McArdle’s disease is a metabolic myopathy characterized by high exertion intolerance linked to a muscle glycogen phosphorylase deficiency (or myophosphorylase). The patients present (often from childhood) excessive fatigability, painful muscle cramps at exercise and stiffness.
The aim of the project is first to evaluate the effects of specific aerobic-type training designed to relieve patients’ difficulties during muscle exercise, in other words reduce their intolerance to exertion. A secondary aim of this study is to characterise better the physiopathology and develop our knowledge about this disease.
Twelve McArdle-affected patients will undergo specific aerobic-type ergocycle training for eight weeks. Three experimental tests will be used, and each repeated three times for the follow-up of this study.
The first test will characterize the physiological response of patients during an isometric muscle exercise of knee extension using an electromyographic surface approach (EMG).
The second test is multiparametric (EMGs, metabolic and cardiorespiratory) with the objective to study the physiological response of patients in a dynamic condition during an incremental strength test and an ergocycle constant power endurance exercise.
The third test consists of using nuclear magnetic resonance (NMR) spectroscopy to analyse the evolution of the biochemical parameters of the muscle at rest, contracted and during recuperation.
This study could lead to the validation of a conditioning protocol of patients affected with metabolic myopathy and an improvement of both their clinical management and therapy.
To summarise, this is a study with individual direct benefits, a controlled crossover trial with two periods of 8 weeks, one without and the other with training. The order of these periods is randomised.