Leg Exercise Research Articles

Impact of Stability Ball Sitting on Peak VO2 and Heart Rate During Arm + Leg Exercise

Impact of Stability Ball Sitting on Peak VO2 and Heart Rate During Arm + Leg Exercise

Effects of Varying Levels of Normobaric Hypoxia on Muscle Oxygenation During Leg Exercise

Previous studies have looked at muscle tissue oxygenation under a wide range of conditions including temperature extremes and in various disease states. PURPOSE: The purpose of this study was to examine the muscle tissue saturation response under varying normobaric hypoxic conditions during different intensities of aerobic exercise (walking and running). METHODS: Twelve healthy, fit participants (27.3 ± 7.1 yrs, 87.5 ± 10.2 kgs) were recruited and completed testing randomly in three different conditions simulating varying levels of hypoxia: 3000 m (MID), 5000 m (HIGH) and while breathing ambient air (LOW). A Higher Peak Mag10® hypoxic generator was used to produce normobaric hypoxia. During the HIGH, MID, and LOW conditions subjects walked for 5 min at 3 mph and then ran for 5 min at 6 mph on a motorized treadmill. Near-infrared spectroscopy (Portamon, Artinis Inc.) was used to measure oxygenated hemoglobin, deoxygenated hemoglobin, total hemoglobin, and tissue saturation index (TSI) throughout the exercise. The Portamon was placed over the vastus lateralis and secured. TSI is used as an index of muscle tissue oxygenation. In this study, the slope of the decline in TSI was determined and used to quantify the muscle oxygenation response. RESULTS: Overall, TSI decreased at a greater rate for running than walking in all three conditions. The decline in TSI was greatest (p<0.05) in the HIGH running condition (−0.023 ± .006) compared to the MID (−.018± .004) and LOW conditions (−.007± .002). There were no differences in TSI slope for the three walking conditions. CONCLUSIONS: These data suggest that muscle oxygenation declined at the fastest rate with running at the greatest level of hypoxia. This probably reflects a greater utilization of oxygen under severe hypoxic conditions in the muscle. Furthermore, running during all levels of hypoxia produced a greater rate of oxygen utilization than walking. Taken together, running at high altitude provides the greatest hypoxic stress to exercising leg muscle.

The role of muscle sympathetic nerve activity in limiting exercise capacity in heart failure.

The role of muscle sympathetic nerve activity in limiting exercise capacity in heart failure.

Sympathetic vasomotor outflow and blood pressure increase during exercise with expiratory resistance.

The purpose of the present study was to elucidate the effect of increasing expiratory muscle work on sympathetic vasoconstrictor outflow and arterial blood pressure (BP) during dynamic exercise. We hypothesized that expiratory muscle fatigue would elicit increases in sympathetic vasomotor outflow and BP during submaximal exercise. The subjects performed four submaximal exercise tests; two were maximal expiratory pressure (PEmax) tests and two were muscle sympathetic nerve activity (MSNA) tests. In each test, the subjects performed two 10-min exercises at 40% peak oxygen uptake using a cycle ergometer in a semirecumbent position [spontaneous breathing for 5 min and voluntary hyperpnoea with and without expiratory resistive breathing for 5 min (breathing frequency: 60 breaths/min, inspiratory and expiratory times were set at 0.5 sec)]. PEmax was estimated before and immediately after exercises. MSNA was recorded via microneurography of the right median nerve at the elbow. PEmax decreased following exercise with expiratory resistive breathing, while no change was found without resistance. A progressive increase in MSNA burst frequency (BF) appeared during exercise with expiratory resistance (MSNA BF, without resistance: +22 ± 5%, with resistance: +44 ± 8%, P < 0.05), accompanied by an augmentation of BP (mean BP, without resistance: +5 ± 2%, with resistance: +29 ± 5%, P < 0.05). These results suggest that an enhancement of expiratory muscle activity leads to increases in sympathetic vasomotor outflow and BP during dynamic leg exercise.

Expiratory Resistive Loading Increases in Sympathetic Vasomotor Outflow and BP During Dynamic Leg Exercise

High intensity voluntary contraction of the inspiratory muscles against resistive loads augments an increase in muscle sympathetic nerve activity (MSNA) with a corresponding increase in arterial blood pressure (BP) through an inspiratory muscle fatigue-induced metaboreflex. We hypothesized that expiratory muscle fatigue would also elicit increases in MSNA and BP during dynamic leg exercise. PURPOSE: The purpose of this study was to clarify the influence of an enhancement of expiratory muscle activity on sympathetic vasoconstrictor outflow and BP during submaximal exercise. METHODS: The subjects performed two 10-min exercise bouts at 40% peak oxygen uptake using a cycle ergometer in a semirecumbent position [spontaneous breathing for 5 min and with or without expiratory resistive breathing for 5 min (breathing frequency: 60 breaths/min, inspiratory and expiratory times were each constant at 0.5 s)]. MSNA was recorded via microneurography of the right median nerve at the elbow. RESULTS: A large increase in MSNA burst frequency (BF) occurred during exercise with expiratory resistance, accompanied by an augmentation of mean BP (MBP) (with resistance: MSNA BF +39.0%, MBP +42.5%, without resistance: MSNA BF: +12.8%, MBP: +22.9%, from resting values). CONCLUSIONS: These results suggest that an enhancement of expiratory muscle activity leads to large increases in muscle sympathetic vasomotor outflow and BP during dynamic leg exercise.

Abstract P5-15-08: Exercise intervention to run away from breast cancer treatment side effects: An integrative approach

Abstract Background. Some studies have shown that exercise increases breast cancer (BC) patients’ quality of life (QoL) during and after treatments. The aim of this study was to investigate the effect of an specific exercise intervention in QoL and in the exercise levels of these patients. Methods. A randomized controlled trial evaluated an intervention (IG) vs a control group (CG) in early stage BC patients who recently finished chemo &amp; radio therapies. Intervention consists on controlled group classes combining aerobic and resistance activities. CG maintained their previous lifestyle. QoL, leisure-time exercise levels (LTEL), chest (CMS) and legs maximal strength (LMS), physical capacity (PC) and some psychological variables, were assessed at baseline and after 3 months in both groups. Women who participated in the IG were followed up (FU) after 6 months. Statistical analysis (SA) were performed using unpaired t-test on continuous variables comparing CG vs IG, considering possible confounders. Pearson correlation analyses were employed to examine possible correlations. 6 months FU data were analyzed comparing baseline and after intervention results using non-parametric test (n=13). SA was performed with SPSS v18 software. 95% CI was calculated and statistical significance level of p &amp;lt; 0.05 was used. Results. 59 women (median 48.97±8.35 years old) completed this study. No differences between groups were observed at baseline. Average attendance rate to the program was 89%. There was a significant rise in LTEL (t123=16.33; p=0.0001) and in QoL (t123=2.88; p=0.005) comparing IG vs CG. Results also showed a correlation between QoL and LTEL in patients of IG only (r=0.22; p=0.013). Significant differences between groups were observed in both physical and psychological variablesafter training program. Table 1. Results summary comparing intervention and control group.VARIABLESIntervention Group (n= 27) Mean±SDControl Group (n=32) Mean±SDFollow-Up (n=13) Mean±SDQoL*+112.88±17.74±103.11±19.26110.96±14.40LTEL*+45.11±14.6114.87±4.7834.56±19.51Body Fat Mass34.63±6.736.47±7.4735.74±4.56Muscle mass41.3±3.1638.78±8.5141.48±2.01Strength Index*+2.6±0.832.12±0.692.32±0.58CMS*+45.89±11.0731.47±9.8753.76±12.42LMS*+93.07±27.369.00±24.94114.65±24.29PC*+32.58±4.9627.08±3.7332.11±7.10FACT-F *+135.94±18.20124.00±24.20138.24±17.49SF-36 Physical Dimension*+48.49±4.8345.61±5.8249.75±2.75SF-36 Psychological Dimension*+43.00±8.1137.03±12.5844.33±7.33Depression*+6.83±7.8312.55±10.775.88±5.19*Significant differences were found between control and intervention group. + Significant differences were maintained between baseline and follow-up assessments. No differences taking into account confounders were observed.Variable changes were maintained in FU participants assessed after 6 months. Correlation between QoL and LTEL (r=0.52; p=0.008) and significant weight loss (χ22=6.08; p=0.048) were observed. Conclusion. These results suggest that a specifically designed BC exercise program increases LTEL, which correlates to a better QoL. This may reduce psychological and physical side effects of systemic treatment in patients with early BC that have recently finished treatments, even producing lifestyle changes in BC patients that could be long lasting. Citation Format: Soraya Casla, Sara López-Tarruella, Yolanda Jerez, Iván Márquez-Rodas, Ricardo Cubedo, Isabel Calvo, Ana Martinez, Sara Cano, Rubén Barakat, Miguel Martín. Exercise intervention to run away from breast cancer treatment side effects: An integrative approach [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P5-15-08.

Limb Specific Vascular Adjustments at Exercise Onset

ObjectiveTo compare the rate of vascular adjustment at the onset of arm vs. leg exercise using the same exercise modality and hydrostatic conditions.Methods10 healthy recreationally active males (21.9±1.9 yrs) completed step increase dynamic exercise protocols (1s contract/2s relax) at 40%, 80% and 100% of peak vascular conductance response. Forearm handgrip and knee extension was performed in supine position with the exercising muscles at heart level. Continuous measures of brachial (forearm) and femoral (leg) artery blood flow (FBF, LBF; Doppler and Echo ultrasound) and arterial blood pressure (MAP; Finometer) were used to calculate forearm (FVC) and leg (LVC) vascular conductance.ResultsFor all exercise intensities, LVC was (p&lt;0.001) but FVC was not (P=0.705) characterized by a subsequent vasoconstriction at ~10 s (Phase IB) following the rapid initial vasodilation (Phase IA). Phase IA LVC amplitude was greater than steady state in the leg at 40% and no different at 80% (P&lt;0.05), but for FVC it was lower than steady state at all exercise intensities (P&lt;0.05). Phase IA had a greater contribution to the total response amplitude in the leg vs. forearm at all exercise intensities (P&lt;0.05) representing an overshoot compared to the Phase II plateau at 40% and 80% (P&lt;0.05). There was a main effect of limb for the Phase II time constant (leg faster than forearm, P&lt;0.05).ConclusionWhen contraction/relaxation modality and hydrostatic environment are controlled for, rapid vasodilatory mechanisms are more sensitive to the onset of exercise in lower vs. upper limbs and can overshoot steady state. Transient vasoconstriction between the initial rapid and secondary slower adjustment is specific to the lower limb. Funding: NSERC 250367‐06.

The Influence of High-Impact Exercise on Cortical and Trabecular Bone Mineral Content and 3D Distribution Across the Proximal Femur in Older Men: A Randomized Controlled Unilateral Intervention.

Regular exercisers have lower fracture risk, despite modest effects of exercise on bone mineral content (BMC). Exercise may produce localized cortical and trabecular bone changes that affect bone strength independently of BMC. We previously demonstrated that brief, daily unilateral hopping exercises increased femoral neck BMC in the exercise leg versus the control leg of older men. This study evaluated the effects of these exercises on cortical and trabecular bone and its 3D distribution across the proximal femur, using clinical CT. Fifty healthy men had pelvic CT scans before and after the exercise intervention. We used hip QCT analysis to quantify BMC in traditional regions of interest and estimate biomechanical variables. Cortical bone mapping localized cortical mass surface density and endocortical trabecular density changes across each proximal femur, which involved registration to a canonical proximal femur model. Following statistical parametric mapping, we visualized and quantified statistically significant changes of variables over time in both legs, and significant differences between legs. Thirty-four men aged mean (SD) 70 (4) years exercised for 12-months, attending 92% of prescribed sessions. In traditional regions of interest, cortical and trabecular BMC increased over time in both legs. Cortical BMC at the trochanter increased more in the exercise than control leg, whereas femoral neck buckling ratio declined more in the exercise than control leg. Across the entire proximal femur, cortical mass surface density increased significantly with exercise (2.7%; p < 0.001), with larger changes (> 6%) at anterior and posterior aspects of the femoral neck and anterior shaft. Endocortical trabecular density also increased (6.4%; p < 0.001), with localized changes of > 12% at the anterior femoral neck, trochanter, and inferior femoral head. Odd impact exercise increased cortical mass surface density and endocortical trabecular density, at regions that may be important to structural integrity. These exercise-induced changes were localized rather than being evenly distributed across the proximal femur.

Dalhousie Pictorial Scales Measuring Dyspnea and Perceived Exertion during Exercise for Children and Adolescents.

Alternative scales to measure dyspnea and perceived exertion have been sought due to concerns regarding understanding and validity of any Borg scale in pediatric populations. To demonstrate content validity of Dalhousie Dyspnea and Perceived Exertion Scales developed for children and adolescents. We obtained ratings for dyspnea and perceived exertion using both Borg CR-10 and Dalhousie Scales during incremental cycle exercise in 100 children and adolescents, healthy or with respiratory disease. Content validity was determined by correlating perceived leg exertion rating versus heart rate or %peak work capacity and dyspnea rating versus ventilation expressed as %peak ventilation. The stimulus-perceptual response was modeled as a quadratic function with a delay term. Reproducibility, cross-modality usage, and language effects were assessed in a small group of Italian children during treadmill exercise. Pictorial ratings of dyspnea and perceived exertion measured by both scale ratings rose as expected with increasing exercise intensity in children and adolescents, demonstrating excellent correlation between perceived leg exertion versus exercise intensity and dyspnea rating versus ventilation (median Spearman ρ ≥ 0.9) with either scale. There were no systematic differences in dyspnea or perceived exertion ratings between children with or without respiratory disease. Understandability and reproducibility of the Dalhousie scales was affirmed in Italian-speaking subjects performing treadmill exercise. Dalhousie Dyspnea and Perceived Exertion Scales offer an alternative to the Borg scale for use during exercise in pediatric subjects. Children and adolescents exhibit large variation in patterns of ratings of dyspnea and perceived exertion in incremental exercise.

Effect of exercise on myocardial energy metabolism and relationship between coronary microvascular dysfunction and abnormal myocardial energetics in diabetic cardiomyopathy

Background Diabetic cardiomyopathy is a well-recognised entity, with multifactorial aetiology. We and others have previously shown impaired myocardial energetics (decreased PCr/ ATP using cardiac 31P Magnetic Resonance Spectroscopy-MRS) in patients with type II diabetes mellitus (T2DM) at rest. Furthermore, diabetic patients are known to have impaired myocardial perfusion reserve even in the absence of epicardial coronary artery disease likely due to microvascular dysfunction. However, it is unknown whether this hypoperfusion is translated to further energetic derangement at stress. Methods 27 patients (13 male, mean age 54±1.5 years; BMI 28±2.7) with T2DM and 24 healthy volunteers of similar age and BMI (13 male, mean age 51±2.6 years; BMI 26±0.84) were studied. Patients were on oral antidiabetic therapies only, with mean HBA1c 7.4±1.3% and no history of diabetic complications. Obstructive coronary artery disease (defined as> 50% lumen diameter reduction) was excluded in all patients by CT coronary angiography. Cardiac 31PMRS (3T) was performed at rest and during 8 minutes of leg exercise lying prone, with 2.5 kg weights attached to both legs. First-pass perfusion images (using a saturation recovery fast-gradient echo sequence and 0.03 mmol/kg bolus of Gadoterate meglumine (Dotarem, Guerbet LLC, France ) were also acquired at stress (3-6 minutes i.v. adenosine, 140 μg/kg/min) and rest at mid ventricular short axis. myocardial perfusion reserve index (MPRI) were measured from perfusion images. Results Left ventricular ejection fraction (LVEF) and mass index (LVMI) were similar in patients with T2DM and healthy volunteers (LVEF 70±1 vs 71±0.9%, p=0.494; LVMI 56.7 ±1.8 vs 52.6±2.4g/m 2 , p=0.168). Increases in rate pressure product with exercise (T2DM 46±36%, healthy volunteers 42±26%, P = 0.69) and adenosine stress (T2DM 40 ± 3%, healthy volunteers 39 ± 3%, P = 0.89) were similar. There was no change in PCr/ATP during exercise in healthy volunteers (rest: 2.03±0.05, exercise:

Impact of l-citrulline supplementation and whole-body vibration training on arterial stiffness and leg muscle function in obese postmenopausal women with high blood pressure

Aging is associated with increased arterial stiffness (pulse wave velocity, PWV) and muscle strength/mass loss. Exercise training alone is not always effective to improve PWV and lean mass (LM) in older women. To investigate the independent and combined effects of whole-body vibration training (WBVT) and l-citrulline supplementation on PWV and muscle function in women, forty-one postmenopausal women aged 58±3years and body mass index (34±2kg/m2) were randomly assigned to the following groups: WBVT, l-citrulline, and WBVT+l-citrulline for 8weeks. WBVT consisted of four leg exercises three times weekly. Aortic (cfPWV) and leg (faPWV) PWV, leg LM index, leg strength, and body fat percentage (BF%) were measured before and after the interventions. WBVT+l-citrulline decreased cfPWV (−0.91±0.21m/s, P<0.01) compared to both groups. All interventions decreased faPWV (P<0.05) similarly. Leg LM index increased (2.7±0.5%, P<0.001) after WBVT+l-citrulline compared with l-citrulline. Both WBVT interventions increased leg strength (~37%, P<0.001) compared to l-citrulline while decreased BF% (~2.0%, P<0.01). Reductions in cfPWV were correlated with increases in leg LM index (r=−0.63, P<0.05). Our findings suggest that leg muscle strength and arterial stiffness can be improved after WBVT, but its combination with l-citrulline supplementation enhanced benefits on aortic stiffness and leg LM. Therefore, WBVT+l-citrulline could be an intervention for improving arterial stiffness and leg muscle function in obese postmenopausal women with prehypertension or hypertension, thereby reducing their cardiovascular and disability risk.

Effects of hybrid cycling versus handcycling on wheelchair-specific fitness and physical activity in people with long-term spinal cord injury: a 16-week randomized controlled trial.

This is an open randomized controlled trial. The objective of this study was to investigate the effects of a 16-week hybrid cycle versus handcycle exercise program on fitness and physical activity in inactive people with long-term spinal cord injury (SCI). The study was conducted in two rehabilitation centers with a specialized SCI unit. Twenty individuals (SCI⩾8 years) were randomly assigned to a hybrid cycle (voluntary arm exercise combined with functional electrical stimulation (FES)-induced leg exercise) or a handcycle group. During 16 weeks, both groups trained twice a week for 30 min at 65-75% heart rate reserve. Outcome measures obtained before, during and after the program were fitness (peak power output, peak oxygen consumption), submaximal VO2 and heart rate (HR), resting HR, wheelchair skill performance time score) and physical activity (distance travelled in wheelchair and Physical Activity Scale for Individuals with Physical Disabilities (PASIPD) score). Changes were examined using a two-factor mixed-measures analysis of variance. For all fitness parameters, except for submaximal VO2, no interaction effects were found. The hybrid cycle group showed a decrease in VO2 over time in contrast to the handcycle group (P=0.045). An overall reduction in HRrest (5±2 b.p.m.; P=0.03) and overall increase in PASIPD score (6.5±2.1; P=0.002) were found after 16 weeks of training. No overall training effects were found for the other fitness and activity outcome measures. In the current study, hybrid cycling and handcycling showed similar effects on fitness and physical activity, indicating that there seem to be no additional benefits of the FES-induced leg exercise over handcycle training alone.

Phase II Pragmatic Randomized Controlled Trial of Patient-Led Therapies (Mirror Therapy and Lower-Limb Exercises) During Inpatient Stroke Rehabilitation

Background and objective. Patient-led therapy has the potential to increase the amount of therapy patients undertake during stroke rehabilitation and to enhance recovery. Our objective was to assess the feasibility and acceptability of 2 patient-led therapies during the acute stages of stroke care: mirror therapy for the upper limb and lower-limb exercises for the lower limb. Methods. This was a blind assessed, multicenter, pragmatic randomized controlled trial of patient-led upper-limb mirror therapy and patient-led lower leg exercises. Stroke survivors with upper and lower limb limitations, undergoing inpatient rehabilitation and able to consent were recruited at least 1 week poststroke. Results. Both interventions proved feasible, with >90% retention. No serious adverse events were reported. Both groups did less therapy than recommended; typically 5 to 15 minutes for 7 days or less. Participants receiving mirror therapy (n = 63) tended to do less practice than those doing lower-limb exercises (n = 31). Those with neglect did 69% less mirror therapy than those without (P = .02), which was not observed in the exercise group. Observed between-group differences were modest but neglect, upper-limb strength, and dexterity showed some improvement in the mirror therapy group. No changes were seen in the lower-limb group. Conclusions. Both patient-led mirror therapy and lower-limb exercises during inpatient stroke care are safe, feasible, and acceptable and warrant further investigation. Practice for 5 to 15 minutes for 7 days is a realistic prescription unless strategies to enhance adherence are included.

Effects of hybrid cycle and handcycle exercise on cardiovascular disease risk factors in people with spinal cord injury: A randomized controlled trial.

To examine the effects of a 16-week exercise programme, using either a hybrid cycle or a handcycle, on cardiovascular disease risk factors in people with spinal cord injury. Nineteen individuals with spinal cord injury ≥ 8 years. Multicentre randomized controlled trial. Both the hybrid cycle group (n = 9) and the handcycle group (n = 10) trained twice a week for 16 weeks on the specific cycle. Outcome measures obtained pre and post the programme were: metabolic syndrome components (waist circumference, systolic and diastolic blood pressure, high-density lipoprotein cholesterol, triglycerides and insulin resistance), inflammatory status (C-reactive protein (CRP), interleukin (IL)-6 and -10), and visceral adiposity (trunk and android fat). For all outcome measures, there were no significant differences over time between the 2 training groups. Overall significant reductions were found for waist circumference (p = 0.001), diastolic blood pressure (p = 0.03), insulin resistance (p = 0.006), CRP (p = 0.05), IL-6 (p = 0.04), IL-6/IL-10 ratio (p = 0.03), and trunk (p = 0.04) and android (p = 0.02) fat percentage. No significant main effects for time were observed for systolic blood pressure, triglycerides, high-density lipoprotein cholesterol, IL-10, and trunk and android fat mass. The 16-week exercise programme, using either a hybrid cycle or a handcycle, found similar beneficial effects on metabolic syndrome components, inflammatory status and visceral adiposity, indicating that there were no additional benefits of functional electrical stimulation-induced leg exercise over handcycle exercise alone.

Divergent muscle sympathetic responses to dynamic leg exercise in heart failure and age-matched healthy subjects.

People with diminished ventricular contraction who develop heart failure have higher sympathetic nerve firing rates at rest compared with healthy individuals of a similar age and this is associated with less exercise capacity. During handgrip exercise, sympathetic nerve activity to muscle is higher in patients with heart failure but the response to leg exercise is unknown because its recording requires stillness. We measured sympathetic activity from one leg while the other leg cycled at a moderate level and observed a decrease in nerve firing rate in healthy subjects but an increase in subjects with heart failure. Because these nerves release noradrenaline, which can restrict muscle blood flow, this observation helps explain the limited exercise capacity of patients with heart failure. Lower nerve traffic during exercise was associated with greater peak oxygen uptake, suggesting that if exercise training attenuated sympathetic outflow functional capacity in heart failure would improve. The reflex fibular muscle sympathetic nerve (MSNA) response to dynamic handgrip exercise is elicited at a lower threshold in heart failure with reduced ejection fraction (HFrEF). The present aim was to test the hypothesis that the contralateral MSNA response to mild to moderate dynamic one-legged exercise is augmented in HFrEF relative to age- and sex-matched controls. Heart rate (HR), blood pressure and MSNA were recorded in 16 patients with HFrEF (left ventricular ejection fraction = 31 ± 2%; age 62 ± 3 years, mean ± SE) and 13 healthy control subjects (56 ± 2 years) before and during 2 min of upright one-legged unloaded cycling followed by 2 min at 50% of peak oxygen uptake (V̇O2,peak). Resting HR and blood pressure were similar between groups whereas MSNA burst frequency was higher (50.0 ± 2.0 vs. 42.3 ± 2.7 bursts min(-1), P = 0.03) and V̇O2,peak lower (18.0 ± 2.0 vs. 32.6 ± 2.8 ml kg(-1) min(-1), P < 0.001) in HFrEF. Exercise increased HR (P < 0.001) with no group difference (P = 0.1). MSNA burst frequency decreased during mild to moderate dynamic exercise in the healthy controls but increased in HFrEF (-5.5 ± 2.0 vs. 6.9 ± 1.8 bursts min(-1), P < 0.001). Exercise capacity correlated inversely with MSNA burst frequency at 50% V̇O2,peak (n = 29; r = -0.64; P < 0.001). At the same relative workload, one-legged dynamic exercise elicited a fall in MSNA burst frequency in healthy subjects but sympathoexcitation in HFrEF, a divergence probably reflecting between-group differences in reflexes engaged by cycling. This finding, coupled with an inverse relationship between MSNA burst frequency during loaded cycling and subjects' V̇O2,peak, is consistent with a neurogenic determinant of exercise capacity in HFrEF.

Arm Exercise Myocardial Perfusion Imaging for Prognostication of Long-Term Outcome

Pharmacologic evaluations constitute ≥50% of imaging stress tests, but exercise reduces adverse effects, improves myocardial perfusion imaging (MPI) quality and diagnostic results, and provides powerful prognostic and clinically important information on exercise capacity and cardiovascular responses to the relevant physiologic stress of exercise. Thus, our purpose was to determine whether arm exercise and MPI variables predict long-term outcome in patients who cannot perform leg exercise. We performed arm exercise MPI stress tests in 253 consecutive patients age 64.5 (10.7) yr (mean (SD)) from 1997 to 2002 and investigated associations of arm exercise and abnormal MPI variables with all-cause mortality, myocardial infarction (MI), coronary artery bypass grafting (CABG), and percutaneous coronary intervention (PCI) during follow-up of 12.0 (1.3) yr. There were 156 deaths (61.7%), 47 patients suffered MI (18.6%), 24 underwent CABG (9.5%), and 50 had PCI (19.8%). Arm exercise capacity and delta HR (peak - resting) were strongly associated with survival after adjustment for significant demographic and clinical variables (Cox multivariate P < 0.0001 and 0.001, respectively). MPI was abnormal in 157 patients (62.1%). An abnormal arm exercise MPI was borderline predictive of mortality by Cox analysis (71.8% vs 46.4% for normal study; univariate P < 0.0001; multivariate P = 0.07) but resulted in 58% relative incremental integrated discrimination improvement over clinical variables for predicting death. Perfusion defect size also strongly predicted mortality (Cox multivariate P = 0.003). An abnormal arm exercise MPI study, perfusion defect type, and size all prognosticated PCI (all P ≤ 0.03) but not MI or CABG. Arm exercise MPI is a valuable approach for outcome prediction in patients unable to perform leg exercise.

Superficial femoral artery endothelial responses to a short-term altered shear rate intervention in healthy men.

In animal and in-vitro models, increased oscillatory shear stress characterized by increased retrograde shear-rate (SR) is associated with acutely decreased endothelial cell function. While previous research suggests a possible detrimental role of elevated retrograde SR on endothelial-function in the brachial artery in humans, little research has been conducted examining arteries in the leg. Examinations of altered shear pattern in the superficial femoral artery (SFA) are important, as this vessel is both prone to atherosclerosis and leg exercise is a common form of activity in humans. Seven healthy men participated; bilateral endothelial-function was assessed via flow-mediated-dilation (FMD) before and after 30-minute unilateral inflations of a thigh blood pressure cuff to either 75 mmHg or 100 mmHg on two separate visits. Inflation of the cuff induced increases in maximum anterograde (p<0.05), maximum retrograde (p<0.01), and oscillatory shear index (OSI) (p<0.001) in the cuffed leg at both inflation pressures. At 100 mmHg the increases in SR were larger in the retrograde than the anterograde direction evidenced by a decrease in mean SR (p<0.01). There was an acute decrease in relative FMD in the cuffed leg alone following inflation to both pressures. These results indicate that in the SFA, altered SR profiles incorporating increased retrograde and OSI influence the attenuation in FMD after a 30-minute unilateral thigh-cuff inflation intervention. Novel information highlighting the importance of OSI calculations and assessments of flow profiles add to current body of knowledge regarding the influence of changes in SR patterns on FMD. Findings from the current study may provide additional insight when designing strategies to combat impaired vascular function in the lower extremity where blood vessels are more prone to atherosclerosis in comparison to the upper extremity.

Effectiveness of Selected Nursing Measures on Level of after Birth Pain among Primipara Mothers

A Study to Evaluate the Effectiveness of selected Nursing Measures (fundal massage, alternate leg exercise) on level of After Birth Pain among Primipara Mothers, using quasi-experimental design(post test only control group design). In experimental group the selected nursing measures helped in reducing the level of after birth pain and 86.6% of primipara mother had only mild pain where as in control group 46.6% of Primipara mothers had moderate pain and 53.3% had severe pain. The findings of the study supported that, with selected nursing measures (Fundal massage, alternative leg lifting exercise), there was reduction in the level of After Birth Pain.

Isometric exercises reduce temporal summation of pressure pain in humans.

Aerobic and isometric exercises are known to decrease pain sensitivity. The effect of different types of exercise on central mechanisms such as temporal summation of pain (TSP) is less clear. This study hypothesized that both aerobic and isometric exercises would increase pressure pain tolerance (PTT) and reduce TSP with greater effects after higher-intensity exercises. One hundred thirty-six healthy subjects (18-65 years; 68 women) participated in two randomized crossover experiments with trials on two different days. PTT and TSP were assessed before and after bicycling and a non-exercise condition (experiment 1), and after low- and high-intensity bicycling and low- and high-intensity isometric arm and leg exercises with the dominant arm/leg (experiment 2). PTT and TSP were assessed before and after each exercise condition on the non-dominant arm and leg by computer-controlled cuff algometry. TSP was assessed by visual analogue scale (VAS) scores of the pain intensity during sequential cuff-pressure stimulation at the pain tolerance intensity related to that specific time point. In experiment 1, bicycling, but not the non-exercise condition, slightly increased PTT when assessed at the leg (p < 0.05). In experiment 2, isometric arm and leg exercises increased PTT and reduced VAS scores to sequential stimulation at the arm and leg (p < 0.05). No systematic difference was found between low- and high-intensity exercises. Different manifestations of hypoalgesia between aerobic and isometric exercises were found. Isometric exercises reduced temporal summation illustrating the potential for exercise as a rehabilitation procedure also targeting the central mechanisms.

What is the optimal type and intensity of leg exercise training in people with chronic obstructive pulmonary disease?

What is the optimal type and intensity of leg exercise training in people with chronic obstructive pulmonary disease?