International Journal of COPD (Aug 2019)
Measuring and monitoring skeletal muscle function in COPD: current perspectives
Abstract
Sarah Marklund,1 Kim-Ly Bui,2 Andre Nyberg11Department of Community Medicine and Rehabilitation, Section of Physiotherapy, Umeå University, Umeå, Sweden; 2Rehabilitation Department, Faculty of Medicine Laval University and Centre de recherche, Laval University Quebec Heart and Lung Institute (CRIUCPQ), Québec, QC, CanadaCorrespondence: Andre NybergDepartment of Community Medicine and Rehabilitation, Section of Physiotherapy, Caring Science Building, Lasarettsbacken 7, Umeå University, Umeå 907 46, SwedenTel +46 090 786 6639Fax +46 90 786 9267Email [email protected]: Skeletal muscle dysfunction is an important systemic consequence of chronic obstructive pulmonary disease (COPD) that worsens the natural cause of the disease. Up to a third of all people with COPD express some form of impairment which encompasses reductions in strength and endurance, as well as an increased fatigability. Considering this complexity, no single test could be used to measure and monitor all aspects of the impaired skeletal muscle function within the COPD population, resulting in a wide range of available tests and measurement techniques. The aim of the current review is to highlight current and new perspectives relevant to skeletal muscle function measurements within the COPD population in order to provide guidance for researchers as well as for clinicians. First of all, standardized and clinically feasible measurement protocols, as well as normative values and predictive equations across the spectrum of impaired function in COPD, are needed before assessment of skeletal muscle function can become a reality in clinical praxis. This should minimally target the quadriceps muscle; however, depending on the objective of measurements, eg, to determine upper limb muscle function or walking capacity, other muscles could also be tested. Furthermore, even though muscle strength measurements are important, current evidence suggests that other aspects, such as the endurance and power capacity of the muscle, should also be considered. Moreover, although static (isometric) measurements have been favored, dynamic measurements of skeletal muscle function should not be neglected as they, in a larger extent than static measurements, are related to tasks of daily living. Lastly, the often modest relationships between functional tests and skeletal muscle function measurements indicate that they evaluate different constructs and thus cannot replace one another. Therefore, for accurate measurements of skeletal muscle function in people with COPD, specific and formal measurements should still be prioritized.Keywords: chronic obstructive pulmonary disease, measurement properties, muscle strength, muscle endurance, muscle power
