***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Introduction Low-to-moderate intensity exercise improves muscle contractile properties and endurance capacity in multiple sclerosis ( MS ) . The impact of high intensity exercise remains unknown . Methods Thirty-four MS patients were r and omized into a sedentary control group ( SED , n = 11 ) and 2 exercise groups that performed 12 weeks of a high intensity interval ( HITR , n = 12 ) or high intensity continuous cardiovascular training ( HCTR , n = 11 ) , both in combination with resistance training . M.vastus lateralis fiber cross sectional area ( CSA ) and proportion , knee-flexor/extensor strength , body composition , maximal endurance capacity and self-reported physical activity levels were assessed before and after 12 weeks . Results Compared to SED , 12 weeks of high intensity exercise  increased mean fiber CSA ( HITR : + 21±7 % , HCTR : + 23±5 % ) . Furthermore , fiber type I CSA increased in HCTR ( + 29±6 % ) , whereas type II ( + 23±7 % ) and IIa ( + 23±6 % , ) CSA increased in HITR . Muscle strength improved in HITR and HCTR ( between + 13±7 % and + 45±20 % ) and body fat percentage tended to decrease ( HITR : -3.9±2.0 % and HCTR : -2.5±1.2 % ) . Furthermore , endurance capacity ( Wmax + 21±4 % , time to exhaustion + 24±5 % , VO2max + 17±5 % ) and lean tissue mass ( + 1.4±0.5 % ) only increased in HITR . Finally self-reported physical activity levels increased 73±19 % and 86±27 % in HCTR and HITR , respectively . Conclusion High intensity cardiovascular exercise combined with resistance training was safe , well tolerated and improved muscle contractile characteristics and endurance capacity in MS . Trial Registration Clinical Trials.gov BACKGROUND Exercise training confers beneficial effects on vascular reactivity in patients with chronic heart failure ( CHF ) . This r and omized study compares the effects of interval cycle training combined with strength training versus interval training alone on vascular reactivity in CHF patients . METHODS Twenty-eight consecutive stable CHF patients ( 23 males , 53 ± 10 years , 28.4 ± 4.1 kg/m(2 ) , left ventricular ejection fraction of 37 ± 12 % ) were r and omly assigned to 3 times ' weekly training sessions for 3 months , consisting of a ) 40 minutes of interval cycle training ( n = 14 ) , versus b ) 20 minutes of similar interval training plus 20 minutes of strength training of the quadriceps , hamstrings , muscles of the shoulder and biceps brachialis ( n = 14 ) . The work/recovery ratio of each session was 30/60 seconds . The intensity of interval training was set at 50 % of the peak workload achieved at the steep ramp test ( consisted of a 25-Watt increase on a cycle ergometer every 10 seconds until exhaustion ) . All patients underwent maximal , symptom-limited cardiopulmonary exercise testing and ultrasound evaluation of vascular reactivity by flow-mediated vasodilation ( FMD ) before and after the program . RESULTS A significant improvement in FMD was observed in the combined training group ( P = 0.002 ) , in contrast to the interval training alone group ( P = NS ) ; the improvement was significantly greater in the combined training than in the interval training alone group ( P < .05 ) . Peak oxygen uptake increased significantly and similarly in both groups , in the interval training group ( P = .03 ) , and in the combined training group ( P = .006 ) . No significant correlation was found between FMD improvement and cardiopulmonary exercise parameters . CONCLUSIONS A combined high-intensity , interval cycle exercise with strength training induces a greater beneficial effect on vascular reactivity rather than interval exercise training alone in CHF patients Traditionally , the effects of physical training in patients with chronic heart failure ( CHF ) are evaluated by changes in peak oxygen uptake ( peak $ $ \dot{V}{\text{O}}_{2 } $ $ ) . The assessment of peak $ $ \dot{V}{\text{O}}_{2 } $ $ , however , is highly dependent on the patients ’ motivation . The aim of the present study was to evaluate the clinical utility of effort-independent exercise variables for detecting training effects in CHF patients . In a prospect i ve controlled trial , patients with stable CHF were allocated to an intervention group ( N = 30 ) , performing a 12-week combined cycle interval and muscle resistance training program , or a control group ( N = 18 ) that was matched for age , gender , body composition and left ventricular ejection fraction . The following effort-independent exercise variables were evaluated : the ventilatory anaerobic threshold ( VAT ) , oxygen uptake efficiency slope ( OUES ) , the $ $ \dot{V}_{\text{E } } /\dot{V}{\text{CO } } _ { 2 } $ $ slope and the time constant of $ $ \dot{V}{\text{O}}_{2 } $ $ kinetics during recovery from submaximal constant-load exercise ( τ-rec ) . In addition to post-training increases in peak $ $ \dot{V}{\text{O}}_{2 } $ $ and peak $ $ \dot{V}_{\text{E } } , $ $ , the intervention group showed significant within and between-group improvements in VAT , OUES and τ-rec . There were no significant differences between relative improvements of the effort-independent exercise variables in the intervention group . In contrast with VAT , which could not be determined in 9 % of the patients , OUES and τ-rec were determined successfully in all patients . Therefore , we conclude that OUES and τ-rec are useful in clinical practice for the assessment of training effects in CHF patients , especially in cases of poor subject effort during symptom-limited exercise testing or when patients are unable to reach a maximal exercise level PURPOSE The aim of this study was to compare the effects of endurance training alone ( ET ) with combined endurance and strength training ( CT ) on hemodynamic and strength parameters in patients with congestive heart failure ( CHF ) . METHODS Twenty male patients with CHF were r and omized into one of two training regimens consisting of endurance training or a combination of endurance and resistance training . Group ET had 40-min interval cycle ergometer endurance training three times per week . Group CT combined endurance and strength training with the same interval endurance training for 20 min , followed by 20 min of strength training .  Left ventricular function was assessed at baseline and after 40 training sessions by echocardiography and radionuclide ventriculography .  Work capacity was measured with cardiopulmonary exercise test ( CPX ) and lactate determination . Strength was measured with an isokinetic dynamometer . RESULTS After 40 sessions , the ET group improved functional class , work capacity , peak torque , and muscular endurance . However , peak O2 remained unchanged . Left ventricular ejection fraction ( LVEF ) and fractional shortening ( FS ) decreased , whereas left ventricular end-diastolic diameter ( LVED ) increased . The CT group improved NYHA score , working capacity , peak O2 , and peak lactate ; peak torque and muscular endurance , LVEF , and FS increased , whereas LVED decreased . Compared with ET , CT was significantly ( P < 0.05 ) better in improving LV function . CONCLUSION Combined endurance/strength training was superior to endurance training alone concerning improvement of LV function , peak VO2 , and strength parameters . It appears that for stable CHF patients , a greater benefit can be derived from this training modality UNLABELLED High intensity interval training ( HIIT ) has become an increasingly popular form of exercise due to its potentially large effects on exercise capacity and small time requirement . This study compared the effects of two HIIT protocol s vs steady-state training on aerobic and anaerobic capacity following 8-weeks of training . Fifty-five untrained college-aged subjects were r and omly assigned to three training groups ( 3x weekly ) . Steady-state ( n = 19 ) exercised ( cycle ergometer ) 20 minutes at 90 % of ventilatory threshold ( VT ) . Tabata ( n = 21 ) completed eight intervals of 20s at 170 % VO2max/10s rest . Meyer ( n = 15 ) completed 13 sets of 30s ( 20 min ) @ 100 % PVO2 max/ 60s recovery , average PO = 90 % VT . Each subject did 24 training sessions during 8 weeks . RESULTS There were significant ( p < 0.05 ) increases in VO2max ( + 19 , + 18 and + 18 % ) and PPO ( + 17 , + 24 and + 14 % ) for each training group , as well as significant increases in peak ( + 8 , + 9 and + 5 % ) & mean ( + 4 , + 7 and + 6 % ) power during Wingate testing , but no significant differences between groups . Measures of the enjoyment of the training program indicated that the Tabata protocol was significantly less enjoyable ( p < 0.05 ) than the steady state and Meyer protocol s , and that the enjoyment of all protocol s declined ( p < 0.05 ) across the duration of the study . The results suggest that although HIIT protocol s are time efficient , they are not superior to conventional exercise training in sedentary young adults . Key pointsSteady state training equivalent to HIIT in untrained studentsMild interval training presents very similar physiologic challenge compared to steady state trainingHIIT ( particularly very high intensity variants were less enjoyable than steady state or mild interval trainingEnjoyment of training decreases across the course of an 8 week experimental training program OBJECTIVE To investigate the effect of physical training ( PTr ) on upper leg muscle area , muscle strength and muscle endurance expressed as upper leg muscle function ( ULMF ) in relation to exercise performance in CHF . DESIGN R and omised to a training ( TG ) or control group ( CG ) . SETTING Outpatient cardiac rehabilitation centre of community hospital . PATIENTS 77 CHF patients ( 59 men and 18 women ) , NYHA class II/III , age 59.8+/-9.3 years , LVEF 27+/-8 % . Sixteen patients dropped out during the intervention period , 61 patients ( M/F:46/15 ) completed the study . INTERVENTION PTr ( combined strength and endurance exercises ) four times per week , twice supervised and twice at home , during 26 weeks . MAIN OUTCOME MEASURES LVEF , body composition , daily physical activity , exercise performance , upper leg muscle area and isokinetic leg muscle variables . RESULTS Workload and peak oxygen consumption decreased in the CG ( -4.1 % and -4 % ) but increased in the TG ( + 5 % and + 4 % ) following PTr ( p<0.05 , ANOVA repeated measures ) . Hamstrings area decreased in the CG and did not change in the TG ( p<0.05 , ANOVA repeated measures ) . ULMF improved in the TG , but remained unchanged in the CG ( + 13.0 % and 0.0 , respectively , p<0.05 ; ANOVA repeated measures ) . At baseline and after intervention nearly 60 % of the variance in maximal workload was explained by ULMF and quadriceps muscle area ( multiple regression analysis ) . CONCLUSIONS In CHF patients , home-based training in conjunction with a supervised strength and endurance training program is safe , feasible and effective and does not require complex training equipment . Physical training prevented loss of hamstrings muscle mass and improved exercise performance by enhancing muscle strength and endurance BACKGROUND Recently , high-intensity interval training has been advocated for the rehabilitation of persons living with heart failure ( HF ) . Home-based training is more convenient for many patients and could augment compliance . However , the safety and efficacy of home-based interval training remains unclear . METHODS We evaluated the safety and efficacy of a supervised home-based exercise program involving a combination of interval and resistance training . Measures of aerobic power , endurance capacity , ventilatory threshold , and quality of life in 40 patients with HF , were taken at baseline and after 12 weeks . Patients were matched and r and omized to either control ( CTL ; n = 20 ) or experimental ( EXP ; n = 20 ) conditions . The EXP group underwent a 12-week high-intensity interval and resistance training program while the CTL group maintained their usual activities of daily living . RESULTS In the EXP group , we found a significant improvement in aerobic power , endurance capacity , ventilatory threshold , and quality of life . There were no significant changes in the CTL group . CONCLUSIONS We have shown that a home-based cardiac rehabilitation program involving interval and resistance training is associated with improved aerobic capacity and quality of life in patients with HF . This research has important implication s for the treatment of HF BACKGROUND The aim of this work was to evaluate the effect of high-intensity interval exercise ( i.e. , 30s at 100 % of max workload , followed by 30s at rest , 45 min 3 days/week working-out schedule for 12 weeks ) on left ventricular function and aortic elastic properties among chronic heart failure ( CHF ) patients . METHODS This study is a phase III clinical trial . Of the 100 consecutive CHF patients ( NYHA classes II-IV , ejection fraction<50 % ) that were r and omly allocated , 72 completed the study ( exercise training group , n=33 , 63 ± 9 years , 88 % men , and  control group , n=39 , 56 ± 11 years , 82 % men ) . All patients underwent cardiopulmonary stress test , non-invasive high-fidelity tonometry of the radial artery , pulse wave velocity measurement using a SphygmoCor device and echocardiography before and after the completion of the training program . RESULTS Both groups reported similar medical characteristics and physical activity status . General 
    Output:
    
The combination of interval training and resistance training showed more effective in increasing cardiorespiratory fitness in patients with heart failure than interval training alone and non-exercise therapy .