Abstract
Individuals with chronic liver disease experience progressive muscle wasting, weakness, fatigue, and decreased quality of life. Liver transplantation is the only treatment for end-stage liver disease with cirrhosis; however, muscle wasting, strength impairments, activity limitations, and health related quality of life do not return to the level of healthy adults. Currently there is no plan of care for rehabilitation of individuals post-liver transplantation. These individuals are only instructed to gradually increase walking and activity. Walking may increase lower extremity muscle strength; however, walking at a self-selected pace is less effective than resistance exercise. The purpose of this dissertation was to compare the benefits of a home exercise program of targeted lower extremity resistance exercise with benefits of progressive walking in individuals who have undergone liver transplantation. In Chapter 2 we performed a study to validate the ability of several outcome measures to detect changes in strength and activity performance in the population with liver disease and post-liver transplantation. The strength impairment measures of Grip Strength, Heel Rising, and Bridging along with activity limitation measures 30 Second Chair Stand and Six Minute Walk Test (6MWT) were able to differentiate strength and activity performance across levels of liver disease severity including post liver transplantation. Liver disease severity was moderately correlated with the strength impairment measures Bridging and Heel Rising but was not correlated with Grip strength. Liver disease severity was moderately correlated with 6MWT and 30-Second Chair-Stand but was not correlated with the SF-36 physical function scale. Strength impairment measures were strongly correlated with the activity limitation measures. Heel Rising and Bridging were strongly correlated with 30-Second Chair-Standing and 6MWT. Grip strength was moderately correlated with 30-Second Chair-Standing. In Chapter 3 we conducted a randomized controlled trial to assess the benefits of resistance exercise to progressive walking as a treatment plan for improving strength and activity performance in individuals post liver transplantation. We also examined the relationships of the change in muscle strength to the change in activity performance. Both the exercise and walking groups improved in strength and activity performance; however, the group performing the resistance exercise improved more. Bridging, 30 Second Chair Standing, Heel Rising, and 6MWT increased more for the exercise group than the walking group. Additionally, changes in strength were related to the changes in activity performance and health related quality of life. Bridging was correlated with Heel Rising, 30 Second Chair Standing, 6MWT, and the Chronic Liver Disease Questionnaire. In Chapter 4 we discuss the clinical relevance of the results of the studies described in the above chapters. We conclude Bridging, Heel Rising, 30 Second Chair Standing, and 6MWT are valid outcome measures to measure changes in strength and activity performance in the population with liver disease. Individuals post liver transplantation improve in strength and activity performance through progressive walking; however, the addition of resistance exercise to the current treatment plan is necessary for greater improvement. Additionally it is clinically relevant that this population was adherent to a home exercise program. Subjects adherent to the exercise program increased in strength and activity performance greater than subjects who were non-adherent.