***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: This study poses two questions : 1 ) is there an abnormality in isokinetic skeletal muscle strength and endurance in mild chronic obstructive pulmonary disease ( COPD ) ? and 2 ) what is the effect of a r and omized , controlled , 12 week hospital outpatient weight training programme in terms of skeletal muscle function and exercise tolerance ? Upper and lower limb isokinetic maximum and sustained muscle function were compared in 43 COPD patients ( age 49+/-11 yrs ) , mean forced expiratory volume in one second ( FEV1 ) 77+/-23 % pred and 52 healthy , sedentary subjects ( age 51 ( 10 ) yrs ) , mean FEV1 109+/-16 % pred . The 43 COPD patients were r and omly allocated into training ( n=26 ) and control ( n=17 ) groups . Isokinetic and isotonic muscle function , whole body endurance , maximal exercise capacity and lung function were measured . The COPD patients had reduced isokinetic muscle function ( with the exception of sustained upper limb strength ) as compared with healthy sedentary subjects . Muscle function improved after weight training in the COPD patients . Whole body endurance during treadmill walking also improved with no change in maximal oxygen consumption . A deficit in skeletal muscle function can be identified in patients with mild chronic obstructive pulmonary disease which can not be explained by factors such as hypoxaemia and malnutrition . Intervention with weight training is effective in countering this deficit which the authors conclude is probably due to muscle deconditioning BACKGROUND AND OBJECTIVE Non-invasive ventilation ( NIV ) might improve peripheral muscle function and exercise capacity in severely disabled patients . This study evaluated the physiological impact of NIV on isokinetic concentric strength and endurance of lower limb muscles in patients with severe COPD . METHODS This clinical trial tested COPD patients ( n = 24 ) and healthy subjects ( n = 18 ) . Subjects underwent isokinetic dynamometry tests while given either bi-level positive airway pressure ventilation ( BV ) or sham ventilation ( SV ) , in a r and omized order with 30 min of rest prior to each intervention . The inspiratory level of BV was set up to 14 cm H(2)O and expiratory pressure up to 6 cm H(2)O. Peripheral oxygen saturation ( SpO(2 ) ) , heart rate ( HR ) , systolic ( SBP ) and diastolic blood pressure ( DBP ) at the peak of exercise were measured for each intervention . RESULTS Compared with controls , COPD patients had lower values of SpO(2 ) and HR ( P < 0.01 ) during both BV and SV and lower values of DBP ( P < 0.01 ) during BV . BV improved SpO(2 ) ( P < 0.01 ) , and reduced SBP in both COPD ( P < 0.01 ) and control groups ( P < 0.05 ) and reduced DBP in COPD patients ( P < 0.01 ) . BV also reduced the fatigue index in COPD patients when compared with SV ( P = 0.003 ) . Variation ( BV-SV ) of total work at the peak of the test was higher in the control group than in the COPD group ( P < 0.05 ) . CONCLUSIONS BV improved SpO(2 ) and reduced the fatigability of the quadriceps muscle in patients with severe COPD . These results support the need for further evaluation of BV as adjunct during high-intensity strength exercise training in these patients Improving reduced skeletal muscle function is important for optimising exercise tolerance and quality of life in chronic obstructive pulmonary disease ( COPD ) patients . By applying high-intensity training to a small muscle group , we hypothesised a normalisation of muscle function . Seven patients with COPD performed 6 weeks ( 3 days·week−1 ) of high-intensity interval aerobic knee extensor exercise training .  Five age-matched healthy individuals served as a reference group  . Muscle oxygen uptake and mitochondrial respiration of the vastus lateralis muscle were measured before and after the 6-week training programme . Initial peak work and maximal mitochondrial respiration were reduced in COPD patients and improved significantly after the training programme . Peak power and maximal mitochondrial respiration in vastus lateralis muscle increased to the level of the control subjects and were mainly mediated via improved complex I respiration . Furthermore , when normalised to citrate synthase activity , no difference in maximal respiration was found either after the intervention or compared to controls , suggesting normal functioning mitochondrial complexes . The present study shows that high-intensity training of a restricted muscle group is highly effective in restoring skeletal muscle function in COPD patients OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity Background Exacerbations of chronic obstructive pulmonary disease ( COPD ) are characterised by increased dyspnoea , reduced quality of life and muscle weakness . Re-exacerbation and hospital admission are common . Pulmonary rehabilitation ( PR ) administered after hospital admission for an exacerbation can improve quality of life and exercise capacity . Objective To determine whether outpatient post-exacerbation PR ( PEPR ) could reduce subsequent hospital admission episodes . Methods Patients admitted to hospital for an exacerbation of COPD were r and omised to receive either usual follow-up care ( UC ) or PEPR after discharge . Hospital admission and emergency department attendances for COPD exacerbations were recorded over a 3-month period and analysed on an intention-to-treat basis . Secondary outcomes included exercise capacity and quadriceps strength . Results 60 patients underwent concealed r and omisation at the time of their hospital discharge ( UC : n=30 , mean ( SD ) age 65 ( 10 ) years , forced expiratory volume in 1 s ( FEV1 ) 52 (22)% predicted ; PEPR : n=30 , 67(10 ) years , 52 (20)% predicted ) . The proportion of patients re-admitted to hospital with an exacerbation was 33 % in the UC group compared with 7 % in those receiving PEPR ( OR 0.15 , 95 % CI 0.03 to 0.72 , p=0.02 ) . The proportion of patients that experienced an exacerbation result ing in an unplanned hospital attendance ( either admission or review and discharge from the emergency department ) was 57 % in the UC group and 27 % in those receiving PEPR ( OR 0.28 , 95 % CI 0.10 to 0.82 , p=0.02 ) . Conclusions Post-exacerbation rehabilitation in COPD can reduce re-exacerbation events that require admission or hospital attendance over a 3-month period . Clinical Trials Registration Number NCT00557115 PURPOSE Lower-limb muscle weakness has often been reported in COPD , and contributes to exercise intolerance . Controversial information is available regarding upper-limb muscle adaptations and the influence of muscle wasting on muscle weakness . We investigated leg and arm muscle function in 59 stable COPD patients ( GOLD stage III ) with preserved fat-free mass ( FFM ) and in 28 patients with reduced FFM relative to age- and sex-matched healthy control subjects and studied the effects of 8 wk of whole-body exercise training . METHODS FFM was measured with bioelectrical impedance analysis .  Isokinetic quadriceps ( F-leg ) and biceps strength ( F-arm ) , as well as quadriceps ( E-leg ) and biceps endurance ( E-arm ) were determined with a Biodex dynamometer . Exercise training consisted of cycle ergometry , treadmill walking , weight training , and gymnastics during 5 d.wk . RESULTS F-leg ( 76.2 + /- 3.6 vs 118.2 + /- 6.3 N.m , P < 0.001 ) and F-arm ( 25.6 + /- 1.3 vs 38.1 + /- 2.1 N.m , P < 0.001 ) were significantly and similarly reduced in the COPD patient group compared with controls . Also , E-leg ( -2.13 + /- 0.12 vs -1.61 + /- 0.11 , P < 0.01 ) , but not E-arm ( -2.72 + /- 0.11 and -2.47 + /- 0.13 NS ) , was decreased in patients . F-leg ( 62.4 + /- 4.3 vs 82.8 + /- 4.7 N.m , P < 0.01 ) , but not F-arm or muscle endurance , was reduced in FFM-depleted compared with non-FFM-depleted patients . Whereas after training F-leg and E-leg significantly increased by 20 % in the whole COPD group , biceps muscle function remained unchanged . CONCLUSION Lower- and upper-limb muscle dysfunction was observed in COPD patients , irrespective of the presence of FFM depletion . Generalized muscle weakness suggests systemic muscular involvement , although the preserved arm endurance and the poor response of arm performance to exercise training is indicative for intrinsic differences in muscular adaptations between leg and arm muscles BACKGROUND In addition to the respiratory limitation in patients with chronic obstructive pulmonary disease ( COPD ) , skeletal muscle abnormalities may occur and contribute to the exercise intolerance . This study assessed the ability of the skeletal muscle of patients with COPD to adapt to individualized exercise training at the gas exchange threshold ( GET ) METHODS : Fourteen patients ( 8 in a training group and 6 controls ) performed the following exercise tests before and after a 3-week training period : an incremental exercise test , maximal voluntary contraction of the quadriceps , and three endurance tests consisting of dynamic contractions of the quadriceps until exhaustion . These endurance tests , characterized by three different power outputs , were used to determine muscle limit times and critical power . RESULTS The results showed that training increased exercise tolerance ( + 11 % for symptom limited peak oxygen consumption ( VO2 sl ] , P < 0.05 ) , maximum voluntary contraction ( + 8 % , P < 0.05 ) , limit times ( from + 45 % to + 161 % , P < 0.05 ) and critical power ( + 39 % , P < 0.05 ) . CONCLUSIONS These findings indicate greater muscle strength and endurance after training in COPD patients and suggest better muscular recruitment and improved oxidative capacity in the exercising muscles . The sharp differences in the magnitude of VO2 sl and limit times suggest that the kinetics of peripheral and central changes in response to training are different . In conclusion , peripheral muscle performance can be increased rapidly in response to an individualized training program at the GET in COPD patients BACKGROUND Most patients with severe COPD are limited by dyspnea and are obliged to exercise at low intensity . Even those undergoing training do not usually have increased peak oxygen uptake ( Vo2 ) .  One-legged exercise , at half the load of two-legged exercise , places the same metabolic dem and s on the targeted muscles but reduces the ventilatory load , enabling patients to increase work capacity . The purpose of this study was to determine whether one-legged exercise training would improve aerobic capacity compared with two-legged training in stable patients with COPD . METHODS Eighteen patients with COPD ( mean FEV(1 ) , 38 + /- 17 % of predicted [ + /- SD ] ) were r and omized to two groups after completing an incremental exercise test . Both trained on a stationary cycle for 30 min , 3 d/wk , for 7 weeks 
    Output:
    
Quadriceps endurance is reduced in individuals with COPD compared with healthy control subjects , independent of the type of task performed