AbstractIntroduction: Chronic Obstructive Pulmonary Disease (COPD) is a complex disease, characterised by progressive airflow obstruction and is a major cause of morbidity, mortality and healthcare usage in the UK. Quadriceps muscle dysfunction is a key cause of exercise intolerance in patients with COPD, manifested by reduced muscle mass and strength. This problem also imposes a burden to the health system as quadriceps dysfunction is an independent predictor of hospitalisation and mortality. Importantly, the quadriceps may provide a target for therapy in an otherwise irreversible lung disease and changes in strength after resistance training (RT) are well documented. Protein supplementation has been successfully used as an adjunct to RT in healthy populations. However the role of this therapeutic combination has not before been studied in a COPD population.
Methods: This thesis describes a randomised controlled trial (RCT) which aims to explore the role of protein supplementation given immediately after RT, upon functional outcomes, in patients with COPD. The hypothesis was that RT, in combination with protein ingestion (at the time of training) will have greater effects on
functional outcomes than RT alone (chapter 4). Secondary aims were to precisely explore the training intensity progression, fatigue profile (chapter 5) and cardio-respiratory load imposed by the RT (chapter 6) and to examine the measurement properties of the ActiTrac® physical activity (PA) monitors (chapter 7). In all
chapters the response to the intervention in patients with COPD, is compared to healthy, age-matched controls.
Results: The overriding message from this thesis is that protein supplementation can not be routinely recommended as an adjunct to RT for patients with COPD. All groups made significant improvements in quadriceps strength and thigh mass after
RT but protein did not augment the outcome. Subjects with evidence of muscle wastage (based on fat-free mass criteria) responded less well to RT, although the study was underpowered to draw meaningful conclusions in this group. Subjects with
COPD made comparable improvements to healthy age-matched controls, despite training at much lower intensities and experiencing greater decay in muscle force during a training session. Moreover, the RT programme was able to sufficiently
activate the cardio-pulmonary system and led to significant improvements in whole-body exercise performance. PA did not change after the 8-week RT programme; suggesting that changes after RT are not routinely translated to increased habitual
activity, particularly when the educational component of rehabilitation is missing.
Conclusions: The RT programme utilised in this thesis was able to significantly improve both strength and endurance-related outcomes in patients with COPD. However, the provision of additional protein at the time of training did not enhance
the benefits. The isokinetic RT programme provided a unique opportunity to precisely explore the training intensity progression, fatigue profile and cardio-respiratory load imposed by the training; comparing patients with COPD and healthy controls. The findings from this work provide some important considerations for clinical practice and require further investigation within a conventional rehabilitation setting.
|Date of Award||2012|
|Supervisor||Sally Singh (Supervisor)|