Relevance of assessing quadriceps endurance in patients with COPD

Abstract

The aims of this study were to investigate whether the impairment in endurance of limb muscles is a general finding in chronic obstructive pulmonary disease (COPD) patients, affecting even those with mild-to-moderate disease or relatively normal physical activity. In addition, this study aimed to determine the physiopathology of exhaustion in local endurance tests and whether the reduction in quadriceps endurance can be predicted from muscle strength measurements.A total of 75 volunteers were assigned to one of two groups according to pulmonary function tests: COPD patients or healthy age-matched controls. Functional assessment included both quadriceps strength (maximum voluntary contraction (QMVC)), and quadriceps endurance (contractions against a load equivalent to 10% QMVC until task failure or for up to a limiting time of 30 min (QTlim)).COPD patients showed a decrease of y43% in QMVC and y77% in QTlim compared with controls. Task failure occurred only in COPD patients and was due to muscle fatigue, since limiting symptoms were associated with a decrease in the median frequency of quadriceps electromyographical signal and a reversible decrease in QMVC. The impairment in skeletal muscle endurance was present even in patients with mild-tomoderate airflow obstruction and individuals with relatively normal physical activity, and was irrespective of lung function variables, anthropometrical data or quadriceps strength.Peripheral muscle endurance was impaired in chronic obstructive pulmonary disease patients, even in those with relatively normal physical activity and mild-to-moderate airflow obstruction. This impairment associated with an early onset of muscle fatigue and could not be predicted from the severity of the disease or the reduction in quadriceps strength. Eur Respir J 2004; 24: 129-136.

Upper and Lower Limb Muscles in Patients With COPD: Similarities in Muscle Efficiency But Differences in Fatigue Resistance

“…[37][38][39] However, to the best of our knowledge, only our study has analyzed the recovery time from fatigue after an upper-limb fatigueinducing protocol. In addition to the greater decrease in strength, compared to the quadriceps femoris, the middle deltoid had longer recovery time of the baseline MVIC.…”

Quantifying physical activity in daily life with questionnaires and motion sensors in COPD

“…Although no specific validation study of the Baecke questionnaire was performed in COPD, this questionnaire was used in three different studies [57][58][59] in which COPD patients had approximately the same airflow obstruction (forced expiratory volume in one second (FEV1) ranging an average 36-41% predicted) and normal body mass index. In these studies, patients from three different countries (Spain, France [57]…”

Treinamento de força para pacientes com doença pulmonar obstrutiva crônica

“…A redução de força, de massa muscular e da concentração de enzimas oxidativas associadas à diminuição do metabolismo de fosfocreatina (2) provocam lactacidose precoce nos pacientes com DPOC (3,4) . A disfunção do sistema muscular esquelético é caracterizada pela diminuição significativa da força e da massa muscular (5)(6)(7) , sendo que a redução da massa muscular é fator de previsão independente para a mortalidade em pacientes com DPOC, especialmente nos pacientes com volume expiratório forçado no primeiro segundo (VEF 1 ) < 50% do previsto (8) . Embora essas alterações musculares tenham causa multifatorial, diversos autores apontam a diminuição crônica do condicionamento como fator mais importante (5,(9)(10)(11)(12) .…”