Relation Between Muscle Architecture and Functional Ability in Children With Duchenne Muscular Dystrophy

Relation Between Gastrocnemius Muscle Architecture and Functional Ability in Ambulatory Children With Duchenne Muscular Dystrophy

Duchenne Muscular Dystrophy (DMD) is a progressive X-linked neuromuscular disorder characterized by muscle degeneration, pseudohypertrophy, and declining functional mobility. This cross-sectional observational study investigates the relationship between gastrocnemius muscle architecture and functional ability in ambulatory children with DMD. Muscle thickness and fascicle length were assessed using ultrasonography and correlated with motor function and ankle plantarflexion during gait.

Duchenne Muscular Dystrophy (DMD) is a genetic neuromuscular disorder characterized by progressive muscle degeneration, fatty infiltration, fibrosis, and loss of functional capacity during childhood. Although pseudohypertrophy may cause apparent enlargement of calf muscles, structural changes do not necessarily reflect muscle quality or functional performance.

This cross-sectional observational study included 26 ambulatory male children aged 6 to 12 years diagnosed with DMD. Participants underwent a single comprehensive assessment session.

Muscle architecture of the medial gastrocnemius muscle was evaluated using 2-dimensional ultrasonography (Mindray DP-10, 7.5 MHz probe) to measure muscle thickness and fascicle length.

Functional ability was assessed using:

• The Motor Function Measure (MFM-32)
• The Vignos Scale
• Timed 10-Meter Walk Test

Ankle plantarflexion range of motion during gait was measured using Kinovea motion analysis software with 2D digital video analysis.

Correlation analysis was performed to determine the relationship between muscle architectural parameters and functional ability measures.

No therapeutic intervention, randomization, or group allocation was performed.

Inclusion Criteria:

• Diagnosed with Duchenne Muscular Dystrophy
• Age 6-12 years
• Ambulatory
• Vignos Scale grades 1-7
• Presence of calf pseudohypertrophy
• Absence of severe cardiac or pulmonary disease

Exclusion Criteria:

• Non-ambulatory
• Severe cognitive impairment
• History of lower limb trauma or fracture
• Inability to cooperate with assessment
• Lack of parental consent