The study investigates the role of dystrophin in protecting the sarcolemma from mechanical stress during muscle contraction. Using mdx mice, which lack dystrophin, the researchers found that these muscles are more susceptible to sarcolemmal rupture compared to normal muscles. The level of sarcolemmal damage was directly related to the magnitude of mechanical stress during contraction rather than the number of muscle activations. This suggests that dystrophin primarily functions to provide mechanical reinforcement to the sarcolemma, protecting it from the stresses developed during muscle contraction. The findings support the hypothesis that dystrophin deficiency leads to increased membrane fragility and contribute to the progression of muscular dystrophy. The methodology used in this study may also be useful for assessing the efficacy of dystrophin gene therapy in mdx mice.The study investigates the role of dystrophin in protecting the sarcolemma from mechanical stress during muscle contraction. Using mdx mice, which lack dystrophin, the researchers found that these muscles are more susceptible to sarcolemmal rupture compared to normal muscles. The level of sarcolemmal damage was directly related to the magnitude of mechanical stress during contraction rather than the number of muscle activations. This suggests that dystrophin primarily functions to provide mechanical reinforcement to the sarcolemma, protecting it from the stresses developed during muscle contraction. The findings support the hypothesis that dystrophin deficiency leads to increased membrane fragility and contribute to the progression of muscular dystrophy. The methodology used in this study may also be useful for assessing the efficacy of dystrophin gene therapy in mdx mice.