FAST CP: The effect of Functional Anaerobic and Strength Training on muscle properties, functional capacity, and gait in adolescents and young adults with Cerebral Palsy

Abstract

Cerebral palsy (CP) is the largest single cause of childhood physical disability. While the brain lesion responsible for CP is static, there is a cascade of secondary musculoskeletal adaptations including reduced muscle size, reduced joint range of motion, increased joint stiffness, and muscle weakness. These secondary alterations progress with age and contribute to a gradual loss of functional capacity into adulthood. Strength training has been used to increase muscle strength in individuals with CP, however it may not be an effective intervention for improving gross mobility-related measures, such as walking performance. It is also unknown whether skeletal muscle in young adults with CP can undergo hypertrophy or architectural adaptations in response to different exercise modes.The general aim of this thesis was to examine the effect of combined functional anaerobic and strength training (FAST) on muscle properties, functional capacity, and gait in adolescents and young adults with CP.A systematic review was undertaken (Chapter 2) to determine the effects of muscle strengthening interventions on skeletal muscle morphology and architecture in children and adolescents with CP. The analysis revealed preliminary evidence that strength training leads to increased muscle size in children and adolescents with CP, accompanied by an increase in muscle strength. Muscle hypertrophy findings may, however, be confounded by factors such as natural growth and concurrent therapies. The findings of this review informed the design of the FAST program and outcome measures used in the following studies to better understand the muscular responses to exercise training in this population.The full study protocol for the FAST intervention is described in Chapter 3. There have been no previous exercise trials conducted in young adults with CP using training parameters that meet established guidelines, that have measured muscle morphology and architecture outcomes. Details of the functional anaerobic and resistance training parameters and progressions according to established guidelines are set out, as well as establishing a-priori outcome measures and the data analysis plan for implementation of the intervention. iii A cross-sectional study was undertaken (Chapter 4) to investigate the relationships between muscle strength, stiffness, and functional capacity in a larger sample of adults with CP. The results of this study demonstrated that maximum isometric plantar flexion strength independently explained 50 -61% of variance in functional capacity outcome measures. Passive medial gastrocnemius muscle fascicle stiffness and ankle joint stiffness were not related to functional capacity measures. These findings suggest lower isometric muscle strength of the plantar flexor muscles contributes to the decline in functional capacity in adults with CP. Chapter 5 investigated the impact of the FAST intervention on lower limb muscle volumes, joint and muscle stiffness, muscle strength, and functional capacity in a sample of 17 young adults with CP...