RESULTS The forced expiratory volume in 1 s ( FEV(1 ) ) , the ratio of FEV(1 ) to forced vital capacity ( FVC ) and body mass index were positively associated with the proportion of type I fibres in COPD .
This review sheds new light on the relationship between skeletal muscle abnormalities and important hallmarks of the disease in severe COPD , and identifies absence of data in GOLD stages 1 - 2 .
This review also provides reference values on fibre type composition for diagnostic purpose s in COPD
BACKGROUND Skeletal muscle dysfunction is a common feature in chronic obstructive pulmonary disease ( COPD ) which is associated with intrinsic muscular abnormalities .
One of the most consistently reported alterations is a shift from fibre type I to II in the vastus lateralis of these patients .
Surprisingly , the relationship between this shift and the severity and phenotype of COPD remains unclear .
A study was conducted to determine whether vastus lateralis muscle fibre type proportions are associated with COPD disease severity and to provide reference values for the proportions of fibre types in the vastus lateralis in COPD .
Skeletal muscle adaptations to interval training in patients with advanced COPD.
STUDY OBJECTIVES To investigate the response to interval exercise ( IE ) training by looking at changes in morphologic and biochemical characteristics of the vastus lateralis muscle , and to compare these changes to those incurred after constant-load exercise ( CLE ) training . DESIGN R and omized , controlled , parallel , two-group study ( IE vs CLE training ) . SETTING Multidisciplinary , outpatient , hospital-based , pulmonary rehabilitation program . PATIENTS Nineteen patients with stable advanced COPD ( mean + /- SEM FEV1 , 40 + /- 4 % predicted ) . INTERVENTIONS Patients ( n = 10 ) assigned to IE training exercised at a mean intensity of 124 + /- 15 % of baseline peak exercise capacity ( peak work rate [ Wpeak ] ) with 30-s work periods interspersed with 30-s rest periods for 45 min/d . Patients ( n = 9 ) allocated to CLE training exercised at a mean intensity of 75 + /- 5 % Wpeak for 30 min/d . Patients exercised 3 d/wk for 10 weeks . MEASUREMENTS AND RESULTS Needle biopsies of the right vastus lateralis muscle were performed before and after rehabilitation . After IE training , the cross-sectional areas of type I and IIa fibers were significantly increased ( type I before , 3,972 + /- 455 microm2 ; after , 4,934 + /- 467 microm2 [ p = 0.004 ] ; type IIa before , 3,695 + /- 372 microm2 ; after , 4,486 + /- 346 microm2 [ p = 0.008 ] ) , whereas the capillary-to-fiber ratio was significantly enlarged ( from 1.13 + /- 0.08 to 1.24 + /- 0.07 [ p = 0.013 ] ) . Citrate synthase activity increased ( from 14.3 + /- 1.4 to 20.5 + /- 4.2 micromol/min/g ) , albeit not significantly ( p = 0.097 ) . There was also a significant improvement in Wpeak ( by 19 + /- 5 % ; p = 0.04 ) and in lactate threshold ( by 17 + /- 5 % ; p = 0.02 ) . The magnitude of changes in all the above variables was not significantly different compared to that incurred after CLE training . During training sessions , however , ratings of dyspnea and leg discomfort , expressed as fraction of values achieved at baseline Wpeak , were significantly lower ( p < 0.05 ) for IE training ( 73 + /- 9 % and 60 + /- 8 % , respectively ) compared to CLE training ( 83 + /- 10 % and 87 + /- 13 % , respectively ) . CONCLUSIONS High-intensity IE training is equally effective to moderately intense CLE training in inducing peripheral muscle adaptations ; however , IE is associated with fewer training symptoms
RESULTS The forced expiratory volume in 1 s ( FEV(1 ) ) , the ratio of FEV(1 ) to forced vital capacity ( FVC ) and body mass index were positively associated with the proportion of type I fibres in COPD .
This review sheds new light on the relationship between skeletal muscle abnormalities and important hallmarks of the disease in severe COPD , and identifies absence of data in GOLD stages 1 - 2 .
This review also provides reference values on fibre type composition for diagnostic purpose s in COPD
BACKGROUND Skeletal muscle dysfunction is a common feature in chronic obstructive pulmonary disease ( COPD ) which is associated with intrinsic muscular abnormalities .
One of the most consistently reported alterations is a shift from fibre type I to II in the vastus lateralis of these patients .
Surprisingly , the relationship between this shift and the severity and phenotype of COPD remains unclear .
A study was conducted to determine whether vastus lateralis muscle fibre type proportions are associated with COPD disease severity and to provide reference values for the proportions of fibre types in the vastus lateralis in COPD .