A new study discovered an association between high fat fraction values and muscles with long fibers in patients with Duchenne muscular dystrophy (DMD).

The study authors explained, “Muscles with longer fibers are theoretically able to reach a high contraction velocity, and it is likely that an impaired force propagation in such fibers increases the inhomogeneity in force distribution, possibly leading to contraction-induced damage.”

These findings suggest that larger muscles are more prone to fat replacement than smaller muscles, and they support the clinical observation of proximal-to-distal muscle degeneration in patients with DMD.

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The study by Veeger et al included 22 DMD patients (mean age, 9.9±3.0 years; age range, 6.5-17.4 years) with longitudinal upper and lower leg magnetic resonance imaging (MRI) scans. There were 39 and 44 usable data sets available for upper and lower legs, respectively.

The pathophysiology of muscle degeneration in patients with DMD is still unclear. In fact, the factors that render some muscles more susceptible to degeneration than others remain to be identified.


Veeger TTJ, van Zwet EW, Al Mohamad D, et al. Muscle architecture is associated with muscle fat replacement in Duchenne and Becker muscular dystrophies. Muscle Nerve. Published online August 12, 2021. doi:10.1002/mus.27399