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 .
Contractile fatigue, muscle morphometry, and blood lactate in chronic obstructive pulmonary disease.
We hypothesized that patients with chronic obstructive pulmonary disease developing contractile fatigue of the quadriceps during cycle exercise may have characteristic metabolic and muscle features that could increase their susceptibility to fatigue , thus differentiating them from those who do not develop fatigue . We examined , in 32 patients , the fiber-type proportion , enzymatic activities , and capillary density in the vastus lateralis and the arterial blood lactate level during constant work-rate cycling exercise . Contractile fatigue was defined as a postexercise fall in quadriceps twitch force greater than 15 % of resting values . Twenty-two patients developed contractile fatigue after exercise . No significant differences were found between fatiguers and non-fatiguers for the endurance time , fiber-type proportion , and oxidative enzyme activities . The lactate dehydrogenase activity was significantly higher ( p < 0.05 ) and muscle capillarization significantly reduced in fatiguers ( p < 0.05 ) . Compared with non-fatiguers , the arterial lactate level during exercise was significantly higher in fatiguers ( p < 0.001 ) . A significant relationship was found between the fall in quadriceps twitch force and lactate dehydrogenase activity , capillary/fiber ratio , and blood lactate level . We conclude that changes in muscle enzymatic profile and capillarization with a greater reliance on glycolytic metabolism during exercise are associated with contractile fatigue in patients with chronic obstructive pulmonary disease
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 .