Neuromuscular impairments to flexibility and strength in adults with muscular dystrophy: acute response to physiotherapy

Jacques, Matthew (2018) Neuromuscular impairments to flexibility and strength in adults with muscular dystrophy: acute response to physiotherapy. Doctoral thesis (PhD), Manchester Metropolitan University.

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Abstract

Muscular dystrophy (MD) is a set of progressive muscle wasting conditions characterised by progressive muscle weakness and limited range of motion (ROM). Current evidence of these clinical features, their associations and impacts on quality of life (QoL) are however, largely focussed on children with Duchenne MD (DMD). By comparison, quantified evidence of these features remains limited in adults with Becker’s MD (BMD), Limb-Girdle MD (LGMD) and Facioscapulohumeral MD (FSHD), and unreported in adults with DMD. Current guidance on living with MD encourages physical activity (PA) and physiotherapy as methods to maintain health and function, however the understanding of PA and the effectiveness of physiotherapy, remains limited in its reporting in adults with MD. Therefore, the aim of this thesis was to quantify lower limb strength and ankle ROM in adults with MD, identify the associations of these clinical features and the impact of muscle weakness on QoL, measure the effectiveness of physiotherapy on ROM, and quantify the progression of muscle weakness, in adults with MD. Healthy adult controls (CTRL) were shown to have greater maximal voluntary contraction (MVC) of plantar-flexion (PFMVC) and knee extension (KEMVC), ROM measures of passive ROM (ROMPassive) and active ROM (ROMActive) than adults with DMD (75%, 92%, 66%, 82%), BMD (51%, 41%, 34%. 55%), LGMD (58%, 53%, 45%, 60%) and FSHD (35%, 25%, 35%, 56%). KEMVC and PFMVC were positively associated with 10m walk time in ambulant adults with MD (r= 0.484 and r= 0.502), and PFMVC was associated with ROMActive in all adults with MD (r= 0.376-.750). Strength (KEMVC) was positively associated with only two domains of QoL, in BMD (r= 0.544 and r= 0.609). By comparison, activities of daily living (positively), self-efficacy (positively), pain (negatively) and fatigue (negatively) were more consistently associated with QoL in adults with MD. The stiffness properties of the Gastrocnemius Medialis (r= -0.494) and muscle tendon unit (MTU) (r= -0.464) were both negatively associated with ROMPassive in BMD and DMD, respectively. Physiotherapy was shown as effective for acutely improving ROMPassive (19%) and decreasing MTU stiffness (-27%), in adults with DMD. PA was shown to explain both the variance in 10m walk time in ambulant adults with MD (R2 = 0.540), and the change in lower limb strength over 12 months in adults with BMD (PFMVC, R2 = 0.585; KEMVC, R2 = 0.532). Change in lower limb muscle strength in adults with DMD was reported as -19% PFMVC and -14% KEMVC per year. Evidence from this thesis suggests in ambulant adults with MD PA is an important measure to promote to help maintain lower limb strength and function. While in non-ambulant adults with MD a shift in focus to measures of pain and fatigue is required, and that there is some benefit from physiotherapy on the ROMPassive of the ankle in DMD, likely due to reductions in the stiffness properties of the MTU.