Table 2.

Changes of muscle pathophysiologic abnormalities induced by exercise training in COPD.

	Muscle alterations	Exercise training effects	References
Morphology/body composition	↓CSA of lower limb muscle ↓FFM	↑with resistance training ↑FFM with combined strength and endurance training	22,23,24
Fiber-type/fiber size	↑% type IIx ↓% type I and MHC ↓fiber cross-sectional area (atrophy)	No significant changes in fiber-type proportion ↑cross-sectional area	25,26
Muscle capillarization	↓capillary contact to cross-sectional area of muscle fiber	↑capillary contact with increased fiber cross-sectional area(proportionally)	25,27
Muscle metabolism	↓ oxidative enzymes capacity	↑capacity with endurance training	27,28
Muscle metabolite concentrations	↓ PCr,/Pi,↓ pH, ↓ATP ↑IMP, ↑lactate	↓lactic acidemia, Normalization pH and PCr,/Pi Recovery of PCr (faster)	29,30
Inflammation	↑inflammatory markers	Insufficient studies
Muscle performance	↓endurance, ↓	↑ endurance/strength	31,32
Exercise capacity level	strength (quadriceps) ↓ strength respiratory muscles ↓exercise capacity	skeletal muscle (↑exercise capacity) No effects on exercise capacity with IMT(COPD) Possible effects of IMT on exercise capacity(CHF) but insufficient evidence