Aerobic Exercise in Duchenne Muscular Dystrophy

The Effect on Muscle Architecture Properties and Motor Functions of Aerobic Training in Children With Duchenne Muscle Dystrophy

Duchenne Muscular Dystrophy (DMD) is the most common neuromuscular disease in childhood with an estimate incidence of 1 in 3500 to 5000 male births. The effect of aerobic training on muscle architectural properties and motor functions such as muscle activation is not clear in DMD. The aim of this study is to investigate the effects of aerobic training on these parameters in children with DMD. Twenty children with DMD included in the study will be divided into two groups as home program and home program+aerobic training with block randomization method. Home program including stretching, respiratory, range of motion and mild resistance exercise with body weight will be asked to apply 3-5 days a week for 12 weeks, aerobic training will be performed 3 days a week for 12 weeks at 60% of their maximum hearth rate with 50 minutes total duration consisting of 10 min warm up and 10 min cool down period. Muscle architectural properties, muscle strength, muscle activation and motor function will be assessed with ultrasonographic, hand-held myometry, surface EMG and Motor Function Measure, consecutively. Assessments will be applied at pre-training and after 12 weeks of training.

Home exercise program Children will be given a home program including stretching, breathing, normal joint movement, body weight and mildly resistant exercises, and children will be asked to do these for 3 to 5 days a week. Also, aerobic training will be performed 3 days a week for 12 weeks at 60% of their maximum hearth rate with 50 minutes total duration consisting of 10 min warm up and 10 min cool down period to children in treatment group.

Home exercise program Children will be given a home program including stretching, breathing, normal joint movement, body weight and mildly resistant exercises, and children will be asked to do this program for 5 days a week.

Aerobic training will be performed 3 days a week for 12 weeks at 60% of their maximum hearth rate with 50 minutes total duration consisting of 10 min warm up and 10 min cool down period to children in treatment group.

Children will be given a home program including stretching, breathing, normal joint movement, body weight and mildly resistant exercises, and children will be asked to do these for 3 to 5 days a week.

Bilateral Vastus Lateralis and Medial Gastrocnemius US evaluations were performed with use of a 5-10 MHz linear probe (Diasus Dynamic Imaging Ltd, Livingston, Scotland,UK). Children were positioned supine with their legs extended and their muscles relaxed for vastus lateralis.Children were positioned prone position with their legs and their muscles relaxed for medial gastrocnemius. While Muscle Thickness and Fascicle Length would be expressed as centimeters, pennation angle would be angularly indicated.

The total scores of the MFM test were determined in three motor function domains: D1 (Standing Position & Transfers), D2 (Axial and Proximal Motor Function) and D3 (Distal Motor Function) (scored between 0-96 points, low score indicate low performance.)

Timed function tests included time taken to stand from a supine position, time taken to run/walk 10 m, time taken to climb 4 standard-sized stairs, time taken to descend 4 standard-sized stairs and time taken to stand one leg stance (both leg).Participants were instructed to travel as far and as fast as possible in six minutes on 25 meter-indoor course.

Assessment of back extensors, hip flexors, hamstring, quadriceps and gastrocnemius muscles. For assessment back extensors, The child was placed in the supine position with his knee fixed at a neutral position, and then shortening was evaluated by having bilateral hip flexion made. For hip flexor, The child was placed in the supine position with his knee fixed at a neutral position, and he was then evaluated by having one leg hip flexion made. Hamstring shortening was measured in a supine position with the hip flexed at 90° and the opposite knee and hip were placed in an extended position. Quadriceps shortening was assessed in a prone position and then by bending knee. For gastrocnemius muscle, the child was placed in a supine position and asked to perform passive ankle dorsiflexion while the knee was extended.

Inclusion criteria: Children had diagnosis of DMD confirmed by genetic analysis, Children had functional level of Grade 1 and 2 according to Vignos Scale. Exclusion criteria: Children had undergone any surgery or suffered injury of the lower limbs, Children had comorbid disease Children were applied regular aerobic training in last 6 months.