, 90% male, mean age 58.4 ± 9.1 yr) were randomized on a 1:1 base to a supervised 12-wk rehabilitation program of either aerobic interval training or aerobic continuous training on a bicycle. At baseline and after 12 wk, numbers of circulating CD34(+)/KDR(+)/CD45dim endothelial progenitor cells (EPCs), CD31(+)/CD3(+)/CXCR4(+) angiogenic T cells, and CD31(+)/CD42b(-) endothelial microparticles (EMPs) were analyzed by flow cytometry. Endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery. After 12 wk of aerobic interval training or aerobic continuous training, numbers of circulating EPCs, angiogenic T cells, and EMPs were comparable with baseline levels. Whereas improvement in peak oxygen consumption was correlated to improvement in FMD (Pearson r = 0.17, P = 0.035), a direct correlation of baseline or posttraining EPCs, angiogenic T cells, and EMP levels with FMD was absent. Baseline EMPs related inversely to the magnitude of the increases in peak oxygen consumption (Spearman rho = -0.245, P = 0.027) and FMD (Spearman rho = -0.374, P = 0.001) following exercise training. In conclusion, endothelial function improvement in response to exercise training in patients with CAD did not relate to altered levels of EPCs and angiogenic T cells and/or a diminished shedding of EMPs into the circulation. EMP flow cytometry may be predictive of the increase in aerobic capacity and endothelial function.

Self-reported physical activity behavior of a multi-ethnic adult population within the urban and rural setting in Suriname.

BACKGROUND: Physical activity (PA) plays an important role in the combat against noncommunicable diseases including cardiovascular diseases. In order to develop appropriate PA intervention programs, there is a need to evaluate PA behavior. So far, there are no published data on PA available for Suriname. Therefore, we aim to describe PA behavior among the multi-ethnic population living in urban and rural areas of Suriname. METHODS: The World Health Organization (WHO) STEPwise approach to chronic disease risk factor surveillance (STEPS) was conducted in a national representative sample (N = 5751; 48.6% men) aged 15-64 years between March and September 2013. Physical activity data were assessed using the Global physical activity questionnaire (GPAQ) and analyzed according to the GPAQ guidelines. The prevalence of meeting the recommended PA level and prevalence ratios (PR) were computed. RESULTS: Only 55.5% of the overall population met the WHO recommended PA levels (urban coastal area: 55.7%, rural coastal area: 57.9%, rural interior area: 49.1%). Women were less likely to meet the recommended PA level (49% vs 62.4%; p < 0.0001) and with increasing age the PR for recommended level of PA decreased (p < 0.0001). Compared to the Hindustani's, the largest ethnic group, the Javanese reported the lowest percentage of people meeting recommended PA level (PR = 0.92; p = 0.07). CONCLUSION: Around half of the population meets the recommended PA level. Future lifestyle interventions aiming at increasing PA should especially focus on women and older individuals as they are less likely to meet the recommended levels of PA.

Supporting health care professionals to improve the processes of shared decision making and self-management in a web-based intervention: randomized controlled trial.

BACKGROUND: Research to assess the effect of interventions to improve the processes of shared decision making and self-management directed at health care professionals is limited. Using the protocol of Intervention Mapping, a Web-based intervention directed at health care professionals was developed to complement and optimize health services in patient-centered care. OBJECTIVE: The objective of the Web-based intervention was to increase health care professionals' intention and encouraging behavior toward patient self-management, following cardiovascular risk management guidelines. METHODS: A randomized controlled trial was used to assess the effect of a theory-based intervention, using a pre-test and post-test design. The intervention website consisted of a module to help improve professionals' behavior, a module to increase patients' intention and risk-reduction behavior toward cardiovascular risk, and a parallel module with a support system for the health care professionals. Health care professionals (n=69) were recruited online and randomly allocated to the intervention group (n=26) or (waiting list) control group (n=43), and invited their patients to participate. The outcome was improved professional behavior toward health education, and was self-assessed through questionnaires based on the Theory of Planned Behavior. Social-cognitive determinants, intention and behavior were measured pre-intervention and at 1-year follow-up. RESULTS: The module to improve professionals' behavior was used by 45% (19/42) of the health care professionals in the intervention group. The module to support the health professional in encouraging behavior toward patients was used by 48% (20/42). The module to improve patients' risk-reduction behavior was provided to 44% (24/54) of patients. In 1 of every 5 patients, the guideline for cardiovascular risk management was used. The Web-based intervention was poorly used. In the intervention group, no differences in social-cognitive determinants, intention and behavior were found for health care professionals, compared with the control group. We narrowed the intervention group and no significant differences were found in intention and behavior, except for barriers. Results showed a significant overall difference in barriers between the intervention and the control group (F1=4.128, P=.02). CONCLUSIONS: The intervention was used by less than half of the participants and did not improve health care professionals' and patients' cardiovascular risk-reduction behavior. The website was not used intensively because of time and organizational constraints. Professionals in the intervention group experienced higher levels of barriers to encouraging patients, than professionals in the control group. No improvements were detected in the processes of shared decision making and patient self-management. Although participant education level was relatively high and the intervention was pre-tested, it is possible that the way the information was presented could be the reason for low participation and high dropout. Further research embedded in professionals' regular consultations with patients is required with specific emphasis on the processes of dissemination and implementation of innovations in patient-centered care. TRIAL REGISTRATION: Netherlands Trial Register Number (NTR): NTR2584; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2584 (Archived by WebCite at http://www.webcitation.org/6STirC66r).

Determinants of physical activity in young adults with tetralogy of Fallot.

BACKGROUND: Although sports participation is allowed to most adult patients with corrected tetralogy of Fallot, a reduced exercise tolerance and reduced perceived physical functioning is often present in these patients. We aimed to investigate daily physical activity in adults with tetralogy of Fallot and to investigate the underlying determinants of physical activity in daily life. METHODS: We studied 73 patients with tetralogy of Fallot (53 male; mean age 27.3 ± 7.9 years) who underwent echocardiography and cardiopulmonary exercise testing, and who completed questionnaires about physical activity and perceived health status. All variables were compared with data from a general population. Relationships were studied by Pearson or Spearman correlation coefficients with correction for multiple testing. RESULTS: Patients were significantly less active compared with the general population (p > 0.05), 55% of all patients were sedentary, 27% had an active or moderately active lifestyle, and 18% of the group had a vigorously active lifestyle. Peak oxygen uptake (71 ± 16%; p < 0.0001) was significantly reduced and related to reduced physical activity levels (r = 0.229; p = 0.017) and perceived physical functioning (r = 0.361; p = 0.002). CONCLUSIONS: Adult patients with tetralogy of Fallot have a sedentary lifestyle and are less active than the general population. Inactivity significantly contributes to reduced exercise capacity, in addition to the impairment based on the cardiac condition. Moreover, reduced exercise capacity and the intensity of sports performed in daily life are related to perceived physical functioning. Individual patient counselling on physical activity might be a low-cost, high-benefit measure to be taken in this patient population.

Exercise capacity, physical activity, and obesity in adults with repaired aortic coarctation.

BACKGROUND: Patients with aortic coarctation (COA) have a reduced exercise capacity and seem to be more prone to adopt a sedentary lifestyle. During clinical practice, we often observe that patients seem to be overweight. However, data on physical activity and weight status in this population are currently not available. OBJECTIVE: This study aimed to describe weight status, self-reported physical activity levels, and self-perceived health status in adults with repaired COA in comparison with healthy counterparts and to investigate the relationships among exercise capacity, physical activity, weight status, and perceived health status. METHODS: We studied 103 COA patients who underwent cardiopulmonary exercise testing and who completed the Flemish Physical Activity Computerized Questionnaire and the short-form 36 health survey questionnaire. RESULTS: Patients with COA show a significantly lower exercise tolerance than what would be expected in healthy persons (P < .0001). Weight status was similar to the overall Belgian population, but a tendency toward higher body mass index was present. Patients with COA report a lower level of habitual physical activity (P < .05) as well as reductions in perceived vitality, general health, and mental health (P < .05). Parameters of habitual physical activity are related to exercise capacity (total energy expenditure: r = 0.278, P = .0015). The more active COA patients report higher scores of perceived physical functioning, general health, and mental health. Overweight patients did not perform significantly different than patients with a healthy weight did. CONCLUSIONS: Adults with repaired COA have a reduced exercise tolerance, which is related to low physical activity levels. Up to one-third of the COA patients we studied are overweight. As a poor exercise capacity identifies patients at risk for hospitalization and death and obesity might adversely influence the development of cardiovascular disease, it is important to improve the exercise capacity in these patients. Guiding patients toward more physical activity in daily life might therefore be the number 1 preventive measure to be taken in this patient group.

Increased pulmonary artery pressures during exercise are related to persistent tricuspid regurgitation after atrial septal defect closure.

OBJECTIVE: Although closure of an atrial septal defect type secundum often normalizes right heart dimensions and pressures, mild tricuspid insufficiency might persist. This study aimed at (1) identification of determinants explaining the persistence of tricuspid insufficiency after atrial septal defect closure, and (2) evaluation of functional capacity of patients with persistent mild tricuspid insufficiency. METHODS AND RESULTS: Twenty-five consecutive patients (age 42+17 y) were included from the outpatient clinic of congenital heart disease at the University Hospitals of Leuven. All underwent transthoracic echocardiography, semi-supine bicycle stress echocardiography and cardio-pulmonary exercise testing. Six patients (24%) had mild tricuspid insufficiency (2/4) compared to 19 patients (76%) with no or minimal tricuspid insufficiency ( 1/4) as assessed by semi-quantitative colour Doppler echocardiography. Mann-Whitney U and Fisher's exact tests were performed where applicable. Patients with persistent mild tricuspid insufficiency were significantly older than those with no or minimal tricuspid insufficiency (P = 0.042). At rest, no differences in right heart configuration, mean pulmonary artery pressure or right ventricular function were found. At peak exercise, mean pulmonary artery pressure was significantly higher in patients with mild persistent tricuspid insufficiency (P = 0.026). Peak oxygen uptake was significantly lower in patients with mild persistent tricuspid insufficiency (P = 0.019). CONCLUSIONS: Mild tricuspid insufficiency after atrial septal defect repair occurs more frequently in older patients and in patients with higher mean pulmonary artery pressure at peak exercise. In patients with mild tricuspid insufficiency, functional capacity was more reduced. Mild tricuspid insufficiency could be a marker of subclinical persistent pressure load on the right ventricle.

Standardised Exercise Prescription for Patients with Chronic Coronary Syndrome and/or Heart Failure: A Consensus Statement from the EXPERT Working Group.

Whereas exercise training, as part of multidisciplinary rehabilitation, is a key component in the management of patients with chronic coronary syndrome (CCS) and/or congestive heart failure (CHF), physicians and exercise professionals disagree among themselves on the type and characteristics of the exercise to be prescribed to these patients, and the exercise prescriptions are not consistent with the international guidelines. This impacts the efficacy and quality of the intervention of rehabilitation. To overcome these barriers, a digital training and decision support system [i.e. EXercise Prescription in Everyday practice & Rehabilitative Training (EXPERT) tool], i.e. a stepwise aid to exercise prescription in patients with CCS and/or CHF, affected by concomitant risk factors and comorbidities, in the setting of multidisciplinary rehabilitation, was developed. The EXPERT working group members reviewed the literature and formulated exercise recommendations (exercise training intensity, frequency, volume, type, session and programme duration) and safety precautions for CCS and/or CHF (including heart transplantation). Also, highly prevalent comorbidities (e.g. peripheral arterial disease) or cardiac devices (e.g. pacemaker, implanted cardioverter defibrillator, left-ventricular assist device) were considered, as well as indications for the in-hospital phase (e.g. after coronary revascularisation or hospitalisation for CHF). The contributions of physical fitness, medications and adverse events during exercise testing were also considered. The EXPERT tool was developed on the basis of this evidence. In this paper, the exercise prescriptions for patients with CCS and/or CHF formulated for the EXPERT tool are presented. Finally, to demonstrate how the EXPERT tool proposes exercise prescriptions in patients with CCS and/or CHF with different combinations of CVD risk factors, three patient cases with solutions are presented.

Reproducibility of different methods to measure the endothelial function.

This study compares the reliability and reproducibility of flow-mediated dilatation (FMD) and peripheral arterial tonometry (PAT) to assess endothelial function. Eighteen volunteers with coronary heart disease underwent simultaneous testing of FMD by means of brachial artery ultrasound scanning and PAT with the EndoPAT 2000. The subjects underwent both tests twice with an interval of 30 minutes and the same protocol was repeated 2 days later. The within-day variability was lower for the FMD measurements than for the PAT measurements (10% versus 18%; p < 0.05). The between-day variability was similar (11%). A significant correlation was found between PAT and FMD (r = 0.57, p < 0.001). The typical errors of measurements for FMD were lower than those for PAT. In conclusion, in this study, FMD demonstrated the best reliability for the within- and between-day and separate day measurements when compared to PAT.

Serial exercise testing in children, adolescents and young adults with Senning repair for transposition of the great arteries.

BACKGROUND: Patients with Senning repair for complete transposition of the great arteries (d-TGA) show an impaired exercise tolerance. Our aim was to investigate changes in exercise capacity in children, adolescents and adults with Senning operation. METHODS: Peak oxygen uptake (peak VO2), oxygen pulse and heart rate were assessed by cardiopulmonary exercise tests (CPET) and compared to normal values. Rates of change were calculated by linear regression analysis. Right ventricular (RV) function was assessed by echocardiography. RESULTS: Thirty-four patients (22 male) performed 3.5 (range 3-6) CPET with an interval of ≥ 6 months. Mean age at first assessment was 16.4 ± 4.27 years. Follow-up period averaged 6.8 ± 2 years. Exercise capacity was reduced (p<0.0005) and the decline of peak VO2 (-1.3 ± 3.7 %/year; p=0.015) and peak oxygen pulse (-1.4 ± 3.0 %/year; p=0.011) was larger than normal, especially before adulthood and in female patients (p<0.01). During adulthood, RV contractility changes were significantly correlated with the decline of peak oxygen pulse (r= -0.504; p=0.047). CONCLUSIONS: In patients with Senning operation for d-TGA, peak VO2 and peak oxygen pulse decrease faster with age compared to healthy controls. This decline is most obvious during childhood and adolescence, and suggests the inability to increase stroke volume to the same extent as healthy peers during growth. Peak VO2 and peak oxygen pulse remain relatively stable during early adulthood. However, when RV contractility decreases, a faster decline in peak oxygen pulse is observed.

Reliability and validity of the ultrasound technique to measure the rectus femoris muscle diameter in older CAD-patients.

BACKGROUND: The increasing age of coronary artery disease (CAD) patients and the occurrence of sarcopenia in the elderly population accompanied by 'fear of moving' and hospitalization in these patients often results in a substantial loss of skeletal muscle mass and muscle strength. Cardiac rehabilitation can improve exercise tolerance and muscle strength in CAD patients but less data describe eventual morphological muscular changes possibly by more difficult access to imaging techniques. Therefore the aim of this study is to assess and quantify the reliability and validity of an easy applicable method, the ultrasound (US) technique, to measure the diameter of rectus femoris muscle in comparison to the muscle dimensions measured with CT scans. METHODS: 45 older CAD patients without cardiac event during the last 9 months were included in this study. 25 patients were tested twice with ultrasound with a two day interval to assess test-retest reliability and 20 patients were tested twice (once with US and once with CT) on the same day to assess the validity of the US technique compared to CT as the gold standard. Isometric and isokinetic muscle testing was performed to test potential zero-order correlations between muscle diameter, muscle volume and muscle force. RESULTS: An intraclass correlation coefficient (ICC) of 0.97 ((95%CL: 0.92 - 0.99) was found for the test-retest reliability of US and the ICC computed between US and CT was 0.92 (95%CL: 0.81 - 0.97). The absolute difference between both techniques was 0.01 ± 0.12 cm (p = 0.66) resulting in a typical percentage error of 4.4%. Significant zero-order correlations were found between local muscle volume and muscle diameter assessed with CT (r = 0.67, p = 0.001) and assessed with US (r = 0.49, p < 0.05). Muscle strength parameters were also significantly correlated with muscle diameter assessed with both techniques (range r = 0.45-r = 0.61, p < 0.05). CONCLUSIONS: Ultrasound imaging can be used as a valid and reliable measurement tool to assess the rectus femoris muscle diameter in older CAD patients.

Ankle proprioception is not targeted by exercises on an unstable surface.

Laboratory study using a repeated measures design. The aim of this study was to determine if ankle proprioception is targeted in exercises on unstable surfaces. Lateral ankle sprain (LAS) has recurrence rates over 70%, which are believed to be due to a reduced accuracy of proprioceptive signals from the ankle. Proprioceptive exercises in rehabilitation of LAS mostly consist of balancing activities on an unstable surface. The methods include 100 healthy adults stood barefoot on a solid surface and a foam pad over a force plate, with occluded vision. Mechanical vibration was used to stimulate proprioceptive output of muscle spindles of triceps surae and lumbar paraspinal musculature. Each trial lasted for 60 s; vibration was applied from the 15th till the 30th second. Changes in mean velocity and mean position of the center of pressure (CoP) as a result of muscle vibration were calculated. Results show that on foam, the effect of triceps surae vibration on mean CoP velocity was significantly smaller than on a solid surface, while for paraspinal musculature vibration the effect was bigger on foam than on solid surface. Similar effects were seen for mean CoP displacement as outcome. Exercises on unstable surfaces appear not to target peripheral ankle proprioception. Exercises on an unstable surface may challenge the capacity of the central nervous system to shift the weighting of sources of proprioceptive signals on balance.

Physical fitness, rather than self-reported physical activities, is more strongly associated with low back pain: evidence from a working population.

INTRODUCTION: Physical activity is suggested to be important for low back pain (LBP) but a major problem is the limited validity of the measurement of physical activities, which is usually based on questionnaires. Physical fitness can be viewed as a more objective measurement and our question was how physical activity based on self-reports and objective measured levels of physical fitness were associated with LBP. MATERIALS AND METHODS: We analyzed cross-sectional data of 1,723 police employees. Physical activity was assessed by questionnaire (SQUASH) measuring type of activity, intensity, and time spent on these activities. Physical fitness was based on muscular dynamic endurance capacity and peak oxygen uptake (VO(2) peak). Severe LBP, interfering with functioning, was defined by pain ratings ≥ 4 on a scale of 0-10. RESULTS: Higher levels of physical fitness, both muscular and aerobic, were associated with less LBP (OR: 0.54; 95% CI: 0.34-0.86, respectively, 0.59: 95%CI: 0.35-0.99). For self-reported physical activity, both a low and a high level of the total physical activity pattern were associated with an increase of LBP (OR: 1.52; 95%CI: 1.00-2.31, respectively, 1.60; 95%CI: 1.05-2.44). CONCLUSION: These findings suggest that physical activity of an intensity that improves physical fitness may be important in the prevention of LBP.

Risk of sports: do we need a pre-participation screening for competitive and leisure athletes?

Sudden cardiac arrest is most often the first clinical manifestation of an underlying cardiovascular disease and usually occurs in previously asymptomatic athletes. The risk benefit ratio of physical exercise differs between young competitive athletes and middle-age/senior individuals engaged in leisure-time sports activity. Competitive sports are associated with an increase in the risk of sudden cardiovascular death (SCD) in susceptible adolescents and young adults with underlying cardiovascular disorders. In middle-age/older individuals, physical activity can be regarded as a 'two-edged sword': vigorous exertion increases the incidence of acute coronary events in those who did not exercise regularly, whereas habitual physical activity reduces the overall risk of myocardial infarction and SCD. Although cardiovascular pre-participation evaluation offers the potential to identify athletes with life-threatening cardiovascular abnormalities before onset of symptoms and may reduce their risk of SCD, there is a significant debate among cardiologists about efficacy, impact of false-positive results and cost-effectiveness of routine screening. This review presents an appraisal of the available data and criticisms concerning screening programmes aimed to prevent SCD of either young competitive athletes or older individuals engaged in leisure-time sports activity.

Muscular strength and diameter as determinants of aerobic power and aerobic power response to exercise training in CAD patients.

OBJECTIVE: Low exercise capacity and skeletal muscle strength are important predictors of all-cause mortality in healthy as well as diseased individuals. Compared to sedentary subjects, CAD patients have a decreased oxygen uptake (peakVO2) and show accompanying increased muscle fatiguability. Despite the known importance of oxygen extraction by peripheral muscles on improving peakVO2 and of the relationship between muscle strength and aerobic capacity, only few studies in CAD patients include measurements of muscle strength before and after cardiac rehabilitation. This study therefore aimed to evaluate how much of the variance in baseline peakVO2 and its response to exercise training can be explained by muscular parameters. METHODS: 260 CAD patients performed maximal incremental cycle ergometer testing and maximal knee muscle strength measurements. The rectus femoris diameter was measured using ultrasound. Zero order correlations were calculated and determinants of baseline and response in peakVO2 were analysed by multiple regression analysis. RESULTS: PeakVO2 and muscle strength and diameter increased significantly after three months of cardiac rehabilitation (P < 0.0001). Zero order correlations showed significant correlations between muscular parameters and baseline peakVO2 (P < 0.0001). 63% of the total variance in baseline peakVO2 could be explained by seven parameters with knee extensor muscular endurance as the strongest predictor (P < 0.0001). 32% of the variation in relative increase in peakVO2 could be explained by 5 determinants of which the increase in muscular endurance was the strongest determinant (P < 0.0001). CONCLUSIONS: Knee extensor muscular endurance and its response after training are the strongest muscular predictors in explaining peakVO2 and its response in CAD patients.