Relationship between functional capacity, dynamic and static muscle function assessments in people with Chronic Obstructive Pulmonary Disease (COPD)

Targeting Limb Muscle Dysfunction in COPD

“…Limb muscle endurance is essential for work tolerance over time, and it has been shown that people with COPD rate leg fatigue higher than dyspnea in exercise tests [47]. Quadriceps endurance also seems to be closer related to functional tests such as the 6-minute walk test than the quadriceps strength [48][49][50], implicating importance for performing daily activities. Contradictory to quadriceps strength, quadriceps endurance to muscle mass ratio is lower in people with COPD compared to people without COPD [51], and people with COPD, regardless of fat-free mass, have a higher degree of fatigue during endurance tests compared to people without COPD [52].…”

“…Static measurements of grip strength have also been used among people with COPD; however, current research is contradictory, and grip strength does not appear to be associated with disease severity or to be decreased more than among the general older population [80], even though this is not a universal finding [81]. Even though static measurements of quadriceps muscle strength is recommended, recent literature suggests that dynamic measures of limb muscle strength should not be neglected as the dynamic capacity of the muscle seems to be more closely related to factors associated with functional tasks, such as walking or standing up from a chair, than isometric (static) measurements [49,79].…”

“…Thus, to date, there is no specific recommendation on how to assess limb muscle endurance among people with COPD, and a vast variation of techniques and strategies have been used, including both static and dynamic measurements [19]. Similarly, as for limb muscle strength assessments, dynamic measurements of quadriceps endurance seem to be more closely related functional tasks than isometric measurements [49].…”

“…Furthermore, the physiotherapist should keep in mind that functional tests and limb muscle function assessments evaluate different constructs (as evident by low to moderate associations between limb muscle function assessments and functional tests), and thus cannot replace another [49,79,84]. Therefore, when deciding on how to assess the limb muscles in COPD, the objective should always be the driving factor.…”