The effects of a 12-week strength training program on skeletal muscle impairments and physical limitations in men with myotonic dystrophy type 1

Background/rationale: Myotonic dystrophy type 1 (DM1) is a genetic multisystemic degenerative disease and represents the most prevalent myopathy in adults. Skeletal muscles are particularly affected, as demonstrated by muscle weakness and atrophy experienced by affected people, which limit their social participation. Purpose/research objectives: The aim of this project is to determine the effects of a 12-week strength training program on skeletal muscle impairments and physical limitations in men with DM1. Relevance: Strength training has been shown to be safe in this population, but it remains unknown if it can trigger muscle hypertrophy process, thus slowing or reversing the significant muscle impairments that characterize this disease. Methods: In this before-after study, a 12-week strength training program (twice a week) of 6 to 8 maximal repetitions (RM) of five different lower limb exercises was completed by 11 men with DM1. The evaluation included: 10 meter walk test (comfortable and maximal speed), 30 second sit-to-stand test, quantitative muscle strength assessment of knee extensors muscle group, 1-RM test for all exercises and an interview about perceived changes. Results: Results showed significant maximal muscle strength increases as well as improvement in all functional tests (p